Allow imgui within init

.gitignore

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

assets/textures.go

@@ -24,7 +24,7 @@ type Texture struct {
 	Pixels []byte
 }
 
-func LoadPNG(file string) (Texture, error) {
+func LoadPNGTexture(file string) (Texture, error) {
 
 	if tex, ok := GetTexturePath(file); ok {
 		return tex, nil
@@ -48,9 +48,10 @@ func LoadPNG(file string) (Texture, error) {
 		Pixels: make([]byte, img.Bounds().Dx()*img.Bounds().Dy()*4),
 	}
 
+	//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
-	for y := 0; y < img.Bounds().Dy(); y++ {
+	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)
@@ -75,7 +76,7 @@ func LoadPNG(file string) (Texture, error) {
 	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.TexImage2D(gl.TEXTURE_2D, 0, gl.RGBA8, tex.Width, tex.Height, 0, gl.RGBA, gl.UNSIGNED_BYTE, unsafe.Pointer(&tex.Pixels[0]))
 	gl.GenerateMipmap(gl.TEXTURE_2D)
 
 	SetTexture(tex)

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 +1,93 @@
 package engine
 
 import (
+	"runtime"
+
+	"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"
 )
 
 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 +96,7 @@ func (w *Window) Destroy() error {
 
 func Init() error {
 
+	runtime.LockOSThread()
 	timing.Init()
 	err := initSDL()
 
@@ -49,15 +129,15 @@ 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) {
 
 	if x == -1 && y == -1 {
 		x = sdl.WINDOWPOS_CENTERED
@@ -68,7 +148,11 @@ 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 {

engine/game.go

@@ -0,0 +1,61 @@
+package engine
+
+import (
+	"github.com/bloeys/nmage/timing"
+	nmageimgui "github.com/bloeys/nmage/ui/imgui"
+	"github.com/go-gl/gl/v4.1-core/gl"
+)
+
+type Game interface {
+	Init()
+
+	FrameStart()
+	Update()
+	Render()
+	FrameEnd()
+	ShouldRun() bool
+
+	GetWindow() *Window
+	GetImGUI() nmageimgui.ImguiInfo
+
+	Deinit()
+}
+
+func Run(g Game) {
+
+	w := g.GetWindow()
+	ui := g.GetImGUI()
+
+	//Simulate an imgui frame during init so any imgui calls are allowed within init
+	tempWidth, tempHeight := w.SDLWin.GetSize()
+	tempFBWidth, tempFBHeight := w.SDLWin.GLGetDrawableSize()
+	ui.FrameStart(float32(tempWidth), float32(tempHeight))
+	g.Init()
+	ui.Render(float32(tempWidth), float32(tempHeight), tempFBWidth, tempFBHeight)
+
+	for g.ShouldRun() {
+
+		//PERF: Cache these
+		width, height := w.SDLWin.GetSize()
+		fbWidth, fbHeight := w.SDLWin.GLGetDrawableSize()
+
+		timing.FrameStarted()
+		w.handleInputs()
+		ui.FrameStart(float32(width), float32(height))
+
+		g.FrameStart()
+
+		g.Update()
+
+		gl.Clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT)
+		g.Render()
+		ui.Render(float32(width), float32(height), fbWidth, fbHeight)
+		w.SDLWin.GLSwap()
+
+		g.FrameEnd()
+		w.Rend.FrameEnd()
+		timing.FrameEnded()
+	}
+
+	g.Deinit()
+}

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) {

main.go

@@ -2,98 +2,80 @@ 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/engine"
 	"github.com/bloeys/nmage/input"
 	"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"
-	"github.com/go-gl/gl/v4.1-core/gl"
+	nmageimgui "github.com/bloeys/nmage/ui/imgui"
 	"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
+// Build simple game
+// Integrate physx
+// Entities and components
+// Camera class
 
