Golang gl.BindVertexArray函数代码示例

func programLoop(window *glfw.Window) {

	// the linked shader program determines how the data will be rendered
	shaders := compileShaders()
	shaderProgram := linkShaders(shaders)

	// VAO contains all the information about the data to be rendered
	VAO := createTriangleVAO()

	for !window.ShouldClose() {
		// poll events and call their registered callbacks
		glfw.PollEvents()

		// perform rendering
		gl.ClearColor(0.2, 0.5, 0.5, 1.0)
		gl.Clear(gl.COLOR_BUFFER_BIT)

		// draw loop
		gl.UseProgram(shaderProgram)      // ensure the right shader program is being used
		gl.BindVertexArray(VAO)           // bind data
		gl.DrawArrays(gl.TRIANGLES, 0, 3) // perform draw call
		gl.BindVertexArray(0)             // unbind data (so we don't mistakenly use/modify it)
		// end of draw loop

		// swap in the rendered buffer
		window.SwapBuffers()
	}
}

/*
 * Creates the Vertex Array Object for a triangle.
 */
func createTriangleVAO(vertices []float32, indices []uint32) uint32 {

	var VAO uint32
	gl.GenVertexArrays(1, &VAO)

	var VBO uint32
	gl.GenBuffers(1, &VBO)

	var EBO uint32
	gl.GenBuffers(1, &EBO)

	// Bind the Vertex Array Object first, then bind and set vertex buffer(s) and attribute pointers()
	gl.BindVertexArray(VAO)

	// copy vertices data into VBO (it needs to be bound first)
	gl.BindBuffer(gl.ARRAY_BUFFER, VBO)
	gl.BufferData(gl.ARRAY_BUFFER, len(vertices)*4, gl.Ptr(vertices), gl.STATIC_DRAW)

	// copy indices into element buffer
	gl.BindBuffer(gl.ELEMENT_ARRAY_BUFFER, EBO)
	gl.BufferData(gl.ELEMENT_ARRAY_BUFFER, len(indices)*4, gl.Ptr(indices), gl.STATIC_DRAW)

	// position
	gl.VertexAttribPointer(0, 3, gl.FLOAT, false, 6*4, gl.PtrOffset(0))
	gl.EnableVertexAttribArray(0)

	// color
	gl.VertexAttribPointer(1, 3, gl.FLOAT, false, 6*4, gl.PtrOffset(3*4))
	gl.EnableVertexAttribArray(1)

	// unbind the VAO (safe practice so we don't accidentally (mis)configure it later)
	gl.BindVertexArray(0)

	return VAO
}

// Render renders the model
func (m *Model) Render() {

	gl.UseProgram(m.currentProgram)
	gl.UniformMatrix4fv(m.modelUniform, 1, false, &m.model[0])

	gl.BindVertexArray(m.vao)

	gl.ActiveTexture(gl.TEXTURE0)

	texture, isLoaded := m.textures.GetTexture(m.data.TextureFile)

	if isLoaded {
		gl.BindTexture(gl.TEXTURE_2D, texture)
	} else {
		if m.data.TextureFile != "" {
			go fmt.Printf("Unable to load texture %s", m.data.TextureFile)
		}
	}

	if m.data.Indexed {
		gl.DrawElements(gl.TRIANGLE_FAN, int32(len(m.data.Indices)), gl.UNSIGNED_INT, gl.PtrOffset(0))
	} else {
		gl.DrawArrays(gl.TRIANGLES, 0, int32(len(m.data.Verts))/m.data.VertSize)
	}

	gl.BindVertexArray(0)
}

/*
 * Creates the Vertex Array Object for a triangle.
 * indices is leftover from earlier samples and not used here.
 */
func createVAO(vertices []float32, indices []uint32) uint32 {

	var VAO uint32
	gl.GenVertexArrays(1, &VAO)

	var VBO uint32
	gl.GenBuffers(1, &VBO)

	var EBO uint32
	gl.GenBuffers(1, &EBO)

	// Bind the Vertex Array Object first, then bind and set vertex buffer(s) and attribute pointers()
	gl.BindVertexArray(VAO)

	// copy vertices data into VBO (it needs to be bound first)
	gl.BindBuffer(gl.ARRAY_BUFFER, VBO)
	gl.BufferData(gl.ARRAY_BUFFER, len(vertices)*4, gl.Ptr(vertices), gl.STATIC_DRAW)

