func (m *Map) Draw() {

	// gl.Enable(gl.PRIMITIVE_RESTART)
	// gl.PrimitiveRestartIndex(PRIMITIVE_RESTART)
	gl.EnableClientState(gl.VERTEX_ARRAY)
	gl.Translatef(float32(m.gridSize/2), float32(m.gridSize/2), 0)

	if m.renderSmooth {
		gl.Enable(gl.BLEND)
		gl.BlendFunc(gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA)
		gl.Enable(gl.POLYGON_SMOOTH)
		gl.Hint(gl.POLYGON_SMOOTH_HINT, gl.NICEST)
	}

	if m.renderMode == 1 {
		gl.LineWidth(1)
		gl.VertexPointer(2, gl.FLOAT, 0, m.gridLines)
		gl.Color3f(0.2, 0.2, 0.2)
		gl.DrawArrays(gl.LINES, 0, len(m.gridLines)/2)
		gl.PolygonMode(gl.FRONT_AND_BACK, gl.LINE)
	}

	for _, vl := range m.vl {
		if len(vl.vertices) > 0 {
			gl.VertexPointer(2, gl.FLOAT, 0, vl.vertices)
			gl.Color3f(vl.colors[0], vl.colors[1], vl.colors[2])
			gl.DrawElements(gl.TRIANGLES, len(vl.indices), gl.UNSIGNED_INT, vl.indices)
		}
	}

}

func (m *Map) Draw() {

	gl.PushMatrix()
	gl.PushAttrib(gl.CURRENT_BIT | gl.ENABLE_BIT | gl.LIGHTING_BIT | gl.POLYGON_BIT | gl.LINE_BIT)

	gl.EnableClientState(gl.VERTEX_ARRAY)
	gl.VertexPointer(3, gl.FLOAT, 0, m.vertices)

	gl.EnableClientState(gl.NORMAL_ARRAY)
	gl.NormalPointer(gl.FLOAT, 0, m.normals)

	// gl.EnableClientState(gl.TEXTURE_COORD_ARRAY)
	// gl.TexCoordPointer(2, gl.FLOAT, 0, m.texcoords)

	gl.EnableClientState(gl.COLOR_ARRAY)
	gl.ColorPointer(3, gl.FLOAT, 0, m.colors)

	// draw solids
	gl.Enable(gl.COLOR_MATERIAL)
	// gl.DrawArrays(gl.TRIANGLE_STRIP, 0, len(m.vertices)/3)

	gl.PolygonMode(gl.FRONT_AND_BACK, gl.LINE)
	gl.LineWidth(1.0)
	gl.Color4f(1, 1, 1, 1)
	gl.DrawArrays(gl.TRIANGLE_STRIP, 0, len(m.vertices)/3)

	gl.PopAttrib()
	gl.PopMatrix()

}

func main() {

	if !glfw.Init() {
		log.Fatal("glfw failed to initialize")
	}
	defer glfw.Terminate()

	window, err := glfw.CreateWindow(640, 480, "Deformable", nil, nil)
	if err != nil {
		log.Fatal(err.Error())
	}

	window.MakeContextCurrent()
	glfw.SwapInterval(1)
	window.SetMouseButtonCallback(handleMouseButton)
	window.SetKeyCallback(handleKeyDown)
	window.SetInputMode(glfw.Cursor, glfw.CursorHidden)

	gl.Init()
	initGL()

	i := 16
	m = GenerateMap(1600/i, 1200/i, i)
	for running && !window.ShouldClose() {

		x, y := window.GetCursorPosition()

		if drawing != 0 {
			m.Add(int(x)+int(camera[0]), int(y)+int(camera[1]), drawing, brushSizes[currentBrushSize])
		}

		gl.Clear(gl.COLOR_BUFFER_BIT)
		gl.LoadIdentity()

		gl.PushMatrix()
		gl.PushAttrib(gl.CURRENT_BIT | gl.ENABLE_BIT | gl.LIGHTING_BIT | gl.POLYGON_BIT | gl.LINE_BIT)
		gl.Translatef(-camera[0], -camera[1], 0)
		m.Draw()
		gl.PopAttrib()
		gl.PopMatrix()

		gl.PushAttrib(gl.COLOR_BUFFER_BIT)
		gl.LineWidth(2)
		gl.Enable(gl.BLEND)
		gl.BlendFunc(gl.ONE_MINUS_DST_COLOR, gl.ZERO)
		// gl.Enable(gl.LINE_SMOOTH)
		// gl.Hint(gl.LINE_SMOOTH_HINT, gl.NICEST)

