Framebuffers+unlit shader+screen quad shader

.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

@@ -45,7 +45,7 @@ type TextureLoadOptions struct {
 	WriteToCache     bool
 	GenMipMaps       bool
 	KeepPixelsInMem  bool
-	TextureIsSrgba   bool
+	NoSrgba          bool
 }
 
 type Cubemap struct {
@@ -103,9 +103,9 @@ func LoadTexturePNG(file string, loadOptions *TextureLoadOptions) (Texture, erro
 	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR)
 
 	// load and generate the texture
-	internalFormat := int32(gl.RGBA8)
-	if loadOptions.TextureIsSrgba {
-		internalFormat = gl.SRGB_ALPHA
+	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]))
@@ -151,9 +151,9 @@ func LoadTextureInMemPngImg(img image.Image, loadOptions *TextureLoadOptions) (T
 	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR)
 
 	// load and generate the texture
-	internalFormat := int32(gl.RGBA8)
-	if loadOptions.TextureIsSrgba {
-		internalFormat = gl.SRGB_ALPHA
+	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]))
@@ -216,9 +216,9 @@ func LoadTextureJpeg(file string, loadOptions *TextureLoadOptions) (Texture, err
 	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR)
 
 	// load and generate the texture
-	internalFormat := int32(gl.RGBA8)
-	if loadOptions.TextureIsSrgba {
-		internalFormat = gl.SRGB_ALPHA
+	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]))
@@ -238,7 +238,12 @@ func LoadTextureJpeg(file string, loadOptions *TextureLoadOptions) (Texture, err
 	return tex, nil
 }
 
-func LoadCubemapTextures(rightTex, leftTex, topTex, botTex, frontTex, backTex string) (Cubemap, error) {
+// LoadCubemapTextures only supports the 'TextureIsSrgba' option
+func LoadCubemapTextures(rightTex, leftTex, topTex, botTex, frontTex, backTex string, loadOptions *TextureLoadOptions) (Cubemap, error) {
+
+	if loadOptions == nil {
+		loadOptions = &TextureLoadOptions{}
+	}
 
 	var imgDecoder func(r io.Reader) (image.Image, error)
 	ext := strings.ToLower(path.Ext(rightTex))
@@ -283,7 +288,12 @@ func LoadCubemapTextures(rightTex, leftTex, topTex, botTex, frontTex, backTex st
 		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(&nrgbaImg.Pix[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)

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 +1,295 @@
+package buffers
+
+import (
+	"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_Renderbuffer
+)
+
+func (f FramebufferAttachmentType) IsValid() bool {
+
+	switch f {
+	case FramebufferAttachmentType_Texture:
+		fallthrough
+	case FramebufferAttachmentType_Renderbuffer:
+		return true
+
+	default:
+		return false
+	}
+}
+
+type FramebufferAttachmentDataFormat int32
+
+const (
+	FramebufferAttachmentDataFormat_Unknown FramebufferAttachmentDataFormat = iota
+	FramebufferAttachmentDataFormat_R32Int
+	FramebufferAttachmentDataFormat_RGBA8
+	FramebufferAttachmentDataFormat_SRGBA
+	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
+}
+
+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_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_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
+	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))
+}
+
+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 !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.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.Attachments = append(fbo.Attachments, a)
+}
+
+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 {
@@ -29,7 +36,23 @@ 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()
+
+	// These two are to fix a bug where state isn't cleared
+	// even after imgui captures the keyboard/mouse.
+	//
+	// For example, if player is moving due to key held and then imgui captures the keyboard,
+	// the player keeps moving even when the key is no longer pressed because the input system never
+	// receives the key up event.
+	if imguiCaptureMouse {
+		input.ClearMouseState()
+	}
+
+	if imguiCaptureKeyboard {
+		input.ClearKeyboardState()
+	}
+
 	for event := sdl.PollEvent(); event != nil; event = sdl.PollEvent() {
 
 		//Fire callbacks
@@ -42,14 +65,18 @@ func (w *Window) handleInputs() {
 
 		case *sdl.MouseWheelEvent:
 
+			if !imguiCaptureMouse {
 				input.HandleMouseWheelEvent(e)
+			}
 
-			xDelta, yDelta := input.GetMouseWheelMotion()
-			imIo.AddMouseWheelDelta(float32(xDelta), float32(yDelta))
+			imIo.AddMouseWheelDelta(float32(e.X), float32(e.Y))
 
 		case *sdl.KeyboardEvent:
 
+			if !imguiCaptureKeyboard {
 				input.HandleKeyboardEvent(e)
+			}
+
 			imIo.AddKeyEvent(nmageimgui.SdlScancodeToImGuiKey(e.Keysym.Scancode), e.Type == sdl.KEYDOWN)
 
 			// Send modifier key updates to imgui
@@ -73,12 +100,29 @@ func (w *Window) handleInputs() {
 			imIo.AddInputCharactersUTF8(e.GetText())
 
 		case *sdl.MouseButtonEvent:
+
+			if !imguiCaptureMouse {
 				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:
+
+			if !imguiCaptureMouse {
 				input.HandleMouseMotionEvent(e)
+			}
 
 		case *sdl.WindowEvent:
+
 			if e.Event == sdl.WINDOWEVENT_SIZE_CHANGED {
 				w.handleWindowResize()
 			}
@@ -88,13 +132,17 @@ 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.
+	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 +181,21 @@ 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
@@ -152,16 +206,12 @@ 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 {
@@ -193,11 +243,13 @@ 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)
 
@@ -215,7 +267,6 @@ func SetSrgbFramebuffer(isEnabled bool) {
 }
 
 func SetVSync(enabled bool) {
-	assert.T(isInited, "engine.Init was not called!")
 
 	if enabled {
 		sdl.GLSetSwapInterval(1)
@@ -223,3 +274,12 @@ 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
 

input/input.go

@@ -31,8 +31,8 @@ type mouseWheelState struct {
 }
 
 var (
-	keyMap        = make(map[sdl.Keycode]*keyState)
-	mouseBtnMap   = make(map[int]*mouseBtnState)
+	keyMap        = make(map[sdl.Keycode]keyState)
+	mouseBtnMap   = make(map[int]mouseBtnState)
 	mouseMotion   = mouseMotionState{}
 	mouseWheel    = mouseWheelState{}
 	quitRequested bool
@@ -40,15 +40,17 @@ var (
 
 func EventLoopStart() {
 
-	for _, v := range keyMap {
+	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
@@ -60,6 +62,16 @@ func EventLoopStart() {
 	quitRequested = false
 }
 