	// size of one whole vertex (sum of attrib sizes)
	var stride int32 = 3*4 + 2*4
	var offset int = 0

	// position
	gl.VertexAttribPointer(0, 3, gl.FLOAT, false, stride, gl.PtrOffset(offset))
	gl.EnableVertexAttribArray(0)
	offset += 3 * 4

	// unbind the VAO (safe practice so we don't accidentally (mis)configure it later)
	gl.BindVertexArray(0)

	return VAO
}

/*
 * Creates the Vertex Array Object for a triangle.
 */
func createTriangleVAO() uint32 {
	vertices := []float32{
		-0.5, -0.5, 0.0,
		0.5, -0.5, 0.0,
		0.0, 0.5, 0.0,
	}

	var VAO uint32
	gl.GenVertexArrays(1, &VAO)

	var VBO uint32
	gl.GenBuffers(1, &VBO)

	// Bind the Vertex Array Object first, then bind and set vertex buffer(s) and attribute pointers()
	gl.BindVertexArray(VAO)

	// copy vertices data into VBO (it needs to be bound first)
	gl.BindBuffer(gl.ARRAY_BUFFER, VBO)
	gl.BufferData(gl.ARRAY_BUFFER, len(vertices)*4, gl.Ptr(vertices), gl.STATIC_DRAW)

	// specify the format of our vertex input
	// (shader) input 0
	// vertex has size 3
	// vertex items are of type FLOAT
	// do not normalize (already done)
	// stride of 3 * sizeof(float) (separation of vertices)
	// offset of where the position data starts (0 for the beginning)
	gl.VertexAttribPointer(0, 3, gl.FLOAT, false, 3*4, gl.PtrOffset(0))
	gl.EnableVertexAttribArray(0)

	// unbind the VAO (safe practice so we don't accidentally (mis)configure it later)
	gl.BindVertexArray(0)

	return VAO
}

// Load loads and sets up the model
func (m *Model) Load(fileName string) {

	m.loadFile(fileName)

	shader := sm.Shader{VertSrcFile: m.data.VertShaderFile, FragSrcFile: m.data.FragShaderFile, Name: fmt.Sprintf("%s:%s", m.data.VertShaderFile, m.data.FragShaderFile)}
	program, err := m.shaders.LoadProgram(shader, false)
	if err != nil {
		return
	}
	m.currentProgram = program

	gl.UseProgram(m.currentProgram)

	m.projection = mgl32.Perspective(mgl32.DegToRad(45.0), float32(windowWidth)/windowHeight, 0.1, 10.0)
	m.projectionUniform = gl.GetUniformLocation(m.currentProgram, gl.Str("projection\x00"))
	gl.UniformMatrix4fv(m.projectionUniform, 1, false, &m.projection[0])

	m.camera = mgl32.LookAtV(mgl32.Vec3{3, 3, 3}, mgl32.Vec3{0, 0, 0}, mgl32.Vec3{0, 1, 0})
	m.cameraUniform = gl.GetUniformLocation(m.currentProgram, gl.Str("camera\x00"))
	gl.UniformMatrix4fv(m.cameraUniform, 1, false, &m.camera[0])

	m.modelUniform = gl.GetUniformLocation(m.currentProgram, gl.Str("model\x00"))
	gl.UniformMatrix4fv(m.modelUniform, 1, false, &m.model[0])

	m.textureUniform = gl.GetUniformLocation(m.currentProgram, gl.Str("tex\x00"))
	gl.Uniform1i(m.textureUniform, 0)

	gl.BindFragDataLocation(m.currentProgram, 0, gl.Str("outputColor\x00"))

	// Load the texture
	m.textures.LoadTexture(m.data.TextureFile, m.data.TextureFile)

