Run init within an imgui frame

.github/workflows/build-nmage.yml

@@ -1,22 +1,28 @@
 name: build-nmage
+
 on:
   create:
   workflow_dispatch:
 
 jobs:
   build-nmage-macos:
-    runs-on: macos-10.15
+    runs-on: macos-12
     steps:
-      - name: Install golang 1.17
-        uses: actions/setup-go@v2
+    
+      - name: Install golang 1.18
+        uses: actions/setup-go@v3
         with:
-          go-version: '^1.17'
+          go-version: '^1.18'
+
       - 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
+
       - name: Install SDL2
         run: brew install sdl2{,_image,_mixer,_ttf,_gfx} pkg-config
+
       - name: Clone nmage
         run: git clone https://github.com/bloeys/nmage
+
       - name: build nmage
         working-directory: nmage
         run: go build .

.gitignore

@@ -14,4 +14,5 @@
 # Dependency directories (remove the comment below to include it)
 vendor/
 .vscode/
-imgui.ini
+imgui.ini
+*~

README.md

@@ -1,6 +1,6 @@
 # nMage
 
-[![build](https://github.com/bloeys/nmage/actions/workflows/run-nmage.yml/badge.svg)](https://github.com/bloeys/nmage/actions/workflows/run-nmage.yml)
+[![build](https://github.com/bloeys/nmage/actions/workflows/build-nmage.yml/badge.svg)](https://github.com/bloeys/nmage/actions/workflows/build-nmage.yml)
 
 nMage is a (hopefully!) high performance 3D Game Engine written in Go being developed [live](https://twitch.tv/bloeys), with recordings posted on [YouTube](https://www.youtube.com/channel/UCCf4qyNGPVwpj1HYFGahs_A).
 

assert/assert.go

@@ -0,0 +1,13 @@
+package assert
+
+import (
+	"github.com/bloeys/nmage/consts"
+	"github.com/bloeys/nmage/logging"
+)
+
+func T(check bool, msg string, args ...any) {
+
+	if consts.Debug && !check {
+		logging.ErrLog.Panicf("Assert failed: "+msg, args...)
+	}
+}

asserts/asserts.go

@@ -1,12 +0,0 @@
-package asserts
-
-import (
-	"github.com/bloeys/nmage/consts"
-	"github.com/bloeys/nmage/logging"
-)
-
-func T(check bool, msg string) {
-	if consts.Debug && !check {
-		logging.ErrLog.Panicln("Assert failed:", msg)
-	}
-}

assets/assets.go

@@ -1,27 +1,32 @@
 package assets
 
 var (
-	Textures     map[uint32]Texture = make(map[uint32]Texture)
-	TexturePaths map[string]uint32  = make(map[string]uint32)
+	Textures     = make(map[uint32]Texture)
+	TexturePaths = make(map[string]uint32)
 )
 
-func SetTexture(t Texture) {
+func AddTextureToCache(t Texture) {
 
-	if _, ok := TexturePaths[t.Path]; ok {
+	if t.Path != "" {
+		if _, ok := TexturePaths[t.Path]; ok {
+			return
+		}
+		println("Loaded texture from path:", t.Path)
+		Textures[t.TexID] = t
+		TexturePaths[t.Path] = t.TexID
 		return
 	}
 
-	println("Loaded texture:", t.Path)
-	Textures[t.TexID] = t
+	println("Loaded in-mem texture with ID:", t.TexID)
 	TexturePaths[t.Path] = t.TexID
 }
 
-func GetTexture(texID uint32) (Texture, bool) {
+func GetTextureFromCacheID(texID uint32) (Texture, bool) {
 	tex, ok := Textures[texID]
 	return tex, ok
 }
 
-func GetTexturePath(path string) (Texture, bool) {
+func GetTextureFromCachePath(path string) (Texture, bool) {
 	tex, ok := Textures[TexturePaths[path]]
 	return tex, ok
 }

assets/textures.go

@@ -2,9 +2,15 @@ package assets
 
 import (
 	"bytes"
+	"fmt"
+	"image"
 	"image/color"
+	"image/jpeg"
 	"image/png"
+	"io"
 	"os"
+	"path"
+	"strings"
 	"unsafe"
 
 	"github.com/go-gl/gl/v4.1-core/gl"
@@ -17,6 +23,7 @@ const (
 )
 
 type Texture struct {
+	//Path only exists for textures loaded from disk
 	Path   string
 	TexID  uint32
 	Width  int32
@@ -24,10 +31,34 @@ type Texture struct {
 	Pixels []byte
 }
 
-func LoadPNG(file string) (Texture, error) {
+type TextureLoadOptions struct {
+	TryLoadFromCache bool
+	WriteToCache     bool
+	GenMipMaps       bool
+	KeepPixelsInMem  bool
+}
 
-	if tex, ok := GetTexturePath(file); ok {
-		return tex, nil
+type Cubemap struct {
+	// These only exists for textures loaded from disk
+	RightPath string
+	LeftPath  string
+	TopPath   string
+	BotPath   string
+	FrontPath string
+	BackPath  string
+	TexID     uint32
+}
+
+func LoadTexturePNG(file string, loadOptions *TextureLoadOptions) (Texture, error) {
+
+	if loadOptions == nil {
+		loadOptions = &TextureLoadOptions{}
+	}
+
+	if loadOptions.TryLoadFromCache {
+		if tex, ok := GetTextureFromCachePath(file); ok {
+			return tex, nil
+		}
 	}
 
 	//Load from disk
@@ -42,27 +73,10 @@ func LoadPNG(file string) (Texture, error) {
 	}
 
 	tex := Texture{
-		Path:   file,
-		Width:  int32(img.Bounds().Dx()),
-		Height: int32(img.Bounds().Dy()),
-		Pixels: make([]byte, img.Bounds().Dx()*img.Bounds().Dy()*4),
+		Path: file,
 	}
 
-	//NOTE: We only support 8-bit channels (32-bit colors) for now
-	i := 0
-	for y := 0; y < img.Bounds().Dy(); y++ {
-		for x := 0; x < img.Bounds().Dx(); x++ {
-
-			c := color.NRGBAModel.Convert(img.At(x, y)).(color.NRGBA)
-
-			tex.Pixels[i] = c.R
-			tex.Pixels[i+1] = c.G
-			tex.Pixels[i+2] = c.B
-			tex.Pixels[i+3] = c.A
-
-			i += 4
-		}
-	}
+	tex.Pixels, tex.Width, tex.Height = pixelsFromNrgbaPng(img)
 
 	//Prepare opengl stuff
 	gl.GenTextures(1, &tex.TexID)
@@ -71,14 +85,224 @@ func LoadPNG(file string) (Texture, error) {
 	// set the texture wrapping/filtering options (on the currently bound texture object)
 	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.REPEAT)
 	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.REPEAT)
-	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR_MIPMAP_LINEAR)
+	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR)
 	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR)
 
 	// load and generate the texture
-	gl.TexImage2D(gl.TEXTURE_2D, 0, gl.RGBA, tex.Width, tex.Height, 0, gl.RGBA, gl.UNSIGNED_BYTE, unsafe.Pointer(&tex.Pixels[0]))
-	gl.GenerateMipmap(gl.TEXTURE_2D)
+	gl.TexImage2D(gl.TEXTURE_2D, 0, gl.RGBA8, tex.Width, tex.Height, 0, gl.RGBA, gl.UNSIGNED_BYTE, unsafe.Pointer(&tex.Pixels[0]))
 
-	SetTexture(tex)
+	if loadOptions.GenMipMaps {
+		gl.GenerateMipmap(tex.TexID)
+	}
+
+	if loadOptions.WriteToCache {
+		AddTextureToCache(tex)
+	}
+
+	if !loadOptions.KeepPixelsInMem {
+		tex.Pixels = nil
+	}
 
 	return tex, nil
 }
+
+func LoadTextureInMemPngImg(img image.Image, loadOptions *TextureLoadOptions) (Texture, error) {
+
+	if loadOptions == nil {
+		loadOptions = &TextureLoadOptions{}
+	}
+
+	tex := Texture{}
+	tex.Pixels, tex.Width, tex.Height = pixelsFromNrgbaPng(img)
+
+	//Prepare opengl stuff
+	gl.GenTextures(1, &tex.TexID)
+	gl.BindTexture(gl.TEXTURE_2D, tex.TexID)
+
+	// set the texture wrapping/filtering options (on the currently bound texture object)
+	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.REPEAT)
+	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.REPEAT)
+	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR)
+	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]))
+
+	if loadOptions.GenMipMaps {
+		gl.GenerateMipmap(tex.TexID)
+	}
+
+	if loadOptions.WriteToCache {
+		AddTextureToCache(tex)
+	}
+
+	if !loadOptions.KeepPixelsInMem {
+		tex.Pixels = nil
+	}
+
+	return tex, nil
+}
+
+func LoadTextureJpeg(file string, loadOptions *TextureLoadOptions) (Texture, error) {
+
+	if loadOptions == nil {
+		loadOptions = &TextureLoadOptions{}
+	}
+
+	if loadOptions.TryLoadFromCache {
+		if tex, ok := GetTextureFromCachePath(file); ok {
+			return tex, nil
+		}
+	}
+
+	//Load from disk
+	fileBytes, err := os.ReadFile(file)
+	if err != nil {
+		return Texture{}, err
+	}
+
+	img, err := jpeg.Decode(bytes.NewReader(fileBytes))
+	if err != nil {
+		return Texture{}, err
+	}
+
+	tex := Texture{
+		Path: file,
+	}
+
+	tex.Pixels, tex.Width, tex.Height = pixelsFromNrgbaPng(img)
+
+	//Prepare opengl stuff
+	gl.GenTextures(1, &tex.TexID)
+	gl.BindTexture(gl.TEXTURE_2D, tex.TexID)
+
+	// set the texture wrapping/filtering options (on the currently bound texture object)
+	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.REPEAT)
+	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.REPEAT)
+	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR)
+	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]))
+
+	if loadOptions.GenMipMaps {
+		gl.GenerateMipmap(tex.TexID)
+	}
+
+	if loadOptions.WriteToCache {
+		AddTextureToCache(tex)
+	}
+
+	if !loadOptions.KeepPixelsInMem {
+		tex.Pixels = nil
+	}
+
+	return tex, nil
+}
+
+func pixelsFromNrgbaPng(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 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)
+	}
+
+	cmap := Cubemap{
+		RightPath: rightTex,
+		LeftPath:  leftTex,
+		TopPath:   topTex,
+		BotPath:   botTex,
+		FrontPath: frontTex,
+		BackPath:  backTex,
+	}
+
+	gl.GenTextures(1, &cmap.TexID)
+	gl.BindTexture(gl.TEXTURE_CUBE_MAP, cmap.TexID)
+
+	// The order here matters
+	texturePaths := []string{rightTex, leftTex, topTex, botTex, frontTex, backTex}
+	for i := uint32(0); i < uint32(len(texturePaths)); i++ {
+
+		fPath := texturePaths[i]
+
+		//Load from disk
+		fileBytes, err := os.ReadFile(fPath)
+		if err != nil {
+			return Cubemap{}, err
+		}
+
+		img, err := imgDecoder(bytes.NewReader(fileBytes))
+		if err != nil {
+			return Cubemap{}, err
+		}
+
+		pixels, width, height := pixelDecoder(img)
+
+		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]))
+	}
+
+	// set the texture wrapping/filtering options (on the currently bound texture object)
+	gl.TexParameteri(gl.TEXTURE_CUBE_MAP, gl.TEXTURE_MIN_FILTER, gl.LINEAR)
+	gl.TexParameteri(gl.TEXTURE_CUBE_MAP, gl.TEXTURE_MAG_FILTER, gl.LINEAR)
+	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)
+
+	return cmap, nil
+}

buffers/buf_usage.go

@@ -3,7 +3,7 @@ package buffers
 import (
 	"fmt"
 
-	"github.com/bloeys/nmage/asserts"
+	"github.com/bloeys/nmage/assert"
 	"github.com/go-gl/gl/v4.1-core/gl"
 )
 
@@ -28,6 +28,6 @@ func (b BufUsage) ToGL() uint32 {
 		return gl.STREAM_DRAW
 	}
 
-	asserts.T(false, fmt.Sprintf("Unexpected BufUsage value '%v'", b))
+	assert.T(false, fmt.Sprintf("Unexpected BufUsage value '%v'", b))
 	return 0
 }

buffers/buffers.go

@@ -10,9 +10,9 @@ type Buffer struct {
 	//BufID is the ID of the VBO
 	BufID uint32
 	//IndexBufID is the ID of the index/element buffer
-	IndexBufID    uint32
-	IndexBufCount int32
-	Stride        int32
+	IndexBufID uint32
+	// IndexBufCount int32
+	Stride int32
 
 	layout []Element
 }
@@ -30,7 +30,28 @@ func (b *Buffer) SetData(values []float32) {
 	gl.BindVertexArray(b.VAOID)
 	gl.BindBuffer(gl.ARRAY_BUFFER, b.BufID)
 