		gl.Translatef(float32(x), float32(y), 0)

		gl.EnableClientState(gl.VERTEX_ARRAY)
		gl.VertexPointer(2, gl.DOUBLE, 0, cursorVerts)
		gl.DrawArrays(gl.LINE_LOOP, 0, 24)
		gl.PopAttrib()

		window.SwapBuffers()
		glfw.PollEvents()
	}

}

func main() {
	if err := glfw.Init(); err != nil {
		fmt.Fprintf(os.Stderr, "%s\n", err.Error())
		return
	}

	defer glfw.Terminate()

	glfw.OpenWindowHint(glfw.FsaaSamples, 4)
	glfw.OpenWindowHint(glfw.OpenGLVersionMajor, 3)
	glfw.OpenWindowHint(glfw.OpenGLVersionMinor, 3)
	glfw.OpenWindowHint(glfw.OpenGLProfile, glfw.OpenGLCoreProfile)

	if err := glfw.OpenWindow(1024, 768, 0, 0, 0, 0, 32, 0, glfw.Windowed); err != nil {
		fmt.Fprintf(os.Stderr, "%s\n", err.Error())
		return
	}

	gl.Init()     // Can't find gl.GLEW_OK or any variation, not sure how to check if this worked
	gl.GetError() // Ignore error

	glfw.SetWindowTitle("Tutorial 02")

	glfw.Enable(glfw.StickyKeys)
	gl.ClearColor(0., 0., 0.4, 0.)

	prog := helper.MakeProgram("SimpleVertexShader.vertexshader", "SimpleFragmentShader.fragmentshader")

	vBufferData := [...]float32{
		-1., -1., 0.,
		1., -1., 0.,
		0., 1., 0.}

	vertexArray := gl.GenVertexArray()
	vertexArray.Bind()
	buffer := gl.GenBuffer()
	buffer.Bind(gl.ARRAY_BUFFER)
	gl.BufferData(gl.ARRAY_BUFFER, len(vBufferData)*4, &vBufferData, gl.STATIC_DRAW)

	// Equivalent to a do... while
	for ok := true; ok; ok = (glfw.Key(glfw.KeyEsc) != glfw.KeyPress && glfw.WindowParam(glfw.Opened) == gl.TRUE) {
		gl.Clear(gl.COLOR_BUFFER_BIT)

		prog.Use()

		attribLoc := gl.AttribLocation(0)
		attribLoc.EnableArray()
		buffer.Bind(gl.ARRAY_BUFFER)
		attribLoc.AttribPointer(3, gl.FLOAT, false, 0, nil)

		gl.DrawArrays(gl.TRIANGLES, 0, 3)

		attribLoc.DisableArray()

		glfw.SwapBuffers()
	}

}

func (ui *UIText) Draw() {
	if ui.text == "" {
		return
	}

	v := ui.align.Vector()
	v.X = (v.X * ui.width)
	v.Y = (v.Y * ui.height)

	mat := engine.TextureMaterial
	if ui.Font.IsSDF() {
		mat = engine.SDFMaterial
	}
	mat.Begin(ui.GameObject())

	mp := mat.ProjMatrix
	mv := mat.ViewMatrix
	mm := mat.ModelMatrix
	tx := mat.Texture
	ti := mat.Tiling
	of := mat.Offset
	color := mat.AddColor
	_ = color

	ui.buffer.Bind(gl.ARRAY_BUFFER)
	mat.Verts.EnableArray()
	mat.Verts.AttribPointer(3, gl.FLOAT, false, 0, uintptr(0))
	mat.UV.EnableArray()
	mat.UV.AttribPointer(2, gl.FLOAT, false, 0, uintptr(ui.texcoordsIndex))

	camera := engine.GetScene().SceneBase().Camera

	view := camera.InvertedMatrix()
	model := engine.Identity()
	model.Translate(v.X, v.Y, 0)
	model.Mul(ui.GameObject().Transform().Matrix())
	model.Translate(0.75, 0.75, 0)
	/*
		view := camera.Transform().Matrix()
		view = view.Invert()
		model := ui.GameObject().Transform().Matrix()
	*/

	mv.UniformMatrix4fv(false, view)
	mp.UniformMatrix4f(false, (*[16]float32)(camera.Projection))
	mm.UniformMatrix4fv(false, model)
	ti.Uniform2f(1, 1)
	of.Uniform2f(0, 0)

	ui.Font.Bind()
	tx.Uniform1i(0)

	color.Uniform4f(ui.Color.R, ui.Color.G, ui.Color.B, ui.Color.A)

	gl.DrawArrays(gl.QUADS, 0, ui.vertexCount)

