Correct modifier keys input to imgui

.github/workflows/build-nmage.yml

@@ -9,10 +9,10 @@ jobs:
     runs-on: macos-12
     steps:
     
-      - name: Install golang 1.18
+      - name: Install golang
         uses: actions/setup-go@v3
         with:
-          go-version: '^1.18'
+          go-version: '>=1.22'
 
       - name: Install assimp-go dylib
         run: sudo mkdir -p /usr/local/lib && sudo wget https://github.com/bloeys/assimp-go/releases/download/v0.4.2/libassimp_darwin_amd64.dylib -O /usr/local/lib/libassimp.5.dylib

assets/textures.go

@@ -4,7 +4,6 @@ import (
 	"bytes"
 	"fmt"
 	"image"
-	"image/color"
 	"image/jpeg"
 	"image/png"
 	"io"
@@ -14,20 +13,31 @@ import (
 	"unsafe"
 
 	"github.com/go-gl/gl/v4.1-core/gl"
+	"github.com/mandykoh/prism"
 )
 
 type ColorFormat int
 
 const (
-	ColorFormat_RGBA8 ColorFormat = iota
+	ColorFormat_Unknown ColorFormat = iota
+	ColorFormat_RGBA8
 )
 
 type Texture struct {
-	//Path only exists for textures loaded from disk
-	Path   string
-	TexID  uint32
-	Width  int32
+	// Path only exists for textures loaded from disk
+	Path string
+
+	TexID uint32
+
+	// Width is the width of the texture in pixels (pixels per row).
+	// Note that the number of bytes constituting a row is MORE than this (e.g. for RGBA8, bytesPerRow=width*4, since we have 4 bytes per pixel)
+	Width int32
+
+	// Height is the height of the texture in pixels (pixels per column).
+	// Note that the number of bytes constituting a column is MORE than this (e.g. for RGBA8, bytesPerColumn=height*4, since we have 4 bytes per pixel)
 	Height int32
+
+	// Pixels usually stored in RGBA format
 	Pixels []byte
 }
 
@@ -36,6 +46,7 @@ type TextureLoadOptions struct {
 	WriteToCache     bool
 	GenMipMaps       bool
 	KeepPixelsInMem  bool
+	NoSrgba          bool
 }
 
 type Cubemap struct {
@@ -67,16 +78,20 @@ func LoadTexturePNG(file string, loadOptions *TextureLoadOptions) (Texture, erro
 		return Texture{}, err
 	}
 
-	img, err := png.Decode(bytes.NewReader(fileBytes))
+	bytesReader := bytes.NewReader(fileBytes)
+	img, err := png.Decode(bytesReader)
 	if err != nil {
 		return Texture{}, err
 	}
 
+	nrgbaImg := prism.ConvertImageToNRGBA(img, 2)
 	tex := Texture{
-		Path: file,
+		Path:   file,
+		Pixels: nrgbaImg.Pix,
+		Width:  int32(nrgbaImg.Bounds().Dx()),
+		Height: int32(nrgbaImg.Bounds().Dy()),
 	}
-
-	tex.Pixels, tex.Width, tex.Height = pixelsFromNrgbaPng(img)
+	flipImgPixelsVertically(tex.Pixels, int(tex.Width), int(tex.Height), 4)
 
 	//Prepare opengl stuff
 	gl.GenTextures(1, &tex.TexID)
@@ -89,7 +104,12 @@ func LoadTexturePNG(file string, loadOptions *TextureLoadOptions) (Texture, erro
 	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR)
 
 	// load and generate the texture
-	gl.TexImage2D(gl.TEXTURE_2D, 0, gl.RGBA8, tex.Width, tex.Height, 0, gl.RGBA, gl.UNSIGNED_BYTE, unsafe.Pointer(&tex.Pixels[0]))
+	internalFormat := int32(gl.SRGB_ALPHA)
+	if loadOptions.NoSrgba {
+		internalFormat = gl.RGBA8
+	}
+
+	gl.TexImage2D(gl.TEXTURE_2D, 0, internalFormat, tex.Width, tex.Height, 0, gl.RGBA, gl.UNSIGNED_BYTE, unsafe.Pointer(&tex.Pixels[0]))
 
 	if loadOptions.GenMipMaps {
 		gl.GenerateMipmap(tex.TexID)
@@ -112,8 +132,14 @@ func LoadTextureInMemPngImg(img image.Image, loadOptions *TextureLoadOptions) (T
 		loadOptions = &TextureLoadOptions{}
 	}
 
-	tex := Texture{}
-	tex.Pixels, tex.Width, tex.Height = pixelsFromNrgbaPng(img)
+	nrgbaImg := prism.ConvertImageToNRGBA(img, 2)
+	tex := Texture{
+		Path:   "",
+		Pixels: nrgbaImg.Pix,
+		Height: int32(nrgbaImg.Bounds().Dy()),
+		Width:  int32(nrgbaImg.Bounds().Dx()),
+	}
+	flipImgPixelsVertically(tex.Pixels, int(tex.Width), int(tex.Height), 4)
 
 	//Prepare opengl stuff
 	gl.GenTextures(1, &tex.TexID)
@@ -126,7 +152,12 @@ func LoadTextureInMemPngImg(img image.Image, loadOptions *TextureLoadOptions) (T
 	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR)
 
 	// load and generate the texture
-	gl.TexImage2D(gl.TEXTURE_2D, 0, gl.RGBA8, tex.Width, tex.Height, 0, gl.RGBA, gl.UNSIGNED_BYTE, unsafe.Pointer(&tex.Pixels[0]))
+	internalFormat := int32(gl.SRGB_ALPHA)
+	if loadOptions.NoSrgba {
+		internalFormat = gl.RGBA8
+	}
+
+	gl.TexImage2D(gl.TEXTURE_2D, 0, internalFormat, tex.Width, tex.Height, 0, gl.RGBA, gl.UNSIGNED_BYTE, unsafe.Pointer(&tex.Pixels[0]))
 
 	if loadOptions.GenMipMaps {
 		gl.GenerateMipmap(tex.TexID)
@@ -166,11 +197,14 @@ func LoadTextureJpeg(file string, loadOptions *TextureLoadOptions) (Texture, err
 		return Texture{}, err
 	}
 
+	nrgbaImg := prism.ConvertImageToNRGBA(img, 2)
 	tex := Texture{
-		Path: file,
+		Path:   file,
+		Pixels: nrgbaImg.Pix,
+		Height: int32(nrgbaImg.Bounds().Dy()),
+		Width:  int32(nrgbaImg.Bounds().Dx()),
 	}
-
-	tex.Pixels, tex.Width, tex.Height = pixelsFromNrgbaPng(img)
+	flipImgPixelsVertically(tex.Pixels, int(tex.Width), int(tex.Height), 4)
 
 	//Prepare opengl stuff
 	gl.GenTextures(1, &tex.TexID)
@@ -183,7 +217,12 @@ func LoadTextureJpeg(file string, loadOptions *TextureLoadOptions) (Texture, err
 	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR)
 
 	// load and generate the texture
-	gl.TexImage2D(gl.TEXTURE_2D, 0, gl.RGBA8, tex.Width, tex.Height, 0, gl.RGBA, gl.UNSIGNED_BYTE, unsafe.Pointer(&tex.Pixels[0]))
+	internalFormat := int32(gl.SRGB_ALPHA)
+	if loadOptions.NoSrgba {
+		internalFormat = gl.RGBA8
+	}
+
+	gl.TexImage2D(gl.TEXTURE_2D, 0, internalFormat, tex.Width, tex.Height, 0, gl.RGBA, gl.UNSIGNED_BYTE, unsafe.Pointer(&tex.Pixels[0]))
 
 	if loadOptions.GenMipMaps {
 		gl.GenerateMipmap(tex.TexID)
@@ -200,65 +239,19 @@ func LoadTextureJpeg(file string, loadOptions *TextureLoadOptions) (Texture, err
 	return tex, nil
 }
 
-func pixelsFromNrgbaPng(img image.Image) (pixels []byte, width, height int32) {
+// LoadCubemapTextures only supports the 'TextureIsSrgba' option
+func LoadCubemapTextures(rightTex, leftTex, topTex, botTex, frontTex, backTex string, loadOptions *TextureLoadOptions) (Cubemap, error) {
 
-	//NOTE: Load bottom left to top right because this is the texture coordinate system used by OpenGL
-	//NOTE: We only support 8-bit channels (32-bit colors) for now
-	i := 0
-	width, height = int32(img.Bounds().Dx()), int32(img.Bounds().Dy())
-	pixels = make([]byte, img.Bounds().Dx()*img.Bounds().Dy()*4)
-	for y := img.Bounds().Dy() - 1; y >= 0; y-- {
-		for x := 0; x < img.Bounds().Dx(); x++ {
-
-			c := color.NRGBAModel.Convert(img.At(x, y)).(color.NRGBA)
-
-			pixels[i] = c.R
-			pixels[i+1] = c.G
-			pixels[i+2] = c.B
-			pixels[i+3] = c.A
-
-			i += 4
-		}
+	if loadOptions == nil {
+		loadOptions = &TextureLoadOptions{}
 	}
 
-	return pixels, width, height
-}
-
-func pixelsFromNrgbaJpg(img image.Image) (pixels []byte, width, height int32) {
-
-	//NOTE: Load bottom left to top right because this is the texture coordinate system used by OpenGL
-	//NOTE: We only support 8-bit channels (32-bit colors) for now
-	i := 0
-	width, height = int32(img.Bounds().Dx()), int32(img.Bounds().Dy())
-	pixels = make([]byte, img.Bounds().Dx()*img.Bounds().Dy()*4)
-	for y := img.Bounds().Dy() - 1; y >= 0; y-- {
-		for x := 0; x < img.Bounds().Dx(); x++ {
-
-			c := color.NRGBAModel.Convert(img.At(x, y)).(color.NRGBA)
-
-			pixels[i] = c.R
-			pixels[i+1] = c.G
-			pixels[i+2] = c.B
-			pixels[i+3] = c.A
-
-			i += 4
-		}
-	}
-
-	return pixels, width, height
-}
-
-func LoadCubemapTextures(rightTex, leftTex, topTex, botTex, frontTex, backTex string) (Cubemap, error) {
-
 	var imgDecoder func(r io.Reader) (image.Image, error)
-	var pixelDecoder func(image.Image) ([]byte, int32, int32)
 	ext := strings.ToLower(path.Ext(rightTex))
 	if ext == ".jpg" || ext == ".jpeg" {
 		imgDecoder = jpeg.Decode
-		pixelDecoder = pixelsFromNrgbaJpg
 	} else if ext == ".png" {
 		imgDecoder = png.Decode
-		pixelDecoder = pixelsFromNrgbaPng
 	} else {
 		return Cubemap{}, fmt.Errorf("unknown image extension: %s. Expected one of: .jpg, .jpeg, .png", ext)
 	}
@@ -292,9 +285,16 @@ func LoadCubemapTextures(rightTex, leftTex, topTex, botTex, frontTex, backTex st
 			return Cubemap{}, err
 		}
 
-		pixels, width, height := pixelDecoder(img)
+		nrgbaImg := prism.ConvertImageToNRGBA(img, 2)
+		height := int32(nrgbaImg.Bounds().Dy())
+		width := int32(nrgbaImg.Bounds().Dx())
 
-		gl.TexImage2D(uint32(gl.TEXTURE_CUBE_MAP_POSITIVE_X)+i, 0, gl.RGBA8, int32(width), int32(height), 0, gl.RGBA, gl.UNSIGNED_BYTE, unsafe.Pointer(&pixels[0]))
+		internalFormat := int32(gl.SRGB_ALPHA)
+		if loadOptions.NoSrgba {
+			internalFormat = gl.RGBA8
+		}
+
+		gl.TexImage2D(uint32(gl.TEXTURE_CUBE_MAP_POSITIVE_X)+i, 0, internalFormat, int32(width), int32(height), 0, gl.RGBA, gl.UNSIGNED_BYTE, unsafe.Pointer(&nrgbaImg.Pix[0]))
 	}
 
 	// set the texture wrapping/filtering options (on the currently bound texture object)
@@ -306,3 +306,21 @@ func LoadCubemapTextures(rightTex, leftTex, topTex, botTex, frontTex, backTex st
 
 	return cmap, nil
 }
+
+func flipImgPixelsVertically(bytes []byte, width, height, bytesPerPixel int) {
+
+	// Flip the image vertically such that (e.g. in an image of 10 rows) rows 0<->9, 1<->8, 2<->7 etc are swapped.
+	// We do this because images are usually stored top-left to bottom-right, while opengl stores textures bottom-left to top-right, so if we don't swap
+	// rows textures will appear inverted
+	widthInBytes := width * bytesPerPixel
+	rowData := make([]byte, width*bytesPerPixel)
+	for rowNum := 0; rowNum < height/2; rowNum++ {
+
+		upperRowStartIndex := rowNum * widthInBytes
+		lowerRowStartIndex := (height - rowNum - 1) * widthInBytes
+		copy(rowData, bytes[upperRowStartIndex:upperRowStartIndex+widthInBytes])
+		copy(bytes[upperRowStartIndex:upperRowStartIndex+widthInBytes], bytes[lowerRowStartIndex:lowerRowStartIndex+widthInBytes])
+		copy(bytes[lowerRowStartIndex:lowerRowStartIndex+widthInBytes], rowData)
+
+	}
+}

buffers/buf_usage.go

@@ -10,8 +10,10 @@ import (
 type BufUsage int
 
 const (
+	BufUsage_Unknown BufUsage = iota
+
 	//Buffer is set only once and used many times
-	BufUsage_Static BufUsage = iota
+	BufUsage_Static
 	//Buffer is changed a lot and used many times
 	BufUsage_Dynamic
 	//Buffer is set only once and used by the GPU at most a few times

buffers/buffers.go

@@ -1,134 +0,0 @@
-package buffers
-
-import (
-	"github.com/bloeys/nmage/logging"
-	"github.com/go-gl/gl/v4.1-core/gl"
-)
-
-type Buffer struct {
-	VAOID uint32
-	// BufID is the ID of the VBO
-	BufID uint32
-	// IndexBufID is the ID of the index/element buffer
-	IndexBufID uint32
-	// IndexBufCount is the number of elements in the index buffer
-	// Updated on SetIndexBufData
-	IndexBufCount int32
-	// IndexBufCount int32
-	Stride int32
-
-	layout []Element
-}
-
-func (b *Buffer) Bind() {
-	gl.BindVertexArray(b.VAOID)
-}
-
-func (b *Buffer) UnBind() {
-	gl.BindVertexArray(0)
-}
-
-func (b *Buffer) SetData(values []float32) {
-
-	gl.BindVertexArray(b.VAOID)
-	gl.BindBuffer(gl.ARRAY_BUFFER, b.BufID)
-
-	sizeInBytes := len(values) * 4
-	if sizeInBytes == 0 {
-		gl.BufferData(gl.ARRAY_BUFFER, 0, gl.Ptr(nil), BufUsage_Static.ToGL())
-	} else {
-		gl.BufferData(gl.ARRAY_BUFFER, sizeInBytes, gl.Ptr(&values[0]), BufUsage_Static.ToGL())
-	}
-
-	gl.BindVertexArray(0)
-	gl.BindBuffer(gl.ARRAY_BUFFER, 0)
-}
-
-func (b *Buffer) SetDataWithUsage(values []float32, usage BufUsage) {
-
-	gl.BindVertexArray(b.VAOID)
-	gl.BindBuffer(gl.ARRAY_BUFFER, b.BufID)
-
-	sizeInBytes := len(values) * 4
-	if sizeInBytes == 0 {
-		gl.BufferData(gl.ARRAY_BUFFER, 0, gl.Ptr(nil), usage.ToGL())
-	} else {
-		gl.BufferData(gl.ARRAY_BUFFER, sizeInBytes, gl.Ptr(&values[0]), usage.ToGL())
-	}
-
-	gl.BindVertexArray(0)
-	gl.BindBuffer(gl.ARRAY_BUFFER, 0)
-}
-
-func (b *Buffer) SetIndexBufData(values []uint32) {
-
-	b.IndexBufCount = int32(len(values))
-	gl.BindVertexArray(b.VAOID)
-	gl.BindBuffer(gl.ELEMENT_ARRAY_BUFFER, b.IndexBufID)
-
-	sizeInBytes := len(values) * 4
-	if sizeInBytes == 0 {
-		gl.BufferData(gl.ELEMENT_ARRAY_BUFFER, 0, gl.Ptr(nil), BufUsage_Static.ToGL())
-	} else {
-		gl.BufferData(gl.ELEMENT_ARRAY_BUFFER, sizeInBytes, gl.Ptr(&values[0]), BufUsage_Static.ToGL())
-	}
-
-	gl.BindVertexArray(0)
-	gl.BindBuffer(gl.ELEMENT_ARRAY_BUFFER, 0)
-}
-
-func (b *Buffer) GetLayout() []Element {
-	e := make([]Element, len(b.layout))
-	copy(e, b.layout)
-	return e
-}
-
-// SetLayout updates the layout object and the corresponding vertex attributes.
-// Vertex attributes are also enabled.
-func (b *Buffer) SetLayout(layout ...Element) {
-
-	b.layout = layout
-
-	b.Stride = 0
-	for i := 0; i < len(b.layout); i++ {
-
-		b.layout[i].Offset = int(b.Stride)
-		b.Stride += b.layout[i].Size()
-	}
-
-	//Set opengl stuff
-	b.Bind()
-
-	//NOTE: VBOs are only bound at 'VertexAttribPointer', not BindBUffer, so we need to bind the buffer and vao here
-	gl.BindBuffer(gl.ARRAY_BUFFER, b.BufID)
-
-	for i := 0; i < len(layout); i++ {
-		gl.EnableVertexAttribArray(uint32(i))
-		gl.VertexAttribPointerWithOffset(uint32(i), layout[i].ElementType.CompCount(), layout[i].ElementType.GLType(), false, b.Stride, uintptr(layout[i].Offset))
-	}
-
-	b.UnBind()
-	gl.BindBuffer(gl.ARRAY_BUFFER, 0)
-}
-
-func NewBuffer(layout ...Element) Buffer {
-
-	b := Buffer{}
-	gl.GenVertexArrays(1, &b.VAOID)
-	if b.VAOID == 0 {
-		logging.ErrLog.Println("Failed to create openGL vertex array object")
-	}
-
-	gl.GenBuffers(1, &b.BufID)
-	if b.BufID == 0 {
-		logging.ErrLog.Println("Failed to create openGL buffer")
-	}
-
-	gl.GenBuffers(1, &b.IndexBufID)
-	if b.IndexBufID == 0 {
-		logging.ErrLog.Println("Failed to create openGL buffer")
-	}
-
-	b.SetLayout(layout...)
-	return b
-}