-	gl.BufferData(gl.ARRAY_BUFFER, len(values)*4, gl.Ptr(values), BufUsage_Static.ToGL())
+	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)
@@ -38,11 +59,16 @@ func (b *Buffer) SetData(values []float32) {
 
 func (b *Buffer) SetIndexBufData(values []uint32) {
 
-	b.IndexBufCount = int32(len(values))
+	// b.IndexBufCount = int32(len(values))
 	gl.BindVertexArray(b.VAOID)
 	gl.BindBuffer(gl.ELEMENT_ARRAY_BUFFER, b.IndexBufID)
 
-	gl.BufferData(gl.ELEMENT_ARRAY_BUFFER, len(values)*4, gl.Ptr(values), BufUsage_Static.ToGL())
+	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)
@@ -54,6 +80,8 @@ func (b *Buffer) GetLayout() []Element {
 	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
@@ -64,6 +92,20 @@ func (b *Buffer) SetLayout(layout ...Element) {
 		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 {

buffers/element.go

@@ -3,7 +3,7 @@ package buffers
 import (
 	"fmt"
 
-	"github.com/bloeys/nmage/asserts"
+	"github.com/bloeys/nmage/assert"
 	"github.com/go-gl/gl/v4.1-core/gl"
 )
 
@@ -45,7 +45,7 @@ func (dt ElementType) GLType() uint32 {
 		return gl.FLOAT
 
 	default:
-		asserts.T(false, fmt.Sprintf("Unknown data type passed. DataType '%v'", dt))
+		assert.T(false, fmt.Sprintf("Unknown data type passed. DataType '%v'", dt))
 		return 0
 	}
 }
@@ -68,7 +68,7 @@ func (dt ElementType) CompSize() int32 {
 		return 4
 
 	default:
-		asserts.T(false, fmt.Sprintf("Unknown data type passed. DataType '%v'", dt))
+		assert.T(false, fmt.Sprintf("Unknown data type passed. DataType '%v'", dt))
 		return 0
 	}
 }
@@ -92,7 +92,7 @@ func (dt ElementType) CompCount() int32 {
 		return 4
 
 	default:
-		asserts.T(false, fmt.Sprintf("Unknown data type passed. DataType '%v'", dt))
+		assert.T(false, fmt.Sprintf("Unknown data type passed. DataType '%v'", dt))
 		return 0
 	}
 }
@@ -116,7 +116,7 @@ func (dt ElementType) Size() int32 {
 		return 4 * 4
 
 	default:
-		asserts.T(false, fmt.Sprintf("Unknown data type passed. DataType '%v'", dt))
+		assert.T(false, fmt.Sprintf("Unknown data type passed. DataType '%v'", dt))
 		return 0
 	}
 }

camera/camera.go

@@ -0,0 +1,100 @@
+package camera
+
+import (
+	"github.com/bloeys/gglm/gglm"
+)
+
+type Type int32
+
+const (
+	Type_Unknown Type = iota
+	Type_Perspective
+	Type_Orthographic
+)
+
+type Camera struct {
+	Type Type
+
+	Pos     gglm.Vec3
+	Forward gglm.Vec3
+	WorldUp gglm.Vec3
+
+	NearClip float32
+	FarClip  float32
+
+	// Perspective data
+	Fov         float32
+	AspectRatio float32
+
+	// Ortho data
+	Left, Right, Top, Bottom float32
+
+	// Matrices
+	ViewMat gglm.Mat4
+	ProjMat gglm.Mat4
+}
+
+// Update recalculates view matrix and projection matrix.
+// Should be called whenever a camera parameter changes
+func (c *Camera) Update() {
+
+	c.ViewMat = gglm.LookAtRH(&c.Pos, c.Pos.Clone().Add(&c.Forward), &c.WorldUp).Mat4
+
+	if c.Type == Type_Perspective {
+		c.ProjMat = *gglm.Perspective(c.Fov, c.AspectRatio, c.NearClip, c.FarClip)
+	} else {
+		c.ProjMat = gglm.Ortho(c.Left, c.Right, c.Top, c.Bottom, c.NearClip, c.FarClip).Mat4
+	}
+}
+
+// UpdateRotation calculates a new forward vector and then calls camera.Update()
+func (c *Camera) UpdateRotation(pitch, yaw float32) {
+
+	dir := gglm.NewVec3(
+		gglm.Cos32(yaw)*gglm.Cos32(pitch),
+		gglm.Sin32(pitch),
+		gglm.Sin32(yaw)*gglm.Cos32(pitch),
+	)
+	c.Forward = *dir.Normalize()
+	c.Update()
+}
+
+func NewPerspective(pos, forward, worldUp *gglm.Vec3, nearClip, farClip, fovRadians, aspectRatio float32) *Camera {
+
+	cam := &Camera{
+		Type:    Type_Perspective,
+		Pos:     *pos,
+		Forward: *forward,
+		WorldUp: *worldUp,
+
+		NearClip: nearClip,
+		FarClip:  farClip,
+
+		Fov:         fovRadians,
+		AspectRatio: aspectRatio,
+	}
+	cam.Update()
+
+	return cam
+}
+
+func NewOrthographic(pos, forward, worldUp *gglm.Vec3, nearClip, farClip, left, right, top, bottom float32) *Camera {
+
+	cam := &Camera{
+		Type:    Type_Orthographic,
+		Pos:     *pos,
+		Forward: *forward,
+		WorldUp: *worldUp,
+
+		NearClip: nearClip,
+		FarClip:  farClip,
+
+		Left:   left,
+		Right:  right,
+		Top:    top,
+		Bottom: bottom,
+	}
+	cam.Update()
+
+	return cam
+}

consts/flags_debug.go

@@ -1,4 +1,4 @@
-//go:build debug
+//go:build !release
 
 package consts
 

consts/flags_release.go

@@ -1,4 +1,4 @@
-//go:build !debug
+//go:build release
 
 package consts
 

engine/engine.go

@@ -1,14 +1,98 @@
 package engine
 
 import (
+	"runtime"
+
+	"github.com/bloeys/nmage/assert"
+	"github.com/bloeys/nmage/input"
+	"github.com/bloeys/nmage/renderer"
 	"github.com/bloeys/nmage/timing"
 	"github.com/go-gl/gl/v4.1-core/gl"
+	"github.com/inkyblackness/imgui-go/v4"
 	"github.com/veandco/go-sdl2/sdl"
 )
 
+var (
+	isInited = false
+)
+
 type Window struct {
-	SDLWin *sdl.Window
-	GlCtx  sdl.GLContext
+	SDLWin         *sdl.Window
+	GlCtx          sdl.GLContext
+	EventCallbacks []func(sdl.Event)
+	Rend           renderer.Render
+}
+
+func (w *Window) handleInputs() {
+
+	input.EventLoopStart()
+	imIO := imgui.CurrentIO()
+
+	for event := sdl.PollEvent(); event != nil; event = sdl.PollEvent() {
+
+		//Fire callbacks
+		for i := 0; i < len(w.EventCallbacks); i++ {
+			w.EventCallbacks[i](event)
+		}
+
+		//Internal processing
+		switch e := event.(type) {
+
+		case *sdl.MouseWheelEvent:
+
+			input.HandleMouseWheelEvent(e)
+
+			xDelta, yDelta := input.GetMouseWheelMotion()
+			imIO.AddMouseWheelDelta(float32(xDelta), float32(yDelta))
+
+		case *sdl.KeyboardEvent:
+			input.HandleKeyboardEvent(e)
+
+			if e.Type == sdl.KEYDOWN {
+				imIO.KeyPress(int(e.Keysym.Scancode))
+			} else if e.Type == sdl.KEYUP {
+				imIO.KeyRelease(int(e.Keysym.Scancode))
+			}
+
+		case *sdl.TextInputEvent:
+			imIO.AddInputCharacters(string(e.Text[:]))
+
+		case *sdl.MouseButtonEvent:
+			input.HandleMouseBtnEvent(e)
+
+		case *sdl.MouseMotionEvent:
+			input.HandleMouseMotionEvent(e)
+
+		case *sdl.WindowEvent:
+			if e.Event == sdl.WINDOWEVENT_SIZE_CHANGED {
+				w.handleWindowResize()
+			}
+
+		case *sdl.QuitEvent:
+			input.HandleQuitEvent(e)
+		}
+	}
+
+	// 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.SetMousePosition(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))
+
+	imIO.KeyShift(sdl.SCANCODE_LSHIFT, sdl.SCANCODE_RSHIFT)
+	imIO.KeyCtrl(sdl.SCANCODE_LCTRL, sdl.SCANCODE_RCTRL)
+	imIO.KeyAlt(sdl.SCANCODE_LALT, sdl.SCANCODE_RALT)
+}
+
+func (w *Window) handleWindowResize() {
+
+	fbWidth, fbHeight := w.SDLWin.GLGetDrawableSize()
+	if fbWidth <= 0 || fbHeight <= 0 {
+		return
+	}
+	gl.Viewport(0, 0, fbWidth, fbHeight)
 }
 
 func (w *Window) Destroy() error {
@@ -17,6 +101,9 @@ func (w *Window) Destroy() error {
 
 func Init() error {
 
+	isInited = true
+
+	runtime.LockOSThread()
 	timing.Init()
 	err := initSDL()
 
@@ -25,7 +112,7 @@ func Init() error {
 
 func initSDL() error {
 
-	err := sdl.Init(sdl.INIT_EVERYTHING)
+	err := sdl.Init(sdl.INIT_TIMER | sdl.INIT_VIDEO)
 	if err != nil {
 		return err
 	}
@@ -49,16 +136,17 @@ func initSDL() error {
 	return nil
 }
 
-func CreateOpenGLWindow(title string, x, y, width, height int32, flags WindowFlags) (*Window, error) {
-	return createWindow(title, x, y, width, height, WindowFlags_OPENGL|flags)
+func CreateOpenGLWindow(title string, x, y, width, height int32, flags WindowFlags, rend renderer.Render) (*Window, error) {
+	return createWindow(title, x, y, width, height, WindowFlags_OPENGL|flags, rend)
 }
 
-func CreateOpenGLWindowCentered(title string, width, height int32, flags WindowFlags) (*Window, error) {
-	return createWindow(title, -1, -1, width, height, WindowFlags_OPENGL|flags)
+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)
 }
 
-func createWindow(title string, x, y, width, height int32, flags WindowFlags) (*Window, error) {
+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
@@ -68,7 +156,11 @@ func createWindow(title string, x, y, width, height int32, flags WindowFlags) (*
 	if err != nil {
 		return nil, err
 	}
-	win := &Window{SDLWin: sdlWin}
+	win := &Window{
+		SDLWin:         sdlWin,
+		EventCallbacks: make([]func(sdl.Event), 0),
+		Rend:           rend,
+	}
 
 	win.GlCtx, err = sdlWin.GLCreateContext()
 	if err != nil {
@@ -94,11 +186,16 @@ func initOpenGL() error {
 	gl.CullFace(gl.BACK)
 	gl.FrontFace(gl.CCW)
 
+	gl.Enable(gl.BLEND)
+	gl.BlendFunc(gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA)
+
 	gl.ClearColor(0, 0, 0, 1)
 	return nil
 }
 
 func SetVSync(enabled bool) {
+	assert.T(isInited, "engine.Init was not called!")
+
 	if enabled {
 		sdl.GLSetSwapInterval(1)
 	} else {

engine/game.go

@@ -0,0 +1,68 @@
+package engine
+
+import (
+	"github.com/bloeys/nmage/timing"
+	nmageimgui "github.com/bloeys/nmage/ui/imgui"
+	"github.com/go-gl/gl/v4.1-core/gl"
+)
+
+var (
+	isRunning = false
+)
+
+type Game interface {
+	Init()
+
+	Update()
+	Render()
+	FrameEnd()
+
+	DeInit()
+}
+
+func Run(g Game, w *Window, ui nmageimgui.ImguiInfo) {
+
+	isRunning = true
+
+	// Run init with an active Imgui frame to allow init full imgui access
+	timing.FrameStarted()
+	w.handleInputs()
+
+	width, height := w.SDLWin.GetSize()
+	ui.FrameStart(float32(width), float32(height))
+
+	g.Init()
+
+	fbWidth, fbHeight := w.SDLWin.GLGetDrawableSize()
+	ui.Render(float32(width), float32(height), fbWidth, fbHeight)
+
+	timing.FrameEnded()
+
+	for isRunning {
+
+		//PERF: Cache these
+		width, height = w.SDLWin.GetSize()
+		fbWidth, fbHeight = w.SDLWin.GLGetDrawableSize()
+
+		timing.FrameStarted()
+		w.handleInputs()
+		ui.FrameStart(float32(width), float32(height))
+
+		g.Update()
+
+		gl.Clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT | gl.STENCIL_BUFFER_BIT)
+		g.Render()
+		ui.Render(float32(width), float32(height), fbWidth, fbHeight)
+		w.SDLWin.GLSwap()
+
+		g.FrameEnd()
+		w.Rend.FrameEnd()
+		timing.FrameEnded()
+	}
+
+	g.DeInit()
+}
+
+func Quit() {
+	isRunning = false
+}

entity/base_comp.go

@@ -0,0 +1,27 @@
+package entity
+
+import "github.com/bloeys/nmage/assert"
+
+var _ Comp = &BaseComp{}
+
+type BaseComp struct {
+	Entity *Entity
+}
+
+func (b *BaseComp) base() {
+}
+
+func (b *BaseComp) Init(parent *Entity) {
+	assert.T(parent != nil, "Component was initialized with a nil parent. That is not allowed.")
+	b.Entity = parent
+}
+
+func (b *BaseComp) Name() string {
+	return "Base Component"
+}
+
+func (b *BaseComp) Update() {
+}
+
+func (b *BaseComp) Destroy() {
+}