 //Low Priority:
-//	Proper Asset loading
-
-type ImguiInfo struct {
-	imCtx *imgui.Context
-
-	vaoID      uint32
-	vboID      uint32
-	indexBufID uint32
-	texID      uint32
-}
+// 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
+// Audio
+// Frustum culling
+// Material system editor with fields automatically extracted from the shader
 
 var (
-	winWidth  int32 = 1280
-	winHeight int32 = 720
-
 	isRunning bool = true
 	window    *engine.Window
 
 	simpleMat *materials.Material
-	imguiMat  *materials.Material
 	cubeMesh  *meshes.Mesh
 
-	modelMat = gglm.NewTrMatId()
-	projMat  = &gglm.Mat4{}
-
-	imguiInfo *ImguiInfo
-
+	modelMat   = gglm.NewTrMatId()
+	projMat    = &gglm.Mat4{}
 	camPos     = gglm.NewVec3(0, 0, -10)
 	camForward = gglm.NewVec3(0, 0, 1)
+
+	lightPos1   = gglm.NewVec3(2, 2, 0)
+	lightColor1 = gglm.NewVec3(1, 1, 1)
 )
 
-func main() {
+type OurGame struct {
+	Win       *engine.Window
+	ImGUIInfo nmageimgui.ImguiInfo
+	Quitting  bool
+}
 
-	runtime.LockOSThread()
-
-	//Init engine
-	err := engine.Init()
-	if err != nil {
-		logging.ErrLog.Fatalln("Failed to init nMage. Err:", err)
-	}
-
-	//Create window
-	window, err = engine.CreateOpenGLWindowCentered("nMage", winWidth, winHeight, engine.WindowFlags_RESIZABLE)
-	if err != nil {
-		logging.ErrLog.Fatalln("Failed to create window. Err: ", err)
-	}
-	defer window.Destroy()
-
-	engine.SetVSync(false)
+func (g *OurGame) Init() {
 
 	//Create materials
 	simpleMat = materials.NewMaterial("Simple Mat", "./res/shaders/simple")
-	imguiMat = materials.NewMaterial("ImGUI Mat", "./res/shaders/imgui")
 
 	//Load meshes
+	var err error
 	cubeMesh, err = meshes.NewMesh("Cube", "./res/models/tex-cube.fbx", asig.PostProcess(0))
 	if err != nil {
 		logging.ErrLog.Fatalln("Failed to load cube mesh. Err: ", err)
 	}
 
-	//Set mesh textures on material
-	for _, v := range cubeMesh.TextureIDs {
-		simpleMat.AddTextureID(v)
+	//Load textures
+	tex, err := assets.LoadPNGTexture("./res/textures/Low poly planet.png")
+	if err != nil {
+		logging.ErrLog.Fatalln("Failed to load texture. Err: ", err)
 	}
 
-	initImGUI()
-
-	//Enable vertex attributes
+	//Configure material
+	simpleMat.DiffuseTex = tex.TexID
 	simpleMat.SetAttribute(cubeMesh.Buf)
 
 	//Movement, scale and rotation
@@ -108,182 +90,28 @@ func main() {
 	updateViewMat()
 
 	//Perspective/Depth
-	projMat := gglm.Perspective(45*gglm.Deg2Rad, float32(winWidth)/float32(winHeight), 0.1, 500)
+	projMat := gglm.Perspective(45*gglm.Deg2Rad, float32(1280)/float32(720), 0.1, 500)
 	simpleMat.SetUnifMat4("projMat", projMat)
 
 	//Lights
-	simpleMat.SetUnifVec3("lightPos1", &lightPos1)
-	simpleMat.SetUnifVec3("lightColor1", &lightColor1)
-
-	//Game loop
-	for isRunning {
-
-		timing.FrameStarted()
-
-		handleInputs()
-		runGameLogic()
-
-		draw()
-
-		timing.FrameEnded()
-
-		window.SDLWin.SetTitle(fmt.Sprintf("FPS: %.0f; Elapsed: %v", 1/timing.DT(), timing.ElapsedTime()))
-	}
+	simpleMat.SetUnifVec3("lightPos1", lightPos1)
+	simpleMat.SetUnifVec3("lightColor1", lightColor1)
 }
 