+func ClearKeyboardState() {
+	clear(keyMap)
+}
+
+func ClearMouseState() {
+	clear(mouseBtnMap)
+	mouseMotion = mouseMotionState{}
+	mouseWheel = mouseWheelState{}
+}
+
 func HandleQuitEvent(e *sdl.QuitEvent) {
 	quitRequested = true
 }
@@ -70,29 +82,31 @@ func IsQuitClicked() bool {
 
 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) {
@@ -109,12 +123,12 @@ 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
 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) {
 	return mouseMotion.XDelta, mouseMotion.YDelta
 }
@@ -141,7 +155,7 @@ func GetMouseWheelMotion() (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 mouseWheel.XDelta > 0 {
@@ -153,7 +167,7 @@ func GetMouseWheelXNorm() int32 {
 	return 0
 }
 
-//returns 1 if mouse wheel yDelta > 0, -1 if yDelta < 0, and 0 otherwise
+// returns 1 if mouse wheel yDelta > 0, -1 if yDelta < 0, and 0 otherwise
 func GetMouseWheelYNorm() int32 {
 
 	if mouseWheel.YDelta > 0 {
@@ -167,8 +181,8 @@ func GetMouseWheelYNorm() int32 {
 
 func KeyClicked(kc sdl.Keycode) bool {
 
-	ks := keyMap[kc]
-	if ks == nil {
+	ks, ok := keyMap[kc]
+	if !ok {
 		return false
 	}
 
@@ -177,8 +191,8 @@ func KeyClicked(kc sdl.Keycode) bool {
 
 func KeyReleased(kc sdl.Keycode) bool {
 
-	ks := keyMap[kc]
-	if ks == nil {
+	ks, ok := keyMap[kc]
+	if !ok {
 		return false
 	}
 
@@ -187,8 +201,8 @@ func KeyReleased(kc sdl.Keycode) bool {
 
 func KeyDown(kc sdl.Keycode) bool {
 
-	ks := keyMap[kc]
-	if ks == nil {
+	ks, ok := keyMap[kc]
+	if !ok {
 		return false
 	}
 
@@ -197,8 +211,8 @@ func KeyDown(kc sdl.Keycode) bool {
 
 func KeyUp(kc sdl.Keycode) bool {
 
-	ks := keyMap[kc]
-	if ks == nil {
+	ks, ok := keyMap[kc]
+	if !ok {
 		return true
 	}
 
@@ -207,8 +221,8 @@ func KeyUp(kc sdl.Keycode) bool {
 
 func MouseClicked(mb int) bool {
 
-	btn := mouseBtnMap[mb]
-	if btn == nil {
+	btn, ok := mouseBtnMap[mb]
+	if !ok {
 		return false
 	}
 
@@ -217,8 +231,8 @@ func MouseClicked(mb int) bool {
 
 func MouseDoubleClicked(mb int) bool {
 
-	btn := mouseBtnMap[mb]
-	if btn == nil {
+	btn, ok := mouseBtnMap[mb]
+	if !ok {
 		return false
 	}
 
@@ -226,8 +240,8 @@ func MouseDoubleClicked(mb int) bool {
 }
 
 func MouseReleased(mb int) bool {
-	btn := mouseBtnMap[mb]
-	if btn == nil {
+	btn, ok := mouseBtnMap[mb]
+	if !ok {
 		return false
 	}
 
@@ -236,8 +250,8 @@ func MouseReleased(mb int) bool {
 
 func MouseDown(mb int) bool {
 
-	btn := mouseBtnMap[mb]
-	if btn == nil {
+	btn, ok := mouseBtnMap[mb]
+	if !ok {
 		return false
 	}
 
@@ -246,8 +260,8 @@ func MouseDown(mb int) bool {
 
 func MouseUp(mb int) bool {
 
-	btn := mouseBtnMap[mb]
-	if btn == nil {
+	btn, ok := mouseBtnMap[mb]
+	if !ok {
 		return true
 	}
 

main.go

@@ -3,10 +3,12 @@ package main
 import (
 	"fmt"
 	"runtime"
+	"strconv"
 
 	imgui "github.com/AllenDang/cimgui-go"
 	"github.com/bloeys/gglm/gglm"
 	"github.com/bloeys/nmage/assets"
+	"github.com/bloeys/nmage/buffers"
 	"github.com/bloeys/nmage/camera"
 	"github.com/bloeys/nmage/engine"
 	"github.com/bloeys/nmage/entity"
@@ -22,16 +24,66 @@ import (
 	"github.com/veandco/go-sdl2/sdl"
 )
 
-// @Todo:
-// Integrate physx
-// Create VAO struct independent from VBO to support multi-VBO use cases (e.g. instancing)
-// Renderer batching
-// Scene graph
-// Separate engine loop from rendering loop? or leave it to the user?
-// Abstract keys enum away from sdl
-// Proper Asset loading
-// Frustum culling
-// Material system editor with fields automatically extracted from the shader
+/*
+@TODO:
+	- Rendering:
+		- Blinn-Phong lighting model ✅
+		- Directional lights ✅
+		- Point lights ✅
+		- Spotlights ✅
+		- HDR
+		- Cascaded shadow mapping
+		- Skeletal animations
+	- Proper model loading (i.e. load model by reading all its meshes, textures, and so on together)
+	- Create VAO struct independent from VBO to support multi-VBO use cases (e.g. instancing) ✅
+	- Renderer batching
+	- Scene graph
+	- Separate engine loop from rendering loop? or leave it to the user?
+	- Abstract keys enum away from sdl
+	- Proper Asset loading
+	- Frustum culling
+	- Material system editor with fields automatically extracted from the shader
+*/
+
+type DirLight struct {
+	Dir           gglm.Vec3
+	DiffuseColor  gglm.Vec3
+	SpecularColor gglm.Vec3
+}
+
+// Check https://wiki.ogre3d.org/tiki-index.php?page=-Point+Light+Attenuation for values
+type PointLight struct {
+	Pos           gglm.Vec3
+	DiffuseColor  gglm.Vec3
+	SpecularColor gglm.Vec3
+
+	Radius float32
+
+	Constant  float32
+	Linear    float32
+	Quadratic float32
+}
+
+type SpotLight struct {
+	Pos           gglm.Vec3
+	Dir           gglm.Vec3
+	DiffuseColor  gglm.Vec3
+	SpecularColor gglm.Vec3
+	InnerCutoff   float32
+	OuterCutoff   float32
+}
+
+// SetCutoffs properly sets the cosine values of the cutoffs using the passed
+// degrees.
+//
+// The light has full intensity within the inner cutoff, falloff between
+// inner-outer cutoff, and zero light beyond the outer cutoff.
+//
+// The inner cuttoff degree must be *smaller* than the outer cutoff
+func (s *SpotLight) SetCutoffs(innerCutoffAngleDeg, outerCutoffAngleDeg float32) {
+	s.InnerCutoff = gglm.Cos32(innerCutoffAngleDeg * gglm.Deg2Rad)
+	s.OuterCutoff = gglm.Cos32(outerCutoffAngleDeg * gglm.Deg2Rad)
+}
 
 const (
 	camSpeed         = 15
@@ -45,30 +97,95 @@ var (
 	window *engine.Window
 
 	pitch float32 = 0
-	yaw   float32 = -90
+	yaw   float32 = -1.5
 	cam   *camera.Camera
 