entity/comp.go

@@ -0,0 +1,62 @@
+package entity
+
+import "github.com/bloeys/nmage/assert"
+
+type Comp interface {
+	// This ensures that implementors of the Comp interface
+	// always embed BaseComp
+	base()
+
+	Name() string
+	Init(parent *Entity)
+	Update()
+	Destroy()
+}
+
+func AddComp[T Comp](e *Entity, c T) {
+
+	assert.T(!HasComp[T](e), "Entity with id '%v' already has component of type '%T'", e.ID, c)
+
+	e.Comps = append(e.Comps, c)
+	c.Init(e)
+}
+
+func HasComp[T Comp](e *Entity) bool {
+
+	for i := 0; i < len(e.Comps); i++ {
+
+		_, ok := e.Comps[i].(T)
+		if ok {
+			return true
+		}
+	}
+
+	return false
+}
+
+func GetComp[T Comp](e *Entity) (out T) {
+
+	for i := 0; i < len(e.Comps); i++ {
+
+		comp, ok := e.Comps[i].(T)
+		if ok {
+			return comp
+		}
+	}
+
+	return out
+}
+
+// DestroyComp calls Destroy on the component and then removes it from the entities component list
+func DestroyComp[T Comp](e *Entity) {
+
+	for i := 0; i < len(e.Comps); i++ {
+
+		comp, ok := e.Comps[i].(T)
+		if ok {
+			comp.Destroy()
+			e.Comps = append(e.Comps[:i], e.Comps[i+1:]...)
+			return
+		}
+	}
+}

entity/entity.go

@@ -0,0 +1,49 @@
+package entity
+
+type EntityFlag byte
+
+const (
+	EntityFlag_None  EntityFlag = 0
+	EntityFlag_Alive EntityFlag = 1 << (iota - 1)
+)
+
+const (
+	GenerationShiftBits = 64 - 8
+	FlagsShiftBits      = 64 - 16
+	IndexBitMask        = 0x00_00_FFFF_FFFF_FFFF
+)
+
+type EntityHandle uint64
+
+type Entity struct {
+
+	// Byte 1: Generation; Byte 2: Flags; Bytes 3-8: Index
+	ID    EntityHandle
+	Comps []Comp
+}
+
+func (e *Entity) HasFlag(ef EntityFlag) bool {
+	return GetFlags(e.ID)&ef > 0
+}
+
+func (e *Entity) UpdateAllComps() {
+	for i := 0; i < len(e.Comps); i++ {
+		e.Comps[i].Update()
+	}
+}
+
+func GetGeneration(id EntityHandle) byte {
+	return byte(id >> GenerationShiftBits)
+}
+
+func GetFlags(id EntityHandle) EntityFlag {
+	return EntityFlag(id >> FlagsShiftBits)
+}
+
+func GetIndex(id EntityHandle) uint64 {
+	return uint64(id & IndexBitMask)
+}
+
+func NewEntityId(generation byte, flags EntityFlag, index uint64) EntityHandle {
+	return EntityHandle(index | (uint64(generation) << GenerationShiftBits) | (uint64(flags) << FlagsShiftBits))
+}

entity/registry.go

@@ -0,0 +1,109 @@
+package entity
+
+import (
+	"github.com/bloeys/nmage/assert"
+)
+
+var (
+	// The number of slots required to be in the free list before the free list
+	// is used for creating new entries
+	FreeListUsageThreshold uint32 = 20
+)
+
+type freeListitem struct {
+	EntityIndex uint64
+	nextFree    *freeListitem
+}
+
+type Registry struct {
+	EntityCount uint64
+	Entities    []Entity
+
+	FreeList     *freeListitem
+	FreeListSize uint32
+}
+
+func (r *Registry) NewEntity() *Entity {
+
+	assert.T(r.EntityCount < uint64(len(r.Entities)), "Can not add more entities to registry because it is full")
+
+	entityToUseIndex := uint64(0)
+	var entityToUse *Entity = nil
+
+	if r.FreeList != nil && r.FreeListSize > FreeListUsageThreshold {
+
+		entityToUseIndex = r.FreeList.EntityIndex
+		entityToUse = &r.Entities[entityToUseIndex]
+		r.FreeList = r.FreeList.nextFree
+		r.FreeListSize--
+	} else {
+
+		for i := 0; i < len(r.Entities); i++ {
+
+			e := &r.Entities[i]
+			if e.HasFlag(EntityFlag_Alive) {
+				continue
+			}
+
+			entityToUse = e
+			entityToUseIndex = uint64(i)
+			break
+		}
+	}
+
+	if entityToUse == nil {
+		panic("failed to create new entity because we did not find a free spot in the registry. Why did the assert not go off?")
+	}
+
+	r.EntityCount++
+	entityToUse.ID = NewEntityId(GetGeneration(entityToUse.ID)+1, EntityFlag_Alive, entityToUseIndex)
+	assert.T(entityToUse.ID != 0, "Entity ID must not be zero")
+	return entityToUse
+}
+
+func (r *Registry) GetEntity(id EntityHandle) *Entity {
+
+	index := GetIndex(id)
+	gen := GetGeneration(id)
+
+	e := &r.Entities[index]
+	eGen := GetGeneration(e.ID)
+
+	if gen != eGen {
+		return nil
+	}
+
+	return e
+}
+
+// FreeEntity calls Destroy on all the entities components, resets the component list, resets the entity flags, then ads this entity to the free list
+func (r *Registry) FreeEntity(id EntityHandle) {
+
+	e := r.GetEntity(id)
+	if e == nil {
+		return
+	}
+
+	for i := 0; i < len(e.Comps); i++ {
+		e.Comps[i].Destroy()
+	}
+
+	r.EntityCount--
+	eIndex := GetIndex(e.ID)
+
+	e.Comps = []Comp{}
+	e.ID = NewEntityId(GetGeneration(e.ID), EntityFlag_None, eIndex)
+
+	r.FreeList = &freeListitem{
+		EntityIndex: eIndex,
+		nextFree:    r.FreeList,
+	}
+	r.FreeListSize++
+}
+
+func NewRegistry(size uint32) *Registry {
+	assert.T(size > 0, "Registry size must be more than zero")
+	return &Registry{
+		Entities: make([]Entity, size),
+	}
+}

go.mod

@@ -1,13 +1,13 @@
 module github.com/bloeys/nmage
 
-go 1.17
+go 1.18
 
-require github.com/veandco/go-sdl2 v0.4.10
+require github.com/veandco/go-sdl2 v0.4.25
 
-require github.com/go-gl/gl v0.0.0-20211025173605-bda47ffaa784
+require github.com/go-gl/gl v0.0.0-20211210172815-726fda9656d6
 
 require (
-	github.com/bloeys/assimp-go v0.4.2
-	github.com/bloeys/gglm v0.3.1
-	github.com/inkyblackness/imgui-go/v4 v4.3.0
+	github.com/bloeys/assimp-go v0.4.4
+	github.com/bloeys/gglm v0.43.0
+	github.com/inkyblackness/imgui-go/v4 v4.6.0
 )

go.sum

@@ -1,17 +1,17 @@
-github.com/bloeys/assimp-go v0.4.2 h1:ArVK74BCFcTO/rCGj2NgZG9xtbjnJdEn5npIeJx1Z04=
-github.com/bloeys/assimp-go v0.4.2/go.mod h1:my3yRxT7CfOztmvi+0svmwbaqw0KFrxaHxncoyaEIP0=
-github.com/bloeys/gglm v0.3.1 h1:Sy9upW7SBsBfDXrSmEhid3aQ+7J7itej+upwcxOnPMQ=
-github.com/bloeys/gglm v0.3.1/go.mod h1:qwJQ0WzV191wAMwlGicbfbChbKoSedMk7gFFX6GnyOk=
+github.com/bloeys/assimp-go v0.4.4 h1:Yn5e/RpE0Oes0YMBy8O7KkwAO4R/RpgrZPJCt08dVIU=
+github.com/bloeys/assimp-go v0.4.4/go.mod h1:my3yRxT7CfOztmvi+0svmwbaqw0KFrxaHxncoyaEIP0=
+github.com/bloeys/gglm v0.43.0 h1:ZpOghR3PHfpkigTDh+FqxLsF0gN8CD6s/bWoei6LyxI=
+github.com/bloeys/gglm v0.43.0/go.mod h1:qwJQ0WzV191wAMwlGicbfbChbKoSedMk7gFFX6GnyOk=
 github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/go-gl/gl v0.0.0-20211025173605-bda47ffaa784 h1:1Zi56D0LNfvkzM+BdoxKryvUEdyWO7LP8oRT+oSYJW0=
-github.com/go-gl/gl v0.0.0-20211025173605-bda47ffaa784/go.mod h1:9YTyiznxEY1fVinfM7RvRcjRHbw2xLBJ3AAGIT0I4Nw=
-github.com/inkyblackness/imgui-go/v4 v4.3.0 h1:iyAzqWXq/dG5+6ckDPhGivtrIo6AywGQMvENKzun04s=
-github.com/inkyblackness/imgui-go/v4 v4.3.0/go.mod h1:g8SAGtOYUP7rYaOB2AsVKCEHmPMDmJKgt4z6d+flhb0=
+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/inkyblackness/imgui-go/v4 v4.6.0 h1:ShcnXEYl80+xREGBY9OpGWePA6FfJChY9Varsm+3jjE=
+github.com/inkyblackness/imgui-go/v4 v4.6.0/go.mod h1:g8SAGtOYUP7rYaOB2AsVKCEHmPMDmJKgt4z6d+flhb0=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/testify v1.3.0 h1:TivCn/peBQ7UY8ooIcPgZFpTNSz0Q2U6UrFlUfqbe0Q=
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
-github.com/veandco/go-sdl2 v0.4.10 h1:8QoD2bhWl7SbQDflIAUYWfl9Vq+mT8/boJFAUzAScgY=
-github.com/veandco/go-sdl2 v0.4.10/go.mod h1:OROqMhHD43nT4/i9crJukyVecjPNYYuCofep6SNiAjY=
+github.com/veandco/go-sdl2 v0.4.25 h1:J5ac3KKOccp/0xGJA1PaNYKPUcZm19IxhDGs8lJofPI=
+github.com/veandco/go-sdl2 v0.4.25/go.mod h1:OROqMhHD43nT4/i9crJukyVecjPNYYuCofep6SNiAjY=

input/input.go

@@ -31,10 +31,11 @@ type mouseWheelState struct {
 }
 
 var (
-	keyMap      = make(map[sdl.Keycode]*keyState)
-	mouseBtnMap = make(map[int]*mouseBtnState)
-	mouseMotion = mouseMotionState{}
-	mouseWheel  = mouseWheelState{}
+	keyMap        = make(map[sdl.Keycode]*keyState)
+	mouseBtnMap   = make(map[int]*mouseBtnState)
+	mouseMotion   = mouseMotionState{}
+	mouseWheel    = mouseWheelState{}
+	quitRequested bool
 )
 
 func EventLoopStart() {
@@ -55,6 +56,16 @@ func EventLoopStart() {
 
 	mouseWheel.XDelta = 0
 	mouseWheel.YDelta = 0
+
+	quitRequested = false
+}
+
+func HandleQuitEvent(e *sdl.QuitEvent) {
+	quitRequested = true
+}
+
+func IsQuitClicked() bool {
+	return quitRequested
 }
 
 func HandleKeyboardEvent(e *sdl.KeyboardEvent) {

level/level.go

@@ -0,0 +1,20 @@
+package level
+
+import (
+	"github.com/bloeys/nmage/assert"
+	"github.com/bloeys/nmage/entity"
+)
+
+type Level struct {
+	*entity.Registry
+	Name string
+}
+
+func NewLevel(name string, maxEntities uint32) *Level {
+
+	assert.T(name != "", "Level name can not be empty")
+	return &Level{
+		Name:     name,
+		Registry: entity.NewRegistry(maxEntities),
+	}
+}

main.go

@@ -2,64 +2,109 @@ package main
 
 import (
 	"fmt"
-	"runtime"
 
-	"github.com/bloeys/assimp-go/asig"
 	"github.com/bloeys/gglm/gglm"
+	"github.com/bloeys/nmage/assets"
+	"github.com/bloeys/nmage/camera"
 	"github.com/bloeys/nmage/engine"
+	"github.com/bloeys/nmage/entity"
 	"github.com/bloeys/nmage/input"
+	"github.com/bloeys/nmage/level"
 	"github.com/bloeys/nmage/logging"
 	"github.com/bloeys/nmage/materials"
 	"github.com/bloeys/nmage/meshes"
+	"github.com/bloeys/nmage/renderer/rend3dgl"
 	"github.com/bloeys/nmage/timing"
+	nmageimgui "github.com/bloeys/nmage/ui/imgui"
 	"github.com/go-gl/gl/v4.1-core/gl"
 	"github.com/inkyblackness/imgui-go/v4"
 	"github.com/veandco/go-sdl2/sdl"
 )
 
-//TODO: Tasks:
-//Engine loop
-//Proper rendering setup
-//Flesh out the material system
-//Object
-//Abstract UI
-//Audio
+// @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
 
