Golang gl.Clear函数代码示例

func (ui *gameUI) drawBaseGame() {
	gl.Clear(gl.COLOR_BUFFER_BIT)
	ui.graphics.drawBackground()

	// draw roads first
	for _, p := range ui.game.GetPlayers() {
		for _, r := range p.GetBuiltRoads() {
			x, y := edgeToScreen(r.Position)
			ui.graphics.drawRoadAt(x, y, r.Position, p.Color)
		}
	}
	// draw buildings above the roads
	for _, p := range ui.game.GetPlayers() {
		for _, s := range p.GetBuiltSettlements() {
			x, y := cornerToScreen(s.Position)
			ui.graphics.drawSettlementAt(x, y, p.Color)
		}
		for _, c := range p.GetBuiltCities() {
			x, y := cornerToScreen(c.Position)
			ui.graphics.drawCityAt(x, y, p.Color)
		}
	}

	ui.graphics.drawRobber(tileToScreen(ui.game.Robber.Position))
}

func drawSlide() {
	gl.Clear(gl.COLOR_BUFFER_BIT)

	gl.MatrixMode(gl.MODELVIEW)
	gl.LoadIdentity()
	gl.Translatef(0, 0, -3.0)

	gl.Begin(gl.QUADS)

	//top left
	gl.TexCoord2f(0, 0)
	gl.Vertex3f(-1, 1, 0)
	//top right
	gl.TexCoord2f(1, 0)
	gl.Vertex3f(1, 1, 0)

	//bottom right
	gl.TexCoord2f(1, 1)
	gl.Vertex3f(1, -1, 0)

	//bottom left
	gl.TexCoord2f(0, 1)
	gl.Vertex3f(-1, -1, 0)

	gl.End()

}

func main() {
	err := glfw.Init()
	if err != nil {
		panic(err)
	}
	defer glfw.Terminate()

	window, err := glfw.CreateWindow(640, 480, "Testing", nil, nil)
	if err != nil {
		panic(err)
	}

	window.MakeContextCurrent()

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

	// int width, height
	// glfw.GetFramebufferSize(window, &width, &height)

	for !window.ShouldClose() {
		// Do OpenGL stuff.
		gl.Clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT)
		gl.Color3f(1, 1, 0)
		gl.Rectf(-0.75, 0.75, 0.75, -0.75)
		gl.Color3f(1, 0, 1)
		gl.Rectf(-0.5, 0.5, 0.5, -0.5)
		window.SwapBuffers()
		glfw.PollEvents()
	}
}

func (c *Context) FillFramebuffer(r, g, b, a float64) error {
	return c.runOnContextThread(func() error {
		gl.ClearColor(float32(r), float32(g), float32(b), float32(a))
		gl.Clear(gl.COLOR_BUFFER_BIT)
		return nil
	})
}

func (ctx *DrawContext) drawHud(o *orrery.Orrery, frametime time.Duration) {
	txt, size, err := ctx.createHudTexture(o, frametime)
	if err != nil {
		log.Fatalf(`can't create texture from text surface: %s`, err)
	}
	defer gl.DeleteTextures(1, &txt)

	gl.MatrixMode(gl.PROJECTION)
	gl.PushMatrix()
	gl.LoadIdentity()
	gl.Ortho(0.0, float64(ctx.width), float64(ctx.height), 0.0, -1.0, 1.0)
	gl.MatrixMode(gl.MODELVIEW)
	gl.LoadIdentity()
	gl.Clear(gl.DEPTH_BUFFER_BIT)

	gl.BindTexture(gl.TEXTURE_2D, txt)
	gl.Enable(gl.TEXTURE_2D)
	defer gl.Disable(gl.TEXTURE_2D)

	gl.Color3f(1, 1, 1)
	gl.Begin(gl.QUADS)
	gl.TexCoord2f(0, 0)
	gl.Vertex2f(0.0, 0.0)
	gl.TexCoord2f(1, 0)
	gl.Vertex2f(float32(size[0]), 0.0)
	gl.TexCoord2f(1, 1)
	gl.Vertex2f(float32(size[0]), float32(size[1]))
	gl.TexCoord2f(0, 1)
	gl.Vertex2f(0.0, float32(size[1]))
	gl.End()