-	simpleMat *materials.Material
-	skyboxMat *materials.Material
+	renderToFbo       = true
+	fboRenderDirectly = true
+	fboScale          = gglm.NewVec2(0.25, 0.25)
+	fboOffset         = gglm.NewVec2(0.75, -0.75)
+	fbo               buffers.Framebuffer
+
+	screenQuadMat *materials.Material
+	unlitMat      *materials.Material
+	whiteMat      *materials.Material
+	containerMat  *materials.Material
+	palleteMat    *materials.Material
+	skyboxMat     *materials.Material
+	debugDepthMat *materials.Material
 
-	chairMesh  *meshes.Mesh
 	cubeMesh   *meshes.Mesh
+	sphereMesh *meshes.Mesh
+	chairMesh  *meshes.Mesh
 	skyboxMesh *meshes.Mesh
 
 	cubeModelMat = gglm.NewTrMatId()
 
-	lightPos1   = gglm.NewVec3(-2, 0, 2)
-	lightColor1 = gglm.NewVec3(1, 1, 1)
-
-	debugDepthMat        *materials.Material
+	drawSkybox           = true
 	debugDrawDepthBuffer bool
 
 	skyboxCmap assets.Cubemap
 
 	dpiScaling float32
+
+	// Light settings
+	ambientColor = gglm.NewVec3(0, 0, 0)
+
+	// Lights
+	dirLight = DirLight{
+		Dir:           *gglm.NewVec3(0, -0.8, 0.2).Normalize(),
+		DiffuseColor:  *gglm.NewVec3(0, 0, 0),
+		SpecularColor: *gglm.NewVec3(0, 0, 0),
+	}
+	pointLights = [...]PointLight{
+		{
+			Pos:           *gglm.NewVec3(0, 5, 0),
+			DiffuseColor:  *gglm.NewVec3(1, 0, 0),
+			SpecularColor: *gglm.NewVec3(1, 1, 1),
+			// These values are for 50m range
+			Constant:  1.0,
+			Linear:    0.09,
+			Quadratic: 0.032,
+		},
+		{
+			Pos:           *gglm.NewVec3(0, -5, 0),
+			DiffuseColor:  *gglm.NewVec3(0, 1, 0),
+			SpecularColor: *gglm.NewVec3(1, 1, 1),
+			Constant:      1.0,
+			Linear:        0.09,
+			Quadratic:     0.032,
+		},
+		{
+			Pos:           *gglm.NewVec3(5, 0, 0),
+			DiffuseColor:  *gglm.NewVec3(1, 1, 1),
+			SpecularColor: *gglm.NewVec3(1, 1, 1),
+			Constant:      1.0,
+			Linear:        0.09,
+			Quadratic:     0.032,
+		},
+		{
+			Pos:           *gglm.NewVec3(-4, 0, 0),
+			DiffuseColor:  *gglm.NewVec3(0, 0, 1),
+			SpecularColor: *gglm.NewVec3(1, 1, 1),
+			Constant:      1.0,
+			Linear:        0.09,
+			Quadratic:     0.032,
+		},
+	}
+	spotLights = [...]SpotLight{
+		{
+			Pos:           *gglm.NewVec3(0, 5, 0),
+			Dir:           *gglm.NewVec3(0, -1, 0),
+			DiffuseColor:  *gglm.NewVec3(0, 1, 1),
+			SpecularColor: *gglm.NewVec3(1, 1, 1),
+			// These must be cosine values
+			InnerCutoff: gglm.Cos32(15 * gglm.Deg2Rad),
+			OuterCutoff: gglm.Cos32(20 * gglm.Deg2Rad),
+		},
+	}
 )
 
-type OurGame struct {
+type Game struct {
 	Win       *engine.Window
 	ImGUIInfo nmageimgui.ImguiInfo
 }
@@ -141,18 +258,20 @@ func main() {
 	}
 	defer window.Destroy()
 
+	engine.SetMSAA(true)
 	engine.SetVSync(false)
+	engine.SetSrgbFramebuffer(true)
 
-	game := &OurGame{
+	game := &Game{
 		Win:       window,
-		ImGUIInfo: nmageimgui.NewImGui(),
+		ImGUIInfo: nmageimgui.NewImGui("./res/shaders/imgui.glsl"),
 	}
 	window.EventCallbacks = append(window.EventCallbacks, game.handleWindowEvents)
 
 	engine.Run(game, window, game.ImGUIInfo)
 }
 
-func (g *OurGame) handleWindowEvents(e sdl.Event) {
+func (g *Game) handleWindowEvents(e sdl.Event) {
 
 	switch e := e.(type) {
 	case *sdl.WindowEvent:
@@ -163,7 +282,7 @@ func (g *OurGame) handleWindowEvents(e sdl.Event) {
 			cam.AspectRatio = float32(width) / float32(height)
 			cam.Update()
 
-			simpleMat.SetUnifMat4("projMat", &cam.ProjMat)
+			palleteMat.SetUnifMat4("projMat", &cam.ProjMat)
 			debugDepthMat.SetUnifMat4("projMat", &cam.ProjMat)
 		}
 	}
@@ -203,17 +322,28 @@ func getDpiScaling(unscaledWindowWidth, unscaledWindowHeight int32) float32 {
 	return dpiScaling
 }
 
-func (g *OurGame) Init() {
+func (g *Game) Init() {
 
 	var err error
 
-	//Create materials
-	simpleMat = materials.NewMaterial("Simple mat", "./res/shaders/simple.glsl")
-	debugDepthMat = materials.NewMaterial("Debug depth mat", "./res/shaders/debug-depth.glsl")
-	skyboxMat = materials.NewMaterial("Skybox mat", "./res/shaders/skybox.glsl")
+	// Camera
+	winWidth, winHeight := g.Win.SDLWin.GetSize()
+	cam = camera.NewPerspective(
+		gglm.NewVec3(0, 0, 10),
+		gglm.NewVec3(0, 0, -1),
+		gglm.NewVec3(0, 1, 0),
+		0.1, 200,
+		45*gglm.Deg2Rad,
+		float32(winWidth)/float32(winHeight),
+	)
 