-//Low Priority:
-//	Proper Asset loading
-
-type ImguiInfo struct {
-	imCtx *imgui.Context
-
-	vaoID      uint32
-	vboID      uint32
-	indexBufID uint32
-	texID      uint32
-}
+const (
+	camSpeed         = 15
+	mouseSensitivity = 0.5
+)
 
 var (
-	winWidth  int32 = 1280
-	winHeight int32 = 720
+	window *engine.Window
 
-	isRunning bool = true
-	window    *engine.Window
+	pitch float32 = 0
+	yaw   float32 = -90
+	cam   *camera.Camera
 
 	simpleMat *materials.Material
-	imguiMat  *materials.Material
-	cubeMesh  *meshes.Mesh
+	skyboxMat *materials.Material
 
-	modelMat = gglm.NewTrMatId()
-	projMat  = &gglm.Mat4{}
+	chairMesh  *meshes.Mesh
+	cubeMesh   *meshes.Mesh
+	skyboxMesh *meshes.Mesh
 
-	imguiInfo *ImguiInfo
+	cubeModelMat = gglm.NewTrMatId()
 
-	camPos     = gglm.NewVec3(0, 0, -10)
-	camForward = gglm.NewVec3(0, 0, 1)
+	lightPos1   = gglm.NewVec3(-2, 0, 2)
+	lightColor1 = gglm.NewVec3(1, 1, 1)
+
+	debugDepthMat        *materials.Material
+	debugDrawDepthBuffer bool
+
+	skyboxCmap assets.Cubemap
 )
 
+type OurGame struct {
+	Win       *engine.Window
+	ImGUIInfo nmageimgui.ImguiInfo
+}
+
+type TransformComp struct {
+	entity.BaseComp
+
+	Pos   *gglm.Vec3
+	Rot   *gglm.Quat
+	Scale *gglm.Vec3
+}
+
+func (t *TransformComp) Name() string {
+	return "Transform Component"
+}
+
+func Test() {
+
+	lvl := level.NewLevel("test level", 1000)
+	e1 := lvl.Registry.NewEntity()
+
+	trComp := entity.GetComp[*TransformComp](e1)
+	fmt.Println("Get comp before adding any:", trComp)
+
+	entity.AddComp(e1, &TransformComp{
+		Pos:   gglm.NewVec3(0, 0, 0),
+		Rot:   gglm.NewQuatEulerXYZ(0, 0, 0),
+		Scale: gglm.NewVec3(0, 0, 0),
+	})
+	trComp = entity.GetComp[*TransformComp](e1)
+	fmt.Println("Get transform comp:", trComp)
+
+	fmt.Printf("Entity: %+v\n", e1)
+	fmt.Printf("Entity: %+v\n", lvl.Registry.NewEntity())
+	fmt.Printf("Entity: %+v\n", lvl.Registry.NewEntity())
+	fmt.Printf("Entity: %+v\n", lvl.Registry.NewEntity())
+}
+
 func main() {
 
-	runtime.LockOSThread()
+	// Test()
+	// return
 
 	//Init engine
 	err := engine.Init()
@@ -68,7 +113,7 @@ func main() {
 	}
 
 	//Create window
-	window, err = engine.CreateOpenGLWindowCentered("nMage", winWidth, winHeight, engine.WindowFlags_RESIZABLE)
+	window, err = engine.CreateOpenGLWindowCentered("nMage", 1280, 720, engine.WindowFlags_RESIZABLE, rend3dgl.NewRend3DGL())
 	if err != nil {
 		logging.ErrLog.Fatalln("Failed to create window. Err: ", err)
 	}
@@ -76,384 +121,257 @@ func main() {
 
 	engine.SetVSync(false)
 
+	game := &OurGame{
+		Win:       window,
+		ImGUIInfo: nmageimgui.NewImGUI(),
+	}
+	window.EventCallbacks = append(window.EventCallbacks, game.handleWindowEvents)
+
+	engine.Run(game, window, game.ImGUIInfo)
+}
+
+func (g *OurGame) handleWindowEvents(e sdl.Event) {
+
+	switch e := e.(type) {
+	case *sdl.WindowEvent:
+		if e.Event == sdl.WINDOWEVENT_SIZE_CHANGED {
+
+			width := e.Data1
+			height := e.Data2
+			cam.AspectRatio = float32(width) / float32(height)
+			cam.Update()
+
+			simpleMat.SetUnifMat4("projMat", &cam.ProjMat)
+			debugDepthMat.SetUnifMat4("projMat", &cam.ProjMat)
+		}
+	}
+}
+
+func (g *OurGame) Init() {
+
+	var err error
+
 	//Create materials
-	simpleMat = materials.NewMaterial("Simple Mat", "./res/shaders/simple")
-	imguiMat = materials.NewMaterial("ImGUI Mat", "./res/shaders/imgui")
+	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")
 
 	//Load meshes
-	cubeMesh, err = meshes.NewMesh("Cube", "./res/models/tex-cube.fbx", asig.PostProcess(0))
+	cubeMesh, err = meshes.NewMesh("Cube", "./res/models/tex-cube.fbx", 0)
 	if err != nil {
-		logging.ErrLog.Fatalln("Failed to load cube mesh. Err: ", err)
+		logging.ErrLog.Fatalln("Failed to load mesh. Err: ", err)
 	}
 
-	//Set mesh textures on material
-	for _, v := range cubeMesh.TextureIDs {
-		simpleMat.AddTextureID(v)
+	chairMesh, err = meshes.NewMesh("Chair", "./res/models/chair.fbx", 0)
+	if err != nil {
+		logging.ErrLog.Fatalln("Failed to load mesh. Err: ", err)
 	}
 
-	initImGUI()
+	skyboxMesh, err = meshes.NewMesh("Skybox", "./res/models/skybox-cube.obj", 0)
+	if err != nil {
+		logging.ErrLog.Fatalln("Failed to load mesh. Err: ", err)
+	}
 
-	//Enable vertex attributes
-	simpleMat.SetAttribute(cubeMesh.Buf)
+	//Load textures
+	tex, err := assets.LoadTexturePNG("./res/textures/pallete-endesga-64-1x.png", nil)
+	if err != nil {
+		logging.ErrLog.Fatalln("Failed to load texture. Err: ", err)
+	}
+
+	skyboxCmap, err = assets.LoadCubemapTextures(
+		"./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",
+	)
+	if err != nil {
+		logging.ErrLog.Fatalln("Failed to load cubemap. Err: ", err)
+	}
+
+	// Configure materials
+	simpleMat.DiffuseTex = tex.TexID
 
 	//Movement, scale and rotation
 	translationMat := gglm.NewTranslationMat(gglm.NewVec3(0, 0, 0))
-	scaleMat := gglm.NewScaleMat(gglm.NewVec3(0.25, 0.25, 0.25))
-	rotMat := gglm.NewRotMat(gglm.NewQuatEuler(gglm.NewVec3(0, 0, 0).AsRad()))
+	scaleMat := gglm.NewScaleMat(gglm.NewVec3(1, 1, 1))
+	rotMat := gglm.NewRotMat(gglm.NewQuatEuler(gglm.NewVec3(-90, -90, 0).AsRad()))
 
-	modelMat.Mul(translationMat.Mul(rotMat.Mul(scaleMat)))
-	simpleMat.SetUnifMat4("modelMat", &modelMat.Mat4)
+	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)
 
-	//Moves objects into the cameras view
 	updateViewMat()
 
-	//Perspective/Depth
-	projMat := gglm.Perspective(45*gglm.Deg2Rad, float32(winWidth)/float32(winHeight), 0.1, 500)
-	simpleMat.SetUnifMat4("projMat", projMat)
-
 	//Lights
-	simpleMat.SetUnifVec3("lightPos1", &lightPos1)
-	simpleMat.SetUnifVec3("lightColor1", &lightColor1)
+	simpleMat.SetUnifVec3("lightPos1", lightPos1)
+	simpleMat.SetUnifVec3("lightColor1", lightColor1)
+}
 
-	//Game loop
-	for isRunning {
+func (g *OurGame) Update() {
 
-		timing.FrameStarted()
-
-		handleInputs()
-		runGameLogic()
-
-		draw()
-
-		timing.FrameEnded()
-
-		window.SDLWin.SetTitle(fmt.Sprintf("FPS: %.0f; Elapsed: %v", 1/timing.DT(), timing.ElapsedTime()))
+	if input.IsQuitClicked() || input.KeyClicked(sdl.K_ESCAPE) {
+		engine.Quit()
 	}
+
+	g.updateCameraLookAround()
+	g.updateCameraPos()
+
+	//Rotating cubes
+	if input.KeyDown(sdl.K_SPACE) {
+		cubeModelMat.Rotate(10*timing.DT()*gglm.Deg2Rad, gglm.NewVec3(1, 1, 1).Normalize())
+	}
+
+	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)
+	}
+
+	if input.KeyClicked(sdl.K_F4) {
+		fmt.Printf("Pos: %s; Forward: %s; |Forward|: %f\n", cam.Pos.String(), cam.Forward.String(), cam.Forward.Mag())
+	}
+
+	g.Win.SDLWin.SetTitle(fmt.Sprint("nMage (", timing.GetAvgFPS(), " fps)"))
+}
+
+func (g *OurGame) updateCameraLookAround() {
+
+	mouseX, mouseY := input.GetMouseMotion()
+	if (mouseX == 0 && mouseY == 0) || !input.MouseDown(sdl.BUTTON_RIGHT) {
+		return
+	}
+
+	// Yaw
+	yaw += float32(mouseX) * mouseSensitivity * timing.DT()
+
+	// Pitch
+	pitch += float32(-mouseY) * mouseSensitivity * timing.DT()
+	if pitch > 89.0 {
+		pitch = 89.0
+	}
+
+	if pitch < -89.0 {
+		pitch = -89.0
+	}
+
+	// Update cam forward
+	cam.UpdateRotation(pitch, yaw)
+
+	updateViewMat()
+}
+
+func (g *OurGame) updateCameraPos() {
+
+	update := false
+
+	var camSpeedScale float32 = 1.0
+	if input.KeyDown(sdl.K_LSHIFT) {
+		camSpeedScale = 2
+	}
+
+	// Forward and backward
+	if input.KeyDown(sdl.K_w) {
+		cam.Pos.Add(cam.Forward.Clone().Scale(camSpeed * camSpeedScale * timing.DT()))
+		update = true
+	} else if input.KeyDown(sdl.K_s) {
+		cam.Pos.Add(cam.Forward.Clone().Scale(-camSpeed * camSpeedScale * timing.DT()))
+		update = true
+	}
+
+	// Left and right
+	if input.KeyDown(sdl.K_d) {
+		cam.Pos.Add(gglm.Cross(&cam.Forward, &cam.WorldUp).Normalize().Scale(camSpeed * camSpeedScale * timing.DT()))
+		update = true
+	} else if input.KeyDown(sdl.K_a) {
+		cam.Pos.Add(gglm.Cross(&cam.Forward, &cam.WorldUp).Normalize().Scale(-camSpeed * camSpeedScale * timing.DT()))
+		update = true
+	}
+
+	if update {
+		updateViewMat()
+	}
+}
+
+func (g *OurGame) Render() {
+
+	matToUse := simpleMat
+	imgui.Checkbox("Debug depth buffer", &debugDrawDepthBuffer)
+	if debugDrawDepthBuffer {
+		matToUse = debugDepthMat
+	}
+
+	tempModelMatrix := cubeModelMat.Clone()
+	window.Rend.Draw(chairMesh, tempModelMatrix, matToUse)
+
+	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)
+		}
+		tempModelMatrix.Translate(gglm.NewVec3(float32(rowSize), -1, 0))
+	}
+
+	g.DrawSkybox()
+}
+
+func (g *OurGame) DrawSkybox() {
+
+	gl.Disable(gl.CULL_FACE)
+	gl.DepthFunc(gl.LEQUAL)
+	skyboxMesh.Buf.Bind()
+	skyboxMat.Bind()
+	gl.ActiveTexture(gl.TEXTURE0)
+	gl.BindTexture(gl.TEXTURE_CUBE_MAP, skyboxCmap.TexID)
+
+	viewMat := cam.ViewMat.Clone()
+	viewMat.Set(0, 3, 0)
+	viewMat.Set(1, 3, 0)
+	viewMat.Set(2, 3, 0)
+	viewMat.Set(3, 0, 0)
+	viewMat.Set(3, 1, 0)
+	viewMat.Set(3, 2, 0)
+	viewMat.Set(3, 3, 0)
+
+	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)
+	}
+
+	gl.DepthFunc(gl.LESS)
+	gl.Enable(gl.CULL_FACE)
+}
+
+func (g *OurGame) FrameEnd() {
+}
+
+func (g *OurGame) DeInit() {
+	g.Win.Destroy()
 }
 