}

func handleText(camera *PerspectiveCamera, text *Text) {
	// Material
	material := text.Material()
	program := material.Program()
	if program == nil {
		program = createTextProgram(text)
		material.SetProgram(program)
	}
	program.Use()
	defer program.Unuse()

	if c, ok := material.(Colored); ok {
		if c.Color() != nil {
			program.uniforms["diffuse"].apply(c.Color())
		}
	}

	if t, ok := material.(Textured); ok {
		texture := t.Texture()
		if texture != nil {
			gl.ActiveTexture(gl.TEXTURE0)
			texture.Bind()
			defer texture.Unbind()
			program.uniforms["texture"].apply(texture)
		}
	}

	for _, attribute := range program.attributes {
		attribute.enable()
		defer attribute.disable()
		attribute.bindBuffer()
		defer attribute.unbindBuffer()
		attribute.pointer()
		attribute.bindBuffer()
	}

	vertexAttrib := gl.AttribLocation(0)
	vertexAttrib.EnableArray()
	defer vertexAttrib.DisableArray()
	text.vertexBuffer.Bind(gl.ARRAY_BUFFER)
	defer text.vertexBuffer.Unbind(gl.ARRAY_BUFFER)
	vertexAttrib.AttribPointer(2, gl.FLOAT, false, 0, nil)

	if t, ok := material.(Wireframed); ok {
		if t.Wireframe() {
			gl.PolygonMode(gl.FRONT_AND_BACK, gl.LINE)
		} else {
			gl.PolygonMode(gl.FRONT_AND_BACK, gl.FILL)
		}
	}

	gl.Enable(gl.BLEND)
	gl.BlendFunc(gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA)

	gl.DrawArrays(gl.TRIANGLES, 0, len(text.Geometry().Vertices))
}

func DrawSprites(tex *Texture, uvs []UV, positions []Vector, scales []Vector, rotations []float32, alings []Align, colors []Color) {

	internalMaterial.Begin(nil)

	mp := internalMaterial.ProjMatrix
	mv := internalMaterial.ViewMatrix
	mm := internalMaterial.ModelMatrix
	tx := internalMaterial.Texture
	ac := internalMaterial.AddColor
	ti := internalMaterial.Tiling
	of := internalMaterial.Offset

	defaultBuffer.Bind(gl.ARRAY_BUFFER)
	internalMaterial.Verts.EnableArray()
	internalMaterial.Verts.AttribPointer(3, gl.FLOAT, false, 0, uintptr(0))
	internalMaterial.UV.EnableArray()
	internalMaterial.UV.AttribPointer(2, gl.FLOAT, false, 0, uintptr(12*4))

	camera := GetScene().SceneBase().Camera
	view := camera.InvertedMatrix()
	mv.UniformMatrix4fv(false, view)
	mp.UniformMatrix4f(false, (*[16]float32)(camera.Projection))

	tex.Bind()
	tx.Uniform1i(0)

	for i := 0; i < len(uvs); i++ {

		uv, position, scale := uvs[i], positions[i], scales[i]

		if !InsideScreen(uv.Ratio, position, scale) {
			continue
		}

		rotation, aling, color := rotations[i], alings[i], colors[i]

		v := aling.Vector()
		v.X *= uv.Ratio

		model := Identity()
		model.Translate(v.X, v.Y, 0)

		model.Scale((scale.X * uv.Ratio), scale.Y, scale.Z)
		model.RotateZ(rotation, -1)
		model.Translate(position.X+0.75, position.Y+0.75, position.Z)

		mm.UniformMatrix4fv(false, model)
		ac.Uniform4f(color.R, color.G, color.B, color.A)
		ti.Uniform2f(uv.U2-uv.U1, uv.V2-uv.V1)
		of.Uniform2f(uv.U1, uv.V1)

		gl.DrawArrays(gl.QUADS, 0, 4)
	}

	internalMaterial.End(nil)
}

func (c *QuadraticCurve) draw(canv *Canvas) {
	p := canv.toGLPoints(c.Points())
	vertices := []float32{
		p[0].X, p[0].Y, 0.0, 0.0,
		p[1].X, p[1].Y, 0.5, 0.0,
		p[2].X, p[2].Y, 1.0, 1.0,
	}
	gl.BufferData(gl.ARRAY_BUFFER, len(vertices)*4, vertices, gl.STATIC_DRAW)
	gl.DrawArrays(gl.TRIANGLES, 0, 3)
}