 	//Load meshes
-	cubeMesh, err = meshes.NewMesh("Cube", "./res/models/tex-cube.fbx", 0)
+	cubeMesh, err = meshes.NewMesh("Cube", "./res/models/cube.fbx", 0)
+	if err != nil {
+		logging.ErrLog.Fatalln("Failed to load mesh. Err: ", err)
+	}
+
+	sphereMesh, err = meshes.NewMesh("Sphere", "./res/models/sphere.fbx", 0)
 	if err != nil {
 		logging.ErrLog.Fatalln("Failed to load mesh. Err: ", err)
 	}
@@ -229,7 +359,27 @@ func (g *OurGame) Init() {
 	}
 
 	//Load textures
-	tex, err := assets.LoadTexturePNG("./res/textures/pallete-endesga-64-1x.png", nil)
+	whiteTex, err := assets.LoadTexturePNG("./res/textures/white.png", &assets.TextureLoadOptions{})
+	if err != nil {
+		logging.ErrLog.Fatalln("Failed to load texture. Err: ", err)
+	}
+
+	blackTex, err := assets.LoadTexturePNG("./res/textures/black.png", &assets.TextureLoadOptions{})
+	if err != nil {
+		logging.ErrLog.Fatalln("Failed to load texture. Err: ", err)
+	}
+
+	containerDiffuseTex, err := assets.LoadTexturePNG("./res/textures/container-diffuse.png", &assets.TextureLoadOptions{})
+	if err != nil {
+		logging.ErrLog.Fatalln("Failed to load texture. Err: ", err)
+	}
+
+	containerSpecularTex, err := assets.LoadTexturePNG("./res/textures/container-specular.png", &assets.TextureLoadOptions{})
+	if err != nil {
+		logging.ErrLog.Fatalln("Failed to load texture. Err: ", err)
+	}
+
+	palleteTex, err := assets.LoadTexturePNG("./res/textures/pallete-endesga-64-1x.png", &assets.TextureLoadOptions{})
 	if err != nil {
 		logging.ErrLog.Fatalln("Failed to load texture. Err: ", err)
 	}
@@ -238,42 +388,173 @@ func (g *OurGame) Init() {
 		"./res/textures/sb-right.jpg", "./res/textures/sb-left.jpg",
 		"./res/textures/sb-top.jpg", "./res/textures/sb-bottom.jpg",
 		"./res/textures/sb-front.jpg", "./res/textures/sb-back.jpg",
+		&assets.TextureLoadOptions{},
 	)
 	if err != nil {
 		logging.ErrLog.Fatalln("Failed to load cubemap. Err: ", err)
 	}
 
-	// Configure materials
-	simpleMat.DiffuseTex = tex.TexID
+	// Create materials and assign any unused texture slots to black
+	screenQuadMat = materials.NewMaterial("Screen Quad Mat", "./res/shaders/screen-quad.glsl")
+	screenQuadMat.SetUnifVec2("scale", fboScale)
+	screenQuadMat.SetUnifVec2("offset", fboOffset)
+	screenQuadMat.SetUnifInt32("material.diffuse", 0)
 
-	//Movement, scale and rotation
+	unlitMat = materials.NewMaterial("Unlit mat", "./res/shaders/simple-unlit.glsl")
+	unlitMat.SetUnifInt32("material.diffuse", 0)
+	unlitMat.SetUnifMat4("projMat", &cam.ProjMat)
+
+	whiteMat = materials.NewMaterial("White mat", "./res/shaders/simple.glsl")
+	whiteMat.Shininess = 64
+	whiteMat.DiffuseTex = whiteTex.TexID
+	whiteMat.SpecularTex = blackTex.TexID
+	whiteMat.NormalTex = blackTex.TexID
+	whiteMat.EmissionTex = blackTex.TexID
+	whiteMat.SetUnifInt32("material.diffuse", 0)
+	whiteMat.SetUnifInt32("material.specular", 1)
+	// whiteMat.SetUnifInt32("material.normal", 2)
+	whiteMat.SetUnifInt32("material.emission", 3)
+	whiteMat.SetUnifMat4("projMat", &cam.ProjMat)
+	whiteMat.SetUnifVec3("ambientColor", ambientColor)
+	whiteMat.SetUnifFloat32("material.shininess", whiteMat.Shininess)
+	whiteMat.SetUnifVec3("dirLight.dir", &dirLight.Dir)
+	whiteMat.SetUnifVec3("dirLight.diffuseColor", &dirLight.DiffuseColor)
+	whiteMat.SetUnifVec3("dirLight.specularColor", &dirLight.SpecularColor)
+
+	containerMat = materials.NewMaterial("Container mat", "./res/shaders/simple.glsl")
+	containerMat.Shininess = 64
+	containerMat.DiffuseTex = containerDiffuseTex.TexID
+	containerMat.SpecularTex = containerSpecularTex.TexID
+	containerMat.NormalTex = blackTex.TexID
+	containerMat.EmissionTex = blackTex.TexID
+	containerMat.SetUnifInt32("material.diffuse", 0)
+	containerMat.SetUnifInt32("material.specular", 1)
+	// containerMat.SetUnifInt32("material.normal", 2)
+	containerMat.SetUnifInt32("material.emission", 3)
+	containerMat.SetUnifMat4("projMat", &cam.ProjMat)
+	containerMat.SetUnifVec3("ambientColor", ambientColor)
+	containerMat.SetUnifFloat32("material.shininess", containerMat.Shininess)
+	containerMat.SetUnifVec3("dirLight.dir", &dirLight.Dir)
+	containerMat.SetUnifVec3("dirLight.diffuseColor", &dirLight.DiffuseColor)
+	containerMat.SetUnifVec3("dirLight.specularColor", &dirLight.SpecularColor)
+
+	palleteMat = materials.NewMaterial("Pallete mat", "./res/shaders/simple.glsl")
+	palleteMat.Shininess = 64
+	palleteMat.DiffuseTex = palleteTex.TexID
+	palleteMat.SpecularTex = blackTex.TexID
+	palleteMat.NormalTex = blackTex.TexID
+	palleteMat.EmissionTex = blackTex.TexID
+	palleteMat.SetUnifInt32("material.diffuse", 0)
+	palleteMat.SetUnifInt32("material.specular", 1)
+	// palleteMat.SetUnifInt32("material.normal", 2)
+	palleteMat.SetUnifInt32("material.emission", 3)
+	palleteMat.SetUnifMat4("projMat", &cam.ProjMat)
+	palleteMat.SetUnifVec3("ambientColor", ambientColor)
+	palleteMat.SetUnifFloat32("material.shininess", palleteMat.Shininess)
+	palleteMat.SetUnifVec3("dirLight.diffuseColor", &dirLight.DiffuseColor)
+	palleteMat.SetUnifVec3("dirLight.specularColor", &dirLight.SpecularColor)
+
+	debugDepthMat = materials.NewMaterial("Debug depth mat", "./res/shaders/debug-depth.glsl")
+	debugDepthMat.SetUnifMat4("projMat", &cam.ProjMat)
+
+	skyboxMat = materials.NewMaterial("Skybox mat", "./res/shaders/skybox.glsl")
+
+	// Movement, scale and rotation
 	translationMat := gglm.NewTranslationMat(gglm.NewVec3(0, 0, 0))
 	scaleMat := gglm.NewScaleMat(gglm.NewVec3(1, 1, 1))
 	rotMat := gglm.NewRotMat(gglm.NewQuatEuler(gglm.NewVec3(-90, -90, 0).AsRad()))
-
 	cubeModelMat.Mul(translationMat.Mul(rotMat.Mul(scaleMat)))
 