 func updateViewMat() {
-	targetPos := camPos.Clone().Add(camForward)
-	viewMat := gglm.LookAt(camPos, targetPos, gglm.NewVec3(0, 1, 0))
-	simpleMat.SetUnifMat4("viewMat", &viewMat.Mat4)
-}
-
-func initImGUI() {
-
-	imguiInfo = &ImguiInfo{
-		imCtx: imgui.CreateContext(nil),
-	}
-
-	imIO := imgui.CurrentIO()
-	imIO.SetBackendFlags(imIO.GetBackendFlags() | imgui.BackendFlagsRendererHasVtxOffset)
-
-	gl.GenVertexArrays(1, &imguiInfo.vaoID)
-	gl.GenBuffers(1, &imguiInfo.vboID)
-	gl.GenBuffers(1, &imguiInfo.indexBufID)
-	gl.GenTextures(1, &imguiInfo.texID)
-
-	// Upload font to gpu
-	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)
-
-	image := imIO.Fonts().TextureDataAlpha8()
-	gl.TexImage2D(gl.TEXTURE_2D, 0, gl.RED, int32(image.Width), int32(image.Height), 0, gl.RED, gl.UNSIGNED_BYTE, image.Pixels)
-
-	// Store our identifier
-	imIO.Fonts().SetTextureID(imgui.TextureID(imguiInfo.texID))
-
-	//Shader attributes
-	imguiMat.Bind()
-	imguiMat.EnableAttribute("Position")
-	imguiMat.EnableAttribute("UV")
-	imguiMat.EnableAttribute("Color")
-	imguiMat.UnBind()
-
-	//Init imgui input mapping
-	keys := map[int]int{
-		imgui.KeyTab:        sdl.SCANCODE_TAB,
-		imgui.KeyLeftArrow:  sdl.SCANCODE_LEFT,
-		imgui.KeyRightArrow: sdl.SCANCODE_RIGHT,
-		imgui.KeyUpArrow:    sdl.SCANCODE_UP,
-		imgui.KeyDownArrow:  sdl.SCANCODE_DOWN,
-		imgui.KeyPageUp:     sdl.SCANCODE_PAGEUP,
-		imgui.KeyPageDown:   sdl.SCANCODE_PAGEDOWN,
-		imgui.KeyHome:       sdl.SCANCODE_HOME,
-		imgui.KeyEnd:        sdl.SCANCODE_END,
-		imgui.KeyInsert:     sdl.SCANCODE_INSERT,
-		imgui.KeyDelete:     sdl.SCANCODE_DELETE,
-		imgui.KeyBackspace:  sdl.SCANCODE_BACKSPACE,
-		imgui.KeySpace:      sdl.SCANCODE_BACKSPACE,
-		imgui.KeyEnter:      sdl.SCANCODE_RETURN,
-		imgui.KeyEscape:     sdl.SCANCODE_ESCAPE,
-		imgui.KeyA:          sdl.SCANCODE_A,
-		imgui.KeyC:          sdl.SCANCODE_C,
-		imgui.KeyV:          sdl.SCANCODE_V,
-		imgui.KeyX:          sdl.SCANCODE_X,
-		imgui.KeyY:          sdl.SCANCODE_Y,
-		imgui.KeyZ:          sdl.SCANCODE_Z,
-	}
-
-	// Keyboard mapping. ImGui will use those indices to peek into the io.KeysDown[] array.
-	for imguiKey, nativeKey := range keys {
-		imIO.KeyMap(imguiKey, nativeKey)
-	}
-}
-
-func handleInputs() {
-
-	input.EventLoopStart()
-	imIO := imgui.CurrentIO()
-
-	for event := sdl.PollEvent(); event != nil; event = sdl.PollEvent() {
-
-		switch e := event.(type) {
-
-		case *sdl.MouseWheelEvent:
-
-			input.HandleMouseWheelEvent(e)
-
-			xDelta, yDelta := input.GetMouseWheelMotion()
-			imIO.AddMouseWheelDelta(float32(xDelta), float32(yDelta))
-
-		case *sdl.KeyboardEvent:
-			input.HandleKeyboardEvent(e)
-
-			if e.Type == sdl.KEYDOWN {
-				imIO.KeyPress(int(e.Keysym.Scancode))
-			} else if e.Type == sdl.KEYUP {
-				imIO.KeyRelease(int(e.Keysym.Scancode))
-			}
-
-		case *sdl.TextInputEvent:
-			imIO.AddInputCharacters(string(e.Text[:]))
-
-		case *sdl.MouseButtonEvent:
-			input.HandleMouseBtnEvent(e)
-
-		case *sdl.MouseMotionEvent:
-			input.HandleMouseMotionEvent(e)
-
-		case *sdl.QuitEvent:
-			isRunning = false
-		}
-	}
-
-	currWinWidth, currWinHeight := window.SDLWin.GetSize()
-	if winWidth != currWinWidth || winHeight != currWinHeight {
-		handleWindowResize(currWinWidth, currWinHeight)
-	}
-
-	// 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.SetMousePosition(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))
-
-	imIO.KeyShift(sdl.SCANCODE_LSHIFT, sdl.SCANCODE_RSHIFT)
-	imIO.KeyCtrl(sdl.SCANCODE_LCTRL, sdl.SCANCODE_RCTRL)
-	imIO.KeyAlt(sdl.SCANCODE_LALT, sdl.SCANCODE_RALT)
-}
-
-func handleWindowResize(newWinWidth, newWinHeight int32) {
-
-	winWidth = newWinWidth
-	winHeight = newWinHeight
-
-	fbWidth, fbHeight := window.SDLWin.GLGetDrawableSize()
-	if fbWidth <= 0 || fbHeight <= 0 {
-		return
-	}
-	gl.Viewport(0, 0, fbWidth, fbHeight)
-
-	projMat = gglm.Perspective(45*gglm.Deg2Rad, float32(winWidth)/float32(winHeight), 0.1, 20)
-	simpleMat.SetUnifMat4("projMat", projMat)
-}
-
-var time uint64 = 0
-var name string = ""
-
-var ambientColor gglm.Vec3 = *gglm.NewVec3(1, 1, 1)
-var ambientColorStrength float32 = 0.1
-
-var lightPos1 gglm.Vec3 = *gglm.NewVec3(2, 2, 0)
-var lightColor1 gglm.Vec3 = *gglm.NewVec3(1, 1, 1)
-
-func runGameLogic() {
-
-	var camSpeed float32 = 15
-	if input.KeyDown(sdl.K_w) {
-		camPos.Data[1] += camSpeed * timing.DT()
-		updateViewMat()
-	}
-	if input.KeyDown(sdl.K_s) {
-		camPos.Data[1] -= camSpeed * timing.DT()
-		updateViewMat()
-	}
-	if input.KeyDown(sdl.K_d) {
-		camPos.Data[0] += camSpeed * timing.DT()
-		updateViewMat()
-	}
-	if input.KeyDown(sdl.K_a) {
-		camPos.Data[0] -= camSpeed * timing.DT()
-		updateViewMat()
-	}
-
-	if input.GetMouseWheelYNorm() > 0 {
-		camPos.Data[2] += 1
-		updateViewMat()
-	} else if input.GetMouseWheelYNorm() < 0 {
-		camPos.Data[2] -= 1
-		updateViewMat()
-	}
-
-	modelMat.Rotate(10*timing.DT()*gglm.Deg2Rad, gglm.NewVec3(1, 1, 1).Normalize())
-	simpleMat.SetUnifMat4("modelMat", &modelMat.Mat4)
-
-	//ImGUI
-	imIO := imgui.CurrentIO()
-	imIO.SetDisplaySize(imgui.Vec2{X: float32(winWidth), Y: float32(winHeight)})
-
-	// Setup time step (we don't use SDL_GetTicks() because it is using millisecond resolution)
-	frequency := sdl.GetPerformanceFrequency()
-	currentTime := sdl.GetPerformanceCounter()
-	if time > 0 {
-		imIO.SetDeltaTime(float32(currentTime-time) / float32(frequency))
-	} else {
-		imIO.SetDeltaTime(1.0 / 60.0)
-	}
-	time = currentTime
-
-	imgui.NewFrame()
-
-	if imgui.SliderFloat3("Ambient Color", &ambientColor.Data, 0, 1) {
-		simpleMat.SetUnifVec3("ambientLightColor", &ambientColor)
-	}
-
-	if imgui.SliderFloat("Ambient Color Strength", &ambientColorStrength, 0, 1) {
-		simpleMat.SetUnifFloat32("ambientStrength", ambientColorStrength)
-	}
-
-	if imgui.SliderFloat3("Light Pos 1", &lightPos1.Data, -10, 10) {
-		simpleMat.SetUnifVec3("lightPos1", &lightPos1)
-	}
-
-	if imgui.SliderFloat3("Light Color 1", &lightColor1.Data, 0, 1) {
-		simpleMat.SetUnifVec3("lightColor1", &lightColor1)
-	}
-
-	imgui.Render()
-}
-
-func draw() {
-
-	gl.Clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT)
-
-	simpleMat.Bind()
-	cubeMesh.Buf.Bind()
-	tempModelMat := modelMat.Clone()
-
-	rowSize := 10
-	for y := 0; y < rowSize; y++ {
-		for x := 0; x < rowSize; x++ {
-			simpleMat.SetUnifMat4("modelMat", &tempModelMat.Translate(gglm.NewVec3(-1, 0, 0)).Mat4)
-			gl.DrawElements(gl.TRIANGLES, cubeMesh.Buf.IndexBufCount, gl.UNSIGNED_INT, gl.PtrOffset(0))
-		}
-		simpleMat.SetUnifMat4("modelMat", &tempModelMat.Translate(gglm.NewVec3(float32(rowSize), -1, 0)).Mat4)
-	}
-	simpleMat.SetUnifMat4("modelMat", &modelMat.Mat4)
-
-	drawUI()
-	window.SDLWin.GLSwap()
-}
-
-func drawUI() {
-
-	// Avoid rendering when minimized, scale coordinates for retina displays (screen coordinates != framebuffer coordinates)
-	fbWidth, fbHeight := window.SDLWin.GLGetDrawableSize()
-	if fbWidth <= 0 || fbHeight <= 0 {
-		return
-	}
-
-	drawData := imgui.RenderedDrawData()
-	drawData.ScaleClipRects(imgui.Vec2{
-		X: float32(fbWidth) / float32(winWidth),
-		Y: float32(fbHeight) / float32(winHeight),
-	})
-
-	// Setup render state: alpha-blending enabled, no face culling, no depth testing, scissor enabled, polygon fill
-	gl.Enable(gl.BLEND)
-	gl.BlendEquation(gl.FUNC_ADD)
-	gl.BlendFunc(gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA)
-	gl.Disable(gl.CULL_FACE)
-	gl.Disable(gl.DEPTH_TEST)
-	gl.Enable(gl.SCISSOR_TEST)
-	gl.PolygonMode(gl.FRONT_AND_BACK, gl.FILL)
-
-	// Setup viewport, orthographic projection matrix
-	// Our visible imgui space lies from draw_data->DisplayPos (top left) to draw_data->DisplayPos+data_data->DisplaySize (bottom right).
-	// DisplayMin is typically (0,0) for single viewport apps.
-
-	imguiMat.Bind()
-
-	gl.Uniform1i(gl.GetUniformLocation(imguiMat.ShaderProg.ID, gl.Str("Texture\x00")), 0)
-
-	//PERF: only update the ortho matrix on window resize
-	orthoMat := gglm.Ortho(0, float32(winWidth), 0, float32(winHeight), 0, 20)
-	imguiMat.SetUnifMat4("ProjMtx", &orthoMat.Mat4)
-	gl.BindSampler(0, 0) // Rely on combined texture/sampler state.
-
-	// Recreate the VAO every time
-	// (This is to easily allow multiple GL contexts. VAO are not shared among GL contexts, and
-	// we don't track creation/deletion of windows so we don't have an obvious key to use to cache them.)
-	gl.BindVertexArray(imguiInfo.vaoID)
-	gl.BindBuffer(gl.ARRAY_BUFFER, imguiInfo.vboID)
-
-	vertexSize, vertexOffsetPos, vertexOffsetUv, vertexOffsetCol := imgui.VertexBufferLayout()
-	imguiMat.EnableAttribute("Position")
-	imguiMat.EnableAttribute("UV")
-	imguiMat.EnableAttribute("Color")
-	gl.VertexAttribPointerWithOffset(uint32(imguiMat.GetAttribLoc("Position")), 2, gl.FLOAT, false, int32(vertexSize), uintptr(vertexOffsetPos))
-	gl.VertexAttribPointerWithOffset(uint32(imguiMat.GetAttribLoc("UV")), 2, gl.FLOAT, false, int32(vertexSize), uintptr(vertexOffsetUv))
-	gl.VertexAttribPointerWithOffset(uint32(imguiMat.GetAttribLoc("Color")), 4, gl.UNSIGNED_BYTE, true, int32(vertexSize), uintptr(vertexOffsetCol))
-
-	indexSize := imgui.IndexBufferLayout()
-	drawType := gl.UNSIGNED_SHORT
-	if indexSize == 4 {
-		drawType = gl.UNSIGNED_INT
-	}
-
-	// Draw
-	for _, list := range drawData.CommandLists() {
-
-		vertexBuffer, vertexBufferSize := list.VertexBuffer()
-		gl.BindBuffer(gl.ARRAY_BUFFER, imguiInfo.vboID)
-		gl.BufferData(gl.ARRAY_BUFFER, vertexBufferSize, vertexBuffer, gl.STREAM_DRAW)
-
-		indexBuffer, indexBufferSize := list.IndexBuffer()
-		gl.BindBuffer(gl.ELEMENT_ARRAY_BUFFER, imguiInfo.indexBufID)
-		gl.BufferData(gl.ELEMENT_ARRAY_BUFFER, indexBufferSize, indexBuffer, gl.STREAM_DRAW)
-
-		for _, cmd := range list.Commands() {
-			if cmd.HasUserCallback() {
-				cmd.CallUserCallback(list)
-			} else {
-
-				gl.BindTexture(gl.TEXTURE_2D, imguiInfo.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.ElementCount()), uint32(drawType), gl.PtrOffset(cmd.IndexOffset()*indexSize), int32(cmd.VertexOffset()))
-			}
-		}
-	}
-
-	//Reset gl state
-	gl.Disable(gl.BLEND)
-	gl.Disable(gl.SCISSOR_TEST)
-	gl.Enable(gl.CULL_FACE)
-	gl.Enable(gl.DEPTH_TEST)
+	cam.Update()
+	simpleMat.SetUnifMat4("viewMat", &cam.ViewMat)
+	debugDepthMat.SetUnifMat4("viewMat", &cam.ViewMat)
 }