func (sp *Sprite) Draw() {
	if sp.Texture != nil && sp.Render {
		/*
			Temporal camera distance check
		*/
		currentUV := sp.UVs[int(sp.animation)]
		if !InsideScreen(currentUV.Ratio, sp.Transform().WorldPosition(), sp.Transform().WorldScale()) {
			return
		}

		renders++

		TextureMaterial.Begin(sp.GameObject())

		mp := TextureMaterial.ProjMatrix
		mv := TextureMaterial.ViewMatrix
		mm := TextureMaterial.ModelMatrix
		tx := TextureMaterial.Texture
		ac := TextureMaterial.AddColor
		ti := TextureMaterial.Tiling
		of := TextureMaterial.Offset

		defaultBuffer.Bind(gl.ARRAY_BUFFER)
		TextureMaterial.Verts.EnableArray()
		TextureMaterial.Verts.AttribPointer(3, gl.FLOAT, false, 0, uintptr(0))
		TextureMaterial.UV.EnableArray()
		TextureMaterial.UV.AttribPointer(2, gl.FLOAT, false, 0, uintptr(12*4))

		v := sp.align.Vector()
		v.X *= currentUV.Ratio

		camera := GetScene().SceneBase().Camera
		view := camera.InvertedMatrix()
		model := Identity()
		model.Scale(currentUV.Ratio, 1, 1)
		model.Translate(v.X, v.Y, 0)
		model.Mul(sp.GameObject().Transform().Matrix())

		mv.UniformMatrix4f(false, (*[16]float32)(&view))
		mp.UniformMatrix4f(false, (*[16]float32)(camera.Projection))
		mm.UniformMatrix4f(false, (*[16]float32)(&model))

		sp.Bind()
		tx.Uniform1i(0)

		ac.Uniform4f(sp.Color.R, sp.Color.G, sp.Color.B, sp.Color.A)
		ti.Uniform2f((currentUV.U2-currentUV.U1)*sp.Tiling.X, (currentUV.V2-currentUV.V1)*sp.Tiling.Y)
		of.Uniform2f(currentUV.U1, currentUV.V1)

		gl.DrawArrays(gl.QUADS, 0, 4)

		TextureMaterial.End(sp.GameObject())
	}
}

func (r *Renderer) Render() {
	gl.Clear(gl.COLOR_BUFFER_BIT)

	r.prog.Use()

	r.vao.Bind()
	r.vbo.Bind(gl.ARRAY_BUFFER)

	gl.DrawArrays(gl.POINTS, 0, len(r.vertices))

	// FIXME: unbind vao/vbo/prog?
}

func (sp *Sprite) DrawScreen() {
	if sp.Texture != nil && sp.Render {

		camera := GetScene().SceneBase().Camera
		pos := sp.Transform().WorldPosition()
		scale := sp.Transform().WorldScale()

		TextureMaterial.Begin(sp.GameObject())

		mp := TextureMaterial.ProjMatrix
		mv := TextureMaterial.ViewMatrix
		mm := TextureMaterial.ModelMatrix
		tx := TextureMaterial.Texture
		ac := TextureMaterial.AddColor
		ti := TextureMaterial.Tiling
		of := TextureMaterial.Offset

		defaultBuffer.Bind(gl.ARRAY_BUFFER)
		TextureMaterial.Verts.EnableArray()
		TextureMaterial.Verts.AttribPointer(3, gl.FLOAT, false, 0, uintptr(0))
		TextureMaterial.UV.EnableArray()
		TextureMaterial.UV.AttribPointer(2, gl.FLOAT, false, 0, uintptr(12*4))

		currentUV := sp.UVs[int(sp.animation)]

		view := Identity()
		model := Identity()
		model.Scale(scale.X*currentUV.Ratio, scale.Y, 1)
		model.Translate((float32(Width)/2)+pos.X+0.75, (float32(Height)/2)+pos.Y+0.75, 1)

		mv.UniformMatrix4fv(false, view)
		mp.UniformMatrix4f(false, (*[16]float32)(camera.Projection))
		mm.UniformMatrix4fv(false, model)

		ti.Uniform2f((currentUV.U2-currentUV.U1)*sp.Tiling.X, (currentUV.V2-currentUV.V1)*sp.Tiling.Y)
		of.Uniform2f(currentUV.U1, currentUV.V1)

		sp.Bind()
		gl.ActiveTexture(gl.TEXTURE0)
		tx.Uniform1i(0)

		//ac.Uniform4f(1, 1, 1, 0)
		ac.Uniform4f(sp.Color.R, sp.Color.G, sp.Color.B, sp.Color.A)

		gl.DrawArrays(gl.QUADS, 0, 4)