buffers/framebuffer.go

@@ -0,0 +1,594 @@
+package buffers
+
+import (
+	"github.com/bloeys/nmage/assert"
+	"github.com/bloeys/nmage/logging"
+	"github.com/go-gl/gl/v4.1-core/gl"
+)
+
+type FramebufferAttachmentType int32
+
+const (
+	FramebufferAttachmentType_Unknown FramebufferAttachmentType = iota
+	FramebufferAttachmentType_Texture
+	FramebufferAttachmentType_Texture_Array
+	FramebufferAttachmentType_Renderbuffer
+	FramebufferAttachmentType_Cubemap
+	FramebufferAttachmentType_Cubemap_Array
+)
+
+func (f FramebufferAttachmentType) IsValid() bool {
+
+	switch f {
+	case FramebufferAttachmentType_Texture:
+		fallthrough
+	case FramebufferAttachmentType_Texture_Array:
+		fallthrough
+	case FramebufferAttachmentType_Renderbuffer:
+		fallthrough
+	case FramebufferAttachmentType_Cubemap:
+		fallthrough
+	case FramebufferAttachmentType_Cubemap_Array:
+		return true
+
+	default:
+		return false
+	}
+}
+
+type FramebufferAttachmentDataFormat int32
+
+const (
+	FramebufferAttachmentDataFormat_Unknown FramebufferAttachmentDataFormat = iota
+	FramebufferAttachmentDataFormat_R32Int
+	FramebufferAttachmentDataFormat_RGBA8
+	FramebufferAttachmentDataFormat_SRGBA
+	FramebufferAttachmentDataFormat_DepthF32
+	FramebufferAttachmentDataFormat_Depth24Stencil8
+)
+
+func (f FramebufferAttachmentDataFormat) IsColorFormat() bool {
+	return f == FramebufferAttachmentDataFormat_R32Int ||
+		f == FramebufferAttachmentDataFormat_RGBA8 ||
+		f == FramebufferAttachmentDataFormat_SRGBA
+}
+
+func (f FramebufferAttachmentDataFormat) IsDepthFormat() bool {
+	return f == FramebufferAttachmentDataFormat_Depth24Stencil8 ||
+		f == FramebufferAttachmentDataFormat_DepthF32
+}
+
+func (f FramebufferAttachmentDataFormat) GlInternalFormat() int32 {
+
+	switch f {
+	case FramebufferAttachmentDataFormat_R32Int:
+		return gl.R32I
+	case FramebufferAttachmentDataFormat_RGBA8:
+		return gl.RGB8
+	case FramebufferAttachmentDataFormat_SRGBA:
+		return gl.SRGB_ALPHA
+	case FramebufferAttachmentDataFormat_DepthF32:
+		return gl.DEPTH_COMPONENT
+	case FramebufferAttachmentDataFormat_Depth24Stencil8:
+		return gl.DEPTH24_STENCIL8
+	default:
+		logging.ErrLog.Fatalf("unknown framebuffer attachment data format. Format=%d\n", f)
+		return 0
+	}
+}
+
+func (f FramebufferAttachmentDataFormat) GlFormat() uint32 {
+
+	switch f {
+	case FramebufferAttachmentDataFormat_R32Int:
+		return gl.RED_INTEGER
+
+	case FramebufferAttachmentDataFormat_RGBA8:
+		fallthrough
+	case FramebufferAttachmentDataFormat_SRGBA:
+		return gl.RGBA
+
+	case FramebufferAttachmentDataFormat_DepthF32:
+		return gl.DEPTH_COMPONENT
+
+	case FramebufferAttachmentDataFormat_Depth24Stencil8:
+		return gl.DEPTH_STENCIL
+
+	default:
+		logging.ErrLog.Fatalf("unknown framebuffer attachment data format. Format=%d\n", f)
+		return 0
+	}
+}
+
+type FramebufferAttachment struct {
+	Id     uint32
+	Type   FramebufferAttachmentType
+	Format FramebufferAttachmentDataFormat
+}
+
+type Framebuffer struct {
+	Id                    uint32
+	ClearFlags            uint32
+	Attachments           []FramebufferAttachment
+	ColorAttachmentsCount uint32
+	Width                 uint32
+	Height                uint32
+}
+
+func (fbo *Framebuffer) Bind() {
+	gl.BindFramebuffer(gl.FRAMEBUFFER, fbo.Id)
+}
+
+func (fbo *Framebuffer) BindWithViewport() {
+	gl.BindFramebuffer(gl.FRAMEBUFFER, fbo.Id)
+	gl.Viewport(0, 0, int32(fbo.Width), int32(fbo.Height))
+}
+
+// Clear calls gl.Clear with the fob's clear flags.
+// Note that the fbo must be complete and bound.
+// Calling this without a bound fbo will clear something else, like your screen.
+func (fbo *Framebuffer) Clear() {
+	gl.Clear(fbo.ClearFlags)
+}
+
+func (fbo *Framebuffer) UnBind() {
+	gl.BindFramebuffer(gl.FRAMEBUFFER, 0)
+}
+
+func (fbo *Framebuffer) UnBindWithViewport(width, height uint32) {
+	gl.BindFramebuffer(gl.FRAMEBUFFER, 0)
+	gl.Viewport(0, 0, int32(width), int32(height))
+}
+
+// IsComplete returns true if OpenGL reports that the fbo is complete/usable.
+// Note that this function binds and then unbinds the fbo
+func (fbo *Framebuffer) IsComplete() bool {
+	fbo.Bind()
+	isComplete := gl.CheckFramebufferStatus(gl.FRAMEBUFFER) == gl.FRAMEBUFFER_COMPLETE
+	fbo.UnBind()
+	return isComplete
+}
+
+func (fbo *Framebuffer) HasColorAttachment() bool {
+	return fbo.ColorAttachmentsCount > 0
+}
+
+func (fbo *Framebuffer) HasDepthAttachment() bool {
+
+	for i := 0; i < len(fbo.Attachments); i++ {
+
+		a := &fbo.Attachments[i]
+		if a.Format.IsDepthFormat() {
+			return true
+		}
+	}
+
+	return false
+}
+
+func (fbo *Framebuffer) NewColorAttachment(
+	attachType FramebufferAttachmentType,
+	attachFormat FramebufferAttachmentDataFormat,
+) {
+
+	if fbo.ColorAttachmentsCount == 8 {
+		logging.ErrLog.Fatalf("failed creating color attachment for framebuffer due it already having %d attached\n", fbo.ColorAttachmentsCount)
+	}
+
+	if !attachType.IsValid() {
+		logging.ErrLog.Fatalf("failed creating color attachment for framebuffer due to unknown attachment type. Type=%d\n", attachType)
+	}
+
+	if attachType == FramebufferAttachmentType_Cubemap || attachType == FramebufferAttachmentType_Cubemap_Array {
+		logging.ErrLog.Fatalf("failed creating color attachment because cubemaps can not be color attachments (at least in this implementation. You might be able to do it manually)\n")
+	}
+
+	if attachType == FramebufferAttachmentType_Texture_Array {
+		logging.ErrLog.Fatalf("failed creating color attachment because texture arrays can not be color attachments (implementation can be updated to support it or you can do it manually)\n")
+	}
+
+	if !attachFormat.IsColorFormat() {
+		logging.ErrLog.Fatalf("failed creating color attachment for framebuffer due to attachment data format not being a valid color type. Data format=%d\n", attachFormat)
+	}
+
+	a := FramebufferAttachment{
+		Type:   attachType,
+		Format: attachFormat,
+	}
+
+	fbo.Bind()
+
+	if attachType == FramebufferAttachmentType_Texture {
+
+		// Create texture
+		gl.GenTextures(1, &a.Id)
+		if a.Id == 0 {
+			logging.ErrLog.Fatalf("failed to generate texture for framebuffer. GlError=%d\n", gl.GetError())
+		}
+
+		gl.BindTexture(gl.TEXTURE_2D, a.Id)
+		gl.TexImage2D(gl.TEXTURE_2D, 0, attachFormat.GlInternalFormat(), int32(fbo.Width), int32(fbo.Height), 0, attachFormat.GlFormat(), gl.UNSIGNED_BYTE, nil)
+
+		gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR)
+		gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR)
+		gl.BindTexture(gl.TEXTURE_2D, 0)
+
+		// Attach to fbo
+		gl.FramebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0+fbo.ColorAttachmentsCount, gl.TEXTURE_2D, a.Id, 0)
+
+	} else if attachType == FramebufferAttachmentType_Renderbuffer {
+
+		// Create rbo
+		gl.GenRenderbuffers(1, &a.Id)
+		if a.Id == 0 {
+			logging.ErrLog.Fatalf("failed to generate render buffer for framebuffer. GlError=%d\n", gl.GetError())
+		}
+
+		gl.BindRenderbuffer(gl.RENDERBUFFER, a.Id)
+		gl.RenderbufferStorage(gl.RENDERBUFFER, uint32(attachFormat.GlInternalFormat()), int32(fbo.Width), int32(fbo.Height))
+		gl.BindRenderbuffer(gl.RENDERBUFFER, 0)
+
+		// Attach to fbo
+		gl.FramebufferRenderbuffer(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0+fbo.ColorAttachmentsCount, gl.RENDERBUFFER, a.Id)
+	}
+
+	fbo.UnBind()
+	fbo.ColorAttachmentsCount++
+	fbo.ClearFlags |= gl.COLOR_BUFFER_BIT
+	fbo.Attachments = append(fbo.Attachments, a)
+}
+
+// SetNoColorBuffer sets the read and draw buffers of this fbo to 'NONE',
+// which tells the graphics driver that we don't want a color buffer for this fbo.
+//
+// This is required because normally an fbo must have a color buffer to be considered complete, but by
+// doing this we get marked as complete even without one.
+//
+// Usually used when you only care about some other buffer, like a depth buffer.
+func (fbo *Framebuffer) SetNoColorBuffer() {
+
+	if fbo.HasColorAttachment() {
+		logging.ErrLog.Fatalf("failed SetNoColorBuffer because framebuffer already has a color attachment\n")
+	}
+
+	fbo.Bind()
+	gl.DrawBuffer(gl.NONE)
+	gl.ReadBuffer(gl.NONE)
+	fbo.UnBind()
+}
+
+func (fbo *Framebuffer) NewDepthAttachment(
+	attachType FramebufferAttachmentType,
+	attachFormat FramebufferAttachmentDataFormat,
+) {
+
+	if fbo.HasDepthAttachment() {
+		logging.ErrLog.Fatalf("failed creating depth attachment for framebuffer because a depth attachment already exists\n")
+	}
+
+	if !attachType.IsValid() {
+		logging.ErrLog.Fatalf("failed creating depth attachment for framebuffer due to unknown attachment type. Type=%d\n", attachType)
+	}
+
+	if !attachFormat.IsDepthFormat() {
+		logging.ErrLog.Fatalf("failed creating depth attachment for framebuffer due to attachment data format not being a valid depth-stencil type. Data format=%d\n", attachFormat)
+	}
+
+	if attachType == FramebufferAttachmentType_Cubemap_Array {
+		logging.ErrLog.Fatalf("failed creating cubemap array depth attachment because 'NewDepthCubemapArrayAttachment' must be used for that\n")
+	}
+
+	if attachType == FramebufferAttachmentType_Texture_Array {
+		logging.ErrLog.Fatalf("failed creating texture array depth attachment because 'NewDepthTextureArrayAttachment' must be used for that\n")
+	}
+
+	a := FramebufferAttachment{
+		Type:   attachType,
+		Format: attachFormat,
+	}
+
+	fbo.Bind()
+
+	if attachType == FramebufferAttachmentType_Texture {
+
+		// Create texture
+		gl.GenTextures(1, &a.Id)
+		if a.Id == 0 {
+			logging.ErrLog.Fatalf("failed to generate texture for framebuffer. GlError=%d\n", gl.GetError())
+		}
+
+		gl.BindTexture(gl.TEXTURE_2D, a.Id)
+		gl.TexImage2D(gl.TEXTURE_2D, 0, attachFormat.GlInternalFormat(), int32(fbo.Width), int32(fbo.Height), 0, attachFormat.GlFormat(), gl.FLOAT, nil)
+
+		gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST)
+		gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST)
+
+		// This is so that any sampling outside the depth map gives a full depth value.
+		// Useful for example when doing shadow maps where we want things outside
+		// the range of the texture to not show shadow
+		borderColor := []float32{1, 1, 1, 1}
+		gl.TexParameterfv(gl.TEXTURE_2D, gl.TEXTURE_BORDER_COLOR, &borderColor[0])
+		gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_BORDER)
+		gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_BORDER)
+
+		gl.BindTexture(gl.TEXTURE_2D, 0)
+
+		// Attach to fbo
+		gl.FramebufferTexture2D(gl.FRAMEBUFFER, gl.DEPTH_ATTACHMENT, gl.TEXTURE_2D, a.Id, 0)
+
+	} else if attachType == FramebufferAttachmentType_Renderbuffer {
+
+		// Create rbo
+		gl.GenRenderbuffers(1, &a.Id)
+		if a.Id == 0 {
+			logging.ErrLog.Fatalf("failed to generate render buffer for framebuffer. GlError=%d\n", gl.GetError())
+		}
+
+		gl.BindRenderbuffer(gl.RENDERBUFFER, a.Id)
+		gl.RenderbufferStorage(gl.RENDERBUFFER, uint32(attachFormat.GlInternalFormat()), int32(fbo.Width), int32(fbo.Height))
+		gl.BindRenderbuffer(gl.RENDERBUFFER, 0)
+
+		// Attach to fbo
+		gl.FramebufferRenderbuffer(gl.FRAMEBUFFER, gl.DEPTH_ATTACHMENT, gl.RENDERBUFFER, a.Id)
+
+	} else if attachType == FramebufferAttachmentType_Cubemap {
+
+		// Create cubemap
+		gl.GenTextures(1, &a.Id)
+		if a.Id == 0 {
+			logging.ErrLog.Fatalf("failed to generate texture for framebuffer. GlError=%d\n", gl.GetError())
+		}
+
+		gl.BindTexture(gl.TEXTURE_CUBE_MAP, a.Id)
+		for i := 0; i < 6; i++ {
+			gl.TexImage2D(uint32(gl.TEXTURE_CUBE_MAP_POSITIVE_X+i), 0, attachFormat.GlInternalFormat(), int32(fbo.Width), int32(fbo.Height), 0, attachFormat.GlFormat(), gl.FLOAT, nil)
+		}
+
+		gl.TexParameteri(gl.TEXTURE_CUBE_MAP, gl.TEXTURE_MIN_FILTER, gl.NEAREST)
+		gl.TexParameteri(gl.TEXTURE_CUBE_MAP, gl.TEXTURE_MAG_FILTER, gl.NEAREST)
+		gl.TexParameteri(gl.TEXTURE_CUBE_MAP, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE)
+		gl.TexParameteri(gl.TEXTURE_CUBE_MAP, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE)
+		gl.TexParameteri(gl.TEXTURE_CUBE_MAP, gl.TEXTURE_WRAP_R, gl.CLAMP_TO_EDGE)
+
+		gl.BindTexture(gl.TEXTURE_2D, 0)
+
+		// Attach to fbo
+		gl.FramebufferTexture(gl.FRAMEBUFFER, gl.DEPTH_ATTACHMENT, a.Id, 0)
+	}
+
+	fbo.UnBind()
+	fbo.ClearFlags |= gl.DEPTH_BUFFER_BIT
+	fbo.Attachments = append(fbo.Attachments, a)
+}
+
+func (fbo *Framebuffer) NewDepthCubemapArrayAttachment(
+	attachFormat FramebufferAttachmentDataFormat,
+	numCubemaps int32,
+) {
+
+	if fbo.HasDepthAttachment() {
+		logging.ErrLog.Fatalf("failed creating cubemap array depth attachment for framebuffer because a depth attachment already exists\n")
+	}
+
+	if !attachFormat.IsDepthFormat() {
+		logging.ErrLog.Fatalf("failed creating depth attachment for framebuffer due to attachment data format not being a valid depth-stencil type. Data format=%d\n", attachFormat)
+	}
+
+	a := FramebufferAttachment{
+		Type:   FramebufferAttachmentType_Cubemap_Array,
+		Format: attachFormat,
+	}
+
+	fbo.Bind()
+
+	// Create cubemap array
+	gl.GenTextures(1, &a.Id)
+	if a.Id == 0 {
+		logging.ErrLog.Fatalf("failed to generate texture for framebuffer. GlError=%d\n", gl.GetError())
+	}
+
+	gl.BindTexture(gl.TEXTURE_CUBE_MAP_ARRAY, a.Id)
+
+	gl.TexImage3D(
+		gl.TEXTURE_CUBE_MAP_ARRAY,
+		0,
+		attachFormat.GlInternalFormat(),
+		int32(fbo.Width),
+		int32(fbo.Height),
+		6*numCubemaps,
+		0,
+		attachFormat.GlFormat(),
+		gl.FLOAT,
+		nil,
+	)
+
+	gl.TexParameteri(gl.TEXTURE_CUBE_MAP_ARRAY, gl.TEXTURE_MIN_FILTER, gl.NEAREST)
+	gl.TexParameteri(gl.TEXTURE_CUBE_MAP_ARRAY, gl.TEXTURE_MAG_FILTER, gl.NEAREST)
+	gl.TexParameteri(gl.TEXTURE_CUBE_MAP_ARRAY, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE)
+	gl.TexParameteri(gl.TEXTURE_CUBE_MAP_ARRAY, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE)
+	gl.TexParameteri(gl.TEXTURE_CUBE_MAP_ARRAY, gl.TEXTURE_WRAP_R, gl.CLAMP_TO_EDGE)
+
+	gl.BindTexture(gl.TEXTURE_2D, 0)
+
+	// Attach to fbo
+	gl.FramebufferTexture(gl.FRAMEBUFFER, gl.DEPTH_ATTACHMENT, a.Id, 0)
+
+	fbo.UnBind()
+	fbo.ClearFlags |= gl.DEPTH_BUFFER_BIT
+	fbo.Attachments = append(fbo.Attachments, a)
+}
+
+func (fbo *Framebuffer) NewDepthTextureArrayAttachment(
+	attachFormat FramebufferAttachmentDataFormat,
+	numTextures int32,
+) {
+
+	if fbo.HasDepthAttachment() {
+		logging.ErrLog.Fatalf("failed creating texture array depth attachment for framebuffer because a depth attachment already exists\n")
+	}
+
+	if !attachFormat.IsDepthFormat() {
+		logging.ErrLog.Fatalf("failed creating depth attachment for framebuffer due to attachment data format not being a valid depth-stencil type. Data format=%d\n", attachFormat)
+	}
+
+	a := FramebufferAttachment{
+		Type:   FramebufferAttachmentType_Texture_Array,
+		Format: attachFormat,
+	}
+
+	fbo.Bind()
+
+	// Create cubemap array
+	gl.GenTextures(1, &a.Id)
+	if a.Id == 0 {
+		logging.ErrLog.Fatalf("failed to generate texture for framebuffer. GlError=%d\n", gl.GetError())
+	}
+
+	gl.BindTexture(gl.TEXTURE_2D_ARRAY, a.Id)
+
+	gl.TexImage3D(
+		gl.TEXTURE_2D_ARRAY,
+		0,
+		attachFormat.GlInternalFormat(),
+		int32(fbo.Width),
+		int32(fbo.Height),
+		numTextures,
+		0,
+		attachFormat.GlFormat(),
+		gl.FLOAT,
+		nil,
+	)
+
+	gl.TexParameteri(gl.TEXTURE_2D_ARRAY, gl.TEXTURE_MIN_FILTER, gl.NEAREST)
+	gl.TexParameteri(gl.TEXTURE_2D_ARRAY, gl.TEXTURE_MAG_FILTER, gl.NEAREST)
+
+	// This is so that any sampling outside the depth map gives a full depth value.
+	// Useful for example when doing shadow maps where we want things outside
+	// the range of the texture to not show shadow
+	borderColor := []float32{1, 1, 1, 1}
+	gl.TexParameterfv(gl.TEXTURE_2D_ARRAY, gl.TEXTURE_BORDER_COLOR, &borderColor[0])
+	gl.TexParameteri(gl.TEXTURE_2D_ARRAY, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_BORDER)
+	gl.TexParameteri(gl.TEXTURE_2D_ARRAY, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_BORDER)
+
+	gl.BindTexture(gl.TEXTURE_2D_ARRAY, 0)
+
+	// Attach to fbo
+	gl.FramebufferTexture(gl.FRAMEBUFFER, gl.DEPTH_ATTACHMENT, a.Id, 0)
+
+	fbo.UnBind()
+	fbo.ClearFlags |= gl.DEPTH_BUFFER_BIT
+	fbo.Attachments = append(fbo.Attachments, a)
+}
+
+func (fbo *Framebuffer) NewDepthStencilAttachment(
+	attachType FramebufferAttachmentType,
+	attachFormat FramebufferAttachmentDataFormat,
+) {
+
+	if fbo.HasDepthAttachment() {
+		logging.ErrLog.Fatalf("failed creating depth-stencil attachment for framebuffer because a depth-stencil attachment already exists\n")
+	}
+
+	if !attachType.IsValid() {
+		logging.ErrLog.Fatalf("failed creating depth-stencil attachment for framebuffer due to unknown attachment type. Type=%d\n", attachType)
+	}
+
+	if !attachFormat.IsDepthFormat() {
+		logging.ErrLog.Fatalf("failed creating depth-stencil attachment for framebuffer due to attachment data format not being a valid depth-stencil type. Data format=%d\n", attachFormat)
+	}
+
+	a := FramebufferAttachment{
+		Type:   attachType,
+		Format: attachFormat,
+	}
+
+	fbo.Bind()
+
+	if attachType == FramebufferAttachmentType_Texture {
+
+		// Create texture
+		gl.GenTextures(1, &a.Id)
+		if a.Id == 0 {
+			logging.ErrLog.Fatalf("failed to generate texture for framebuffer. GlError=%d\n", gl.GetError())
+		}
+
+		gl.BindTexture(gl.TEXTURE_2D, a.Id)
+		gl.TexImage2D(gl.TEXTURE_2D, 0, attachFormat.GlInternalFormat(), int32(fbo.Width), int32(fbo.Height), 0, attachFormat.GlFormat(), gl.UNSIGNED_INT_24_8, nil)
+
+		gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST)
+		gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST)
+		gl.BindTexture(gl.TEXTURE_2D, 0)
+
+		// Attach to fbo
+		gl.FramebufferTexture2D(gl.FRAMEBUFFER, gl.DEPTH_STENCIL_ATTACHMENT, gl.TEXTURE_2D, a.Id, 0)
+
+	} else if attachType == FramebufferAttachmentType_Renderbuffer {
+
+		// Create rbo
+		gl.GenRenderbuffers(1, &a.Id)
+		if a.Id == 0 {
+			logging.ErrLog.Fatalf("failed to generate render buffer for framebuffer. GlError=%d\n", gl.GetError())
+		}
+
+		gl.BindRenderbuffer(gl.RENDERBUFFER, a.Id)
+		gl.RenderbufferStorage(gl.RENDERBUFFER, uint32(attachFormat.GlInternalFormat()), int32(fbo.Width), int32(fbo.Height))
+		gl.BindRenderbuffer(gl.RENDERBUFFER, 0)
+
+		// Attach to fbo
+		gl.FramebufferRenderbuffer(gl.FRAMEBUFFER, gl.DEPTH_STENCIL_ATTACHMENT, gl.RENDERBUFFER, a.Id)
+	}
+
+	fbo.UnBind()
+	fbo.ClearFlags |= gl.DEPTH_BUFFER_BIT | gl.STENCIL_BUFFER_BIT
+	fbo.Attachments = append(fbo.Attachments, a)
+}
+
+// SetCubemapArrayLayerFace 'binds' a single face of a cubemap from the cubemap
+// array to the fbo, such that rendering only affects that one face and the others inaccessible.
+//
+// If this is not called, the default is that the entire cubemap array and all the faces in it
+// are bound and available for use when binding the fbo.
+func (fbo *Framebuffer) SetCubemapArrayLayerFace(layerFace int32) {
+
+	for i := 0; i < len(fbo.Attachments); i++ {
+
+		a := &fbo.Attachments[i]
+		if a.Type != FramebufferAttachmentType_Cubemap_Array {
+			continue
+		}
+
+		assert.T(a.Format.IsDepthFormat(), "SetCubemapFromArray called but a cubemap array is set on a color attachment, which is not currently handled. Code must be updated!")
+		gl.FramebufferTextureLayer(gl.FRAMEBUFFER, gl.DEPTH_ATTACHMENT, a.Id, 0, layerFace)
+		return
+	}
+
+	logging.ErrLog.Fatalf("SetCubemapFromArray failed because no cubemap array attachment was found on fbo. Fbo=%+v\n", *fbo)
+}
+
+func (fbo *Framebuffer) Delete() {
+
+	if fbo.Id == 0 {
+		return
+	}
+
+	gl.DeleteFramebuffers(1, &fbo.Id)
+	fbo.Id = 0
+}
+
+func NewFramebuffer(width, height uint32) Framebuffer {
+
+	// It is allowed to have attachments of differnt sizes in one FBO,
+	// but that complicates things (e.g. which size to use for gl.viewport) and I don't see much use
+	// for it now, so we will have all attachments share size
+	fbo := Framebuffer{
+		Width:  width,
+		Height: height,
+	}
+
+	gl.GenFramebuffers(1, &fbo.Id)
+	if fbo.Id == 0 {
+		logging.ErrLog.Fatalf("failed to generate framebuffer. GlError=%d\n", gl.GetError())
+	}
+
+	return fbo
+}