materials/material.go

@@ -2,7 +2,7 @@ package materials
 
 import (
 	"github.com/bloeys/gglm/gglm"
-	"github.com/bloeys/nmage/buffers"
+	"github.com/bloeys/nmage/assert"
 	"github.com/bloeys/nmage/logging"
 	"github.com/bloeys/nmage/shaders"
 	"github.com/go-gl/gl/v4.1-core/gl"
@@ -11,50 +11,53 @@ import (
 type Material struct {
 	Name       string
 	ShaderProg shaders.ShaderProgram
-	TexIDs     []uint32
+
+	DiffuseTex uint32
+
+	UnifLocs   map[string]int32
+	AttribLocs map[string]int32
 }
 
 func (m *Material) Bind() {
 
 	gl.UseProgram(m.ShaderProg.ID)
-	for i, v := range m.TexIDs {
-		gl.ActiveTexture(gl.TEXTURE0 + uint32(i))
-		gl.BindTexture(gl.TEXTURE_2D, v)
-	}
+
+	gl.ActiveTexture(gl.TEXTURE0)
+	gl.BindTexture(gl.TEXTURE_2D, m.DiffuseTex)
 }
 
 func (m *Material) UnBind() {
-
 	gl.UseProgram(0)
-	for i := range m.TexIDs {
-		gl.ActiveTexture(gl.TEXTURE0 + uint32(i))
-		gl.BindTexture(gl.TEXTURE_2D, 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 {
-	return gl.GetAttribLocation(m.ShaderProg.ID, gl.Str(attribName+"\x00"))
-}
 
-func (m *Material) SetAttribute(bufObj buffers.Buffer) {
-
-	bufObj.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, bufObj.BufID)
-
-	layout := bufObj.GetLayout()
-	for i := 0; i < len(layout); i++ {
-		gl.EnableVertexAttribArray(uint32(i))
-		gl.VertexAttribPointer(uint32(i), layout[i].ElementType.CompCount(), layout[i].ElementType.GLType(), false, bufObj.Stride, gl.PtrOffset(layout[i].Offset))
+	loc, ok := m.AttribLocs[attribName]
+	if ok {
+		return loc
 	}
 
-	bufObj.UnBind()
-	gl.BindBuffer(gl.ARRAY_BUFFER, 0)
+	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
 }
 
-func (m *Material) AddTextureID(texID uint32) {
-	m.TexIDs = append(m.TexIDs, texID)
+func (m *Material) GetUnifLoc(uniformName string) int32 {
+
+	loc, ok := m.UnifLocs[uniformName]
+	if ok {
+		return loc
+	}
+
+	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
 }
 
 func (m *Material) EnableAttribute(attribName string) {
@@ -66,43 +69,35 @@ func (m *Material) DisableAttribute(attribName string) {
 }
 
 func (m *Material) SetUnifInt32(uniformName string, val int32) {
-	loc := gl.GetUniformLocation(m.ShaderProg.ID, gl.Str(uniformName+"\x00"))
-	gl.ProgramUniform1i(m.ShaderProg.ID, loc, val)
+	gl.ProgramUniform1i(m.ShaderProg.ID, m.GetUnifLoc(uniformName), val)
 }
 
 func (m *Material) SetUnifFloat32(uniformName string, val float32) {
-	loc := gl.GetUniformLocation(m.ShaderProg.ID, gl.Str(uniformName+"\x00"))
-	gl.ProgramUniform1f(m.ShaderProg.ID, loc, val)
+	gl.ProgramUniform1f(m.ShaderProg.ID, m.GetUnifLoc(uniformName), val)
 }
 
 func (m *Material) SetUnifVec2(uniformName string, vec2 *gglm.Vec2) {
-	loc := gl.GetUniformLocation(m.ShaderProg.ID, gl.Str(uniformName+"\x00"))
-	gl.ProgramUniform2fv(m.ShaderProg.ID, loc, 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) {
-	loc := gl.GetUniformLocation(m.ShaderProg.ID, gl.Str(uniformName+"\x00"))
-	gl.ProgramUniform3fv(m.ShaderProg.ID, loc, 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) {
-	loc := gl.GetUniformLocation(m.ShaderProg.ID, gl.Str(uniformName+"\x00"))
-	gl.ProgramUniform4fv(m.ShaderProg.ID, loc, 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) {
-	loc := gl.GetUniformLocation(m.ShaderProg.ID, gl.Str(uniformName+"\x00"))
-	gl.ProgramUniformMatrix2fv(m.ShaderProg.ID, loc, 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) {
-	loc := gl.GetUniformLocation(m.ShaderProg.ID, gl.Str(uniformName+"\x00"))
-	gl.ProgramUniformMatrix3fv(m.ShaderProg.ID, loc, 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) {
-	loc := gl.GetUniformLocation(m.ShaderProg.ID, gl.Str(uniformName+"\x00"))
-	gl.ProgramUniformMatrix4fv(m.ShaderProg.ID, loc, 1, false, &mat4.Data[0][0])
+	gl.ProgramUniformMatrix4fv(m.ShaderProg.ID, m.GetUnifLoc(uniformName), 1, false, &mat4.Data[0][0])
 }
 
 func (m *Material) Delete() {
@@ -111,24 +106,20 @@ func (m *Material) Delete() {
 
 func NewMaterial(matName, shaderPath string) *Material {
 
-	shdrProg, err := shaders.NewShaderProgram()
+	shdrProg, err := shaders.LoadAndCompileCombinedShader(shaderPath)
 	if err != nil {
-		logging.ErrLog.Fatalln("Failed to create new shader program. Err: ", err)
+		logging.ErrLog.Fatalln("Failed to create new material. Err: ", err)
 	}
 
-	vertShader, err := shaders.LoadAndCompilerShader(shaderPath+".vert.glsl", shaders.VertexShaderType)
-	if err != nil {
-		logging.ErrLog.Fatalln("Failed to load and create vertex shader. Err: ", err)
-	}
-
-	fragShader, err := shaders.LoadAndCompilerShader(shaderPath+".frag.glsl", shaders.FragmentShaderType)
-	if err != nil {
-		logging.ErrLog.Fatalln("Failed to load and create fragment shader. Err: ", err)
-	}
-
-	shdrProg.AttachShader(vertShader)
-	shdrProg.AttachShader(fragShader)
-	shdrProg.Link()
-
-	return &Material{Name: matName, ShaderProg: shdrProg}
+	return &Material{Name: matName, ShaderProg: shdrProg, UnifLocs: make(map[string]int32), AttribLocs: make(map[string]int32)}
+}
+
+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)
+	}
+
+	return &Material{Name: matName, ShaderProg: shdrProg, UnifLocs: make(map[string]int32), AttribLocs: make(map[string]int32)}
 }

meshes/mesh.go

@@ -6,16 +6,20 @@ import (
 
 	"github.com/bloeys/assimp-go/asig"
 	"github.com/bloeys/gglm/gglm"
-	"github.com/bloeys/nmage/asserts"
-	"github.com/bloeys/nmage/assets"
+	"github.com/bloeys/nmage/assert"
 	"github.com/bloeys/nmage/buffers"
-	"github.com/bloeys/nmage/logging"
 )
 
+type SubMesh struct {
+	BaseVertex int32
+	BaseIndex  uint32
+	IndexCount int32
+}
+
 type Mesh struct {
-	Name       string
-	TextureIDs []uint32
-	Buf        buffers.Buffer
+	Name      string
+	Buf       buffers.Buffer
+	SubMeshes []SubMesh
 }
 
 func NewMesh(name, modelPath string, postProcessFlags asig.PostProcess) (*Mesh, error) {
@@ -30,45 +34,68 @@ func NewMesh(name, modelPath string, postProcessFlags asig.PostProcess) (*Mesh,
 		return nil, errors.New("No meshes found in file: " + modelPath)
 	}
 
-	mesh := &Mesh{Name: name}
-	sceneMesh := scene.Meshes[0]
-	mesh.Buf = buffers.NewBuffer()
-
-	asserts.T(len(sceneMesh.TexCoords[0]) > 0, "Mesh has no UV0")
-	layoutToUse := []buffers.Element{{ElementType: buffers.DataTypeVec3}, {ElementType: buffers.DataTypeVec3}, {ElementType: buffers.DataTypeVec2}}
-
-	if len(sceneMesh.ColorSets) > 0 && len(sceneMesh.ColorSets[0]) > 0 {
-		layoutToUse = append(layoutToUse, buffers.Element{ElementType: buffers.DataTypeVec4})
+	mesh := &Mesh{
+		Name:      name,
+		Buf:       buffers.NewBuffer(),
+		SubMeshes: make([]SubMesh, 0, 1),
 	}
-	mesh.Buf.SetLayout(layoutToUse...)
 
-	//Load diffuse textures
-	mat := scene.Materials[sceneMesh.MaterialIndex]
-	if asig.GetMaterialTextureCount(mat, asig.TextureTypeDiffuse) > 0 {
-		texInfo, err := asig.GetMaterialTexture(mat, asig.TextureTypeDiffuse, 0)
-		if err != nil {
-			logging.ErrLog.Fatalf("Failed to get material texture of index 0. Err: %e\n", err)
+	// 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)
+
+	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)
 		}
 
-		tex, err := assets.LoadPNG(texInfo.Path)
-		if err != nil {
-			logging.ErrLog.Fatalf("Loading PNG with path '%s' failed. Err: %e\n", texInfo.Path, err)
+		layoutToUse := []buffers.Element{{ElementType: buffers.DataTypeVec3}, {ElementType: buffers.DataTypeVec3}, {ElementType: buffers.DataTypeVec2}}
+		if len(sceneMesh.ColorSets) > 0 && len(sceneMesh.ColorSets[0]) > 0 {
+			layoutToUse = append(layoutToUse, buffers.Element{ElementType: buffers.DataTypeVec4})
 		}
 
-		mesh.TextureIDs = append(mesh.TextureIDs, tex.TexID)
+		if i == 0 {
+			mesh.Buf.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))
+
+			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))
+				}
+			}
+		}
+
+		arrs := []arrToInterleave{{V3s: sceneMesh.Vertices}, {V3s: sceneMesh.Normals}, {V2s: v3sToV2s(sceneMesh.TexCoords[0])}}
+		if len(sceneMesh.ColorSets) > 0 && len(sceneMesh.ColorSets[0]) > 0 {
+			arrs = append(arrs, arrToInterleave{V4s: sceneMesh.ColorSets[0]})
+		}
+
+		indices := flattenFaces(sceneMesh.Faces)
+		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,
+			// Which index (in the index buffer) to start from
+			BaseIndex: uint32(len(indexBufData)),
+			// How many indices in this submesh
+			IndexCount: int32(len(indices)),
+		})
+
+		vertexBufData = append(vertexBufData, interleave(arrs...)...)
+		indexBufData = append(indexBufData, indices...)
 	}
 
-	var values []float32
-	arrs := []arrToInterleave{{V3s: sceneMesh.Vertices}, {V3s: sceneMesh.Normals}, {V2s: v3sToV2s(sceneMesh.TexCoords[0])}}
-
-	if len(sceneMesh.ColorSets) > 0 && len(sceneMesh.ColorSets[0]) > 0 {
-		arrs = append(arrs, arrToInterleave{V4s: sceneMesh.ColorSets[0]})
-	}
-
-	values = interleave(arrs...)
-
-	mesh.Buf.SetData(values)
-	mesh.Buf.SetIndexBufData(flattenFaces(sceneMesh.Faces))
+	// 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)
 	return mesh, nil
 }
 