		TextureMaterial.End(sp.GameObject())
	}
}

func DrawSprite(tex *Texture, uv UV, position Vector, scale Vector, rotation float32, aling Align, color Color) {
	if !InsideScreen(uv.Ratio, position, scale) {
		return
	}

	internalMaterial.Begin(nil)

	mp := internalMaterial.ProjMatrix
	mv := internalMaterial.ViewMatrix
	mm := internalMaterial.ModelMatrix
	tx := internalMaterial.Texture
	ac := internalMaterial.AddColor
	ti := internalMaterial.Tiling
	of := internalMaterial.Offset

	defaultBuffer.Bind(gl.ARRAY_BUFFER)
	internalMaterial.Verts.EnableArray()
	internalMaterial.Verts.AttribPointer(3, gl.FLOAT, false, 0, uintptr(0))
	internalMaterial.UV.EnableArray()
	internalMaterial.UV.AttribPointer(2, gl.FLOAT, false, 0, uintptr(12*4))

	v := aling.Vector()
	v.X *= uv.Ratio

	camera := GetScene().SceneBase().Camera
	view := camera.InvertedMatrix()
	model := Identity()
	model.Translate(v.X, v.Y, 0)

	model.Scale(scale.X*uv.Ratio, scale.Y, scale.Z)
	model.RotateZ(rotation, -1)
	model.Translate(position.X+0.75, position.Y+0.75, position.Z)

	mv.UniformMatrix4fv(false, view)
	mp.UniformMatrix4f(false, (*[16]float32)(camera.Projection))
	mm.UniformMatrix4fv(false, model)
	ac.Uniform4i(int(color.R), int(color.G), int(color.B), int(color.A))
	ti.Uniform2f(uv.U2-uv.U1, uv.V2-uv.V1)
	of.Uniform2f(uv.U1, uv.V1)

	tx.Uniform1i(0)

	tex.Bind()

	gl.DrawArrays(gl.QUADS, 0, 4)

	internalMaterial.End(nil)
}

func (self *OpenGLRenderer) renderOne(operation render.RenderOperation, renderState RenderState) {
	mesh := operation.Mesh
	material := operation.Material
	transform := operation.Transform

	// No attributes? no loaded or empty? Better way to handle this than spamming
	// the console?
	if mesh.VertexArrayObj == nil {
		log.Println("WARNING: Trying to render an invalid mesh", mesh)
		return
	}

	vertexArrayObj := mesh.VertexArrayObj.(gl.VertexArray)
	vertexArrayObj.Bind()

	material.Shader.Program.Use()
	material.Shader.Program.SetUniformMatrix(
		"modelViewProjection",
		renderState.ViewProjection.Times(transform),
	)

	if material.Texture != nil {
		glTexture := material.Texture.Id.(gl.Texture)
		gl.ActiveTexture(gl.TEXTURE0)

		if !material.IsCubeMap {
			glTexture.Bind(gl.TEXTURE_2D)
			defer glTexture.Unbind(gl.TEXTURE_2D)
			material.Shader.Program.SetUniformUnit("textureSampler", 0)
		} else {
			gl.Disable(gl.DEPTH_TEST)
			defer gl.Enable(gl.DEPTH_TEST)

			glTexture.Bind(gl.TEXTURE_CUBE_MAP)
			defer glTexture.Unbind(gl.TEXTURE_CUBE_MAP)
			material.Shader.Program.SetUniformUnit("cubeMap", 0)
		}
	}

	if len(mesh.IndexList) == 0 {
		gl.DrawArrays(gl.TRIANGLES, 0, len(mesh.VertexList)*3)
	} else {
		gl.DrawElements(gl.TRIANGLES, len(mesh.IndexList), gl.UNSIGNED_INT, nil)
	}
}

// Arrays mode uses vertex arrays which involves gl*Pointer calls and
// directly passing in the vertex data on every render pass. This is slower
// than using VBO's, because the data has to be uploaded to the GPU on every
// render pass, but it is useful for older systems where glBufferData is
// not available.
func (mb *MeshBuffer) renderArrays(mode gl.GLenum, m Mesh, pa, ca, na, ta, ia *Attr) {
	ps, pc := m[mbPositionKey][0], m[mbPositionKey][1]
	is, ic := m[mbIndexKey][0], m[mbIndexKey][1]
	cc := m[mbColorKey][1]
	nc := m[mbNormalKey][1]
	tc := m[mbTexCoordKey][1]

	gl.PushClientAttrib(gl.CLIENT_VERTEX_ARRAY_BIT)
	defer gl.PopClientAttrib()