buffers/index_buffer.go

@@ -0,0 +1,46 @@
+package buffers
+
+import (
+	"github.com/bloeys/nmage/logging"
+	"github.com/go-gl/gl/v4.1-core/gl"
+)
+
+type IndexBuffer struct {
+	Id uint32
+	// IndexBufCount is the number of elements in the index buffer. Updated in IndexBuffer.SetData
+	IndexBufCount int32
+}
+
+func (ib *IndexBuffer) Bind() {
+	gl.BindBuffer(gl.ELEMENT_ARRAY_BUFFER, ib.Id)
+}
+
+func (ib *IndexBuffer) UnBind() {
+	gl.BindBuffer(gl.ELEMENT_ARRAY_BUFFER, 0)
+}
+
+func (ib *IndexBuffer) SetData(values []uint32) {
+
+	ib.Bind()
+
+	sizeInBytes := len(values) * 4
+	ib.IndexBufCount = int32(len(values))
+
+	if sizeInBytes == 0 {
+		gl.BufferData(gl.ELEMENT_ARRAY_BUFFER, 0, gl.Ptr(nil), BufUsage_Static.ToGL())
+	} else {
+		gl.BufferData(gl.ELEMENT_ARRAY_BUFFER, sizeInBytes, gl.Ptr(&values[0]), BufUsage_Static.ToGL())
+	}
+}
+
+func NewIndexBuffer() IndexBuffer {
+
+	ib := IndexBuffer{}
+
+	gl.GenBuffers(1, &ib.Id)
+	if ib.Id == 0 {
+		logging.ErrLog.Println("Failed to create OpenGL buffer")
+	}
+
+	return ib
+}

buffers/vertex_array.go

@@ -0,0 +1,54 @@
+package buffers
+
+import (
+	"github.com/bloeys/nmage/logging"
+	"github.com/go-gl/gl/v4.1-core/gl"
+)
+
+type VertexArray struct {
+	Id          uint32
+	Vbos        []VertexBuffer
+	IndexBuffer IndexBuffer
+}
+
+func (va *VertexArray) Bind() {
+	gl.BindVertexArray(va.Id)
+}
+
+func (va *VertexArray) UnBind() {
+	gl.BindVertexArray(0)
+}
+
+func (va *VertexArray) AddVertexBuffer(vbo VertexBuffer) {
+
+	// NOTE: VBOs are only bound at 'VertexAttribPointer' (and related) calls
+
+	va.Bind()
+	vbo.Bind()
+
+	for i := 0; i < len(vbo.layout); i++ {
+
+		l := &vbo.layout[i]
+
+		gl.EnableVertexAttribArray(uint32(i))
+		gl.VertexAttribPointerWithOffset(uint32(i), l.ElementType.CompCount(), l.ElementType.GLType(), false, vbo.Stride, uintptr(l.Offset))
+	}
+}
+
+func (va *VertexArray) SetIndexBuffer(ib IndexBuffer) {
+	va.Bind()
+	ib.Bind()
+	va.IndexBuffer = ib
+}
+
+func NewVertexArray() VertexArray {
+
+	vao := VertexArray{}
+
+	gl.GenVertexArrays(1, &vao.Id)
+	if vao.Id == 0 {
+		logging.ErrLog.Println("Failed to create OpenGL vertex array object")
+	}
+
+	return vao
+}

buffers/vertex_buffer.go

@@ -0,0 +1,63 @@
+package buffers
+
+import (
+	"github.com/bloeys/nmage/logging"
+	"github.com/go-gl/gl/v4.1-core/gl"
+)
+
+type VertexBuffer struct {
+	Id     uint32
+	Stride int32
+	layout []Element
+}
+
+func (vb *VertexBuffer) Bind() {
+	gl.BindBuffer(gl.ARRAY_BUFFER, vb.Id)
+}
+
+func (vb *VertexBuffer) UnBind() {
+	gl.BindBuffer(gl.ARRAY_BUFFER, 0)
+}
+
+func (vb *VertexBuffer) SetData(values []float32, usage BufUsage) {
+
+	vb.Bind()
+
+	sizeInBytes := len(values) * 4
+	if sizeInBytes == 0 {
+		gl.BufferData(gl.ARRAY_BUFFER, 0, gl.Ptr(nil), usage.ToGL())
+	} else {
+		gl.BufferData(gl.ARRAY_BUFFER, sizeInBytes, gl.Ptr(&values[0]), usage.ToGL())
+	}
+}
+
+func (vb *VertexBuffer) GetLayout() []Element {
+	e := make([]Element, len(vb.layout))
+	copy(e, vb.layout)
+	return e
+}
+
+func (vb *VertexBuffer) SetLayout(layout ...Element) {
+
+	vb.Stride = 0
+	vb.layout = layout
+
+	for i := 0; i < len(vb.layout); i++ {
+
+		vb.layout[i].Offset = int(vb.Stride)
+		vb.Stride += vb.layout[i].Size()
+	}
+}
+
+func NewVertexBuffer(layout ...Element) VertexBuffer {
+
+	vb := VertexBuffer{}
+
+	gl.GenBuffers(1, &vb.Id)
+	if vb.Id == 0 {
+		logging.ErrLog.Println("Failed to create OpenGL buffer")
+	}
+
+	vb.SetLayout(layout...)
+	return vb
+}

engine/engine.go

@@ -15,6 +15,13 @@ import (
 
 var (
 	isInited = false
+
+	isSdlButtonLeftDown   = false
+	isSdlButtonMiddleDown = false
+	isSdlButtonRightDown  = false
+
+	ImguiRelativeMouseModePosX float32
+	ImguiRelativeMouseModePosY float32
 )
 
 type Window struct {
@@ -26,10 +33,13 @@ type Window struct {
 
 func (w *Window) handleInputs() {
 
-	input.EventLoopStart()
 	imIo := imgui.CurrentIO()
 
-	// @TODO: Would be nice to have imgui package process its own events via a callback instead of it being part of engine code
+	imguiCaptureMouse := imIo.WantCaptureMouse()
+	imguiCaptureKeyboard := imIo.WantCaptureKeyboard()
+
+	input.EventLoopStart(imguiCaptureMouse, imguiCaptureKeyboard)
+
 	for event := sdl.PollEvent(); event != nil; event = sdl.PollEvent() {
 
 		//Fire callbacks
@@ -43,42 +53,42 @@ func (w *Window) handleInputs() {
 		case *sdl.MouseWheelEvent:
 
 			input.HandleMouseWheelEvent(e)
-
-			xDelta, yDelta := input.GetMouseWheelMotion()
-			imIo.AddMouseWheelDelta(float32(xDelta), float32(yDelta))
+			imIo.AddMouseWheelDelta(float32(e.X), float32(e.Y))
 
 		case *sdl.KeyboardEvent:
 
 			input.HandleKeyboardEvent(e)
+
+			// Send modifier key updates to imgui (based on the imgui SDL backend)
+			imIo.AddKeyEvent(imgui.ModCtrl, e.Keysym.Mod&sdl.KMOD_CTRL != 0)
+			imIo.AddKeyEvent(imgui.ModShift, e.Keysym.Mod&sdl.KMOD_SHIFT != 0)
+			imIo.AddKeyEvent(imgui.ModAlt, e.Keysym.Mod&sdl.KMOD_ALT != 0)
+			imIo.AddKeyEvent(imgui.ModSuper, e.Keysym.Mod&sdl.KMOD_GUI != 0)
+
 			imIo.AddKeyEvent(nmageimgui.SdlScancodeToImGuiKey(e.Keysym.Scancode), e.Type == sdl.KEYDOWN)
 