-	// Camera
-	winWidth, winHeight := g.Win.SDLWin.GetSize()
-	cam = camera.NewPerspective(
-		gglm.NewVec3(0, 0, 10),
-		gglm.NewVec3(0, 0, -1),
-		gglm.NewVec3(0, 1, 0),
-		0.1, 200,
-		45*gglm.Deg2Rad,
-		float32(winWidth)/float32(winHeight),
-	)
-	simpleMat.SetUnifMat4("projMat", &cam.ProjMat)
-	debugDepthMat.SetUnifMat4("projMat", &cam.ProjMat)
-
+	g.updateLights()
 	updateViewMat()
 
-	//Lights
-	simpleMat.SetUnifVec3("lightPos1", lightPos1)
-	simpleMat.SetUnifVec3("lightColor1", lightColor1)
+	g.initFbo()
 }
 
-func (g *OurGame) Update() {
+func (g *Game) initFbo() {
+
+	fbWidth, fbHeight := g.Win.SDLWin.GLGetDrawableSize()
+	if fbWidth <= 0 || fbHeight <= 0 {
+		panic("what?")
+	}
+
+	fbo = buffers.NewFramebuffer(uint32(fbWidth), uint32(fbHeight))
+
+	fbo.NewColorAttachment(
+		buffers.FramebufferAttachmentType_Texture,
+		buffers.FramebufferAttachmentDataFormat_SRGBA,
+	)
+
+	fbo.NewDepthStencilAttachment(
+		buffers.FramebufferAttachmentType_Renderbuffer,
+		buffers.FramebufferAttachmentDataFormat_Depth24Stencil8,
+	)
+}
+
+func (g *Game) updateLights() {
+
+	for i := 0; i < len(pointLights); i++ {
+
+		pl := &pointLights[i]
+		indexString := "pointLights[" + strconv.Itoa(i) + "]"
+
+		whiteMat.SetUnifVec3(indexString+".pos", &pl.Pos)
+		containerMat.SetUnifVec3(indexString+".pos", &pl.Pos)
+		palleteMat.SetUnifVec3(indexString+".pos", &pl.Pos)
+
+		whiteMat.SetUnifVec3(indexString+".diffuseColor", &pl.DiffuseColor)
+		containerMat.SetUnifVec3(indexString+".diffuseColor", &pl.DiffuseColor)
+		palleteMat.SetUnifVec3(indexString+".diffuseColor", &pl.DiffuseColor)
+
+		whiteMat.SetUnifVec3(indexString+".specularColor", &pl.SpecularColor)
+		containerMat.SetUnifVec3(indexString+".specularColor", &pl.SpecularColor)
+		palleteMat.SetUnifVec3(indexString+".specularColor", &pl.SpecularColor)
+
+		whiteMat.SetUnifFloat32(indexString+".constant", pl.Constant)
+		containerMat.SetUnifFloat32(indexString+".constant", pl.Constant)
+		palleteMat.SetUnifFloat32(indexString+".constant", pl.Constant)
+
+		whiteMat.SetUnifFloat32(indexString+".linear", pl.Linear)
+		containerMat.SetUnifFloat32(indexString+".linear", pl.Linear)
+		palleteMat.SetUnifFloat32(indexString+".linear", pl.Linear)
+
+		whiteMat.SetUnifFloat32(indexString+".quadratic", pl.Quadratic)
+		containerMat.SetUnifFloat32(indexString+".quadratic", pl.Quadratic)
+		palleteMat.SetUnifFloat32(indexString+".quadratic", pl.Quadratic)
+	}
+
+	for i := 0; i < len(spotLights); i++ {
+
+		l := &spotLights[i]
+		indexString := "spotLights[" + strconv.Itoa(i) + "]"
+
+		whiteMat.SetUnifVec3(indexString+".pos", &l.Pos)
+		containerMat.SetUnifVec3(indexString+".pos", &l.Pos)
+		palleteMat.SetUnifVec3(indexString+".pos", &l.Pos)
+
+		whiteMat.SetUnifVec3(indexString+".dir", &l.Dir)
+		containerMat.SetUnifVec3(indexString+".dir", &l.Dir)
+		palleteMat.SetUnifVec3(indexString+".dir", &l.Dir)
+
+		whiteMat.SetUnifVec3(indexString+".diffuseColor", &l.DiffuseColor)
+		containerMat.SetUnifVec3(indexString+".diffuseColor", &l.DiffuseColor)
+		palleteMat.SetUnifVec3(indexString+".diffuseColor", &l.DiffuseColor)
+
+		whiteMat.SetUnifVec3(indexString+".specularColor", &l.SpecularColor)
+		containerMat.SetUnifVec3(indexString+".specularColor", &l.SpecularColor)
+		palleteMat.SetUnifVec3(indexString+".specularColor", &l.SpecularColor)
+
+		whiteMat.SetUnifFloat32(indexString+".innerCutoff", l.InnerCutoff)
+		containerMat.SetUnifFloat32(indexString+".innerCutoff", l.InnerCutoff)
+		palleteMat.SetUnifFloat32(indexString+".innerCutoff", l.InnerCutoff)
+
+		whiteMat.SetUnifFloat32(indexString+".outerCutoff", l.OuterCutoff)
+		containerMat.SetUnifFloat32(indexString+".outerCutoff", l.OuterCutoff)
+		palleteMat.SetUnifFloat32(indexString+".outerCutoff", l.OuterCutoff)
+	}
+}
+
+func (g *Game) Update() {
 
 	if input.IsQuitClicked() || input.KeyClicked(sdl.K_ESCAPE) {
 		engine.Quit()
@@ -282,31 +563,12 @@ func (g *OurGame) Update() {
 	g.updateCameraLookAround()
 	g.updateCameraPos()
 
-	imgui.ShowDemoWindow()
-
 	//Rotating cubes
 	if input.KeyDown(sdl.K_SPACE) {
 		cubeModelMat.Rotate(10*timing.DT()*gglm.Deg2Rad, gglm.NewVec3(1, 1, 1).Normalize())
 	}
 