@@ -92,9 +119,9 @@ type arrToInterleave struct {
 
 func (a *arrToInterleave) get(i int) []float32 {
 
-	asserts.T(len(a.V2s) == 0 || len(a.V3s) == 0, "One array should be set in arrToInterleave, but both arrays are set")
-	asserts.T(len(a.V2s) == 0 || len(a.V4s) == 0, "One array should be set in arrToInterleave, but both arrays are set")
-	asserts.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 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")
 
 	if len(a.V2s) > 0 {
 		return a.V2s[i].Data[:]
@@ -107,8 +134,8 @@ func (a *arrToInterleave) get(i int) []float32 {
 
 func interleave(arrs ...arrToInterleave) []float32 {
 
-	asserts.T(len(arrs) > 0, "No input sent to interleave")
-	asserts.T(len(arrs[0].V2s) > 0 || len(arrs[0].V3s) > 0 || len(arrs[0].V4s) > 0, "Interleave arrays are empty")
+	assert.T(len(arrs) > 0, "No input sent to interleave")
+	assert.T(len(arrs[0].V2s) > 0 || len(arrs[0].V3s) > 0 || len(arrs[0].V4s) > 0, "Interleave arrays are empty")
 
 	elementCount := 0
 	if len(arrs[0].V2s) > 0 {
@@ -123,7 +150,7 @@ func interleave(arrs ...arrToInterleave) []float32 {
 	totalSize := 0
 	for i := 0; i < len(arrs); i++ {
 
-		asserts.T(len(arrs[i].V2s) == elementCount || len(arrs[i].V3s) == elementCount || len(arrs[i].V4s) == elementCount, "Mesh vertex data given to interleave is not the same length")
+		assert.T(len(arrs[i].V2s) == elementCount || len(arrs[i].V3s) == elementCount || len(arrs[i].V4s) == elementCount, "Mesh vertex data given to interleave is not the same length")
 
 		if len(arrs[i].V2s) > 0 {
 			totalSize += len(arrs[i].V2s) * 2
@@ -144,34 +171,9 @@ func interleave(arrs ...arrToInterleave) []float32 {
 	return out
 }
 
-func flattenVec3(vec3s []gglm.Vec3) []float32 {
-
-	floats := make([]float32, len(vec3s)*3)
-	for i := 0; i < len(vec3s); i++ {
-		floats[i*3+0] = vec3s[i].X()
-		floats[i*3+1] = vec3s[i].Y()
-		floats[i*3+2] = vec3s[i].Z()
-	}
-
-	return floats
-}
-
-func flattenVec4(vec4s []gglm.Vec4) []float32 {
-
-	floats := make([]float32, len(vec4s)*4)
-	for i := 0; i < len(vec4s); i++ {
-		floats[i*4+0] = vec4s[i].X()
-		floats[i*4+1] = vec4s[i].Y()
-		floats[i*4+2] = vec4s[i].Z()
-		floats[i*4+3] = vec4s[i].W()
-	}
-
-	return floats
-}
-
 func flattenFaces(faces []asig.Face) []uint32 {
 
-	asserts.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, fmt.Sprintf("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++ {

renderer/rend3dgl/rend3dgl.go

@@ -0,0 +1,44 @@
+package rend3dgl
+
+import (
+	"github.com/bloeys/gglm/gglm"
+	"github.com/bloeys/nmage/materials"
+	"github.com/bloeys/nmage/meshes"
+	"github.com/bloeys/nmage/renderer"
+	"github.com/go-gl/gl/v4.1-core/gl"
+)
+
+var _ renderer.Render = &Rend3DGL{}
+
+type Rend3DGL struct {
+	BoundMesh *meshes.Mesh
+	BoundMat  *materials.Material
+}
+
+func (r3d *Rend3DGL) Draw(mesh *meshes.Mesh, trMat *gglm.TrMat, mat *materials.Material) {
+
+	if mesh != r3d.BoundMesh {
+		mesh.Buf.Bind()
+		r3d.BoundMesh = mesh
+	}
+
+	if mat != r3d.BoundMat {
+		mat.Bind()
+		r3d.BoundMat = mat
+	}
+
+	mat.SetUnifMat4("modelMat", &trMat.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 (r3d *Rend3DGL) FrameEnd() {
+	r3d.BoundMesh = nil
+	r3d.BoundMat = nil
+}
+
+func NewRend3DGL() *Rend3DGL {
+	return &Rend3DGL{}
+}

renderer/renderer.go

@@ -0,0 +1,12 @@
+package renderer
+
+import (
+	"github.com/bloeys/gglm/gglm"
+	"github.com/bloeys/nmage/materials"
+	"github.com/bloeys/nmage/meshes"
+)
+
+type Render interface {
+	Draw(mesh *meshes.Mesh, trMat *gglm.TrMat, mat *materials.Material)
+	FrameEnd()
+}

res/models/obj.obj

@@ -1,46 +0,0 @@
-# Blender v2.92.0 OBJ File: ''
-# www.blender.org
-mtllib obj.mtl
-o Cube
-v 2.275618 1.000000 0.349413
-v 3.520138 -1.000000 0.102233
-v 2.275618 1.000000 0.752820
-v 3.520138 -1.000000 1.000000
-v 0.244520 1.000000 0.349413
-v -1.000000 -1.000000 0.102233
-v 0.244520 1.000000 0.752820
-v -1.000000 -1.000000 1.000000
-vt 0.806168 0.568832
-vt 0.693832 0.681168
-vt 0.693832 0.568832
-vt 0.375000 1.000000
-vt 0.375000 0.750000
-vt 0.375000 0.000000
-vt 0.625000 0.250000
-vt 0.375000 0.250000
-vt 0.375000 0.500000
-vt 0.125000 0.750000
-vt 0.125000 0.500000
-vt 0.806168 0.681168
-vt 0.625000 0.931168
-vt 0.625000 0.068832
-vn 0.0000 1.0000 0.0000
-vn 0.0000 0.1227 0.9924
-vn -0.8490 0.5283 0.0000
-vn 0.0000 -1.0000 0.0000
-vn 0.8490 0.5283 0.0000
-vn 0.0000 0.1227 -0.9924
-usemtl Material
-s off
-f 5/1/1 3/2/1 1/3/1
-f 3/2/2 8/4/2 4/5/2
-f 8/6/3 5/7/3 6/8/3
-f 2/9/4 8/10/4 6/11/4
-f 1/3/5 4/5/5 2/9/5
-f 5/7/6 2/9/6 6/8/6
-f 5/1/1 7/12/1 3/2/1
-f 3/2/2 7/13/2 8/4/2
-f 8/6/3 7/14/3 5/7/3
-f 2/9/4 4/5/4 8/10/4
-f 1/3/5 3/2/5 4/5/5
-f 5/7/6 1/3/6 2/9/6

res/models/skybox-cube.obj

@@ -0,0 +1,38 @@
+# Blender v2.92.0 OBJ File: 'chair.blend'
+# www.blender.org
+o Cube.002_Cube.005
+v -1.000000 -1.000000 1.000000
+v -1.000000 1.000000 1.000000
+v -1.000000 -1.000000 -1.000000
+v -1.000000 1.000000 -1.000000
+v 1.000000 -1.000000 1.000000
+v 1.000000 1.000000 1.000000
+v 1.000000 -1.000000 -1.000000
+v 1.000000 1.000000 -1.000000
+vt 0.375000 0.000000
+vt 0.625000 0.000000
+vt 0.625000 0.250000
+vt 0.375000 0.250000
+vt 0.625000 0.500000
+vt 0.375000 0.500000
+vt 0.625000 0.750000
+vt 0.375000 0.750000
+vt 0.625000 1.000000
+vt 0.375000 1.000000
+vt 0.125000 0.500000
+vt 0.125000 0.750000
+vt 0.875000 0.500000
+vt 0.875000 0.750000
+vn -1.0000 0.0000 0.0000
+vn 0.0000 0.0000 -1.0000
+vn 1.0000 0.0000 0.0000
+vn 0.0000 0.0000 1.0000
+vn 0.0000 -1.0000 0.0000
+vn 0.0000 1.0000 0.0000
+s off
+f 1/1/1 2/2/1 4/3/1 3/4/1
+f 3/4/2 4/3/2 8/5/2 7/6/2
+f 7/6/3 8/5/3 6/7/3 5/8/3
+f 5/8/4 6/7/4 2/9/4 1/10/4
+f 3/11/5 7/6/5 5/8/5 1/12/5
+f 8/5/6 4/13/6 2/14/6 6/7/6

res/shaders/debug-depth.glsl

@@ -1,3 +1,4 @@
+//shader:vertex
 #version 410
 
 layout(location=0) in vec3 vertPosIn;
@@ -23,4 +24,29 @@ void main()
     fragPos = vec3(modelMat * vec4(vertPosIn, 1.0));
 
     gl_Position = projMat * viewMat * modelMat * vec4(vertPosIn, 1.0);
-}
+}
+
+//shader:fragment
+#version 410
+
+in vec3 vertColor;
+in vec3 vertNormal;
+in vec2 vertUV0;
+in vec3 fragPos;
+
+out vec4 fragColor;
+
+uniform float near = 0.1;
+uniform float far  = 200.0;
+  
+float LinearizeDepth(float depth) 
+{
+    float z = depth * 2.0 - 1.0; // back to NDC 
+    return (2.0 * near * far) / (far + near - z * (far - near));	
+}
+
+void main()
+{
+    float depth = LinearizeDepth(gl_FragCoord.z) / far;
+    fragColor = vec4(vec3(depth), 1.0);
+} 

res/shaders/imgui.frag.glsl

@@ -1,13 +0,0 @@
-#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/imgui.vert.glsl

@@ -1,17 +0,0 @@
-#version 410
-
-uniform mat4 ProjMtx;
-
-in vec2 Position;
-in vec2 UV;
-in vec4 Color;
-
-out vec2 Frag_UV;
-out vec4 Frag_Color;
-
-void main()
-{
-    Frag_UV = UV;
-    Frag_Color = Color;
-    gl_Position = ProjMtx * vec4(Position.xy, 0, 1);
-}

res/shaders/simple.frag.glsl

@@ -1,26 +0,0 @@
-#version 410
-
-uniform float ambientStrength = 0.1;
-uniform vec3 ambientLightColor = vec3(1, 1, 1);
-
-uniform vec3 lightPos1;
-uniform vec3 lightColor1;
-
-uniform sampler2D diffTex;
-
-in vec3 vertColor;
-in vec3 vertNormal;
-in vec2 vertUV0;
-in vec3 fragPos;
-
-out vec4 fragColor;
-
-void main()
-{
-    vec3 lightDir = normalize(lightPos1 - fragPos);  
-    float diffStrength = max(0.0, dot(normalize(vertNormal), lightDir));
-
-    vec3 finalAmbientColor = ambientLightColor * ambientStrength;
-    vec4 texColor = texture(diffTex, vertUV0);
-    fragColor = vec4(texColor.rgb * vertColor * (finalAmbientColor + diffStrength*lightColor1) , texColor.a);
-} 

res/shaders/simple.glsl

@@ -0,0 +1,55 @@
+//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()
+{
+    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
+
+uniform float ambientStrength = 0;
+uniform vec3 ambientLightColor = vec3(1, 1, 1);
+
+uniform vec3 lightPos1;
+uniform vec3 lightColor1;
+
+uniform sampler2D diffTex;
+
+in vec3 vertColor;
+in vec3 vertNormal;
+in vec2 vertUV0;
+in vec3 fragPos;
+
+out vec4 fragColor;
+
+void main()
+{
+    vec3 lightDir = normalize(lightPos1 - fragPos);  
+    float diffStrength = max(0.0, dot(normalize(vertNormal), lightDir));
+
+    vec3 finalAmbientColor = ambientLightColor * ambientStrength;
+    vec4 texColor = texture(diffTex, vertUV0);
+    fragColor = vec4(texColor.rgb * vertColor * (finalAmbientColor + diffStrength*lightColor1) , texColor.a);
+} 

res/shaders/skybox.glsl

@@ -0,0 +1,33 @@
+//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 vertUV0;
+
+uniform mat4 viewMat;
+uniform mat4 projMat;
+
+void main()
+{
+    vertUV0 = vec3(vertPosIn.x, vertPosIn.y, -vertPosIn.z);
+    vec4 pos = projMat * viewMat * vec4(vertPosIn, 1.0);
+    gl_Position = pos.xyww;
+}
+
+//shader:fragment
+#version 410
+
+in vec3 vertUV0;
+
+out vec4 fragColor;
+
+uniform samplerCube skybox;
+
+void main()
+{
+    fragColor = texture(skybox, vertUV0);
+} 

shaders/shaders.go

@@ -1,6 +1,7 @@
 package shaders
 
 import (
+	"bytes"
 	"errors"
 	"os"
 	"strings"
@@ -28,14 +29,69 @@ func NewShaderProgram() (ShaderProgram, error) {
 	return ShaderProgram{ID: id}, nil
 }
 
-func LoadAndCompilerShader(shaderPath string, shaderType ShaderType) (Shader, error) {
+func LoadAndCompileCombinedShader(shaderPath string) (ShaderProgram, error) {
 
-	shaderSource, err := os.ReadFile(shaderPath)
+	combinedSource, err := os.ReadFile(shaderPath)
 	if err != nil {
 		logging.ErrLog.Println("Failed to read shader. Err: ", err)
-		return Shader{}, err
+		return ShaderProgram{}, err
 	}
 