	gl.PopMatrix()
}

// OpenGL draw function
func draw() {
	gl.Clear(gl.COLOR_BUFFER_BIT)
	gl.Enable(gl.BLEND)
	gl.Enable(gl.POINT_SMOOTH)
	gl.Enable(gl.LINE_SMOOTH)
	gl.BlendFunc(gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA)
	gl.LoadIdentity()

	gl.Begin(gl.LINES)
	gl.Color3f(.2, .2, .2)
	for i := range staticLines {
		x := staticLines[i].GetAsSegment().A.X
		y := staticLines[i].GetAsSegment().A.Y
		gl.Vertex3f(float32(x), float32(y), 0)
		x = staticLines[i].GetAsSegment().B.X
		y = staticLines[i].GetAsSegment().B.Y
		gl.Vertex3f(float32(x), float32(y), 0)
	}
	gl.End()

	gl.Color4f(.3, .3, 1, .8)
	// draw balls
	for _, ball := range balls {
		gl.PushMatrix()
		pos := ball.Body.Position()
		rot := ball.Body.Angle() * chipmunk.DegreeConst
		gl.Translatef(float32(pos.X), float32(pos.Y), 0.0)
		gl.Rotatef(float32(rot), 0, 0, 1)
		drawCircle(float64(ballRadius), 60)
		gl.PopMatrix()
	}
}

func main() {
	err := glfw.Init()
	if err != nil {
		panic(err)
	}
	defer glfw.Terminate()
	fp, err := os.Open("example.tmx")
	if err != nil {
		panic(err)
	}

	m, err := tmx.NewMap(fp)
	if err != nil {
		panic(err)
	}

	var monitor *glfw.Monitor
	window, err := glfw.CreateWindow(screenWidth, screenHeight, "Map Renderer", monitor, nil)
	if err != nil {
		panic(err)
	}

	window.MakeContextCurrent()

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

	width, height := window.GetFramebufferSize()
	gl.Clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT)
	gl.ClearColor(1.0, 1.0, 1.0, 1.0)
	gl.Viewport(0, 0, int32(width), int32(height))
	gl.MatrixMode(gl.PROJECTION)
	gl.LoadIdentity()
	gl.Ortho(0, float64(width), float64(height), 0, -1, 1)
	gl.Enable(gl.BLEND)
	gl.BlendFunc(gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA)
	canvas := newOpenGLCanvas(width, height, float32(width)/float32(screenWidth), float32(height)/float32(screenHeight))
	renderer := tmx.NewRenderer(*m, canvas)
	fps := 0
	startTime := time.Now().UnixNano()
	timer := tmx.CreateTimer()
	timer.Start()
	for !window.ShouldClose() {
		elapsed := float64(timer.GetElapsedTime()) / (1000 * 1000)
		renderer.Render(int64(math.Ceil(elapsed)))
		fps++
		if time.Now().UnixNano()-startTime > 1000*1000*1000 {
			log.Println(fps)
			startTime = time.Now().UnixNano()
			fps = 0
		}

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

func (d *Director) Step() {
	gl.Clear(gl.COLOR_BUFFER_BIT)
	timestamp := glfw.GetTime()
	dt := timestamp - d.timestamp
	d.timestamp = timestamp
	if d.view != nil {
		d.view.Update(timestamp, dt)
	}
}

func drawScene(w *glfw.Window) {
	width, height := w.GetFramebufferSize()
	ratio := float32(width) / float32(height)
	var x1, x2, y1, y2 float32
	if ratio > 1 {
		x1, x2, y1, y2 = -ratio, ratio, -1, 1
	} else {
		x1, x2, y1, y2 = -1, 1, -1/ratio, 1/ratio
	}

	gl.Viewport(0, 0, int32(width), int32(height))
	gl.Clear(gl.COLOR_BUFFER_BIT)

	// Applies subsequent matrix operations to the projection matrix stack
	gl.MatrixMode(gl.PROJECTION)

	gl.LoadIdentity()                                                   // replace the current matrix with the identity matrix
	gl.Ortho(float64(x1), float64(x2), float64(y1), float64(y2), 1, -1) // multiply the current matrix with an orthographic matrix

