Golang gl.Begin函数代码示例

func drawMap(cx, cy, zoom float64, triangles p2t.TriArray) {

	for i := 0; i < len(triangles); i++ {
		t := triangles[i]
		a := t.Point[0]
		b := t.Point[1]
		c := t.Point[2]

		//constrainedColor(t.constrained_edge[2])
		gl.Begin(gl.LINES)
		gl.Vertex2f(float32(a.X), float32(a.Y))
		gl.Vertex2f(float32(b.X), float32(b.Y))
		gl.End()

		//constrainedColor(t.constrained_edge[0])
		gl.Begin(gl.LINES)
		gl.Vertex2f(float32(b.X), float32(b.Y))
		gl.Vertex2f(float32(c.X), float32(c.Y))
		gl.End()

		//constrainedColor(t.constrained_edge[1])
		gl.Begin(gl.LINES)
		gl.Vertex2f(float32(c.X), float32(c.Y))
		gl.Vertex2f(float32(a.X), float32(a.Y))
		gl.End()
	}
}

func drawShip(angle gl.GLfloat) {
	gl.PushMatrix()
	gl.Translatef(x, y, 0.0)
	gl.Rotatef(angle, 0.0, 0.0, 1.0)
	if thrust {
		gl.Color3f(1.0, 0.0, 0.0)
		gl.Begin(gl.LINE_STRIP)
		gl.Vertex2f(-0.75, -0.5)
		gl.Vertex2f(-1.75, 0)
		gl.Vertex2f(-0.75, 0.5)
		gl.End()
	}
	gl.Color3f(1.0, 1.0, 0.0)
	gl.Begin(gl.LINE_LOOP)
	gl.Vertex2f(2.0, 0.0)
	gl.Vertex2f(-1.0, -1.0)
	gl.Vertex2f(-0.5, 0.0)
	gl.Vertex2f(-1.0, 1.0)
	gl.Vertex2f(2.0, 0.0)
	gl.End()
	if shield {
		gl.Color3f(0.1, 0.1, 1.0)
		gl.Begin(gl.LINE_LOOP)
		for rad := 0.0; rad < 12.0; rad += 1.0 {
			gl.Vertex2f(
				gl.GLfloat(2.3*math.Cos(2*float64(rad)/math.Pi)+0.2),
				gl.GLfloat(2.0*math.Sin(2*float64(rad)/math.Pi)))
		}
		gl.End()
	}
	gl.PopMatrix()
}

// Here goes our drawing code
func drawGLScene() {
	// Clear the screen and depth buffer
	gl.Clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT)

	// Move left 1.5 units and into the screen 6.0 units.
	gl.LoadIdentity()
	gl.Translatef(-1.5, 0.0, -6.0)
	gl.Rotatef(float32(rtri), 0.0, 1.0, 0.0) // Rotate the triangle on the Y axis

	gl.Begin(gl.TRIANGLES)       // Draw triangles
	gl.Color3f(1.0, 0.0, 0.0)    // Set The Color To Red
	gl.Vertex3f(0.0, 1.0, 0.0)   // top
	gl.Color3f(0.0, 1.0, 0.0)    // Set The Color To Red
	gl.Vertex3f(-1.0, -1.0, 0.0) // bottom left
	gl.Color3f(0.0, 0.0, 1.0)    // Set The Color To Red
	gl.Vertex3f(1.0, -1.0, 0.0)  // bottom right
	gl.End()                     // finish drawing the triangle

	// Move right 3 units
	gl.LoadIdentity()
	gl.Translatef(1.5, 0.0, -6.0)
	gl.Color3f(0.5, 0.5, 1.0)                 // Set The Color To Blue One Time Only
	gl.Rotatef(float32(rquad), 1.0, 0.0, 0.0) // rotate the quad on the X axis

	gl.Begin(gl.QUADS)           // draw quads
	gl.Vertex3f(-1.0, 1.0, 0.0)  // top left
	gl.Vertex3f(1.0, 1.0, 0.0)   // top right
	gl.Vertex3f(1.0, -1.0, 0.0)  // bottom right
	gl.Vertex3f(-1.0, -1.0, 0.0) // bottom left
	gl.End()                     // done drawing the quad