-	imgui.Begin("Debug controls")
-	if imgui.DragFloat3("Cam Pos", &cam.Pos.Data) {
-		updateViewMat()
-	}
-	if imgui.DragFloat3("Cam Forward", &cam.Forward.Data) {
-		updateViewMat()
-	}
-
-	if imgui.DragFloat3("Light Pos 1", &lightPos1.Data) {
-		simpleMat.SetUnifVec3("lightPos1", lightPos1)
-	}
-
-	if imgui.DragFloat3("Light Color 1", &lightColor1.Data) {
-		simpleMat.SetUnifVec3("lightColor1", lightColor1)
-	}
-
-	imgui.Checkbox("Debug depth buffer", &debugDrawDepthBuffer)
-	imgui.End()
+	g.showDebugWindow()
 
 	if input.KeyClicked(sdl.K_F4) {
 		fmt.Printf("Pos: %s; Forward: %s; |Forward|: %f\n", cam.Pos.String(), cam.Forward.String(), cam.Forward.Mag())
@@ -315,7 +577,186 @@ func (g *OurGame) Update() {
 	g.Win.SDLWin.SetTitle(fmt.Sprint("nMage (", timing.GetAvgFPS(), " fps)"))
 }
 
-func (g *OurGame) updateCameraLookAround() {
+func (g *Game) showDebugWindow() {
+
+	imgui.ShowDemoWindow()
+
+	imgui.Begin("Debug controls")
+
+	// Camera
+	imgui.Text("Camera")
+	if imgui.DragFloat3("Cam Pos", &cam.Pos.Data) {
+		updateViewMat()
+	}
+	if imgui.DragFloat3("Cam Forward", &cam.Forward.Data) {
+		updateViewMat()
+	}
+
+	imgui.Spacing()
+
+	// Ambient light
+	imgui.Text("Ambient Light")
+
+	if imgui.DragFloat3("Ambient Color", &ambientColor.Data) {
+		whiteMat.SetUnifVec3("ambientColor", ambientColor)
+		containerMat.SetUnifVec3("ambientColor", ambientColor)
+		palleteMat.SetUnifVec3("ambientColor", ambientColor)
+	}
+
+	imgui.Spacing()
+
+	// Specular
+	imgui.Text("Specular Settings")
+
+	if imgui.DragFloat("Specular Shininess", &whiteMat.Shininess) {
+		whiteMat.SetUnifFloat32("material.shininess", whiteMat.Shininess)
+		containerMat.SetUnifFloat32("material.shininess", whiteMat.Shininess)
+		palleteMat.SetUnifFloat32("material.shininess", whiteMat.Shininess)
+	}
+
+	imgui.Spacing()
+
+	// Directional light
+	imgui.Text("Directional Light")
+
+	if imgui.DragFloat3("Direction", &dirLight.Dir.Data) {
+		whiteMat.SetUnifVec3("dirLight.dir", &dirLight.Dir)
+		containerMat.SetUnifVec3("dirLight.dir", &dirLight.Dir)
+		palleteMat.SetUnifVec3("dirLight.dir", &dirLight.Dir)
+	}
+
+	if imgui.DragFloat3("Diffuse Color", &dirLight.DiffuseColor.Data) {
+		whiteMat.SetUnifVec3("dirLight.diffuseColor", &dirLight.DiffuseColor)
+		containerMat.SetUnifVec3("dirLight.diffuseColor", &dirLight.DiffuseColor)
+		palleteMat.SetUnifVec3("dirLight.diffuseColor", &dirLight.DiffuseColor)
+	}
+
+	if imgui.DragFloat3("Specular Color", &dirLight.SpecularColor.Data) {
+		whiteMat.SetUnifVec3("dirLight.specularColor", &dirLight.SpecularColor)
+		containerMat.SetUnifVec3("dirLight.specularColor", &dirLight.SpecularColor)
+		palleteMat.SetUnifVec3("dirLight.specularColor", &dirLight.SpecularColor)
+	}
+
+	imgui.Spacing()
+
+	// Point lights
+	if imgui.BeginListBoxV("Point Lights", imgui.Vec2{Y: 200}) {
+
+		for i := 0; i < len(pointLights); i++ {
+
+			pl := &pointLights[i]
+			indexNumString := strconv.Itoa(i)
+
+			if !imgui.TreeNodeExStrV("Point Light "+indexNumString, imgui.TreeNodeFlagsSpanAvailWidth) {
+				continue
+			}
+
+			indexString := "pointLights[" + indexNumString + "]"
+
+			if imgui.DragFloat3("Pos", &pl.Pos.Data) {
+				whiteMat.SetUnifVec3(indexString+".pos", &pl.Pos)
+				containerMat.SetUnifVec3(indexString+".pos", &pl.Pos)
+				palleteMat.SetUnifVec3(indexString+".pos", &pl.Pos)
+			}
+
+			if imgui.DragFloat3("Diffuse Color", &pl.DiffuseColor.Data) {
+				whiteMat.SetUnifVec3(indexString+".diffuseColor", &pl.DiffuseColor)
+				containerMat.SetUnifVec3(indexString+".diffuseColor", &pl.DiffuseColor)
+				palleteMat.SetUnifVec3(indexString+".diffuseColor", &pl.DiffuseColor)
+			}
+
+			if imgui.DragFloat3("Specular Color", &pl.SpecularColor.Data) {
+				whiteMat.SetUnifVec3(indexString+".specularColor", &pl.SpecularColor)
+				containerMat.SetUnifVec3(indexString+".specularColor", &pl.SpecularColor)
+				palleteMat.SetUnifVec3(indexString+".specularColor", &pl.SpecularColor)
+			}
+
+			imgui.TreePop()
+		}
+
+		imgui.EndListBox()
+	}
+
+	// Spot lights
+	if imgui.BeginListBoxV("Spot Lights", imgui.Vec2{Y: 200}) {
+
+		for i := 0; i < len(spotLights); i++ {
+
+			l := &spotLights[i]
+			indexNumString := strconv.Itoa(i)
+
+			if !imgui.TreeNodeExStrV("Spot Light "+indexNumString, imgui.TreeNodeFlagsSpanAvailWidth) {
+				continue
+			}
+
+			indexString := "spotLights[" + indexNumString + "]"
+
+			if imgui.DragFloat3("Pos", &l.Pos.Data) {
+				whiteMat.SetUnifVec3(indexString+".pos", &l.Pos)
+				containerMat.SetUnifVec3(indexString+".pos", &l.Pos)
+				palleteMat.SetUnifVec3(indexString+".pos", &l.Pos)
+			}
+
+			if imgui.DragFloat3("Dir", &l.Dir.Data) {
+				whiteMat.SetUnifVec3(indexString+".dir", &l.Dir)
+				containerMat.SetUnifVec3(indexString+".dir", &l.Dir)
+				palleteMat.SetUnifVec3(indexString+".dir", &l.Dir)
+			}
+
+			if imgui.DragFloat3("Diffuse Color", &l.DiffuseColor.Data) {
+				whiteMat.SetUnifVec3(indexString+".diffuseColor", &l.DiffuseColor)
+				containerMat.SetUnifVec3(indexString+".diffuseColor", &l.DiffuseColor)
+				palleteMat.SetUnifVec3(indexString+".diffuseColor", &l.DiffuseColor)
+			}
+
+			if imgui.DragFloat3("Specular Color", &l.SpecularColor.Data) {
+				whiteMat.SetUnifVec3(indexString+".specularColor", &l.SpecularColor)
+				containerMat.SetUnifVec3(indexString+".specularColor", &l.SpecularColor)
+				palleteMat.SetUnifVec3(indexString+".specularColor", &l.SpecularColor)
+			}
+
+			if imgui.DragFloat("Inner Cutoff", &l.InnerCutoff) {
+				whiteMat.SetUnifFloat32(indexString+".innerCutoff", l.InnerCutoff)
+				containerMat.SetUnifFloat32(indexString+".innerCutoff", l.InnerCutoff)
+				palleteMat.SetUnifFloat32(indexString+".innerCutoff", l.InnerCutoff)
+			}
+
+			if imgui.DragFloat("Outer Cutoff", &l.OuterCutoff) {
+				whiteMat.SetUnifFloat32(indexString+".outerCutoff", l.OuterCutoff)
+				containerMat.SetUnifFloat32(indexString+".outerCutoff", l.OuterCutoff)
+				palleteMat.SetUnifFloat32(indexString+".outerCutoff", l.OuterCutoff)
+			}
+
+			imgui.TreePop()
+		}
+
+		imgui.EndListBox()
+	}
+
+	// Fbo
+	imgui.Text("Framebuffer")
+
+	imgui.Checkbox("Render to FBO", &renderToFbo)
+	imgui.Checkbox("Render Directly", &fboRenderDirectly)
+
+	if imgui.DragFloat2("Scale", &fboScale.Data) {
+		screenQuadMat.SetUnifVec2("scale", fboScale)
+	}
+
+	if imgui.DragFloat2("Offset", &fboOffset.Data) {
+		screenQuadMat.SetUnifVec2("offset", fboOffset)
+	}
+
+	// Other
+	imgui.Text("Other Settings")
+
+	imgui.Checkbox("Draw Skybox", &drawSkybox)
+	imgui.Checkbox("Debug depth buffer", &debugDrawDepthBuffer)
+
+	imgui.End()
+}
+
+func (g *Game) updateCameraLookAround() {
 