	// Applies subsequent matrix operations to the modelview matrix stack
	gl.MatrixMode(gl.MODELVIEW)

	gl.LoadIdentity()

	gl.LineWidth(1)
	gl.Begin(gl.LINE)   // delimit the vertices of a primitive or a group of like primitives
	gl.Color3f(0, 0, 0) // set the current color
	gl.Vertex3f(0, y1, 0)
	gl.Vertex3f(0, y2, 0)
	gl.Vertex3f(x1, 0, 0)
	gl.Vertex3f(x2, 0, 0)
	gl.End()

	gl.Rotatef(float32(glfw.GetTime()*50), 0, 0, 1) // multiply the current matrix by a rotation matrix

	s := float32(.95)

	gl.Begin(gl.TRIANGLES)
	gl.Color3f(1, 0, 0)  // set the current color
	gl.Vertex3f(0, s, 0) // specify a vertex
	gl.Color3f(0, 1, 0)
	gl.Vertex3f(s*.866, s*-0.5, 0)
	gl.Color3f(0, 0, 1)
	gl.Vertex3f(s*-.866, s*-0.5, 0)
	gl.End()

	gl.LineWidth(5)
	gl.Begin(gl.LINE_LOOP)
	for i := float64(0); i < 2*math.Pi; i += .05 {
		r, g, b := hsb2rgb(float32(i/(2*math.Pi)), 1, 1)
		gl.Color3f(r, g, b)
		gl.Vertex3f(s*float32(math.Sin(i)), s*float32(math.Cos(i)), 0)
	}
	gl.End()

}

func main() {
	runtime.LockOSThread()

	if err := glfw.Init(); err != nil {
		panic(err)
	}
	defer glfw.Terminate()

	window, err := glfw.CreateWindow(800, 600, "fontstash example", nil, nil)
	if err != nil {
		panic(err)
	}

	window.MakeContextCurrent()
	glfw.SwapInterval(1)
	gl.Init()

	data, err := ioutil.ReadFile(filepath.Join("..", "ClearSans-Regular.ttf"))
	if err != nil {
		panic(err)
	}

	gl.Enable(gl.TEXTURE_2D)

	tmpBitmap := make([]byte, 512*512)
	cdata, err, _, tmpBitmap := truetype.BakeFontBitmap(data, 0, 32, tmpBitmap, 512, 512, 32, 96)
	var ftex uint32
	gl.GenTextures(1, &ftex)
	gl.BindTexture(gl.TEXTURE_2D, ftex)
	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR)
	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR)
	gl.TexImage2D(gl.TEXTURE_2D, 0, gl.ALPHA, 512, 512, 0,
		gl.ALPHA, gl.UNSIGNED_BYTE, unsafe.Pointer(&tmpBitmap[0]))

	gl.ClearColor(0.3, 0.3, 0.32, 1.)

	for !window.ShouldClose() {
		gl.Clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT)
		gl.MatrixMode(gl.PROJECTION)
		gl.LoadIdentity()
		gl.Ortho(0, 800, 600, 0, 0, 1)
		gl.MatrixMode(gl.MODELVIEW)
		gl.LoadIdentity()
		gl.Disable(gl.DEPTH_TEST)
		gl.Color4ub(255, 255, 255, 255)
		gl.Enable(gl.BLEND)
		gl.BlendFunc(gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA)

		my_print(100, 100, "The quick brown fox jumps over the fence", ftex, cdata)

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

func draw() {
	gl.Clear(gl.COLOR_BUFFER_BIT)
	gl.Enable(gl.BLEND)
	gl.Enable(gl.POINT_SMOOTH)
	gl.Enable(gl.LINE_SMOOTH)
	gl.BlendFunc(gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA)
	gl.LoadIdentity()

	//Transform screen to keep player in middle. Added intentation to make obvious the push matrix is like a block
	gl.PushMatrix()
	// gl.Translatef((1280/2)-float32(player.x), 0, 0.0)

	// gl.Begin(gl.LINES)
	// gl.Color3f(.2, .5, .2)
	// for i := range staticLines {
	// 	x := staticLines[i].GetAsSegment().A.X
	// 	y := staticLines[i].GetAsSegment().A.Y
	// 	gl.Vertex3f(float32(x), float32(y), 0)
	// 	x = staticLines[i].GetAsSegment().B.X
	// 	y = staticLines[i].GetAsSegment().B.Y
	// 	gl.Vertex3f(float32(x), float32(y), 0)
	// }
	// gl.End()

	gl.Color4f(player.color_r, player.color_g, player.color_b, player.color_a)