	// Draw to the screen
	sdl.GL_SwapBuffers()

	rtri += 0.2   // Increase The Rotation Variable For The Triangle
	rquad -= 0.15 // Decrease The Rotation Variable For The Quad

	// Gather our frames per second
	frames++
	t := sdl.GetTicks()
	if t-t0 >= 5000 {
		seconds := (t - t0) / 1000.0
		fps := frames / seconds
		fmt.Println(frames, "frames in", seconds, "seconds =", fps, "FPS")
		t0 = t
		frames = 0
	}
}

func (pen *Pen) lineTo(p Point) {

	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.Color4f(0.0, 0.0, 0.0, 0.1)

	gl.Begin(gl.LINES)

	for _, s := range pen.points {

		if s.x == 0 && s.y == 0 {
			continue
		}

		if p.distanceTo(s) < 20.0 {

			gl.Vertex2i(int(p.x), int(p.y))
			gl.Vertex2i(int(s.x), int(s.y))

		}

	}

	gl.End()

	pen.n = (pen.n + 1) % len(pen.points)
	pen.points[pen.n] = p

	pen.moveTo(p)

}

func (f *Font) DrawText2D(x int, y int, color [3]byte, scale float, txt string) (endw int, endh int) {
	gl.LoadIdentity()
	//	gl.Translatef(0.0, 0.0, -2.0);

	glEnable2D()
	gl.Disable(gl.DEPTH_TEST)

	texture, initial, intermediarya, intermediary, w, h := f.setupTextRendering(color, txt)

	locX := gl.GLfloat(x)
	locY := gl.GLfloat(y)
	wi := gl.GLfloat(w) * gl.GLfloat(scale)
	he := gl.GLfloat(h) * gl.GLfloat(scale)

	/* Draw a quad at location */
	gl.Begin(gl.QUADS)
	/* Recall that the origin is in the lower-left corner
	   That is why the TexCoords specify different corners
	   than the Vertex coors seem to. */
	gl.TexCoord2f(0.0, 1.0)
	gl.Vertex2f(locX, locY)
	gl.TexCoord2f(1.0, 1.0)
	gl.Vertex2f(locX+wi, locY)
	gl.TexCoord2f(1.0, 0.0)
	gl.Vertex2f(locX+wi, locY+he)
	gl.TexCoord2f(0.0, 0.0)
	gl.Vertex2f(locX, locY+he)
	gl.End()

	endw, endh = f.teardownTextRendering(texture, initial, intermediarya, intermediary)

	gl.Enable(gl.DEPTH_TEST)
	glDisable2D()
	return
}

func main() {

	ret := glfw.Init()

	print(ret)

	ret = glfw.OpenWindow(300, 300, 0, 0, 0, 0, 0, 0, glfw.WINDOW)

	print(ret)

	if gl.Init() != 0 {
		panic("glew error")
	}

	running := true

	for running {

		gl.Begin(gl.TRIANGLES)
		gl.Vertex3f(0, 0, 0)
		gl.Vertex3f(0, 1, 0)
		gl.Vertex3f(1, 1, 0)
		gl.End()

		glfw.SwapBuffers()

		running = glfw.GetKey(glfw.KEY_ESC) == 0 && glfw.GetWindowParam(glfw.OPENED) != 0