	if pc > 0 {
		gl.EnableClientState(gl.VERTEX_ARRAY)
		defer gl.DisableClientState(gl.VERTEX_ARRAY)
		gl.VertexPointer(pa.size, pa.typ, 0, pa.ptr(0))
	}

	if cc > 0 {
		gl.EnableClientState(gl.COLOR_ARRAY)
		defer gl.DisableClientState(gl.COLOR_ARRAY)
		gl.ColorPointer(ca.size, ca.typ, 0, ca.ptr(0))
	}

	if nc > 0 {
		gl.EnableClientState(gl.NORMAL_ARRAY)
		defer gl.DisableClientState(gl.NORMAL_ARRAY)
		gl.NormalPointer(na.typ, 0, na.ptr(0))
	}

	if tc > 0 {
		gl.EnableClientState(gl.TEXTURE_COORD_ARRAY)
		defer gl.DisableClientState(gl.TEXTURE_COORD_ARRAY)
		gl.TexCoordPointer(ta.size, ta.typ, 0, ta.ptr(0))
	}

	if ic > 0 {
		gl.EnableClientState(gl.INDEX_ARRAY)
		defer gl.DisableClientState(gl.INDEX_ARRAY)
		gl.IndexPointer(ia.typ, 0, ia.ptr(0))
		gl.DrawElements(mode, ic, ia.typ, ia.ptr(is*ia.size))
	} else {
		gl.DrawArrays(mode, ps, pc)
	}
}

func Tick() {
	timer = float32(glfw.Time())

	gl.Clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT)

	program.Use()

	camera.Tick()

	modelViewMatrixUniform.UniformMatrix4fv(camera.modelViewMatrix[:])
	projectionMatrixUniform.UniformMatrix4fv(camera.projectionMatrix[:])
	timerUniform.Uniform1f(timer)

	positionAttrib.EnableArray()
	texcoordAttrib.EnableArray()

	gl.ActiveTexture(gl.TEXTURE0)
	textures[0].Bind(gl.TEXTURE_2D)
	textureUniforms[0].Uniform1i(0)

	gl.ActiveTexture(gl.TEXTURE1)
	textures[1].Bind(gl.TEXTURE_2D)
	textureUniforms[1].Uniform1i(1)

	sizeOfVertex := int(unsafe.Sizeof(Vertex{}))
	posoffset := uintptr(0)
	texoffset := unsafe.Offsetof(Vertex{}.texcoord)
	for _, renderObject := range renderObjects {
		renderObject.vertexBuffer.Bind(gl.ARRAY_BUFFER)
		positionAttrib.AttribPointer(3, gl.FLOAT, false, sizeOfVertex, posoffset)
		texcoordAttrib.AttribPointer(2, gl.FLOAT, false, sizeOfVertex, texoffset)

		gl.DrawArrays(gl.TRIANGLES, 0, renderObject.numVerticies)
	}

	positionAttrib.DisableArray()
	texcoordAttrib.DisableArray()
	gl.ProgramUnuse()

	glfw.SwapBuffers()
}

func (d *DrawImage) render() error {
	fn := func(idx int) (err error) {
		defer func() {
			//err = recover()
		}()
		vbuf := gl.GenBuffer()
		vbuf.Bind(gl.ARRAY_BUFFER)
		gl.BufferData(gl.ARRAY_BUFFER, len(d.vertex[idx])*4, d.vertex[idx], gl.STATIC_DRAW)
		panicGlError()
		defer vbuf.Delete()

		uvbuf := gl.GenBuffer()
		uvbuf.Bind(gl.ARRAY_BUFFER)
		gl.BufferData(gl.ARRAY_BUFFER, len(d.uv[idx])*4, d.uv[idx], gl.STATIC_DRAW)
		panicGlError()
		defer uvbuf.Delete()

		vloc := gl.AttribLocation(0)
		vloc.EnableArray()
		vbuf.Bind(gl.ARRAY_BUFFER)
		vloc.AttribPointer(3, gl.FLOAT, false, 0, nil)
		panicGlError()
		defer vloc.DisableArray()

		uvloc := gl.AttribLocation(1)
		uvloc.EnableArray()
		uvbuf.Bind(gl.ARRAY_BUFFER)
		uvloc.AttribPointer(2, gl.FLOAT, false, 0, nil)
		panicGlError()
		defer uvloc.DisableArray()

		gl.DrawArrays(gl.TRIANGLES, 0, 3)

		return checkGlError()
	}
	if err := fn(0); err != nil {
		return err
	}
	return fn(1)
}