-			// Send modifier key updates to imgui
-			if e.Keysym.Sym == sdl.K_LCTRL || e.Keysym.Sym == sdl.K_RCTRL {
-				imIo.SetKeyCtrl(e.Type == sdl.KEYDOWN)
-			}
-
-			if e.Keysym.Sym == sdl.K_LSHIFT || e.Keysym.Sym == sdl.K_RSHIFT {
-				imIo.SetKeyShift(e.Type == sdl.KEYDOWN)
-			}
-
-			if e.Keysym.Sym == sdl.K_LALT || e.Keysym.Sym == sdl.K_RALT {
-				imIo.SetKeyAlt(e.Type == sdl.KEYDOWN)
-			}
-
-			if e.Keysym.Sym == sdl.K_LGUI || e.Keysym.Sym == sdl.K_RGUI {
-				imIo.SetKeySuper(e.Type == sdl.KEYDOWN)
-			}
-
 		case *sdl.TextInputEvent:
 			imIo.AddInputCharactersUTF8(e.GetText())
 
 		case *sdl.MouseButtonEvent:
+
 			input.HandleMouseBtnEvent(e)
+			isPressed := e.State == sdl.PRESSED
+
+			if e.Button == sdl.BUTTON_LEFT {
+				isSdlButtonLeftDown = isPressed
+			} else if e.Button == sdl.BUTTON_MIDDLE {
+				isSdlButtonMiddleDown = isPressed
+			} else if e.Button == sdl.BUTTON_RIGHT {
+				isSdlButtonRightDown = isPressed
+			}
 
 		case *sdl.MouseMotionEvent:
+
 			input.HandleMouseMotionEvent(e)
 
 		case *sdl.WindowEvent:
+
 			if e.Event == sdl.WINDOWEVENT_SIZE_CHANGED {
 				w.handleWindowResize()
 			}
@@ -88,13 +98,17 @@ func (w *Window) handleInputs() {
 		}
 	}
 
-	// If a mouse press event came, always pass it as "mouse held this frame", so we don't miss click-release events that are shorter than 1 frame.
-	x, y, _ := sdl.GetMouseState()
-	imIo.SetMousePos(imgui.Vec2{X: float32(x), Y: float32(y)})
+	if sdl.GetRelativeMouseMode() {
+		imIo.SetMousePos(imgui.Vec2{X: ImguiRelativeMouseModePosX, Y: ImguiRelativeMouseModePosY})
+	} else {
+		x, y, _ := sdl.GetMouseState()
+		imIo.SetMousePos(imgui.Vec2{X: float32(x), Y: float32(y)})
+	}
 
-	imIo.SetMouseButtonDown(0, input.MouseDown(sdl.BUTTON_LEFT))
-	imIo.SetMouseButtonDown(1, input.MouseDown(sdl.BUTTON_RIGHT))
-	imIo.SetMouseButtonDown(2, input.MouseDown(sdl.BUTTON_MIDDLE))
+	// If a mouse press event came, always pass it as "mouse held this frame", so we don't miss click-release events that are shorter than 1 frame.
+	imIo.SetMouseButtonDown(imgui.MouseButtonLeft, isSdlButtonLeftDown)
+	imIo.SetMouseButtonDown(imgui.MouseButtonRight, isSdlButtonRightDown)
+	imIo.SetMouseButtonDown(imgui.MouseButtonMiddle, isSdlButtonMiddleDown)
 }
 
 func (w *Window) handleWindowResize() {
@@ -133,15 +147,21 @@ func initSDL() error {
 	sdl.GLSetAttribute(sdl.MAJOR_VERSION, 4)
 	sdl.GLSetAttribute(sdl.MINOR_VERSION, 1)
 
-	// R(0-255) G(0-255) B(0-255)
 	sdl.GLSetAttribute(sdl.GL_RED_SIZE, 8)
 	sdl.GLSetAttribute(sdl.GL_GREEN_SIZE, 8)
 	sdl.GLSetAttribute(sdl.GL_BLUE_SIZE, 8)
+	sdl.GLSetAttribute(sdl.GL_ALPHA_SIZE, 8)
 
 	sdl.GLSetAttribute(sdl.GL_DOUBLEBUFFER, 1)
 	sdl.GLSetAttribute(sdl.GL_DEPTH_SIZE, 24)
 	sdl.GLSetAttribute(sdl.GL_STENCIL_SIZE, 8)
 
+	sdl.GLSetAttribute(sdl.GL_FRAMEBUFFER_SRGB_CAPABLE, 1)
+
+	// Allows us to do MSAA
+	sdl.GLSetAttribute(sdl.GL_MULTISAMPLEBUFFERS, 1)
+	sdl.GLSetAttribute(sdl.GL_MULTISAMPLESAMPLES, 4)
+
 	sdl.GLSetAttribute(sdl.GL_CONTEXT_PROFILE_MASK, sdl.GL_CONTEXT_PROFILE_CORE)
 
 	return nil
@@ -152,21 +172,18 @@ func CreateOpenGLWindow(title string, x, y, width, height int32, flags WindowFla
 }
 
 func CreateOpenGLWindowCentered(title string, width, height int32, flags WindowFlags, rend renderer.Render) (*Window, error) {
-	return createWindow(title, -1, -1, width, height, WindowFlags_OPENGL|flags, rend)
+	return createWindow(title, sdl.WINDOWPOS_CENTERED, sdl.WINDOWPOS_CENTERED, width, height, WindowFlags_OPENGL|flags, rend)
 }
 
 func createWindow(title string, x, y, width, height int32, flags WindowFlags, rend renderer.Render) (*Window, error) {
 
-	assert.T(isInited, "engine.Init was not called!")
-	if x == -1 && y == -1 {
-		x = sdl.WINDOWPOS_CENTERED
-		y = sdl.WINDOWPOS_CENTERED
-	}
+	assert.T(isInited, "engine.Init() was not called!")
 
 	sdlWin, err := sdl.CreateWindow(title, x, y, width, height, uint32(flags))
 	if err != nil {
 		return nil, err
 	}
+
 	win := &Window{
 		SDLWin:         sdlWin,
 		EventCallbacks: make([]func(sdl.Event), 0),
@@ -183,6 +200,10 @@ func createWindow(title string, x, y, width, height int32, flags WindowFlags, re
 		return nil, err
 	}
 
+	// Get rid of the blinding white startup screen (unfortunately there is still one frame of white)
+	gl.Clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT | gl.STENCIL_BUFFER_BIT)
+	sdlWin.GLSwap()
+
 	return win, err
 }
 
@@ -193,19 +214,31 @@ func initOpenGL() error {
 	}
 
 	gl.Enable(gl.DEPTH_TEST)
+	gl.Enable(gl.STENCIL_TEST)
 	gl.Enable(gl.CULL_FACE)
 	gl.CullFace(gl.BACK)
 	gl.FrontFace(gl.CCW)
 
 	gl.Enable(gl.BLEND)
+	gl.Enable(gl.MULTISAMPLE)
+	gl.Enable(gl.FRAMEBUFFER_SRGB)
 	gl.BlendFunc(gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA)
 
 	gl.ClearColor(0, 0, 0, 1)
+
 	return nil
 }
 
+func SetSrgbFramebuffer(isEnabled bool) {
+
+	if isEnabled {
+		gl.Enable(gl.FRAMEBUFFER_SRGB)
+	} else {
+		gl.Disable(gl.FRAMEBUFFER_SRGB)
+	}
+}
+
 func SetVSync(enabled bool) {
-	assert.T(isInited, "engine.Init was not called!")
 
 	if enabled {
 		sdl.GLSetSwapInterval(1)
@@ -213,3 +246,12 @@ func SetVSync(enabled bool) {
 		sdl.GLSetSwapInterval(0)
 	}
 }
+
+func SetMSAA(isEnabled bool) {
+
+	if isEnabled {
+		gl.Enable(gl.MULTISAMPLE)
+	} else {
+		gl.Disable(gl.MULTISAMPLE)
+	}
+}

go.mod

@@ -1,6 +1,6 @@
 module github.com/bloeys/nmage
 
-go 1.18
+go 1.22
 
 require github.com/veandco/go-sdl2 v0.4.35
 
@@ -11,4 +11,9 @@ require (
 	github.com/bloeys/gglm v0.43.0
 )
 
-require github.com/AllenDang/cimgui-go v0.0.0-20230720025235-f2ff398a66b2
+require (
+	github.com/AllenDang/cimgui-go v0.0.0-20230720025235-f2ff398a66b2
+	github.com/mandykoh/prism v0.35.1
+)
+
+require github.com/mandykoh/go-parallel v0.1.0 // indirect

go.sum

@@ -6,5 +6,35 @@ github.com/bloeys/gglm v0.43.0 h1:ZpOghR3PHfpkigTDh+FqxLsF0gN8CD6s/bWoei6LyxI=
 github.com/bloeys/gglm v0.43.0/go.mod h1:qwJQ0WzV191wAMwlGicbfbChbKoSedMk7gFFX6GnyOk=
 github.com/go-gl/gl v0.0.0-20211210172815-726fda9656d6 h1:zDw5v7qm4yH7N8C8uWd+8Ii9rROdgWxQuGoJ9WDXxfk=
 github.com/go-gl/gl v0.0.0-20211210172815-726fda9656d6/go.mod h1:9YTyiznxEY1fVinfM7RvRcjRHbw2xLBJ3AAGIT0I4Nw=
+github.com/mandykoh/go-parallel v0.1.0 h1:7vJMNMC4dsbgZdkAb2A8tV5ENY1v7VxIO1wzQWZoT8k=
+github.com/mandykoh/go-parallel v0.1.0/go.mod h1:lkYHqG1JNTaSS6lG+PgFCnyMd2VDy8pH9jN9pY899ig=
+github.com/mandykoh/prism v0.35.1 h1:JbQfQarANxSWlgJEpjv+E7DvtrqBaVP1YgJfZPvo6ME=
+github.com/mandykoh/prism v0.35.1/go.mod h1:3miB3EAJ0IggYl/4eBB5MmawRbyJI1gKDtbrVvk8Q9I=
 github.com/veandco/go-sdl2 v0.4.35 h1:NohzsfageDWGtCd9nf7Pc3sokMK/MOK+UA2QMJARWzQ=
 github.com/veandco/go-sdl2 v0.4.35/go.mod h1:OROqMhHD43nT4/i9crJukyVecjPNYYuCofep6SNiAjY=
+github.com/yuin/goldmark v1.4.13/go.mod h1:6yULJ656Px+3vBD8DxQVa3kxgyrAnzto9xy5taEt/CY=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/crypto v0.0.0-20210921155107-089bfa567519/go.mod h1:GvvjBRRGRdwPK5ydBHafDWAxML/pGHZbMvKqRZ5+Abc=
+golang.org/x/image v0.5.0 h1:5JMiNunQeQw++mMOz48/ISeNu3Iweh/JaZU8ZLqHRrI=
+golang.org/x/image v0.5.0/go.mod h1:FVC7BI/5Ym8R25iw5OLsgshdUBbT1h5jZTpA+mvAdZ4=
+golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4/go.mod h1:jJ57K6gSWd91VN4djpZkiMVwK6gcyfeH4XE8wZrZaV4=
+golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
+golang.org/x/net v0.0.0-20210226172049-e18ecbb05110/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
+golang.org/x/net v0.0.0-20220722155237-a158d28d115b/go.mod h1:XRhObCWvk6IyKnWLug+ECip1KBveYUHfp+8e9klMJ9c=
+golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sync v0.0.0-20220722155255-886fb9371eb4/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20220722155257-8c9f86f7a55f/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
+golang.org/x/term v0.0.0-20210927222741-03fcf44c2211/go.mod h1:jbD1KX2456YbFQfuXm/mYQcufACuNUgVhRMnK/tPxf8=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
+golang.org/x/text v0.3.7/go.mod h1:u+2+/6zg+i71rQMx5EYifcz6MCKuco9NR6JIITiCfzQ=
+golang.org/x/text v0.7.0/go.mod h1:mrYo+phRRbMaCq/xk9113O4dZlRixOauAjOtrjsXDZ8=
+golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
+golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
+golang.org/x/tools v0.1.12/go.mod h1:hNGJHUnrk76NpqgfD5Aqm5Crs+Hm0VOH/i9J2+nxYbc=
+golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=

input/input.go

@@ -1,6 +1,23 @@
+// The input package provides an interface to mouse and keyboard inputs
+// like key clicks and releases, along with some higher level constructs like
+// pressed/released this frames, double clicks, and normalized inputs.
+//
+// The input package has two sets of functions for most cases, where one
+// is in the form 'xy' and the other 'xyCaptured'. The captured form
+// always returns normal events even if the mouse or keyboard are captured
+// by the UI system. The 'xy' form however will return zero/false if the
+// respective input device is currently captured (with the exception of mouse position, that is always correctly returned).
+//
+// For most cases, you want to use the 'xy' form. For example, you only want to receive
+// key down events for game character movement when the UI isn't capturing the keyboard,
+// because otherwise the character will move while typing in a UI textbox.
+//
+// The functions IsMouseCaptured and IsKeyboardCaptured are also available.
 package input
 
-import "github.com/veandco/go-sdl2/sdl"
+import (
+	"github.com/veandco/go-sdl2/sdl"
+)
 
 type keyState struct {
 	Key                 sdl.Keycode
@@ -31,24 +48,33 @@ type mouseWheelState struct {
 }
 
 var (
-	keyMap        = make(map[sdl.Keycode]*keyState)
-	mouseBtnMap   = make(map[int]*mouseBtnState)
-	mouseMotion   = mouseMotionState{}
-	mouseWheel    = mouseWheelState{}
-	quitRequested bool
+	mouseWheel  = mouseWheelState{}
+	mouseMotion = mouseMotionState{}
+	mouseBtnMap = make(map[int]mouseBtnState)
+	keyMap      = make(map[sdl.Keycode]keyState)
+
+	isQuitRequested    bool
+	isMouseCaptured    bool
+	isKeyboardCaptured bool
 )
 
-func EventLoopStart() {
+func EventLoopStart(mouseGotCaptured, keyboardGotCaptured bool) {
 
-	for _, v := range keyMap {
+	isMouseCaptured = mouseGotCaptured
+	isKeyboardCaptured = keyboardGotCaptured
+
+	// Update per-frame state
+	for k, v := range keyMap {
 		v.IsPressedThisFrame = false
 		v.IsReleasedThisFrame = false
+		keyMap[k] = v
 	}
 
-	for _, v := range mouseBtnMap {
+	for k, v := range mouseBtnMap {
 		v.IsPressedThisFrame = false
 		v.IsReleasedThisFrame = false
 		v.IsDoubleClicked = false
+		mouseBtnMap[k] = v
 	}
 
 	mouseMotion.XDelta = 0
@@ -57,42 +83,62 @@ func EventLoopStart() {
 	mouseWheel.XDelta = 0
 	mouseWheel.YDelta = 0
 
-	quitRequested = false
+	isQuitRequested = false
+}
+
+func ClearKeyboardState() {
+	clear(keyMap)
+}
+
+func ClearMouseState() {
+	clear(mouseBtnMap)
+	mouseMotion = mouseMotionState{}
+	mouseWheel = mouseWheelState{}
 }
 
 func HandleQuitEvent(e *sdl.QuitEvent) {
-	quitRequested = true
+	isQuitRequested = true
+}
+
+func IsMouseCaptured() bool {
+	return isMouseCaptured
+}
+
+func IsKeyboardCaptured() bool {
+	return isKeyboardCaptured
 }
 
 func IsQuitClicked() bool {
-	return quitRequested
+	return isQuitRequested
 }
 
 func HandleKeyboardEvent(e *sdl.KeyboardEvent) {
 
-	ks := keyMap[e.Keysym.Sym]
-	if ks == nil {
-		ks = &keyState{Key: e.Keysym.Sym}
-		keyMap[ks.Key] = ks
+	ks, ok := keyMap[e.Keysym.Sym]
+	if !ok {
+		ks = keyState{Key: e.Keysym.Sym}
 	}
 
 	ks.State = int(e.State)
 	ks.IsPressedThisFrame = e.State == sdl.PRESSED && e.Repeat == 0
 	ks.IsReleasedThisFrame = e.State == sdl.RELEASED && e.Repeat == 0
+
+	keyMap[ks.Key] = ks
 }
 
 func HandleMouseBtnEvent(e *sdl.MouseButtonEvent) {
 
-	mb := mouseBtnMap[int(e.Button)]
-	if mb == nil {
-		mb = &mouseBtnState{Btn: int(e.Button)}
-		mouseBtnMap[int(e.Button)] = mb
+	mb, ok := mouseBtnMap[int(e.Button)]
+	if !ok {
+		mb = mouseBtnState{Btn: int(e.Button)}
 	}
 
 	mb.State = int(e.State)
 	mb.IsDoubleClicked = e.Clicks == 2 && e.State == sdl.PRESSED
 	mb.IsPressedThisFrame = e.State == sdl.PRESSED
 	mb.IsReleasedThisFrame = e.State == sdl.RELEASED
+
+	mouseBtnMap[int(e.Button)] = mb
 }
 
 func HandleMouseMotionEvent(e *sdl.MouseMotionEvent) {
@@ -109,18 +155,36 @@ func HandleMouseWheelEvent(e *sdl.MouseWheelEvent) {
 	mouseWheel.YDelta = e.Y
 }
 