	}

}

func drawFrame() {

	gl.LoadIdentity()
	gl.LineWidth(5.0)
	gl.Enable(gl.POINT_SMOOTH)
	gl.Enable(gl.LINE_SMOOTH)

	gl.Color4f(gl.GLfloat(FrameColor[0]), gl.GLfloat(FrameColor[1]), gl.GLfloat(FrameColor[2]), 0.1)

	m := PlayArea

	t := 1.0 * m
	b := -1.0 * m
	r := 1.0 * m
	l := -1.0 * m

	gl.Begin(gl.LINE_STRIP)

	zo := -5.0

	gl.Vertex3f(gl.GLfloat(l), gl.GLfloat(t), gl.GLfloat(zo))
	gl.Vertex3f(gl.GLfloat(r), gl.GLfloat(t), gl.GLfloat(zo))
	gl.Vertex3f(gl.GLfloat(r), gl.GLfloat(b), gl.GLfloat(zo))
	gl.Vertex3f(gl.GLfloat(l), gl.GLfloat(b), gl.GLfloat(zo))
	gl.Vertex3f(gl.GLfloat(l), gl.GLfloat(t), gl.GLfloat(zo))

	gl.End()

}

func drawBullets() {
	gl.Begin(gl.POINTS)
	gl.Color3f(1.0, 0.0, 1.0)
	for i := 0; i < MAX_BULLETS; i++ {
		if bullet[i].inuse {
			gl.Vertex2f(bullet[i].x, bullet[i].y)
		}
	}
	gl.End()
}

func display() {
	gl.Clear(gl.COLOR_BUFFER_BIT)
	gl.Begin(gl.TRIANGLES)
	gl.Color3f(0.0, 0.0, 1.0) /* blue */
	gl.Vertex2i(0, 0)
	gl.Color3f(0.0, 1.0, 0.0) /* green */
	gl.Vertex2i(200, 200)
	gl.Color3f(1.0, 0.0, 0.0) /* red */
	gl.Vertex2i(20, 200)
	gl.End()
	gl.Flush() /* Single buffered, so needs a flush. */
}

// Here goes our drawing code
func drawGLScene() {
	// Clear the screen and depth buffer
	gl.Clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT)

	// Move left 1.5 units and into the screen 6.0 units.
	gl.LoadIdentity()
	gl.Translatef(-1.5, 0.0, -6.0)

	gl.Begin(gl.TRIANGLES)       // Draw triangles
	gl.Vertex3f(0.0, 1.0, 0.0)   // top
	gl.Vertex3f(-1.0, -1.0, 0.0) // bottom left
	gl.Vertex3f(1.0, -1.0, 0.0)  // bottom right
	gl.End()                     // finish drawing the triangle

	// Move right 3 units
	gl.Translatef(3.0, 0.0, 0.0)

	gl.Begin(gl.QUADS)           // draw quads
	gl.Vertex3f(-1.0, 1.0, 0.0)  // top left
	gl.Vertex3f(1.0, 1.0, 0.0)   // top right
	gl.Vertex3f(1.0, -1.0, 0.0)  // bottom right
	gl.Vertex3f(-1.0, -1.0, 0.0) // bottom left
	gl.End()                     // done drawing the quad

	// Draw to the screen
	sdl.GL_SwapBuffers()

	// Gather our frames per second
	frames++
	t := sdl.GetTicks()
	if t-t0 >= 5000 {
		seconds := (t - t0) / 1000.0
		fps := frames / seconds
		fmt.Println(frames, "frames in", seconds, "seconds =", fps, "FPS")
		t0 = t
		frames = 0
	}
}

func drawBlock(x, y int, color TetrisBlockColor) {
	glx := gl.GLint(x)
	gly := gl.GLint(y)

	gl.Color3ub(color.R/2, color.G/2, color.B/2)
	gl.Begin(gl.QUADS)
	gl.Vertex2i(int(glx), int(gly))
	gl.Vertex2i(int(glx+blockSize), int(gly))
	gl.Vertex2i(int(glx+blockSize), int(gly+blockSize))
	gl.Vertex2i(int(glx), int(gly+blockSize))
	gl.Color3ub(color.R, color.G, color.B)
	gl.Vertex2i(int(glx+smallBlockOffset), int(gly+smallBlockOffset))
	gl.Vertex2i(int(glx+blockSize-smallBlockOffset), int(gly+smallBlockOffset))
	gl.Vertex2i(int(glx+blockSize-smallBlockOffset), int(gly+blockSize-smallBlockOffset))
	gl.Vertex2i(int(glx+smallBlockOffset), int(gly+blockSize-smallBlockOffset))
	gl.End()
}