func (this *Game) render() {
	gl.ClearColor(0, 0, 0, 0)
	gl.Clear(gl.COLOR_BUFFER_BIT)
	switch this.gameState {
	case initialized:
		this.text.Printf(0.75, -1, "Hit space to play!")
	case running:
		this.program.Use()
		this.vao.Bind()
		this.elements.Each(func(_ int, e Element) {
			if e.isDead() {
				return
			}
			location := e.Location()
			scale := float32(e.Size())

			translateMatrix := NewMatrix4x4(1.0)
			translateMatrix[3] = Vector4{float32(location.x), float32(location.y), -1, 1}
			scaleMatrix := NewMatrix4x4(1.0)
			scaleMatrix[0].x = scale
			scaleMatrix[1].y = scale
			modelToCameraMatrix := translateMatrix.mult(scaleMatrix)
			clipMatrix := this.cameraToClipMatrix.mult(modelToCameraMatrix)
			var clipMatrixArray = clipMatrix.toa()
			this.cameraToClipMatrixUniform.UniformMatrix4f(false, &clipMatrixArray)
			this.colorUniform.Uniform4fv(1, e.Color())
			gl.DrawArrays(gl.LINE_LOOP, 0, 100)
		})
		this.vao.Unbind()
		this.program.Unuse()
		this.text.Printf(0.05, 0, "Score: %d", this.player.score)
		this.text.Printf(0.35, 0, "Distance travelled: %f", this.totalTime*10)
	case won:
		this.text.Printf(0.75, -1, "You won! Hit space to play again.")
	case lost:
		this.text.Printf(0.5, -1, "You lost! Hit space to play again.")
	}
}

func (p *Path) glDraw(canv *Canvas) {
	for e := p.Segs.Front(); e != nil; e = e.Next() {
		e.Value.(PathSegment).Draw(canv)
	}

	if GetPt(p.endPoints.Back()).Mathgl().ApproxEqual(
		GetPt(p.endPoints.Front()).Mathgl()) {
		p.endPoints.Remove(p.endPoints.Back())
	}

	if p.endPoints.Len() < 3 {
		return
	}

	gGl.Activate(gGl.TriangleDrawer)

	gl.BlendFunc(gl.ONE_MINUS_DST_ALPHA, gl.ZERO)
	defer gl.BlendFunc(gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA)

	pa := make(p2t.PointArray, 0, p.endPoints.Len())
	for e := p.endPoints.Front(); e != nil; e = e.Next() {
		p := GetPt(e)
		pa = append(pa, &p2t.Point{X: float64(p.X), Y: float64(p.Y)})
	}
	p2t.Init(pa)
	triArr := p2t.Triangulate()
	vertices := make([]float32, 6, 6)
	for _, tri := range triArr {
		for i, triPt := range tri.Point {
			pt := canv.toGLPoint(Pt(triPt.X, triPt.Y))
			vertices[i*2] = pt.X
			vertices[i*2+1] = pt.Y
		}
		gl.BufferData(gl.ARRAY_BUFFER, len(vertices)*4, vertices, gl.STATIC_DRAW)
		gl.DrawArrays(gl.TRIANGLES, 0, 3)
	}
}

// renderBuffered uses VBO's. This is the preferred mode for systems
// where shader support is not present or deemed necessary.
func (mb *MeshBuffer) renderBuffered(mode gl.GLenum, m Mesh, pa, ca, na, ta, ia *Attr) {
	ps, pc := m[mbPositionKey][0], m[mbPositionKey][1]
	is, ic := m[mbIndexKey][0], m[mbIndexKey][1]
	cc := m[mbColorKey][1]
	nc := m[mbNormalKey][1]
	tc := m[mbTexCoordKey][1]

	if pc > 0 {
		gl.EnableClientState(gl.VERTEX_ARRAY)
		defer gl.DisableClientState(gl.VERTEX_ARRAY)

		pa.bind()
		if pa.Invalid() {
			pa.buffer()
		}
		gl.VertexPointer(pa.size, pa.typ, 0, uintptr(0))
		pa.unbind()
	}

	if cc > 0 {
		gl.EnableClientState(gl.COLOR_ARRAY)
		defer gl.DisableClientState(gl.COLOR_ARRAY)

		ca.bind()
		if ca.Invalid() {
			ca.buffer()
		}
		gl.ColorPointer(ca.size, ca.typ, 0, uintptr(0))
		ca.unbind()
	}

	if nc > 0 {
		gl.EnableClientState(gl.NORMAL_ARRAY)
		defer gl.DisableClientState(gl.NORMAL_ARRAY)