-func updateViewMat() {
-	targetPos := camPos.Clone().Add(camForward)
-	viewMat := gglm.LookAt(camPos, targetPos, gglm.NewVec3(0, 1, 0))
-	simpleMat.SetUnifMat4("viewMat", &viewMat.Mat4)
+func (g *OurGame) FrameStart() {
 }
 
-func initImGUI() {
+func (g *OurGame) Update() {
 
-	imguiInfo = &ImguiInfo{
-		imCtx: imgui.CreateContext(nil),
+	if input.IsQuitClicked() {
+		g.Quitting = true
 	}
 
-	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)
-
+	winWidth, winHeight := g.Win.SDLWin.GetSize()
 	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() {
 
+	//Camera movement
 	var camSpeed float32 = 15
 	if input.KeyDown(sdl.K_w) {
 		camPos.Data[1] += camSpeed * timing.DT()
@@ -310,150 +138,78 @@ func runGameLogic() {
 		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)
+	//Rotating cubes
+	if input.KeyDown(sdl.K_SPACE) {
+		modelMat.Rotate(10*timing.DT()*gglm.Deg2Rad, gglm.NewVec3(1, 1, 1).Normalize())
+		simpleMat.SetUnifMat4("modelMat", &modelMat.Mat4)
 	}
 
-	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()
+	imgui.DragFloat3("Cam Pos", &camPos.Data)
 }
 
-func draw() {
+func (g *OurGame) Render() {
 
-	gl.Clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT)
-
-	simpleMat.Bind()
-	cubeMesh.Buf.Bind()
 	tempModelMat := modelMat.Clone()
 
-	rowSize := 10
+	rowSize := 100
 	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))
+			tempModelMat.Translate(gglm.NewVec3(-1, 0, 0))
+			window.Rend.Draw(cubeMesh, tempModelMat, simpleMat)
 		}
-		simpleMat.SetUnifMat4("modelMat", &tempModelMat.Translate(gglm.NewVec3(float32(rowSize), -1, 0)).Mat4)
+		tempModelMat.Translate(gglm.NewVec3(float32(rowSize), -1, 0))
 	}
-	simpleMat.SetUnifMat4("modelMat", &modelMat.Mat4)
 
-	drawUI()
-	window.SDLWin.GLSwap()
+	g.GetWindow().SDLWin.SetTitle(fmt.Sprint("nMage (", timing.GetAvgFPS(), " fps)"))
 }
 
-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)
+func (g *OurGame) FrameEnd() {
+}
+
+func (g *OurGame) ShouldRun() bool {
+	return !g.Quitting
+}
+
+func (g *OurGame) GetWindow() *engine.Window {
+	return g.Win
+}
+
+func (g *OurGame) GetImGUI() nmageimgui.ImguiInfo {
+	return g.ImGUIInfo
+}
+
+func (g *OurGame) Deinit() {
+	g.Win.Destroy()
+}
+
+func main() {
+
+	//Init engine
+	err := engine.Init()
+	if err != nil {
+		logging.ErrLog.Fatalln("Failed to init nMage. Err:", err)
+	}
+
+	//Create window
+	window, err = engine.CreateOpenGLWindowCentered("nMage", 1280, 720, engine.WindowFlags_RESIZABLE, rend3dgl.NewRend3DGL())
+	if err != nil {
+		logging.ErrLog.Fatalln("Failed to create window. Err: ", err)
+	}
+	defer window.Destroy()
+
+	engine.SetVSync(false)
+
+	game := &OurGame{
+		Win:       window,
+		ImGUIInfo: nmageimgui.NewImGUI(),
+	}
+
+	engine.Run(game)
+	return
+}
+
+func updateViewMat() {
+	targetPos := camPos.Clone().Add(camForward)
+	viewMat := gglm.LookAt(camPos, targetPos, gglm.NewVec3(0, 1, 0))
+	simpleMat.SetUnifMat4("viewMat", &viewMat.Mat4)
 }