func drawQuad(x, y, w, h int, u, v, u2, v2 float32) {
	gl.Begin(gl.QUADS)

	gl.TexCoord2f(float32(u), float32(v))
	gl.Vertex2i(int(x), int(y))

	gl.TexCoord2f(float32(u2), float32(v))
	gl.Vertex2i(int(x+w), int(y))

	gl.TexCoord2f(float32(u2), float32(v2))
	gl.Vertex2i(int(x+w), int(y+h))

	gl.TexCoord2f(float32(u), float32(v2))
	gl.Vertex2i(int(x), int(y+h))

	gl.End()
}

func drawQuad(x, y, w, h int, u, v, u2, v2 float) {
	gl.Begin(gl.QUADS)

	gl.TexCoord2f(gl.GLfloat(u), gl.GLfloat(v))
	gl.Vertex2i(gl.GLint(x), gl.GLint(y))

	gl.TexCoord2f(gl.GLfloat(u2), gl.GLfloat(v))
	gl.Vertex2i(gl.GLint(x+w), gl.GLint(y))

	gl.TexCoord2f(gl.GLfloat(u2), gl.GLfloat(v2))
	gl.Vertex2i(gl.GLint(x+w), gl.GLint(y+h))

	gl.TexCoord2f(gl.GLfloat(u), gl.GLfloat(v2))
	gl.Vertex2i(gl.GLint(x), gl.GLint(y+h))

	gl.End()
}

// Here goes our drawing code
func drawGLScene(sector Sector) {
	xtrans := gl.GLfloat(-xpos)
	ztrans := gl.GLfloat(-zpos)
	ytrans := gl.GLfloat(-walkbias - 0.25)
	scenroty := gl.GLfloat(360.0 - yrot)

	// Clear the screen and depth buffer
	gl.Clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT)

	// reset the view
	gl.LoadIdentity()

	// Rotate up and down to look up and down
	gl.Rotatef(float32(lookupdown), 1.0, 0.0, 0.0)
	// Rotate depending on direction player is facing
	gl.Rotatef(float32(scenroty), 0.0, 1.0, 0.0)
	// translate the scene based on player position
	gl.Translatef(float32(xtrans), float32(ytrans), float32(ztrans))

	gl.BindTexture(gl.TEXTURE_2D, uint(textures[filter]))

	for _, vertices := range sector {
		gl.Begin(gl.TRIANGLES)
		for _, triangle := range *vertices {
			gl.Normal3f(0.0, 0.0, 1.0)
			gl.TexCoord2f(float32(triangle.u), float32(triangle.v))
			gl.Vertex3f(float32(triangle.x), float32(triangle.y), float32(triangle.z))
		}
		gl.End()
	}

	// Draw to the screen
	sdl.GL_SwapBuffers()

	// Gather our frames per second
	frames++
	t := sdl.GetTicks()
	if t-t0 >= 5000 {
		seconds := (t - t0) / 1000.0
		fps := frames / seconds
		fmt.Println(frames, "frames in", seconds, "seconds =", fps, "FPS")
		t0 = t
		frames = 0
	}
}

func drawSelection(p1, p2 Point) {
	min, max := minMaxPoints(p1, p2)

	gl.Color3ub(255, 0, 0)
	gl.Begin(gl.LINES)
	gl.Vertex2i(int(min.X), int(min.Y))
	gl.Vertex2i(int(max.X), int(min.Y))

	gl.Vertex2i(int(min.X), int(min.Y))
	gl.Vertex2i(int(min.X), int(max.Y))

	gl.Vertex2i(int(max.X), int(max.Y))
	gl.Vertex2i(int(max.X), int(min.Y))

	gl.Vertex2i(int(max.X), int(max.Y))
	gl.Vertex2i(int(min.X), int(max.Y))
	gl.End()
	gl.Color3ub(255, 255, 255)
}