	// Configure the vertex data
	gl.GenVertexArrays(1, &m.vao)
	gl.BindVertexArray(m.vao)

	var vbo uint32
	gl.GenBuffers(1, &vbo)
	gl.BindBuffer(gl.ARRAY_BUFFER, vbo)
	gl.BufferData(gl.ARRAY_BUFFER, len(m.data.Verts)*4, gl.Ptr(m.data.Verts), gl.STATIC_DRAW)

	vertAttrib := uint32(gl.GetAttribLocation(m.currentProgram, gl.Str("vert\x00")))
	gl.EnableVertexAttribArray(vertAttrib)
	gl.VertexAttribPointer(vertAttrib, 3, gl.FLOAT, false, m.data.VertSize*4, gl.PtrOffset(0)) // 4:number of bytes in a float32

	texCoordAttrib := uint32(gl.GetAttribLocation(m.currentProgram, gl.Str("vertTexCoord\x00")))
	gl.EnableVertexAttribArray(texCoordAttrib)
	gl.VertexAttribPointer(texCoordAttrib, 2, gl.FLOAT, true, m.data.VertSize*4, gl.PtrOffset(3*4)) // 4:number of bytes in a float32

	if m.data.Indexed {
		var indices uint32
		gl.GenBuffers(1, &indices)
		gl.BindBuffer(gl.ELEMENT_ARRAY_BUFFER, indices)
		gl.BufferData(gl.ELEMENT_ARRAY_BUFFER, len(m.data.Indices)*4, gl.Ptr(m.data.Indices), gl.STATIC_DRAW)
	}

	gl.BindVertexArray(0)
}

func (self *Application) setup() error {
	gl.GenVertexArrays(1, &self.Triangles)
	gl.BindVertexArray(self.Triangles)

	trianglesVertices := []float32{
		-0.9, -0.9,
		0.85, -0.9,
		-0.9, 0.85,
		0.9, -0.85,
		0.9, 0.9,
		-0.85, 0.9,
	}

	gl.GenBuffers(1, &self.ArrayBuffer)
	gl.BindBuffer(gl.ARRAY_BUFFER, self.ArrayBuffer)
	gl.BufferData(gl.ARRAY_BUFFER, len(trianglesVertices)*4, gl.Ptr(trianglesVertices), gl.STATIC_DRAW)

	program, err := util.LoadShaders([]util.ShaderInfo{
		util.ShaderInfo{gl.VERTEX_SHADER, "triangles.vert"},
		util.ShaderInfo{gl.FRAGMENT_SHADER, "triangles.frag"},
	})
	if err != nil {
		return err
	}
	gl.UseProgram(program)

	gl.VertexAttribPointer(vPosition, 2, gl.FLOAT, false, 0, gl.Ptr(nil))
	gl.EnableVertexAttribArray(vPosition)

	return nil
}

func (me *GlObj) Draw(c *Core) {
	gl.UseProgram(c.Progs[me.Prog])
	gl.BindVertexArray(c.Vao[me.Vao])
	// shoud check if texture has been set for current object
	gl.ActiveTexture(gl.TEXTURE0)
	gl.BindTexture(gl.TEXTURE_2D, c.Textures[me.Texture])
	gl.DrawArrays(gl.TRIANGLES, 0, me.nbTriangles)
}

func createVao() uint32 {
	var vbo = createVbo(getPoints())

	var vao uint32
	gl.GenVertexArrays(1, &vao)
	gl.BindVertexArray(vao)
	gl.EnableVertexAttribArray(0)
	gl.BindBuffer(gl.ARRAY_BUFFER, vbo)
	gl.VertexAttribPointer(0, 3, gl.FLOAT, false, 0, nil)
	return vao
}

func drawLoop(win *glfw.Window, vao uint32, shader uint32) {
	for !win.ShouldClose() {
		gl.Clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT)
		gl.BindVertexArray(vao)
		gl.UseProgram(shader)
		gl.DrawArrays(gl.TRIANGLES, 0, 3)

		glfw.PollEvents()
		win.SwapBuffers()
	}
}

func Run() {
	if err := glfw.Init(); err != nil {
		glog.Fatalln("failed to initialize glfw", err)
	}
	defer glfw.Terminate()

	setupWindowOptions()
	window, err := glfw.CreateWindow(WindowWidth, WindowHeight, "Game", nil, nil)
	if err != nil {
		panic(err)
	}
	window.MakeContextCurrent()