materials/material.go

@@ -2,6 +2,7 @@ package materials
 
 import (
 	"github.com/bloeys/gglm/gglm"
+	"github.com/bloeys/nmage/asserts"
 	"github.com/bloeys/nmage/buffers"
 	"github.com/bloeys/nmage/logging"
 	"github.com/bloeys/nmage/shaders"
@@ -11,29 +12,53 @@ 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"))
+
+	loc, ok := m.AttribLocs[attribName]
+	if ok {
+		return loc
+	}
+
+	loc = gl.GetAttribLocation(m.ShaderProg.ID, gl.Str(attribName+"\x00"))
+	asserts.T(loc != -1, "Attribute '"+attribName+"' doesn't exist on material "+m.Name)
+	m.AttribLocs[attribName] = loc
+	return loc
+}
+
+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"))
+	asserts.T(loc != -1, "Uniform '"+uniformName+"' doesn't exist on material "+m.Name)
+	m.UnifLocs[uniformName] = loc
+	return loc
 }
 
 func (m *Material) SetAttribute(bufObj buffers.Buffer) {
@@ -53,10 +78,6 @@ func (m *Material) SetAttribute(bufObj buffers.Buffer) {
 	gl.BindBuffer(gl.ARRAY_BUFFER, 0)
 }
 
-func (m *Material) AddTextureID(texID uint32) {
-	m.TexIDs = append(m.TexIDs, texID)
-}
-
 func (m *Material) EnableAttribute(attribName string) {
 	gl.EnableVertexAttribArray(uint32(m.GetAttribLoc(attribName)))
 }
@@ -66,43 +87,35 @@ 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() {
@@ -130,5 +143,5 @@ func NewMaterial(matName, shaderPath string) *Material {
 	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)}
 }

meshes/mesh.go

@@ -7,15 +7,12 @@ 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/buffers"
-	"github.com/bloeys/nmage/logging"
 )
 
 type Mesh struct {
-	Name       string
-	TextureIDs []uint32
-	Buf        buffers.Buffer
+	Name string
+	Buf  buffers.Buffer
 }
 
 func NewMesh(name, modelPath string, postProcessFlags asig.PostProcess) (*Mesh, error) {
@@ -42,22 +39,6 @@ func NewMesh(name, modelPath string, postProcessFlags asig.PostProcess) (*Mesh,
 	}
 	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)
-		}
-
-		tex, err := assets.LoadPNG(texInfo.Path)
-		if err != nil {
-			logging.ErrLog.Fatalf("Loading PNG with path '%s' failed. Err: %e\n", texInfo.Path, err)
-		}
-
-		mesh.TextureIDs = append(mesh.TextureIDs, tex.TexID)
-	}
-
 	var values []float32
 	arrs := []arrToInterleave{{V3s: sceneMesh.Vertices}, {V3s: sceneMesh.Normals}, {V2s: v3sToV2s(sceneMesh.TexCoords[0])}}
 

renderer/rend3dgl/rend3dgl.go

@@ -0,0 +1,41 @@
+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)
+	gl.DrawElements(gl.TRIANGLES, mesh.Buf.IndexBufCount, gl.UNSIGNED_INT, gl.PtrOffset(0))
+}
+
+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()
+}

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)
+	}
 }
 
-//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 +1,218 @@
+package nmageimgui
+
+import (
+	"github.com/bloeys/gglm/gglm"
+	"github.com/bloeys/nmage/asserts"
+	"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 {
+		asserts.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 {
+		asserts.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()
+
+	gl.Uniform1i(gl.GetUniformLocation(i.Mat.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)
+	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.BLEND)
+	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
+}
+
+func NewImGUI() ImguiInfo {
+
+	imguiInfo := ImguiInfo{
+		ImCtx: imgui.CreateContext(nil),
+		Mat:   materials.NewMaterial("ImGUI Mat", "./res/shaders/imgui"),
+	}
+
+	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
+}