-//GetMousePos returns the window coordinates of the mouse
+// GetMousePos returns the window coordinates of the mouse regardless of whether the mouse is captured or not
 func GetMousePos() (x, y int32) {
 	return mouseMotion.XPos, mouseMotion.YPos
 }
 
-//GetMouseMotion returns how many pixels were moved last frame
+// GetMouseMotion returns how many pixels were moved last frame
 func GetMouseMotion() (xDelta, yDelta int32) {
+
+	if isMouseCaptured {
+		return 0, 0
+	}
+
+	return GetMouseMotionCaptured()
+}
+
+func GetMouseMotionCaptured() (xDelta, yDelta int32) {
 	return mouseMotion.XDelta, mouseMotion.YDelta
 }
 
 func GetMouseMotionNorm() (xDelta, yDelta int32) {
 
+	if isMouseCaptured {
+		return 0, 0
+	}
+
+	return GetMouseMotionNormCaptured()
+}
+
+func GetMouseMotionNormCaptured() (xDelta, yDelta int32) {
+
 	x, y := mouseMotion.XDelta, mouseMotion.YDelta
 	if x > 0 {
 		x = 1
@@ -138,12 +202,31 @@ func GetMouseMotionNorm() (xDelta, yDelta int32) {
 }
 
 func GetMouseWheelMotion() (xDelta, yDelta int32) {
+
+	if isMouseCaptured {
+		return 0, 0
+	}
+
+	return GetMouseWheelMotionCaptured()
+}
+
+func GetMouseWheelMotionCaptured() (xDelta, yDelta int32) {
 	return mouseWheel.XDelta, mouseWheel.YDelta
 }
 
-//GetMouseWheelXNorm returns 1 if mouse wheel xDelta > 0, -1 if xDelta < 0, and 0 otherwise
+// GetMouseWheelXNorm returns 1 if mouse wheel xDelta > 0, -1 if xDelta < 0, and 0 otherwise
 func GetMouseWheelXNorm() int32 {
 
+	if isMouseCaptured {
+		return 0
+	}
+
+	return GetMouseWheelXNormCaptured()
+}
+
+// GetMouseWheelXNormCaptured returns 1 if mouse wheel xDelta > 0, -1 if xDelta < 0, and 0 otherwise
+func GetMouseWheelXNormCaptured() int32 {
+
 	if mouseWheel.XDelta > 0 {
 		return 1
 	} else if mouseWheel.XDelta < 0 {
@@ -153,9 +236,19 @@ func GetMouseWheelXNorm() int32 {
 	return 0
 }
 
-//returns 1 if mouse wheel yDelta > 0, -1 if yDelta < 0, and 0 otherwise
+// GetMouseWheelYNorm returns 1 if mouse wheel yDelta > 0, -1 if yDelta < 0, and 0 otherwise
 func GetMouseWheelYNorm() int32 {
 
+	if isMouseCaptured {
+		return 0
+	}
+
+	return GetMouseWheelYNormCaptured()
+}
+
+// GetMouseWheelYNormCaptured returns 1 if mouse wheel yDelta > 0, -1 if yDelta < 0, and 0 otherwise
+func GetMouseWheelYNormCaptured() int32 {
+
 	if mouseWheel.YDelta > 0 {
 		return 1
 	} else if mouseWheel.YDelta < 0 {
@@ -167,8 +260,17 @@ func GetMouseWheelYNorm() int32 {
 
 func KeyClicked(kc sdl.Keycode) bool {
 
-	ks := keyMap[kc]
-	if ks == nil {
+	if isKeyboardCaptured {
+		return false
+	}
+
+	return KeyClickedCaptured(kc)
+}
+
+func KeyClickedCaptured(kc sdl.Keycode) bool {
+
+	ks, ok := keyMap[kc]
+	if !ok {
 		return false
 	}
 
@@ -177,8 +279,17 @@ func KeyClicked(kc sdl.Keycode) bool {
 
 func KeyReleased(kc sdl.Keycode) bool {
 
-	ks := keyMap[kc]
-	if ks == nil {
+	if isKeyboardCaptured {
+		return false
+	}
+
+	return KeyReleasedCaptured(kc)
+}
+
+func KeyReleasedCaptured(kc sdl.Keycode) bool {
+
+	ks, ok := keyMap[kc]
+	if !ok {
 		return false
 	}
 
@@ -187,8 +298,17 @@ func KeyReleased(kc sdl.Keycode) bool {
 
 func KeyDown(kc sdl.Keycode) bool {
 
-	ks := keyMap[kc]
-	if ks == nil {
+	if isKeyboardCaptured {
+		return false
+	}
+
+	return KeyDownCaptured(kc)
+}
+
+func KeyDownCaptured(kc sdl.Keycode) bool {
+
+	ks, ok := keyMap[kc]
+	if !ok {
 		return false
 	}
 
@@ -197,8 +317,17 @@ func KeyDown(kc sdl.Keycode) bool {
 
 func KeyUp(kc sdl.Keycode) bool {
 
-	ks := keyMap[kc]
-	if ks == nil {
+	if isKeyboardCaptured {
+		return false
+	}
+
+	return KeyUpCaptured(kc)
+}
+
+func KeyUpCaptured(kc sdl.Keycode) bool {
+
+	ks, ok := keyMap[kc]
+	if !ok {
 		return true
 	}
 
@@ -207,8 +336,17 @@ func KeyUp(kc sdl.Keycode) bool {
 
 func MouseClicked(mb int) bool {
 
-	btn := mouseBtnMap[mb]
-	if btn == nil {
+	if isMouseCaptured {
+		return false
+	}
+
+	return MouseClickedCaptued(mb)
+}
+
+func MouseClickedCaptued(mb int) bool {
+
+	btn, ok := mouseBtnMap[mb]
+	if !ok {
 		return false
 	}
 
@@ -217,8 +355,17 @@ func MouseClicked(mb int) bool {
 
 func MouseDoubleClicked(mb int) bool {
 
-	btn := mouseBtnMap[mb]
-	if btn == nil {
+	if isMouseCaptured {
+		return false
+	}
+
+	return MouseDoubleClickedCaptured(mb)
+}
+
+func MouseDoubleClickedCaptured(mb int) bool {
+
+	btn, ok := mouseBtnMap[mb]
+	if !ok {
 		return false
 	}
 
@@ -226,8 +373,18 @@ func MouseDoubleClicked(mb int) bool {
 }
 
 func MouseReleased(mb int) bool {
-	btn := mouseBtnMap[mb]
-	if btn == nil {
+
+	if isMouseCaptured {
+		return false
+	}
+
+	return MouseReleasedCaptured(mb)
+}
+
+func MouseReleasedCaptured(mb int) bool {
+
+	btn, ok := mouseBtnMap[mb]
+	if !ok {
 		return false
 	}
 
@@ -236,8 +393,17 @@ func MouseReleased(mb int) bool {
 
 func MouseDown(mb int) bool {
 
-	btn := mouseBtnMap[mb]
-	if btn == nil {
+	if isMouseCaptured {
+		return false
+	}
+
+	return MouseDownCaptued(mb)
+}
+
+func MouseDownCaptued(mb int) bool {
+
+	btn, ok := mouseBtnMap[mb]
+	if !ok {
 		return false
 	}
 
@@ -246,8 +412,17 @@ func MouseDown(mb int) bool {
 
 func MouseUp(mb int) bool {
 
-	btn := mouseBtnMap[mb]
-	if btn == nil {
+	if isMouseCaptured {
+		return false
+	}
+
+	return MouseUpCaptured(mb)
+}
+
+func MouseUpCaptured(mb int) bool {
+
+	btn, ok := mouseBtnMap[mb]
+	if !ok {
 		return true
 	}
 

materials/material.go

@@ -8,30 +8,92 @@ import (
 	"github.com/go-gl/gl/v4.1-core/gl"
 )
 
+type TextureSlot uint32
+
+const (
+	TextureSlot_Diffuse          TextureSlot = 0
+	TextureSlot_Specular         TextureSlot = 1
+	TextureSlot_Normal           TextureSlot = 2
+	TextureSlot_Emission         TextureSlot = 3
+	TextureSlot_Cubemap          TextureSlot = 10
+	TextureSlot_Cubemap_Array    TextureSlot = 11
+	TextureSlot_ShadowMap1       TextureSlot = 12
+	TextureSlot_ShadowMap_Array1 TextureSlot = 13
+)
+
 type Material struct {
 	Name       string
 	ShaderProg shaders.ShaderProgram
 
-	DiffuseTex uint32
-
 	UnifLocs   map[string]int32
 	AttribLocs map[string]int32
+
+	// @TODO do this in a better way. Perhaps something like how we do fbo attachments
+	// Phong shading
+	DiffuseTex  uint32
+	SpecularTex uint32
+	NormalTex   uint32
+	EmissionTex uint32
+
+	// Shininess of specular highlights
+	Shininess float32
+
+	// Cubemaps
+	CubemapTex      uint32
+	CubemapArrayTex uint32
+
+	// Shadowmaps
+	ShadowMapTex1      uint32
+	ShadowMapTexArray1 uint32
 }
 
 func (m *Material) Bind() {
 
-	gl.UseProgram(m.ShaderProg.ID)
+	m.ShaderProg.Bind()
 
-	gl.ActiveTexture(gl.TEXTURE0)
-	gl.BindTexture(gl.TEXTURE_2D, m.DiffuseTex)
+	if m.DiffuseTex != 0 {
+		gl.ActiveTexture(uint32(gl.TEXTURE0 + TextureSlot_Diffuse))
+		gl.BindTexture(gl.TEXTURE_2D, m.DiffuseTex)
+	}
+
+	if m.SpecularTex != 0 {
+		gl.ActiveTexture(uint32(gl.TEXTURE0 + TextureSlot_Specular))
+		gl.BindTexture(gl.TEXTURE_2D, m.SpecularTex)
+	}
+
+	if m.NormalTex != 0 {
+		gl.ActiveTexture(uint32(gl.TEXTURE0 + TextureSlot_Normal))
+		gl.BindTexture(gl.TEXTURE_2D, m.NormalTex)
+	}
+
+	if m.EmissionTex != 0 {
+		gl.ActiveTexture(uint32(gl.TEXTURE0 + TextureSlot_Emission))
+		gl.BindTexture(gl.TEXTURE_2D, m.EmissionTex)
+	}
+
+	if m.CubemapTex != 0 {
+		gl.ActiveTexture(uint32(gl.TEXTURE0 + TextureSlot_Cubemap))
+		gl.BindTexture(gl.TEXTURE_CUBE_MAP, m.CubemapTex)
+	}
+
+	if m.CubemapArrayTex != 0 {
+		gl.ActiveTexture(uint32(gl.TEXTURE0 + TextureSlot_Cubemap_Array))
+		gl.BindTexture(gl.TEXTURE_CUBE_MAP_ARRAY, m.CubemapArrayTex)
+	}
+
+	if m.ShadowMapTex1 != 0 {
+		gl.ActiveTexture(uint32(gl.TEXTURE0 + TextureSlot_ShadowMap1))
+		gl.BindTexture(gl.TEXTURE_2D, m.ShadowMapTex1)
+	}
+
+	if m.ShadowMapTexArray1 != 0 {
+		gl.ActiveTexture(uint32(gl.TEXTURE0 + TextureSlot_ShadowMap_Array1))
+		gl.BindTexture(gl.TEXTURE_2D_ARRAY, m.ShadowMapTexArray1)
+	}
 }
 
 func (m *Material) UnBind() {
 	gl.UseProgram(0)
-
-	//TODO: Should we unbind textures here? Are these two lines needed?
-	// gl.ActiveTexture(gl.TEXTURE0)
-	// gl.BindTexture(gl.TEXTURE_2D, 0)
 }
 
 func (m *Material) GetAttribLoc(attribName string) int32 {
@@ -41,7 +103,7 @@ func (m *Material) GetAttribLoc(attribName string) int32 {
 		return loc
 	}
 
-	loc = gl.GetAttribLocation(m.ShaderProg.ID, gl.Str(attribName+"\x00"))
+	loc = gl.GetAttribLocation(m.ShaderProg.Id, gl.Str(attribName+"\x00"))
 	assert.T(loc != -1, "Attribute '"+attribName+"' doesn't exist on material "+m.Name)
 	m.AttribLocs[attribName] = loc
 	return loc
@@ -54,7 +116,7 @@ func (m *Material) GetUnifLoc(uniformName string) int32 {
 		return loc
 	}
 
-	loc = gl.GetUniformLocation(m.ShaderProg.ID, gl.Str(uniformName+"\x00"))
+	loc = gl.GetUniformLocation(m.ShaderProg.Id, gl.Str(uniformName+"\x00"))
 	assert.T(loc != -1, "Uniform '"+uniformName+"' doesn't exist on material "+m.Name)
 	m.UnifLocs[uniformName] = loc
 	return loc
@@ -69,46 +131,46 @@ func (m *Material) DisableAttribute(attribName string) {
 }
 
 func (m *Material) SetUnifInt32(uniformName string, val int32) {
-	gl.ProgramUniform1i(m.ShaderProg.ID, m.GetUnifLoc(uniformName), val)
+	gl.ProgramUniform1i(m.ShaderProg.Id, m.GetUnifLoc(uniformName), val)
 }
 
 func (m *Material) SetUnifFloat32(uniformName string, val float32) {
-	gl.ProgramUniform1f(m.ShaderProg.ID, m.GetUnifLoc(uniformName), val)
+	gl.ProgramUniform1f(m.ShaderProg.Id, m.GetUnifLoc(uniformName), val)
 }
 
 func (m *Material) SetUnifVec2(uniformName string, vec2 *gglm.Vec2) {
-	gl.ProgramUniform2fv(m.ShaderProg.ID, m.GetUnifLoc(uniformName), 1, &vec2.Data[0])
+	gl.ProgramUniform2fv(m.ShaderProg.Id, m.GetUnifLoc(uniformName), 1, &vec2.Data[0])
 }
 
 func (m *Material) SetUnifVec3(uniformName string, vec3 *gglm.Vec3) {
-	gl.ProgramUniform3fv(m.ShaderProg.ID, m.GetUnifLoc(uniformName), 1, &vec3.Data[0])
+	gl.ProgramUniform3fv(m.ShaderProg.Id, m.GetUnifLoc(uniformName), 1, &vec3.Data[0])
 }
 
 func (m *Material) SetUnifVec4(uniformName string, vec4 *gglm.Vec4) {
-	gl.ProgramUniform4fv(m.ShaderProg.ID, m.GetUnifLoc(uniformName), 1, &vec4.Data[0])
+	gl.ProgramUniform4fv(m.ShaderProg.Id, m.GetUnifLoc(uniformName), 1, &vec4.Data[0])
 }
 
 func (m *Material) SetUnifMat2(uniformName string, mat2 *gglm.Mat2) {
-	gl.ProgramUniformMatrix2fv(m.ShaderProg.ID, m.GetUnifLoc(uniformName), 1, false, &mat2.Data[0][0])
+	gl.ProgramUniformMatrix2fv(m.ShaderProg.Id, m.GetUnifLoc(uniformName), 1, false, &mat2.Data[0][0])
 }
 
 func (m *Material) SetUnifMat3(uniformName string, mat3 *gglm.Mat3) {
-	gl.ProgramUniformMatrix3fv(m.ShaderProg.ID, m.GetUnifLoc(uniformName), 1, false, &mat3.Data[0][0])
+	gl.ProgramUniformMatrix3fv(m.ShaderProg.Id, m.GetUnifLoc(uniformName), 1, false, &mat3.Data[0][0])
 }
 
 func (m *Material) SetUnifMat4(uniformName string, mat4 *gglm.Mat4) {
-	gl.ProgramUniformMatrix4fv(m.ShaderProg.ID, m.GetUnifLoc(uniformName), 1, false, &mat4.Data[0][0])
+	gl.ProgramUniformMatrix4fv(m.ShaderProg.Id, m.GetUnifLoc(uniformName), 1, false, &mat4.Data[0][0])
 }
 
 func (m *Material) Delete() {
-	gl.DeleteProgram(m.ShaderProg.ID)
+	gl.DeleteProgram(m.ShaderProg.Id)
 }
 
 func NewMaterial(matName, shaderPath string) *Material {
 
 	shdrProg, err := shaders.LoadAndCompileCombinedShader(shaderPath)
 	if err != nil {
-		logging.ErrLog.Fatalln("Failed to create new material. Err: ", err)
+		logging.ErrLog.Fatalf("Failed to create new material '%s'. Err: %s\n", matName, err.Error())
 	}
 
 	return &Material{Name: matName, ShaderProg: shdrProg, UnifLocs: make(map[string]int32), AttribLocs: make(map[string]int32)}
@@ -118,7 +180,7 @@ func NewMaterialSrc(matName string, shaderSrc []byte) *Material {
 
 	shdrProg, err := shaders.LoadAndCompileCombinedShaderSrc(shaderSrc)
 	if err != nil {
-		logging.ErrLog.Fatalln("Failed to create new material. Err: ", err)
+		logging.ErrLog.Fatalf("Failed to create new material '%s'. Err: %s\n", matName, err.Error())
 	}
 
 	return &Material{Name: matName, ShaderProg: shdrProg, UnifLocs: make(map[string]int32), AttribLocs: make(map[string]int32)}

meshes/mesh.go

@@ -2,7 +2,6 @@ package meshes
 
 import (
 	"errors"
-	"fmt"
 