		na.bind()
		if na.Invalid() {
			na.buffer()
		}
		gl.NormalPointer(na.typ, 0, uintptr(0))
		na.unbind()
	}

	if tc > 0 {
		gl.EnableClientState(gl.TEXTURE_COORD_ARRAY)
		defer gl.DisableClientState(gl.TEXTURE_COORD_ARRAY)

		ta.bind()
		if ta.Invalid() {
			ta.buffer()
		}
		gl.TexCoordPointer(ta.size, ta.typ, 0, uintptr(0))
		ta.unbind()
	}

	if ic > 0 {
		ia.bind()

		if ia.Invalid() {
			ia.buffer()
		}

		gl.PushClientAttrib(gl.CLIENT_VERTEX_ARRAY_BIT)
		gl.DrawElements(mode, ic, ia.typ, uintptr(is*ia.stride))
		gl.PopClientAttrib()
		ia.unbind()
	} else {
		pa.bind()
		gl.PushClientAttrib(gl.CLIENT_VERTEX_ARRAY_BIT)
		gl.DrawArrays(mode, ps, pc)
		gl.PopClientAttrib()
		pa.unbind()
	}
}

func (r *RenderTarget) Render(verts []Vertex, primType PrimitiveType, states RenderStates) {
	// Nothing to draw?
	if len(verts) == 0 {
		return
	}

	// First set the persistent OpenGL states if it's the very first call
	if !r.glStatesSet {
		r.resetGlStates()
	}

	// Check if the vertex count is low enough so that we can pre-transform them
	useVertexCache := len(verts) <= vertexCacheSize
	if useVertexCache {
		// Pre-transform the vertices and store them into the vertex cache
		for i := 0; i < len(verts); i++ {
			r.vpCache[i] = states.Transform.TransformPoint(verts[i].Pos)
			r.vcCache[i] = verts[i].Color
			r.vtCache[i] = verts[i].TexCoords
		}

		// Since vertices are transformed, we must use an identity transform to render them
		if !r.useVertexCache {
			r.applyTransform(IdentityTransform())
		}
	} else {
		r.applyTransform(states.Transform)
	}

	// Apply the view
	if r.viewChanged {
		r.applyCurrentView()
	}

	// Apply the blend mode
	if states.BlendMode != r.lastBlendMode {
		r.applyBlendMode(states.BlendMode)
	}

	// Apply the texture
	var textureId uint64
	if states.Texture != nil {
		textureId = states.Texture.cacheId
	}
	if textureId != r.lastTextureId {
		r.applyTexture(states.Texture)
	}

	// Apply the shader
	// TODO
	/*if states.shader {
		applyShader(states.shader);
	}*/

	// #########################################

	if !useVertexCache {
		// Find the OpenGL primitive type
		modes := [...]gl.GLenum{gl.POINTS, gl.LINES, gl.LINE_STRIP, gl.TRIANGLES,
			gl.TRIANGLE_STRIP, gl.TRIANGLE_FAN, gl.QUADS}
		mode := modes[primType]

		gl.Begin(mode)

		for i, _ := range verts {
			gl.TexCoord2f(verts[i].TexCoords.X, verts[i].TexCoords.Y)
			gl.Color4f(float32(verts[i].Color.R)/255, float32(verts[i].Color.G)/255,
				float32(verts[i].Color.B)/255, float32(verts[i].Color.A)/255)
			gl.Vertex2f(verts[i].Pos.X, verts[i].Pos.Y)
		}

		gl.End()
	}

	// #########################################

	// Setup the pointers to the vertices' components
	// ... and if we already used it previously, we don't need to set the pointers again
	if useVertexCache {
		if !r.useVertexCache {
			gl.VertexPointer(2, gl.FLOAT, 0, r.vpCache[:])
			gl.ColorPointer(4, gl.UNSIGNED_BYTE, 0, r.vcCache[:])
			gl.TexCoordPointer(2, gl.FLOAT, 0, r.vtCache[:])
		}

		// Find the OpenGL primitive type
		modes := [...]gl.GLenum{gl.POINTS, gl.LINES, gl.LINE_STRIP, gl.TRIANGLES,
			gl.TRIANGLE_STRIP, gl.TRIANGLE_FAN, gl.QUADS}
		mode := modes[primType]

		// Draw the primitives
		gl.DrawArrays(mode, 0, len(verts))
	}

	// Unbind the shader, if any
	// TODO
	/*if (states.shader) {
		r.applyShader(nil)
	}*/

//.........这里部分代码省略.........