	//Draw Player
	gl.PushMatrix()
	rot := player.rot
	pos_x := player.x
	pos_y := player.y

	gl.Translatef(pos_x, pos_y, 0.0)
	gl.Rotatef(float32(rot), 0, 0, 1)
	drawCircle(float64(BALL_RADIUS), 20)
	gl.PopMatrix()

	//Draw the grapple
	gl.PushMatrix()
	gl.Translatef(player.hook.x_end, player.hook.y_end, 0.0)
	drawCircle(float64(5), 5)
	gl.PopMatrix()

	//Grapple Line
	gl.LineWidth(2.5)
	gl.Color3f(1.0, 0.0, 0.0)
	gl.Begin(gl.LINES)
	gl.Vertex3f(player.x, player.y, 0.0)
	gl.Vertex3f(player.hook.x_end, player.hook.y_end, 0)
	gl.End()

	//Second Pop
	gl.PopMatrix()
}

func drawgl() {
	gl.Clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT)

	gl.Begin(gl.TRIANGLES)
	gl.Color3f(1.0, 0.0, 0.0)
	gl.Vertex2f(0.5, 0.0)
	gl.Color3f(0.0, 1.0, 0.0)
	gl.Vertex2f(-0.5, -0.5)
	gl.Color3f(0.0, 0.0, 1.0)
	gl.Vertex2f(-0.5, 0.5)
	gl.End()
}

func (state *State) Reset(window *glfw.Window) {
	gl.ClearColor(1, 1, 1, 1)
	gl.Clear(gl.COLOR_BUFFER_BIT)
	gl.MatrixMode(gl.MODELVIEW)
	gl.LoadIdentity()

	gl.Disable(gl.DEPTH)
	gl.Enable(gl.FRAMEBUFFER_SRGB)

	width, height := window.GetSize()
	gl.Viewport(0, 0, int32(width), int32(height))
	gl.Ortho(0, float64(width), float64(height), 0, 30, -30)
}

func render(w *Window) {
	for !w.GlWindow.ShouldClose() {
		//Reset?
		gl.Clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT)

		if w.DrawFunc != nil {
			w.DrawFunc()
		}
		// Maintenance
		w.GlWindow.SwapBuffers()
		glfw.PollEvents()
	}

}

// OpenGL draw function
func draw() {
	gl.Clear(gl.COLOR_BUFFER_BIT)
	gl.Enable(gl.BLEND)
	gl.Enable(gl.POINT_SMOOTH)
	gl.Enable(gl.LINE_SMOOTH)
	gl.BlendFunc(gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA)
	gl.LoadIdentity()

	player := game.Player

	//Transform screen.
	gl.PushMatrix()
	gl.Translatef((1280/2)-float32((player.Body.Position().X)), 0, 0.0)

	gl.Begin(gl.LINES)
	gl.Color3f(.2, .5, .2)
	for _, segment := range game.Level.GetChipmunkSegments() {
		x := segment.GetAsSegment().A.X
		y := segment.GetAsSegment().A.Y
		gl.Vertex3f(float32(x), float32(y), 0)
		x = segment.GetAsSegment().B.X
		y = segment.GetAsSegment().B.Y
		gl.Vertex3f(float32(x), float32(y), 0)
	}
	gl.End()

	gl.Color4f(.9, .1, 1, .9)
	// draw balls
	for _, enemy := range game.Enemies {
		gl.PushMatrix()
		pos := enemy.Body.Position()
		rot := enemy.Body.Angle() * game.DegreeConst
		gl.Translatef(float32(pos.X), float32(pos.Y), 0.0)
		gl.Rotatef(float32(rot), 0, 0, 1)
		drawCircle(float64(enemy.Radius), 60)
		gl.PopMatrix()
	}
	gl.Color4f(.3, .3, 1, .8)
	//Draw Player
	gl.PushMatrix()
	pos := player.Body.Position()
	rot := player.Body.Angle() * game.DegreeConst
	gl.Translatef(float32(pos.X), float32(pos.Y), 0.0)
	gl.Rotatef(float32(rot), 0, 0, 1)
	drawCircle(float64(player.Radius), 60)
	gl.PopMatrix()

	gl.PopMatrix()
}