+	return LoadAndCompileCombinedShaderSrc(combinedSource)
+
+}
+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'")
+	}
+
+	shdrProg, err := NewShaderProgram()
+	if err != nil {
+		return ShaderProgram{}, errors.New("failed to create new shader program. Err: " + err.Error())
+	}
+
+	loadedShdrCount := 0
+	for i := 0; i < len(shaderSources); i++ {
+
+		src := shaderSources[i]
+
+		//This can happen when the shader type is at the start of the file
+		if len(bytes.TrimSpace(src)) == 0 {
+			continue
+		}
+
+		var shdrType ShaderType
+		if bytes.HasPrefix(src, []byte("vertex")) {
+			src = src[6:]
+			shdrType = VertexShaderType
+		} else if bytes.HasPrefix(src, []byte("fragment")) {
+			src = src[8:]
+			shdrType = FragmentShaderType
+		} else {
+			return ShaderProgram{}, errors.New("unknown shader type. Must be '//shader:vertex' or '//shader:fragment'")
+		}
+
+		shdr, err := CompileShaderOfType(src, shdrType)
+		if err != nil {
+			return ShaderProgram{}, err
+		}
+
+		loadedShdrCount++
+		shdrProg.AttachShader(shdr)
+	}
+
+	if loadedShdrCount == 0 {
+		return ShaderProgram{}, errors.New("no valid shaders found. Please put '//shader:vertex' or '//shader:fragment' before your shaders")
+	}
+
+	shdrProg.Link()
+	return shdrProg, nil
+}
+
+func CompileShaderOfType(shaderSource []byte, shaderType ShaderType) (Shader, error) {
+
 	shaderID := gl.CreateShader(uint32(shaderType))
 	if shaderID == 0 {
 		logging.ErrLog.Println("Failed to create shader.")

timing/timing.go

@@ -1,11 +1,19 @@
 package timing
 
-import "time"
+import (
+	"time"
+)
 
 var (
 	dt         float32 = 0.01
 	frameStart time.Time
 	startTime  time.Time
+
+	//fps calculator vars
+	dtAccum                  float32 = 1
+	lastElapsedTime          uint64  = 0
+	framesSinceLastFPSUpdate uint    = 0
+	avgFps                   float32 = 1
 )
 
 func Init() {
@@ -13,18 +21,42 @@ func Init() {
 }
 
 func FrameStarted() {
+
 	frameStart = time.Now()
+
+	//fps stuff
+	dtAccum += dt
+	framesSinceLastFPSUpdate++
+	et := ElapsedTime()
+	if et > lastElapsedTime {
+		avgDT := dtAccum / float32(framesSinceLastFPSUpdate)
+		avgFps = 1 / avgDT
+
+		dtAccum = 0
+		framesSinceLastFPSUpdate = 0
+	}
+	lastElapsedTime = et
 }
 
 func FrameEnded() {
+
+	//Calculate new dt
 	dt = float32(time.Since(frameStart).Seconds())
+	if dt == 0 {
+		dt = float32(time.Microsecond.Seconds())
+	}
 }
 
-//DT is frame deltatime in milliseconds
+//DT is frame deltatime in seconds
 func DT() float32 {
 	return dt
 }
 
+//GetAvgFPS returns the fps averaged over 1 second
+func GetAvgFPS() float32 {
+	return avgFps
+}
+
 //ElapsedTime is time since game start
 func ElapsedTime() uint64 {
 	return uint64(time.Since(startTime).Seconds())

ui/imgui/imgui.go

@@ -0,0 +1,252 @@
+package nmageimgui
+
+import (
+	"github.com/bloeys/gglm/gglm"
+	"github.com/bloeys/nmage/assert"
+	"github.com/bloeys/nmage/materials"
+	"github.com/bloeys/nmage/timing"
+	"github.com/go-gl/gl/v4.1-core/gl"
+	"github.com/inkyblackness/imgui-go/v4"
+	"github.com/veandco/go-sdl2/sdl"
+)
+
+type ImguiInfo struct {
+	ImCtx *imgui.Context
+
+	Mat        *materials.Material
+	VaoID      uint32
+	VboID      uint32
+	IndexBufID uint32
+	TexID      uint32
+}
+
+func (i *ImguiInfo) FrameStart(winWidth, winHeight float32) {
+
+	if err := i.ImCtx.SetCurrent(); err != nil {
+		assert.T(false, "Setting imgui ctx as current failed. Err: "+err.Error())
+	}
+
+	imIO := imgui.CurrentIO()
+	imIO.SetDisplaySize(imgui.Vec2{X: float32(winWidth), Y: float32(winHeight)})
+	imIO.SetDeltaTime(timing.DT())
+
+	imgui.NewFrame()
+}
+
+func (i *ImguiInfo) Render(winWidth, winHeight float32, fbWidth, fbHeight int32) {
+
+	if err := i.ImCtx.SetCurrent(); err != nil {
+		assert.T(false, "Setting imgui ctx as current failed. Err: "+err.Error())
+	}
+
+	imgui.Render()
+
+	// Avoid rendering when minimized, scale coordinates for retina displays (screen coordinates != framebuffer coordinates)
+	if fbWidth <= 0 || fbHeight <= 0 {
+		return
+	}
+
+	drawData := imgui.RenderedDrawData()
+	drawData.ScaleClipRects(imgui.Vec2{
+		X: float32(fbWidth) / float32(winWidth),
+		Y: float32(fbHeight) / float32(winHeight),
+	})
+
+	// Setup render state: alpha-blending enabled, no face culling, no depth testing, scissor enabled, polygon fill
+	gl.Enable(gl.BLEND)
+	gl.BlendEquation(gl.FUNC_ADD)
+	gl.BlendFunc(gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA)
+	gl.Disable(gl.CULL_FACE)
+	gl.Disable(gl.DEPTH_TEST)
+	gl.Enable(gl.SCISSOR_TEST)
+	gl.PolygonMode(gl.FRONT_AND_BACK, gl.FILL)
+
+	// Setup viewport, orthographic projection matrix
+	// Our visible imgui space lies from draw_data->DisplayPos (top left) to draw_data->DisplayPos+data_data->DisplaySize (bottom right).
+	// DisplayMin is typically (0,0) for single viewport apps.
+
+	i.Mat.Bind()
+	i.Mat.SetUnifInt32("Texture", 0)
+
+	//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.
+
+	// Recreate the VAO every time
+	// (This is to easily allow multiple GL contexts. VAO are not shared among GL contexts, and
+	// we don't track creation/deletion of windows so we don't have an obvious key to use to cache them.)
+	gl.BindVertexArray(i.VaoID)
+	gl.BindBuffer(gl.ARRAY_BUFFER, i.VboID)
+
+	vertexSize, vertexOffsetPos, vertexOffsetUv, vertexOffsetCol := imgui.VertexBufferLayout()
+	i.Mat.EnableAttribute("Position")
+	i.Mat.EnableAttribute("UV")
+	i.Mat.EnableAttribute("Color")
+	gl.VertexAttribPointerWithOffset(uint32(i.Mat.GetAttribLoc("Position")), 2, gl.FLOAT, false, int32(vertexSize), uintptr(vertexOffsetPos))
+	gl.VertexAttribPointerWithOffset(uint32(i.Mat.GetAttribLoc("UV")), 2, gl.FLOAT, false, int32(vertexSize), uintptr(vertexOffsetUv))
+	gl.VertexAttribPointerWithOffset(uint32(i.Mat.GetAttribLoc("Color")), 4, gl.UNSIGNED_BYTE, true, int32(vertexSize), uintptr(vertexOffsetCol))
+
+	indexSize := imgui.IndexBufferLayout()
+	drawType := gl.UNSIGNED_SHORT
+	if indexSize == 4 {
+		drawType = gl.UNSIGNED_INT
+	}
+
+	// Draw
+	for _, list := range drawData.CommandLists() {
+
+		vertexBuffer, vertexBufferSize := list.VertexBuffer()
+		gl.BindBuffer(gl.ARRAY_BUFFER, i.VboID)
+		gl.BufferData(gl.ARRAY_BUFFER, vertexBufferSize, vertexBuffer, gl.STREAM_DRAW)
+
+		indexBuffer, indexBufferSize := list.IndexBuffer()
+		gl.BindBuffer(gl.ELEMENT_ARRAY_BUFFER, i.IndexBufID)
+		gl.BufferData(gl.ELEMENT_ARRAY_BUFFER, indexBufferSize, indexBuffer, gl.STREAM_DRAW)
+
+		for _, cmd := range list.Commands() {
+			if cmd.HasUserCallback() {
+				cmd.CallUserCallback(list)
+			} else {
+
+				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.ElementCount()), uint32(drawType), gl.PtrOffset(cmd.IndexOffset()*indexSize), int32(cmd.VertexOffset()))
+			}
+		}
+	}
+
+	//Reset gl state
+	gl.Disable(gl.SCISSOR_TEST)
+	gl.Enable(gl.CULL_FACE)
+	gl.Enable(gl.DEPTH_TEST)
+}
+
+func (i *ImguiInfo) AddFontTTF(fontPath string, fontSize float32, fontConfig *imgui.FontConfig, glyphRanges *imgui.GlyphRanges) imgui.Font {
+
+	fontConfigToUse := imgui.DefaultFontConfig
+	if fontConfig != nil {
+		fontConfigToUse = *fontConfig
+	}
+
+	glyphRangesToUse := imgui.EmptyGlyphRanges
+	if glyphRanges != nil {
+		glyphRangesToUse = *glyphRanges
+	}
+
+	imIO := imgui.CurrentIO()
+
+	a := imIO.Fonts()
+	f := a.AddFontFromFileTTFV(fontPath, fontSize, fontConfigToUse, glyphRangesToUse)
+	image := a.TextureDataAlpha8()
+
+	gl.BindTexture(gl.TEXTURE_2D, i.TexID)
+	gl.TexImage2D(gl.TEXTURE_2D, 0, gl.RED, int32(image.Width), int32(image.Height), 0, gl.RED, gl.UNSIGNED_BYTE, image.Pixels)
+
+	return f
+}
+
+const imguiShdrSrc = `
+//shader:vertex
+#version 410
+
+uniform mat4 ProjMtx;
+
+in vec2 Position;
+in vec2 UV;
+in vec4 Color;
+
+out vec2 Frag_UV;
+out vec4 Frag_Color;
+
+void main()
+{
+    Frag_UV = UV;
+    Frag_Color = 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);
+}
+`
+
+func NewImGUI() ImguiInfo {
+
+	imguiInfo := ImguiInfo{
+		ImCtx: imgui.CreateContext(nil),
+		Mat:   materials.NewMaterialSrc("ImGUI Mat", []byte(imguiShdrSrc)),
+	}
+
+	imIO := imgui.CurrentIO()
+	imIO.SetBackendFlags(imIO.GetBackendFlags() | imgui.BackendFlagsRendererHasVtxOffset)
+
+	gl.GenVertexArrays(1, &imguiInfo.VaoID)
+	gl.GenBuffers(1, &imguiInfo.VboID)
+	gl.GenBuffers(1, &imguiInfo.IndexBufID)
+	gl.GenTextures(1, &imguiInfo.TexID)
+
+	// Upload font to gpu
+	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)
+
+	image := imIO.Fonts().TextureDataAlpha8()
+	gl.TexImage2D(gl.TEXTURE_2D, 0, gl.RED, int32(image.Width), int32(image.Height), 0, gl.RED, gl.UNSIGNED_BYTE, image.Pixels)
+
+	// Store our identifier
+	imIO.Fonts().SetTextureID(imgui.TextureID(imguiInfo.TexID))
+
+	//Shader attributes
+	imguiInfo.Mat.Bind()
+	imguiInfo.Mat.EnableAttribute("Position")
+	imguiInfo.Mat.EnableAttribute("UV")
+	imguiInfo.Mat.EnableAttribute("Color")
+	imguiInfo.Mat.UnBind()
+
+	//Init imgui input mapping
+	keys := map[int]int{
+		imgui.KeyTab:        sdl.SCANCODE_TAB,
+		imgui.KeyLeftArrow:  sdl.SCANCODE_LEFT,
+		imgui.KeyRightArrow: sdl.SCANCODE_RIGHT,
+		imgui.KeyUpArrow:    sdl.SCANCODE_UP,
+		imgui.KeyDownArrow:  sdl.SCANCODE_DOWN,
+		imgui.KeyPageUp:     sdl.SCANCODE_PAGEUP,
+		imgui.KeyPageDown:   sdl.SCANCODE_PAGEDOWN,
+		imgui.KeyHome:       sdl.SCANCODE_HOME,
+		imgui.KeyEnd:        sdl.SCANCODE_END,
+		imgui.KeyInsert:     sdl.SCANCODE_INSERT,
+		imgui.KeyDelete:     sdl.SCANCODE_DELETE,
+		imgui.KeyBackspace:  sdl.SCANCODE_BACKSPACE,
+		imgui.KeySpace:      sdl.SCANCODE_BACKSPACE,
+		imgui.KeyEnter:      sdl.SCANCODE_RETURN,
+		imgui.KeyEscape:     sdl.SCANCODE_ESCAPE,
+		imgui.KeyA:          sdl.SCANCODE_A,
+		imgui.KeyC:          sdl.SCANCODE_C,
+		imgui.KeyV:          sdl.SCANCODE_V,
+		imgui.KeyX:          sdl.SCANCODE_X,
+		imgui.KeyY:          sdl.SCANCODE_Y,
+		imgui.KeyZ:          sdl.SCANCODE_Z,
+	}
+
+	// Keyboard mapping. ImGui will use those indices to peek into the io.KeysDown[] array.
+	for imguiKey, nativeKey := range keys {
+		imIO.KeyMap(imguiKey, nativeKey)
+	}
+
+	return imguiInfo
+}