 	mouseX, mouseY := input.GetMouseMotion()
 	if (mouseX == 0 && mouseY == 0) || !input.MouseDown(sdl.BUTTON_RIGHT) {
@@ -327,12 +768,12 @@ func (g *OurGame) updateCameraLookAround() {
 
 	// Pitch
 	pitch += float32(-mouseY) * mouseSensitivity * timing.DT()
-	if pitch > 89.0 {
-		pitch = 89.0
+	if pitch > 1.5 {
+		pitch = 1.5
 	}
 
-	if pitch < -89.0 {
-		pitch = -89.0
+	if pitch < -1.5 {
+		pitch = -1.5
 	}
 
 	// Update cam forward
@@ -341,7 +782,7 @@ func (g *OurGame) updateCameraLookAround() {
 	updateViewMat()
 }
 
-func (g *OurGame) updateCameraPos() {
+func (g *Game) updateCameraPos() {
 
 	update := false
 
@@ -373,33 +814,79 @@ func (g *OurGame) updateCameraPos() {
 	}
 }
 
-func (g *OurGame) Render() {
+func (g *Game) Render() {
 
-	matToUse := simpleMat
-	if debugDrawDepthBuffer {
-		matToUse = debugDepthMat
+	if renderToFbo {
+		fbo.Bind()
+		gl.Clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT | gl.STENCIL_BUFFER_BIT)
 	}
 
 	tempModelMatrix := cubeModelMat.Clone()
-	window.Rend.Draw(chairMesh, tempModelMatrix, matToUse)
 
+	whiteMat.SetUnifVec3("camPos", &cam.Pos)
+	containerMat.SetUnifVec3("camPos", &cam.Pos)
+	palleteMat.SetUnifVec3("camPos", &cam.Pos)
+
+	sunMat := palleteMat
+	chairMat := palleteMat
+	cubeMat := containerMat
+	if debugDrawDepthBuffer {
+		sunMat = debugDepthMat
+		chairMat = debugDepthMat
+		cubeMat = debugDepthMat
+	}
+
+	// Draw dir light
+	window.Rend.Draw(sphereMesh, gglm.NewTrMatId().Translate(gglm.NewVec3(0, 10, 0)).Scale(gglm.NewVec3(0.1, 0.1, 0.1)), sunMat)
+
+	// Draw point lights
+	for i := 0; i < len(pointLights); i++ {
+
+		pl := &pointLights[i]
+		window.Rend.Draw(cubeMesh, gglm.NewTrMatId().Translate(&pl.Pos).Scale(gglm.NewVec3(0.1, 0.1, 0.1)), sunMat)
+	}
+
+	// Chair
+	window.Rend.Draw(chairMesh, tempModelMatrix, chairMat)
+
+	// Ground
+	window.Rend.Draw(cubeMesh, gglm.NewTrMatId().Translate(gglm.NewVec3(0, -3, 0)).Scale(gglm.NewVec3(20, 1, 20)), cubeMat)
+
+	// Cubes
 	rowSize := 1
 	for y := 0; y < rowSize; y++ {
 		for x := 0; x < rowSize; x++ {
 			tempModelMatrix.Translate(gglm.NewVec3(-6, 0, 0))
-			window.Rend.Draw(cubeMesh, tempModelMatrix, matToUse)
+			window.Rend.Draw(cubeMesh, tempModelMatrix, cubeMat)
 		}
 		tempModelMatrix.Translate(gglm.NewVec3(float32(rowSize), -1, 0))
 	}
 
+	if drawSkybox {
 		g.DrawSkybox()
+	}
+
+	if renderToFbo {
+
+		fbo.UnBind()
+
+		if fboRenderDirectly {
+			renderToFbo = false
+			g.Render()
+			renderToFbo = true
+		}
+
+		screenQuadMat.DiffuseTex = fbo.Attachments[0].Id
+		screenQuadMat.Bind()
+		gl.DrawArrays(gl.TRIANGLES, 0, 6)
+	}
 }
 