 	"github.com/bloeys/assimp-go/asig"
 	"github.com/bloeys/gglm/gglm"
@@ -18,7 +17,7 @@ type SubMesh struct {
 
 type Mesh struct {
 	Name      string
-	Buf       buffers.Buffer
+	Vao       buffers.VertexArray
 	SubMeshes []SubMesh
 }
 
@@ -36,21 +35,25 @@ func NewMesh(name, modelPath string, postProcessFlags asig.PostProcess) (*Mesh,
 
 	mesh := &Mesh{
 		Name:      name,
-		Buf:       buffers.NewBuffer(),
+		Vao:       buffers.NewVertexArray(),
 		SubMeshes: make([]SubMesh, 0, 1),
 	}
 
+	vbo := buffers.NewVertexBuffer()
+	ibo := buffers.NewIndexBuffer()
+
 	// Initial sizes assuming one submesh that has vertex pos+normals+texCoords, and 3 indices per face
 	var vertexBufData []float32 = make([]float32, 0, len(scene.Meshes[0].Vertices)*3*3*2)
 	var indexBufData []uint32 = make([]uint32, 0, len(scene.Meshes[0].Faces)*3)
 
+	// fmt.Printf("\nMesh %s has %d meshe(s) with first mesh having %d vertices\n", name, len(scene.Meshes), len(scene.Meshes[0].Vertices))
+
 	for i := 0; i < len(scene.Meshes); i++ {
 
 		sceneMesh := scene.Meshes[i]
 
 		if len(sceneMesh.TexCoords[0]) == 0 {
 			sceneMesh.TexCoords[0] = make([]gglm.Vec3, len(sceneMesh.Vertices))
-			println("Zeroing tex coords for submesh", i)
 		}
 
 		layoutToUse := []buffers.Element{{ElementType: buffers.DataTypeVec3}, {ElementType: buffers.DataTypeVec3}, {ElementType: buffers.DataTypeVec2}}
@@ -59,17 +62,20 @@ func NewMesh(name, modelPath string, postProcessFlags asig.PostProcess) (*Mesh,
 		}
 
 		if i == 0 {
-			mesh.Buf.SetLayout(layoutToUse...)
+			vbo.SetLayout(layoutToUse...)
 		} else {
 
-			// @NOTE: Require that all submeshes have the same vertex buffer layout
-			firstSubmeshLayout := mesh.Buf.GetLayout()
-			assert.T(len(firstSubmeshLayout) == len(layoutToUse), fmt.Sprintf("Vertex layout of submesh %d does not equal vertex layout of the first submesh. Original layout: %v; This layout: %v", i, firstSubmeshLayout, layoutToUse))
+			// @TODO @NOTE: This requirement is because we are using one VAO+VBO for all
+			// the meshes and so the buffer must have one format.
+			//
+			// If we want to allow different layouts then we can simply create one vbo per layout and put
+			// meshes of the same layout in the same vbo, and we store the index of the vbo the mesh
+			// uses in the submesh struct.
+			firstSubmeshLayout := vbo.GetLayout()
+			assert.T(len(firstSubmeshLayout) == len(layoutToUse), "Vertex layout of submesh '%d' of mesh '%s' at path '%s' does not equal vertex layout of the first submesh. Original layout: %v; This layout: %v", i, name, modelPath, firstSubmeshLayout, layoutToUse)
 
 			for i := 0; i < len(firstSubmeshLayout); i++ {
-				if firstSubmeshLayout[i].ElementType != layoutToUse[i].ElementType {
-					panic(fmt.Sprintf("Vertex layout of submesh %d does not equal vertex layout of the first submesh. Original layout: %v; This layout: %v", i, firstSubmeshLayout, layoutToUse))
-				}
+				assert.T(firstSubmeshLayout[i].ElementType == layoutToUse[i].ElementType, "Vertex layout of submesh '%d' of mesh '%s' at path '%s' does not equal vertex layout of the first submesh. Original layout: %v; This layout: %v", i, name, modelPath, firstSubmeshLayout, layoutToUse)
 			}
 		}
 
@@ -82,7 +88,7 @@ func NewMesh(name, modelPath string, postProcessFlags asig.PostProcess) (*Mesh,
 		mesh.SubMeshes = append(mesh.SubMeshes, SubMesh{
 
 			// Index of the vertex to start from (e.g. if index buffer says use vertex 5, and BaseVertex=3, the vertex used will be vertex 8)
-			BaseVertex: int32(len(vertexBufData)*4) / mesh.Buf.Stride,
+			BaseVertex: int32(len(vertexBufData)*4) / vbo.Stride,
 			// Which index (in the index buffer) to start from
 			BaseIndex: uint32(len(indexBufData)),
 			// How many indices in this submesh
@@ -93,9 +99,16 @@ func NewMesh(name, modelPath string, postProcessFlags asig.PostProcess) (*Mesh,
 		indexBufData = append(indexBufData, indices...)
 	}
 
-	// fmt.Printf("!!! Vertex count: %d; Submeshes: %+v\n", len(vertexBufData)*4/int(mesh.Buf.Stride), mesh.SubMeshes)
-	mesh.Buf.SetData(vertexBufData)
-	mesh.Buf.SetIndexBufData(indexBufData)
+	vbo.SetData(vertexBufData, buffers.BufUsage_Static)
+	ibo.SetData(indexBufData)
+
+	mesh.Vao.AddVertexBuffer(vbo)
+	mesh.Vao.SetIndexBuffer(ibo)
+
+	// This is needed so that if you load meshes one after the other the
+	// following mesh doesn't attach its vbo/ibo to this vao
+	mesh.Vao.UnBind()
+
 	return mesh, nil
 }
 
@@ -119,9 +132,9 @@ type arrToInterleave struct {
 
 func (a *arrToInterleave) get(i int) []float32 {
 
-	assert.T(len(a.V2s) == 0 || len(a.V3s) == 0, "One array should be set in arrToInterleave, but both arrays are set")
-	assert.T(len(a.V2s) == 0 || len(a.V4s) == 0, "One array should be set in arrToInterleave, but both arrays are set")
-	assert.T(len(a.V3s) == 0 || len(a.V4s) == 0, "One array should be set in arrToInterleave, but both arrays are set")
+	assert.T(len(a.V2s) == 0 || len(a.V3s) == 0, "One array should be set in arrToInterleave, but multiple arrays are set")
+	assert.T(len(a.V2s) == 0 || len(a.V4s) == 0, "One array should be set in arrToInterleave, but multiple arrays are set")
+	assert.T(len(a.V3s) == 0 || len(a.V4s) == 0, "One array should be set in arrToInterleave, but multiple arrays are set")
 
 	if len(a.V2s) > 0 {
 		return a.V2s[i].Data[:]
@@ -173,7 +186,7 @@ func interleave(arrs ...arrToInterleave) []float32 {
 
 func flattenFaces(faces []asig.Face) []uint32 {
 
-	assert.T(len(faces[0].Indices) == 3, fmt.Sprintf("Face doesn't have 3 indices. Index count: %v\n", len(faces[0].Indices)))
+	assert.T(len(faces[0].Indices) == 3, "Face doesn't have 3 indices. Index count: %v\n", len(faces[0].Indices))
 
 	uints := make([]uint32, len(faces)*3)
 	for i := 0; i < len(faces); i++ {

registry/registry.go

@@ -77,6 +77,10 @@ func (r *Registry[T]) New() (*T, Handle) {
 
 func (r *Registry[T]) Get(id Handle) *T {
 
+	if id.IsZero() {
+		return nil
+	}
+
 	index := id.Index()
 	assert.T(index < uint64(len(r.Handles)), "Failed to get entity because of invalid entity handle. Handle index is %d while registry only has %d slots. Handle: %+v", index, r.ItemCount, id)
 

registry/registry_handle.go

@@ -16,6 +16,12 @@ const (
 // Byte 1: Generation; Byte 2: Flags; Bytes 3-8: Index
 type Handle uint64
 
+// IsZero reports whether the handle is in its default 'zero' state.
+// A zero handle is an invalid handle that does NOT point to any entity
+func (h Handle) IsZero() bool {
+	return h == 0
+}
+
 func (h Handle) HasFlag(ef HandleFlag) bool {
 	return h.Flags()&ef > 0
 }

renderer/rend3dgl/rend3dgl.go

@@ -2,6 +2,7 @@ package rend3dgl
 
 import (
 	"github.com/bloeys/gglm/gglm"
+	"github.com/bloeys/nmage/buffers"
 	"github.com/bloeys/nmage/materials"
 	"github.com/bloeys/nmage/meshes"
 	"github.com/bloeys/nmage/renderer"
@@ -11,23 +12,56 @@ import (
 var _ renderer.Render = &Rend3DGL{}
 
 type Rend3DGL struct {
+	BoundVao  *buffers.VertexArray
 	BoundMesh *meshes.Mesh
 	BoundMat  *materials.Material
 }
 
-func (r3d *Rend3DGL) Draw(mesh *meshes.Mesh, trMat *gglm.TrMat, mat *materials.Material) {
+func (r *Rend3DGL) DrawMesh(mesh *meshes.Mesh, modelMat *gglm.TrMat, mat *materials.Material) {
 
-	if mesh != r3d.BoundMesh {
-		mesh.Buf.Bind()
-		r3d.BoundMesh = mesh
+	if mesh != r.BoundMesh {
+		mesh.Vao.Bind()
+		r.BoundMesh = mesh
 	}
 
-	if mat != r3d.BoundMat {
+	if mat != r.BoundMat {
 		mat.Bind()
-		r3d.BoundMat = mat
+		r.BoundMat = mat
 	}
 
-	mat.SetUnifMat4("modelMat", &trMat.Mat4)
+	mat.SetUnifMat4("modelMat", &modelMat.Mat4)
+
+	for i := 0; i < len(mesh.SubMeshes); i++ {
+		gl.DrawElementsBaseVertexWithOffset(gl.TRIANGLES, mesh.SubMeshes[i].IndexCount, gl.UNSIGNED_INT, uintptr(mesh.SubMeshes[i].BaseIndex), mesh.SubMeshes[i].BaseVertex)
+	}
+}
+
+func (r *Rend3DGL) DrawVertexArray(mat *materials.Material, vao *buffers.VertexArray, firstElement int32, elementCount int32) {
+
+	if vao != r.BoundVao {
+		vao.Bind()
+		r.BoundVao = vao
+	}
+
+	if mat != r.BoundMat {
+		mat.Bind()
+		r.BoundMat = mat
+	}
+
+	gl.DrawArrays(gl.TRIANGLES, firstElement, elementCount)
+}
+
+func (r *Rend3DGL) DrawCubemap(mesh *meshes.Mesh, mat *materials.Material) {
+
+	if mesh != r.BoundMesh {
+		mesh.Vao.Bind()
+		r.BoundMesh = mesh
+	}
+
+	if mat != r.BoundMat {
+		mat.Bind()
+		r.BoundMat = mat
+	}
 
 	for i := 0; i < len(mesh.SubMeshes); i++ {
 		gl.DrawElementsBaseVertexWithOffset(gl.TRIANGLES, mesh.SubMeshes[i].IndexCount, gl.UNSIGNED_INT, uintptr(mesh.SubMeshes[i].BaseIndex), mesh.SubMeshes[i].BaseVertex)

renderer/renderer.go

@@ -2,11 +2,14 @@ package renderer
 
 import (
 	"github.com/bloeys/gglm/gglm"
+	"github.com/bloeys/nmage/buffers"
 	"github.com/bloeys/nmage/materials"
 	"github.com/bloeys/nmage/meshes"
 )
 
 type Render interface {
-	Draw(mesh *meshes.Mesh, trMat *gglm.TrMat, mat *materials.Material)
+	DrawMesh(mesh *meshes.Mesh, trMat *gglm.TrMat, mat *materials.Material)
+	DrawVertexArray(mat *materials.Material, vao *buffers.VertexArray, firstElement int32, count int32)
+	DrawCubemap(mesh *meshes.Mesh, mat *materials.Material)
 	FrameEnd()
 }

res/shaders/array-depth-map.glsl

@@ -0,0 +1,54 @@
+//shader:vertex
+#version 410
+
+layout(location=0) in vec3 vertPosIn;
+
+uniform mat4 modelMat;
+
+void main()
+{
+    gl_Position = modelMat * vec4(vertPosIn, 1);
+}
+
+//shader:geometry
+#version 410
+
+layout (triangles) in;
+
+#define NUM_PROJ_VIEW_MATS 4
+
+// 3 * NUM_PROJ_VIEW_MATS
+layout (triangle_strip, max_vertices=12) out;
+
+// This is the same number as max spot lights or whatever else is being rendered
+uniform mat4 projViewMats[NUM_PROJ_VIEW_MATS];
+
+out vec4 FragPos;
+
+void main()
+{
+    for(int projViewMatIndex = 0; projViewMatIndex < NUM_PROJ_VIEW_MATS; projViewMatIndex++){
+
+        gl_Layer = projViewMatIndex;
+        mat4 projViewMat = projViewMats[projViewMatIndex];
+
+        for(int i = 0; i < 3; i++)
+        {
+            FragPos = gl_in[i].gl_Position;
+            gl_Position = projViewMat * FragPos;
+            EmitVertex();
+        }
+        EndPrimitive();
+    }
+}
+
+//shader:fragment
+#version 410
+
+in vec4 FragPos;
+
+void main()
+{
+    // This implicitly writes to the depth buffer with no color operations
+    // Equivalent: gl_FragDepth = gl_FragCoord.z;
+}

res/shaders/debug-depth.glsl

@@ -13,17 +13,18 @@ out vec3 fragPos;
 
 //MVP = Model View Projection
 uniform mat4 modelMat;
-uniform mat4 viewMat;
-uniform mat4 projMat;
+uniform mat4 projViewMat;
 
 void main()
 {
     vertNormal = mat3(transpose(inverse(modelMat))) * vertNormalIn;
     vertUV0 = vertUV0In;
     vertColor = vertColorIn;
-    fragPos = vec3(modelMat * vec4(vertPosIn, 1.0));
 
-    gl_Position = projMat * viewMat * modelMat * vec4(vertPosIn, 1.0);
+    vec4 modelVert = modelMat * vec4(vertPosIn, 1);
+    fragPos = modelVert.xyz;
+
+    gl_Position = projViewMat * modelVert;
 }
 