	//initilize Glow
	if err := gl.Init(); err != nil {
		panic(err)
	}

	version := gl.GoStr(gl.GetString(gl.VERSION))
	fmt.Println("OpenGL version", version)

	shaderSource, err := ReadShaders("colorShader")
	if err != nil {
		panic(err)
	}
	program, err := NewProgram(shaderSource)
	if err != nil {
		panic(err)
	}
	program.Use()

	sprite := &SpriteComponent{-.5, -.5, 1, 1}
	sprite.ReloadGraphics()

	vertAttrib := uint32(gl.GetAttribLocation(program.program, CStr("vertPosition")))
	gl.EnableVertexAttribArray(vertAttrib)
	gl.VertexAttribPointer(vertAttrib, 3, gl.FLOAT, false, 0, gl.PtrOffset(0))

	gl.Enable(gl.DEPTH_TEST)
	gl.DepthFunc(gl.LESS)
	gl.ClearColor(1.0, 1.0, 1.0, 1.0)

	for !window.ShouldClose() {
		gl.Clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT)

		program.Use()

		gl.BindVertexArray(sprite.vaoID)
		gl.DrawArrays(gl.TRIANGLES, 0, 2*3)

		window.SwapBuffers()
		glfw.PollEvents()
	}
}

// NewBillboard creates a 2D billboard for rendering
func (font *Font) NewBillboard(text string, maxWidth int, maxHeight int, size float64, dpi float64, color color.Color) *Billboard {
	b := &Billboard{}

	b.texWidth = maxWidth
	b.texHeight = maxHeight

	image, renderedWidth, renderedHeight := font.createTexture(text, b.texWidth, b.texHeight, size, dpi, color)

	b.size = size
	b.dpi = dpi
	b.text = text
	b.font = font
	b.rgba = color

	b.Width = renderedWidth
	b.Height = renderedHeight
	var vao uint32

	gl.GenVertexArrays(1, &vao)
	gl.BindVertexArray(vao)

	var vbo uint32
	gl.GenBuffers(1, &vbo)
	gl.BindBuffer(gl.ARRAY_BUFFER, vbo)

	w := float32(maxWidth)
	h := float32(maxHeight)

	billboardVertices := []float32{
		w, h, 0.0, 1.0, 1.0,
		0.0, 0.0, 0.0, 0.0, 0.0,
		0.0, h, 0.0, 0.0, 1.0,

		w, h, 0.0, 1.0, 1.0,
		0.0, 0.0, 0.0, 0.0, 0.0,
		w, 0.0, 0.0, 1.0, 0.0,
	}

	gl.BufferData(gl.ARRAY_BUFFER, len(billboardVertices)*4, gl.Ptr(billboardVertices), gl.STATIC_DRAW)

	vertAttrib := uint32(0)
	gl.EnableVertexAttribArray(vertAttrib)
	gl.VertexAttribPointer(vertAttrib, 3, gl.FLOAT, false, 5*4, gl.PtrOffset(0))

	texCoordAttrib := uint32(1)
	gl.EnableVertexAttribArray(texCoordAttrib)
	gl.VertexAttribPointer(texCoordAttrib, 2, gl.FLOAT, false, 5*4, gl.PtrOffset(3*4))

	b.vao = vao
	b.image = image

	return b
}

// word only for small file
func (me *Core) AddGlObj(buf []float32, size, stride int32) *GlObj {
	n := me.nbObj
	var vao uint32
	gl.GenVertexArrays(1, &vao)
	gl.BindVertexArray(vao)
	me.Vao[n] = vao

	var obj GlObj
	obj.Vao = n
	obj.nbTriangles = int32(len(buf)) / stride

	obj.AddProperty(VertLoc, buf, size, stride, 0)
	me.nbObj++
	return &obj
}

// allow only basic obj, no text or effect for now
func (me *Core) AddGlObj(buf []float32, size int32) *GlObj {
	n := me.nbObj
	var vao uint32
	gl.GenVertexArrays(1, &vao)
	gl.BindVertexArray(vao)
	me.Vao[n] = vao

	var obj GlObj
	obj.Vao = n
	obj.nbTriangles = int32(len(buf)) / 3 // 3 will most probably change

	obj.AddProperty(0, buf, size)
	me.nbObj++
	return &obj
}

func NewVBO() (vbo *VBO) {
	// create and bind the required VAO object
	var vao uint32
	gl.GenVertexArrays(1, &vao)
	gl.BindVertexArray(vao)

	// create a VBO to hold the vertex data
	var vboVerts uint32
	var vboIndices uint32
	gl.GenBuffers(1, &vboVerts)
	gl.GenBuffers(1, &vboIndices)

	vbo = &VBO{vao, vboVerts, vboIndices}
	return vbo
}