-func (g *OurGame) DrawSkybox() {
+func (g *Game) DrawSkybox() {
 
 	gl.Disable(gl.CULL_FACE)
 	gl.DepthFunc(gl.LEQUAL)
-	skyboxMesh.Buf.Bind()
+	skyboxMesh.Vao.Bind()
 	skyboxMat.Bind()
 	gl.ActiveTexture(gl.TEXTURE0)
 	gl.BindTexture(gl.TEXTURE_CUBE_MAP, skyboxCmap.TexID)
@@ -415,7 +902,6 @@ func (g *OurGame) DrawSkybox() {
 
 	skyboxMat.SetUnifMat4("viewMat", viewMat)
 	skyboxMat.SetUnifMat4("projMat", &cam.ProjMat)
-	// window.Rend.Draw(cubeMesh, gglm.NewTrMatId(), skyboxMat)
 	for i := 0; i < len(skyboxMesh.SubMeshes); i++ {
 		gl.DrawElementsBaseVertexWithOffset(gl.TRIANGLES, skyboxMesh.SubMeshes[i].IndexCount, gl.UNSIGNED_INT, uintptr(skyboxMesh.SubMeshes[i].BaseIndex), skyboxMesh.SubMeshes[i].BaseVertex)
 	}
@@ -424,15 +910,18 @@ func (g *OurGame) DrawSkybox() {
 	gl.Enable(gl.CULL_FACE)
 }
 
-func (g *OurGame) FrameEnd() {
+func (g *Game) FrameEnd() {
 }
 
-func (g *OurGame) DeInit() {
+func (g *Game) DeInit() {
 	g.Win.Destroy()
 }
 
 func updateViewMat() {
 	cam.Update()
-	simpleMat.SetUnifMat4("viewMat", &cam.ViewMat)
+	unlitMat.SetUnifMat4("viewMat", &cam.ViewMat)
+	whiteMat.SetUnifMat4("viewMat", &cam.ViewMat)
+	containerMat.SetUnifMat4("viewMat", &cam.ViewMat)
+	palleteMat.SetUnifMat4("viewMat", &cam.ViewMat)
 	debugDepthMat.SetUnifMat4("viewMat", &cam.ViewMat)
 }

materials/material.go

@@ -12,10 +12,16 @@ type Material struct {
 	Name       string
 	ShaderProg shaders.ShaderProgram
 
-	DiffuseTex uint32
-
 	UnifLocs   map[string]int32
 	AttribLocs map[string]int32
+
+	// Phong shading
+	DiffuseTex  uint32
+	SpecularTex uint32
+	NormalTex   uint32
+	EmissionTex uint32
+
+	Shininess float32
 }
 
 func (m *Material) Bind() {
@@ -24,6 +30,15 @@ func (m *Material) Bind() {
 
 	gl.ActiveTexture(gl.TEXTURE0)
 	gl.BindTexture(gl.TEXTURE_2D, m.DiffuseTex)
+
+	gl.ActiveTexture(gl.TEXTURE1)
+	gl.BindTexture(gl.TEXTURE_2D, m.SpecularTex)
+
+	gl.ActiveTexture(gl.TEXTURE2)
+	gl.BindTexture(gl.TEXTURE_2D, m.NormalTex)
+
+	gl.ActiveTexture(gl.TEXTURE3)
+	gl.BindTexture(gl.TEXTURE_2D, m.EmissionTex)
 }
 
 func (m *Material) UnBind() {
@@ -32,6 +47,15 @@ func (m *Material) UnBind() {
 	//TODO: Should we unbind textures here? Are these two lines needed?
 	// gl.ActiveTexture(gl.TEXTURE0)
 	// gl.BindTexture(gl.TEXTURE_2D, 0)
+
+	// gl.ActiveTexture(gl.TEXTURE1)
+	// gl.BindTexture(gl.TEXTURE_2D, 0)
+
+	// gl.ActiveTexture(gl.TEXTURE2)
+	// gl.BindTexture(gl.TEXTURE_2D, 0)
+
+	// gl.ActiveTexture(gl.TEXTURE3)
+	// gl.BindTexture(gl.TEXTURE_2D, 0)
 }
 
 func (m *Material) GetAttribLoc(attribName 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

@@ -18,7 +18,7 @@ type Rend3DGL struct {
 func (r3d *Rend3DGL) Draw(mesh *meshes.Mesh, trMat *gglm.TrMat, mat *materials.Material) {
 
 	if mesh != r3d.BoundMesh {
-		mesh.Buf.Bind()
+		mesh.Vao.Bind()
 		r3d.BoundMesh = mesh
 	}
 

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/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 viewMat;
+uniform mat4 projMat;
+
+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);
+}
+
+//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

@@ -18,7 +18,12 @@ uniform mat4 projMat;
 
 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));
@@ -29,13 +34,50 @@ void main()
 //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;
+};
+
+uniform DirLight dirLight;
+
+struct PointLight {
+    vec3 pos;
+    vec3 diffuseColor;
+    vec3 specularColor;
+    float constant;
+    float linear;
+    float quadratic;
+};
+
+#define NUM_POINT_LIGHTS 16
+uniform PointLight pointLights[NUM_POINT_LIGHTS];
+
+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 vec3 camPos;
+uniform vec3 ambientColor = vec3(0.2, 0.2, 0.2);
 
 in vec3 vertColor;
 in vec3 vertNormal;
@@ -44,12 +86,108 @@ in vec3 fragPos;
 
 out vec4 fragColor;
 
+// Global variables used as cache for lighting calculations
+vec4 diffuseTexColor;
+vec4 specularTexColor;
+vec4 emissionTexColor;
+vec3 normalizedVertNorm;
+vec3 viewDir;
+
+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;
+
+    return finalDiffuse + finalSpecular;
+}
+
+vec3 CalcPointLight(PointLight pointLight)
+{
+    // 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 = 1.0 / (pointLight.constant + pointLight.linear * distToLight + pointLight.quadratic * (distToLight * distToLight));  
+
+    return (finalDiffuse + finalSpecular) * attenuation;
+}
+
+vec3 CalcSpotLight(SpotLight light)
+{
+    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, 0.0, 1.0);
+
+    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;
+
+    return (finalDiffuse + finalSpecular) * intensity;
+}
+
 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]);
+    }
+
+    for (int i = 0; i < NUM_SPOT_LIGHTS; i++)
+    {
+        finalColor += CalcSpotLight(spotLights[i]);
+    }
+
+    vec3 finalEmission = emissionTexColor.rgb;
+    vec3 finalAmbient = ambientColor * diffuseTexColor.rgb;
+
+    fragColor = vec4(finalColor + finalAmbient + finalEmission, 1);
 }

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) {
@@ -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()