 //shader:fragment

res/shaders/depth-map.glsl

@@ -0,0 +1,21 @@
+//shader:vertex
+#version 410
+
+layout(location=0) in vec3 vertPosIn;
+
+uniform mat4 modelMat;
+uniform mat4 projViewMat;
+
+void main()
+{
+    gl_Position = projViewMat * modelMat * vec4(vertPosIn, 1);
+}
+
+//shader:fragment
+#version 410
+
+void main()
+{
+    // This implicitly writes to the depth buffer with no color operations
+    // Equivalent: gl_FragDepth = gl_FragCoord.z;
+}

res/shaders/imgui.glsl

@@ -0,0 +1,47 @@
+//shader:vertex
+#version 410
+
+uniform mat4 ProjMtx;
+
+in vec2 Position;
+in vec2 UV;
+in vec4 Color;
+
+out vec2 Frag_UV;
+out vec4 Frag_Color;
+
+// Imgui doesn't handle srgb correctly, and looks too bright and wrong in srgb buffers (see: https://github.com/ocornut/imgui/issues/578).
+// While not a complete fix (that would require changes in imgui itself), moving incoming srgba colors to linear in the vertex shader helps make things look better.
+vec4 srgba_to_linear(vec4 srgbaColor){
+
+    #define gamma_correction 2.2
+
+    return vec4(
+        pow(srgbaColor.r, gamma_correction),
+        pow(srgbaColor.g, gamma_correction),
+        pow(srgbaColor.b, gamma_correction),
+        srgbaColor.a
+    );
+}
+
+void main()
+{
+    Frag_UV = UV;
+    Frag_Color = srgba_to_linear(Color);
+    gl_Position = ProjMtx * vec4(Position.xy, 0, 1);
+}
+
+//shader:fragment
+#version 410
+
+uniform sampler2D Texture;
+
+in vec2 Frag_UV;
+in vec4 Frag_Color;
+
+out vec4 Out_Color;
+
+void main()
+{
+    Out_Color = vec4(Frag_Color.rgb, Frag_Color.a * texture(Texture, Frag_UV.st).r);
+}

res/shaders/omnidirectional-depth-map.glsl

@@ -0,0 +1,65 @@
+//shader:vertex
+#version 410
+
+layout(location=0) in vec3 vertPosIn;
+
+uniform mat4 modelMat;
+
+void main()
+{
+    gl_Position = modelMat * vec4(vertPosIn, 1);
+}
+
+//shader:geometry
+#version 410
+
+layout (triangles) in;
+
+// Cubemap means 6 faces, and the
+// input 3 triangle vertices are drawn once per face, so 6*3=18
+layout (triangle_strip, max_vertices=18) out;
+
+uniform int cubemapIndex;
+uniform mat4 cubemapProjViewMats[6];
+
+out vec4 FragPos;
+
+void main()
+{
+    for(int face = 0; face < 6; ++face)
+    {
+        // Built in variable that specifies which cubemap face we are rendering to
+        // and only works when a cubemap is attached to the active fbo.
+        //
+        // We use an additional index here because our fbo has a cubemap array
+        gl_Layer = (cubemapIndex * 6) + face;
+
+        // Transform each triangle vertex
+        for(int i = 0; i < 3; ++i)
+        {
+            FragPos = gl_in[i].gl_Position;
+            gl_Position = cubemapProjViewMats[face] * FragPos;
+            EmitVertex();
+        }
+        EndPrimitive();
+    }
+}
+
+//shader:fragment
+#version 410
+
+in vec4 FragPos;
+
+uniform vec3 lightPos;
+uniform float farPlane;
+
+void main()
+{
+    // Get distance between fragment and light source
+    float lightDistance = length(FragPos.xyz - lightPos);
+
+    // Map to [0, 1] by dividing by far plane and use it as our depth
+    lightDistance = lightDistance / farPlane;
+
+    gl_FragDepth = lightDistance;
+}

res/shaders/screen-quad.glsl

@@ -0,0 +1,45 @@
+//shader:vertex
+#version 410
+
+out vec2 vertUV0;
+
+// Hardcoded vertex positions for a fullscreen quad.
+// Format: vec4(pos.x, pos.y, uv0.x, uv0.y)
+vec4 quadData[6] = vec4[](
+    vec4(-1.0,  1.0, 0.0, 1.0),
+    vec4(-1.0, -1.0, 0.0, 0.0),
+    vec4(1.0, -1.0, 1.0, 0.0),
+    vec4(-1.0,  1.0, 0.0, 1.0),
+    vec4(1.0, -1.0, 1.0, 0.0),
+    vec4(1.0,  1.0, 1.0, 1.0)
+);
+
+uniform vec2 scale = vec2(1, 1);
+uniform vec2 offset = vec2(0, 0);
+
+void main()
+{
+    vec4 vertData = quadData[gl_VertexID];
+
+    vertUV0 = vertData.zw;
+    gl_Position = vec4((vertData.xy * scale) + offset, 0.0, 1.0);
+}
+
+//shader:fragment
+#version 410
+
+struct Material {
+    sampler2D diffuse;
+};
+
+uniform Material material;
+
+in vec2 vertUV0;
+
+out vec4 fragColor;
+
+void main()
+{
+    vec4 diffuseTexColor = texture(material.diffuse, vertUV0);
+    fragColor = vec4(diffuseTexColor.rgb, 1);
+}

res/shaders/simple-unlit.glsl

@@ -0,0 +1,54 @@
+//shader:vertex
+#version 410
+
+layout(location=0) in vec3 vertPosIn;
+layout(location=1) in vec3 vertNormalIn;
+layout(location=2) in vec2 vertUV0In;
+layout(location=3) in vec3 vertColorIn;
+
+out vec3 vertNormal;
+out vec2 vertUV0;
+out vec3 vertColor;
+out vec3 fragPos;
+
+//MVP = Model View Projection
+uniform mat4 modelMat;
+uniform mat4 projViewMat;
+
+void main()
+{
+    // @TODO: Calculate this on the CPU and send it as a uniform
+    //
+    // This produces the normal matrix that multiplies with the model normal to produce the
+    // world space normal. Based on 'One last thing' section from: https://learnopengl.com/Lighting/Basic-Lighting
+    vertNormal = mat3(transpose(inverse(modelMat))) * vertNormalIn;
+    
+    vertUV0 = vertUV0In;
+    vertColor = vertColorIn;
+
+    vec4 modelVert = modelMat * vec4(vertPosIn, 1);
+    fragPos = modelVert.xyz;
+    gl_Position = projViewMat * modelVert;
+}
+
+//shader:fragment
+#version 410
+
+struct Material {
+    sampler2D diffuse;
+};
+
+uniform Material material;
+
+in vec3 vertColor;
+in vec3 vertNormal;
+in vec2 vertUV0;
+in vec3 fragPos;
+
+out vec4 fragColor;
+
+void main()
+{
+    vec4 diffuseTexColor = texture(material.diffuse, vertUV0);
+    fragColor = vec4(diffuseTexColor.rgb, 1);
+}

res/shaders/simple.glsl

@@ -6,50 +6,311 @@ layout(location=1) in vec3 vertNormalIn;
 layout(location=2) in vec2 vertUV0In;
 layout(location=3) in vec3 vertColorIn;
 
+uniform mat4 modelMat;
+uniform mat4 projViewMat;
+uniform mat4 dirLightProjViewMat;
+
+#define NUM_SPOT_LIGHTS 4
+uniform mat4 spotLightProjViewMats[NUM_SPOT_LIGHTS];
+
 out vec3 vertNormal;
 out vec2 vertUV0;
 out vec3 vertColor;
 out vec3 fragPos;
-
-//MVP = Model View Projection
-uniform mat4 modelMat;
-uniform mat4 viewMat;
-uniform mat4 projMat;
+out vec4 fragPosDirLight;
+out vec4 fragPosSpotLight[NUM_SPOT_LIGHTS];
 
 void main()
 {
+    // @TODO: Calculate this on the CPU and send it as a uniform
+    //
+    // This produces the normal matrix that multiplies with the model normal to produce the
+    // world space normal. Based on 'One last thing' section from: https://learnopengl.com/Lighting/Basic-Lighting
     vertNormal = mat3(transpose(inverse(modelMat))) * vertNormalIn;
+    
     vertUV0 = vertUV0In;
     vertColor = vertColorIn;
-    fragPos = vec3(modelMat * vec4(vertPosIn, 1.0));
 
-    gl_Position = projMat * viewMat * modelMat * vec4(vertPosIn, 1.0);
+    vec4 modelVert = modelMat * vec4(vertPosIn, 1);
+    fragPos = modelVert.xyz;
+    fragPosDirLight = dirLightProjViewMat * vec4(fragPos, 1);
+
+    for (int i = 0; i < NUM_SPOT_LIGHTS; i++)
+        fragPosSpotLight[i] = spotLightProjViewMats[i] * vec4(fragPos, 1);
+
+    gl_Position = projViewMat * modelVert;
 }
 
 //shader:fragment
 #version 410
 
-uniform float ambientStrength = 0;
-uniform vec3 ambientLightColor = vec3(1, 1, 1);
+struct Material {
+    sampler2D diffuse;
+    sampler2D specular;
+    // sampler2D normal;
+    sampler2D emission;
+    float shininess;
+};
 
-uniform vec3 lightPos1;
-uniform vec3 lightColor1;
+uniform Material material;
 
-uniform sampler2D diffTex;
+struct DirLight {
+    vec3 dir;
+    vec3 diffuseColor;
+    vec3 specularColor;
+    sampler2D shadowMap;
+};
+
+uniform DirLight dirLight;
+
+struct PointLight {
+    vec3 pos;
+    vec3 diffuseColor;
+    vec3 specularColor;
+    float constant;
+    float linear;
+    float quadratic;
+    float farPlane;
+};
+
+#define NUM_POINT_LIGHTS 8
+uniform PointLight pointLights[NUM_POINT_LIGHTS];
+uniform samplerCubeArray pointLightCubeShadowMaps;
+
+struct SpotLight {
+    vec3 pos;
+    vec3 dir;
+    vec3 diffuseColor;
+    vec3 specularColor;
+    float innerCutoff;
+    float outerCutoff;
+};
+
+#define NUM_SPOT_LIGHTS 4
+uniform SpotLight spotLights[NUM_SPOT_LIGHTS];
+uniform sampler2DArray spotLightShadowMaps;
+
+uniform vec3 camPos;
+uniform vec3 ambientColor = vec3(0.2, 0.2, 0.2);
 
 in vec3 vertColor;
 in vec3 vertNormal;
 in vec2 vertUV0;
 in vec3 fragPos;
+in vec4 fragPosDirLight;
+in vec4 fragPosSpotLight[NUM_SPOT_LIGHTS];
 
 out vec4 fragColor;
 
+// Global variables used as cache for lighting calculations
+vec4 diffuseTexColor;
+vec4 specularTexColor;
+vec4 emissionTexColor;
+vec3 normalizedVertNorm;
+vec3 viewDir;
+
+float CalcDirShadow(sampler2D shadowMap, vec3 lightDir)
+{
+    // Move from clip space to NDC
+    vec3 projCoords = fragPosDirLight.xyz / fragPosDirLight.w;
+
+    // Move from [-1,1] to [0, 1]
+    projCoords = projCoords * 0.5 + 0.5;
+
+    // If sampling outside the depth texture then force 'no shadow'
+    if(projCoords.z > 1)
+        return 0;
+
+    // currentDepth is the fragment depth from the light's perspective
+    float currentDepth = projCoords.z;
+
+    // Bias in the range [0.005, 0.05] depending on the angle, where a higher
+    // angle gives a higher bias, as shadow acne gets worse with angle
+    float bias = max(0.05 * (1 - dot(normalizedVertNorm, lightDir)), 0.005);
+
+    // 'Percentage Close Filtering'.
+    // Basically get soft shadows by averaging this texel and surrounding ones
+    float shadow = 0;
+    vec2 texelSize = 1 / textureSize(shadowMap, 0);
+    for(int x = -1; x <= 1; x++)
+    {
+        for(int y = -1; y <= 1; y++)
+        {
+            float pcfDepth = texture(shadowMap, projCoords.xy + vec2(x, y) * texelSize).r; 
+
+            // If our depth is larger than the lights closest depth at the texel we checked (projCoords),
+            // then there is something closer to the light than us, and so we are in shadow
+            shadow += currentDepth - bias > pcfDepth ? 1 : 0;
+        }
+    }
+
+    shadow /= 9;
+
+    return shadow;
+}
+
+vec3 CalcDirLight()
+{
+    vec3 lightDir = normalize(-dirLight.dir);
+
+    // Diffuse
+    float diffuseAmount = max(0.0, dot(normalizedVertNorm, lightDir));
+    vec3 finalDiffuse = diffuseAmount * dirLight.diffuseColor * diffuseTexColor.rgb;
+
+    // Specular
+    vec3 halfwayDir = normalize(lightDir + viewDir);
+    float specularAmount = pow(max(dot(normalizedVertNorm, halfwayDir), 0.0), material.shininess);
+    vec3 finalSpecular = specularAmount * dirLight.specularColor * specularTexColor.rgb;
+
+    // Shadow
+    float shadow = CalcDirShadow(dirLight.shadowMap, lightDir);
+
+    return (finalDiffuse + finalSpecular) * (1 - shadow);
+}
+
+float CalcPointShadow(int lightIndex, vec3 lightPos, vec3 lightDir, float farPlane) {
+
+    vec3 lightToFrag = fragPos - lightPos;
+
+    float closestDepth = texture(pointLightCubeShadowMaps, vec4(lightToFrag, lightIndex)).r;
+
+    // We stored depth in the cubemap in the range [0, 1], so now we move back to [0, farPlane]
+    closestDepth *= farPlane;
+
+    // Get depth of current fragment
+    float currentDepth = length(lightToFrag);
+
+    float bias = max(0.05 * (1 - dot(normalizedVertNorm, lightDir)), 0.005);
+    float shadow = currentDepth -  bias > closestDepth ? 1.0 : 0.0;
+
+    return shadow;
+}
+
+vec3 CalcPointLight(PointLight pointLight, int lightIndex)
+{
+    // Ignore unset lights
+    if (pointLight.constant == 0){
+        return vec3(0);
+    }
+
+    vec3 lightDir = normalize(pointLight.pos - fragPos);
+
+    // Diffuse
+    float diffuseAmount = max(0.0, dot(normalizedVertNorm, lightDir));
+    vec3 finalDiffuse = diffuseAmount * pointLight.diffuseColor * diffuseTexColor.rgb;
+
+    // Specular
+    vec3 halfwayDir = normalize(lightDir + viewDir);
+    float specularAmount = pow(max(dot(normalizedVertNorm, halfwayDir), 0.0), material.shininess);
+    vec3 finalSpecular = specularAmount * pointLight.specularColor * specularTexColor.rgb;
+
+    // Attenuation
+    float distToLight = length(pointLight.pos - fragPos);
+    float attenuation = 1 / (pointLight.constant + pointLight.linear * distToLight + pointLight.quadratic * (distToLight * distToLight));  
+
+    // Shadow
+    float shadow = CalcPointShadow(lightIndex, pointLight.pos, lightDir, pointLight.farPlane);
+
+    return (finalDiffuse + finalSpecular) * attenuation * (1 - shadow);
+}
+
+float CalcSpotShadow(vec3 lightDir, int lightIndex)
+{
+    // Move from clip space to NDC
+    vec3 projCoords = fragPosSpotLight[lightIndex].xyz / fragPosSpotLight[lightIndex].w;
+
+    // Move from [-1,1] to [0, 1]
+    projCoords = projCoords * 0.5 + 0.5;
+
+    // If sampling outside the depth texture then force 'no shadow'
+    if(projCoords.z > 1)
+        return 0;
+
+    // currentDepth is the fragment depth from the light's perspective
+    float currentDepth = projCoords.z;
+
+    // Bias in the range [0.005, 0.05] depending on the angle, where a higher
+    // angle gives a higher bias, as shadow acne gets worse with angle
+    float bias = max(0.05 * (1 - dot(normalizedVertNorm, lightDir)), 0.005);
+
+    // 'Percentage Close Filtering'.
+    // Basically get soft shadows by averaging this texel and surrounding ones
+    float shadow = 0;
+    vec2 texelSize = 1 / textureSize(spotLightShadowMaps, 0).xy;
+    for(int x = -1; x <= 1; x++)
+    {
+        for(int y = -1; y <= 1; y++)
+        {
+            float pcfDepth = texture(spotLightShadowMaps, vec3(projCoords.xy + vec2(x, y) * texelSize, lightIndex)).r; 
+
+            // If our depth is larger than the lights closest depth at the texel we checked (projCoords),
+            // then there is something closer to the light than us, and so we are in shadow
+            shadow += currentDepth - bias > pcfDepth ? 1 : 0;
+        }
+    }
+
+    shadow /= 9;
+
+    return shadow;
+}
+
+vec3 CalcSpotLight(SpotLight light, int lightIndex)
+{
+    if (light.innerCutoff == 0)
+        return vec3(0);
+
+    vec3 fragToLightDir = normalize(light.pos - fragPos);
+
+    // Spot light cone with full intensity within inner cutoff,
+    // and falloff between inner-outer cutoffs, and zero
+    // light after outer cutoff
+    float theta = dot(fragToLightDir, normalize(-light.dir));
+    float epsilon = (light.innerCutoff - light.outerCutoff);
+    float intensity = clamp((theta - light.outerCutoff) / epsilon, float(0), float(1));
+
+    if (intensity == 0)
+        return vec3(0);
+
+    // Diffuse
+    float diffuseAmount = max(0.0, dot(normalizedVertNorm, fragToLightDir));
+    vec3 finalDiffuse = diffuseAmount * light.diffuseColor * diffuseTexColor.rgb;
+
+    // Specular
+    vec3 halfwayDir = normalize(fragToLightDir + viewDir);
+    float specularAmount = pow(max(dot(normalizedVertNorm, halfwayDir), 0.0), material.shininess);
+    vec3 finalSpecular = specularAmount * light.specularColor * specularTexColor.rgb;
+
+    // Shadow
+    float shadow = CalcSpotShadow(fragToLightDir, lightIndex);
+
+    return (finalDiffuse + finalSpecular) * intensity * (1 - shadow);
+}
+
 void main()
 {
-    vec3 lightDir = normalize(lightPos1 - fragPos);  
-    float diffStrength = max(0.0, dot(normalize(vertNormal), lightDir));
+    // Shared values
+    diffuseTexColor = texture(material.diffuse, vertUV0);
+    specularTexColor = texture(material.specular, vertUV0);
+    emissionTexColor = texture(material.emission, vertUV0);
 
-    vec3 finalAmbientColor = ambientLightColor * ambientStrength;
-    vec4 texColor = texture(diffTex, vertUV0);
-    fragColor = vec4(texColor.rgb * vertColor * (finalAmbientColor + diffStrength*lightColor1) , texColor.a);
-} 
+    normalizedVertNorm = normalize(vertNormal);
+    viewDir = normalize(camPos - fragPos);
+
+    // Light contributions
+    vec3 finalColor = CalcDirLight();
+
+    for (int i = 0; i < NUM_POINT_LIGHTS; i++)
+    {
+        finalColor += CalcPointLight(pointLights[i], i);
+    }
+
+    for (int i = 0; i < NUM_SPOT_LIGHTS; i++)
+    {
+        finalColor += CalcSpotLight(spotLights[i], i);
+    }
+
+    vec3 finalEmission = emissionTexColor.rgb;
+    vec3 finalAmbient = ambientColor * diffuseTexColor.rgb;
+
+    fragColor = vec4(finalColor + finalAmbient + finalEmission, 1);
+}

res/shaders/skybox.glsl

@@ -8,13 +8,12 @@ layout(location=3) in vec3 vertColorIn;
 
 out vec3 vertUV0;
 
-uniform mat4 viewMat;
-uniform mat4 projMat;
+uniform mat4 projViewMat;
 
 void main()
 {
     vertUV0 = vec3(vertPosIn.x, vertPosIn.y, -vertPosIn.z);
-    vec4 pos = projMat * viewMat * vec4(vertPosIn, 1.0);
+    vec4 pos = projViewMat * vec4(vertPosIn, 1.0);
     gl_Position = pos.xyww;
 }
 

shaders/shader_program.go

@@ -6,32 +6,48 @@ import (
 )
 
 type ShaderProgram struct {
-	ID           uint32
-	VertShaderID uint32
-	FragShaderID uint32
+	Id           uint32
+	VertShaderId uint32
+	FragShaderId uint32
+	GeomShaderId uint32
 }
 
 func (sp *ShaderProgram) AttachShader(shader Shader) {
 
-	gl.AttachShader(sp.ID, shader.ID)
-	switch shader.ShaderType {
-	case VertexShaderType:
-		sp.VertShaderID = shader.ID
-	case FragmentShaderType:
-		sp.FragShaderID = shader.ID
+	gl.AttachShader(sp.Id, shader.Id)
+	switch shader.Type {
+	case ShaderType_Vertex:
+		sp.VertShaderId = shader.Id
+	case ShaderType_Fragment:
+		sp.FragShaderId = shader.Id
+	case ShaderType_Geometry:
+		sp.GeomShaderId = shader.Id
 	default:
-		logging.ErrLog.Println("Unknown shader type ", shader.ShaderType, " for ID ", shader.ID)
+		logging.ErrLog.Fatalf("Unknown shader type '%d' for shader id '%d'\n", shader.Type, shader.Id)
 	}
 }
 
 func (sp *ShaderProgram) Link() {
 
-	gl.LinkProgram(sp.ID)
+	gl.LinkProgram(sp.Id)
 
-	if sp.VertShaderID != 0 {
-		gl.DeleteShader(sp.VertShaderID)
+	if sp.VertShaderId != 0 {
+		gl.DeleteShader(sp.VertShaderId)
 	}
-	if sp.FragShaderID != 0 {
-		gl.DeleteShader(sp.FragShaderID)
+
+	if sp.FragShaderId != 0 {
+		gl.DeleteShader(sp.FragShaderId)
+	}
+
+	if sp.GeomShaderId != 0 {
+		gl.DeleteShader(sp.GeomShaderId)
 	}
 }
+
+func (s *ShaderProgram) Bind() {
+	gl.UseProgram(s.Id)
+}
+
+func (s *ShaderProgram) UnBind() {
+	gl.UseProgram(0)
+}

shaders/shader_types.go

@@ -1,10 +1,31 @@
 package shaders
 
-import "github.com/go-gl/gl/v4.1-core/gl"
+import (
+	"github.com/bloeys/nmage/logging"
+	"github.com/go-gl/gl/v4.1-core/gl"
+)
 
-type ShaderType int
+type ShaderType int32
+
+func (s ShaderType) ToGl() uint32 {
+
+	switch s {
+	case ShaderType_Vertex:
+		return gl.VERTEX_SHADER
+	case ShaderType_Fragment:
+		return gl.FRAGMENT_SHADER
+	case ShaderType_Geometry:
+		return gl.GEOMETRY_SHADER
+
+	default:
+		logging.ErrLog.Fatalf("Unknown shader type '%d'\n", s)
+		return 0
+	}
+}
 
 const (
-	VertexShaderType   ShaderType = gl.VERTEX_SHADER
-	FragmentShaderType ShaderType = gl.FRAGMENT_SHADER
+	ShaderType_Unknown ShaderType = iota
+	ShaderType_Vertex
+	ShaderType_Fragment
+	ShaderType_Geometry
 )

shaders/shaders.go

@@ -3,6 +3,7 @@ package shaders
 import (
 	"bytes"
 	"errors"
+	"fmt"
 	"os"
 	"strings"
 
@@ -11,12 +12,13 @@ import (
 )
 
 type Shader struct {
-	ID         uint32
-	ShaderType ShaderType
+	Id   uint32
+	Type ShaderType
 }
 
-func (s Shader) Delete() {
-	gl.DeleteShader(s.ID)
+func (s *Shader) Delete() {
+	gl.DeleteShader(s.Id)
+	s.Id = 0
 }
 
 func NewShaderProgram() (ShaderProgram, error) {
@@ -26,7 +28,7 @@ func NewShaderProgram() (ShaderProgram, error) {
 		return ShaderProgram{}, errors.New("failed to create shader program")
 	}
 
-	return ShaderProgram{ID: id}, nil
+	return ShaderProgram{Id: id}, nil
 }
 
 func LoadAndCompileCombinedShader(shaderPath string) (ShaderProgram, error) {
@@ -43,8 +45,8 @@ func LoadAndCompileCombinedShader(shaderPath string) (ShaderProgram, error) {
 func LoadAndCompileCombinedShaderSrc(shaderSrc []byte) (ShaderProgram, error) {
 
 	shaderSources := bytes.Split(shaderSrc, []byte("//shader:"))
-	if len(shaderSources) == 1 {
-		return ShaderProgram{}, errors.New("failed to read combined shader. Did not find '//shader:vertex' or '//shader:fragment'")
+	if len(shaderSources) < 2 {
+		return ShaderProgram{}, errors.New("failed to read combined shader. The minimum shader types to have are '//shader:vertex' and '//shader:fragment'")
 	}
 
 	shdrProg, err := NewShaderProgram()
@@ -65,12 +67,15 @@ func LoadAndCompileCombinedShaderSrc(shaderSrc []byte) (ShaderProgram, error) {
 		var shdrType ShaderType
 		if bytes.HasPrefix(src, []byte("vertex")) {
 			src = src[6:]
-			shdrType = VertexShaderType
+			shdrType = ShaderType_Vertex
 		} else if bytes.HasPrefix(src, []byte("fragment")) {
 			src = src[8:]
-			shdrType = FragmentShaderType
+			shdrType = ShaderType_Fragment
+		} else if bytes.HasPrefix(src, []byte("geometry")) {
+			src = src[8:]
+			shdrType = ShaderType_Geometry
 		} else {
-			return ShaderProgram{}, errors.New("unknown shader type. Must be '//shader:vertex' or '//shader:fragment'")
+			return ShaderProgram{}, errors.New("unknown shader type. Must be '//shader:vertex' or '//shader:fragment' or '//shader:geometry'")
 		}
 
 		shdr, err := CompileShaderOfType(src, shdrType)
@@ -83,7 +88,15 @@ func LoadAndCompileCombinedShaderSrc(shaderSrc []byte) (ShaderProgram, error) {
 	}
 
 	if loadedShdrCount == 0 {
-		return ShaderProgram{}, errors.New("no valid shaders found. Please put '//shader:vertex' or '//shader:fragment' before your shaders")
+		return ShaderProgram{}, errors.New("no valid shaders found. Please put '//shader:vertex' or '//shader:fragment' or '//shader:geometry' before your shaders")
+	}
+
+	if shdrProg.VertShaderId == 0 {
+		return ShaderProgram{}, errors.New("no valid vertex shader found. Please put '//shader:vertex' before your vertex shader")
+	}
+
+	if shdrProg.FragShaderId == 0 {
+		return ShaderProgram{}, errors.New("no valid fragment shader found. Please put '//shader:fragment' before your vertex shader")
 	}
 
 	shdrProg.Link()
@@ -92,41 +105,40 @@ func LoadAndCompileCombinedShaderSrc(shaderSrc []byte) (ShaderProgram, error) {
 
 func CompileShaderOfType(shaderSource []byte, shaderType ShaderType) (Shader, error) {
 
-	shaderID := gl.CreateShader(uint32(shaderType))
-	if shaderID == 0 {
-		logging.ErrLog.Println("Failed to create shader.")
-		return Shader{}, errors.New("failed to create shader")
+	shaderId := gl.CreateShader(shaderType.ToGl())
+	if shaderId == 0 {
+		return Shader{}, fmt.Errorf("failed to create OpenGl shader. OpenGl Error=%d", gl.GetError())
 	}
 
 	//Load shader source and compile
 	shaderCStr, shaderFree := gl.Strs(string(shaderSource) + "\x00")
 	defer shaderFree()
-	gl.ShaderSource(shaderID, 1, shaderCStr, nil)
+	gl.ShaderSource(shaderId, 1, shaderCStr, nil)
 
-	gl.CompileShader(shaderID)
-	if err := getShaderCompileErrors(shaderID); err != nil {
-		gl.DeleteShader(shaderID)
+	gl.CompileShader(shaderId)
+	if err := getShaderCompileErrors(shaderId); err != nil {
+		gl.DeleteShader(shaderId)
 		return Shader{}, err
 	}
 
-	return Shader{ID: shaderID, ShaderType: shaderType}, nil
+	return Shader{Id: shaderId, Type: shaderType}, nil
 }
 
-func getShaderCompileErrors(shaderID uint32) error {
+func getShaderCompileErrors(shaderId uint32) error {
 
 	var compiledSuccessfully int32
-	gl.GetShaderiv(shaderID, gl.COMPILE_STATUS, &compiledSuccessfully)
+	gl.GetShaderiv(shaderId, gl.COMPILE_STATUS, &compiledSuccessfully)
 	if compiledSuccessfully == gl.TRUE {
 		return nil
 	}
 
 	var logLength int32
-	gl.GetShaderiv(shaderID, gl.INFO_LOG_LENGTH, &logLength)
+	gl.GetShaderiv(shaderId, gl.INFO_LOG_LENGTH, &logLength)
 
 	log := gl.Str(strings.Repeat("\x00", int(logLength)))
-	gl.GetShaderInfoLog(shaderID, logLength, nil, log)
+	gl.GetShaderInfoLog(shaderId, logLength, nil, log)
 
 	errMsg := gl.GoStr(log)
-	logging.ErrLog.Println("Compilation of shader with id ", shaderID, " failed. Err: ", errMsg)
+	logging.ErrLog.Println("Compilation of shader with id ", shaderId, " failed. Err: ", errMsg)
 	return errors.New(errMsg)
 }

ui/imgui/imgui.go

@@ -16,7 +16,8 @@ type ImguiInfo struct {
 	VaoID      uint32
 	VboID      uint32
 	IndexBufID uint32
-	TexID      uint32
+	// This is a pointer so we can send a stable pointer to C code
+	TexID *uint32
 }
 
 func (i *ImguiInfo) FrameStart(winWidth, winHeight float32) {
@@ -67,7 +68,7 @@ func (i *ImguiInfo) Render(winWidth, winHeight float32, fbWidth, fbHeight int32)
 	i.Mat.Bind()
 	i.Mat.SetUnifInt32("Texture", 0)
 
-	//PERF: only update the ortho matrix on window resize
+	// @PERF: only update the ortho matrix on window resize
 	orthoMat := gglm.Ortho(0, float32(winWidth), 0, float32(winHeight), 0, 20)
 	i.Mat.SetUnifMat4("ProjMtx", &orthoMat.Mat4)
 	gl.BindSampler(0, 0) // Rely on combined texture/sampler state.
@@ -108,11 +109,12 @@ func (i *ImguiInfo) Render(winWidth, winHeight float32, fbWidth, fbHeight int32)
 				cmd.CallUserCallback(list)
 			} else {
 
-				gl.BindTexture(gl.TEXTURE_2D, i.TexID)
+				gl.ActiveTexture(gl.TEXTURE0)
+				gl.BindTexture(gl.TEXTURE_2D, *i.TexID)
 				clipRect := cmd.ClipRect()
 				gl.Scissor(int32(clipRect.X), int32(fbHeight)-int32(clipRect.W), int32(clipRect.Z-clipRect.X), int32(clipRect.W-clipRect.Y))
 
-				gl.DrawElementsBaseVertex(gl.TRIANGLES, int32(cmd.ElemCount()), uint32(drawType), gl.PtrOffset(int(cmd.IdxOffset())*indexSize), int32(cmd.VtxOffset()))
+				gl.DrawElementsBaseVertexWithOffset(gl.TRIANGLES, int32(cmd.ElemCount()), uint32(drawType), uintptr(int(cmd.IdxOffset())*indexSize), int32(cmd.VtxOffset()))
 			}
 		}
 	}
@@ -141,13 +143,14 @@ func (i *ImguiInfo) AddFontTTF(fontPath string, fontSize float32, fontConfig *im
 	f := a.AddFontFromFileTTFV(fontPath, fontSize, fontConfigToUse, glyphRangesToUse.Data())
 	pixels, width, height, _ := a.GetTextureDataAsAlpha8()
 
-	gl.BindTexture(gl.TEXTURE_2D, i.TexID)
+	gl.ActiveTexture(gl.TEXTURE0)
+	gl.BindTexture(gl.TEXTURE_2D, *i.TexID)
 	gl.TexImage2D(gl.TEXTURE_2D, 0, gl.RED, int32(width), int32(height), 0, gl.RED, gl.UNSIGNED_BYTE, pixels)
 
 	return f
 }
 
-const imguiShdrSrc = `
+const DefaultImguiShader = `
 //shader:vertex
 #version 410
 
@@ -160,10 +163,24 @@ in vec4 Color;
 out vec2 Frag_UV;
 out vec4 Frag_Color;
 
+// Imgui doesn't handle srgb correctly, and looks too bright and wrong in srgb buffers (see: https://github.com/ocornut/imgui/issues/578).
+// While not a complete fix (that would require changes in imgui itself), moving incoming srgba colors to linear in the vertex shader helps make things look better.
+vec4 srgba_to_linear(vec4 srgbaColor){
+
+    #define gamma_correction 2.2
+
+    return vec4(
+        pow(srgbaColor.r, gamma_correction),
+        pow(srgbaColor.g, gamma_correction),
+        pow(srgbaColor.b, gamma_correction),
+        srgbaColor.a
+    );
+}
+
 void main()
 {
     Frag_UV = UV;
-    Frag_Color = Color;
+    Frag_Color = srgba_to_linear(Color);
     gl_Position = ProjMtx * vec4(Position.xy, 0, 1);
 }
 
@@ -183,11 +200,21 @@ void main()
 }
 `
 
-func NewImGui() ImguiInfo {
+// NewImGui setups imgui using the passed shader.
+// If the path is empty a default nMage shader is used
+func NewImGui(shaderPath string) ImguiInfo {
+
+	var imguiMat *materials.Material
+	if shaderPath == "" {
+		imguiMat = materials.NewMaterialSrc("ImGUI Mat", []byte(DefaultImguiShader))
+	} else {
+		imguiMat = materials.NewMaterial("ImGUI Mat", shaderPath)
+	}
 
 	imguiInfo := ImguiInfo{
 		ImCtx: imgui.CreateContext(),
-		Mat:   materials.NewMaterialSrc("ImGUI Mat", []byte(imguiShdrSrc)),
+		Mat:   imguiMat,
+		TexID: new(uint32),
 	}
 
 	io := imgui.CurrentIO()
@@ -197,10 +224,11 @@ func NewImGui() ImguiInfo {
 	gl.GenVertexArrays(1, &imguiInfo.VaoID)
 	gl.GenBuffers(1, &imguiInfo.VboID)
 	gl.GenBuffers(1, &imguiInfo.IndexBufID)
-	gl.GenTextures(1, &imguiInfo.TexID)
+	gl.GenTextures(1, imguiInfo.TexID)
 
 	// Upload font to gpu
-	gl.BindTexture(gl.TEXTURE_2D, imguiInfo.TexID)
+	gl.ActiveTexture(gl.TEXTURE0)
+	gl.BindTexture(gl.TEXTURE_2D, *imguiInfo.TexID)
 	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR)
 	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR)
 	gl.PixelStorei(gl.UNPACK_ROW_LENGTH, 0)
@@ -209,7 +237,7 @@ func NewImGui() ImguiInfo {
 	gl.TexImage2D(gl.TEXTURE_2D, 0, gl.RED, int32(width), int32(height), 0, gl.RED, gl.UNSIGNED_BYTE, pixels)
 
 	// Store our identifier
-	io.Fonts().SetTexID(imgui.TextureID(uintptr(imguiInfo.TexID)))
+	io.Fonts().SetTexID(imgui.TextureID(imguiInfo.TexID))
 
 	//Shader attributes
 	imguiInfo.Mat.Bind()