Golang Context.VertexAttribPointer方法代码示例

func onPaint(glctx gl.Context, sz size.Event) {
	//gl.Enable(gl.DEPTH_TEST)
	//gl.DepthFunc(gl.LESS)
	//清场
	glctx.ClearColor(1, 1, 1, 1) //设置背景颜色
	glctx.Clear(gl.COLOR_BUFFER_BIT)
	glctx.Clear(gl.DEPTH_BUFFER_BIT)

	//使用program
	glctx.UseProgram(program)

	//gl.Uniform4f(color, 0, 0.5, 0.8, 1)//设置color对象值,设置4个浮点数.
	//offset有两个值X,Y,窗口左上角为(0,0),右下角为(1,1)
	//gl.Uniform4f(offset,5.0,1.0,1.0,1.0 )
	//gl.Uniform2f(offset,offsetx,offsety )//为2参数的uniform变量赋值
	//log.Println("offset:",offsetx,offsety, 0, 0)
	glctx.UniformMatrix4fv(scan, []float32{
		touchLocX/float32(sz.WidthPt)*4 - 2, 0, 0, 0,
		0, touchLocY/float32(sz.HeightPt)*4 - 2, 0, 0,
		0, 0, 0, 0,
		0, 0, 0, 1,
	})
	/*glVertexAttribPointer 指定了渲染时索引值为 index 的顶点属性数组的数据格式和位置。调用gl.vertexAttribPointer()方法，
		把顶点着色器中某个属性相对应的通用属性索引连接到绑定的webGLBUffer对象上。
	index 指定要修改的顶点属性的索引值
	size    指定每个顶点属性的组件数量。必须为1、2、3或者4。初始值为4。（如position是由3个（x,y,z）组成，而颜色是4个（r,g,b,a））
	type    指定数组中每个组件的数据类型。可用的符号常量有GL_BYTE, GL_UNSIGNED_BYTE, GL_SHORT,GL_UNSIGNED_SHORT, GL_FIXED,
		和 GL_FLOAT，初始值为GL_FLOAT。
	normalized  指定当被访问时，固定点数据值是否应该被归一化（GL_TRUE）或者直接转换为固定点值（GL_FALSE）。
	stride  指定连续顶点属性之间的偏移量。如果为0，那么顶点属性会被理解为：它们是紧密排列在一起的。初始值为0。
	pointer 指定第一个组件在数组的第一个顶点属性中的偏移量。该数组与GL_ARRAY_BUFFER绑定，储存于缓冲区中。初始值为0；
	*/

	glctx.BindBuffer(gl.ARRAY_BUFFER, positionbuf)
	glctx.EnableVertexAttribArray(position)
	defer glctx.DisableVertexAttribArray(position)//必须全部缓存导入完成后再关闭
	glctx.VertexAttribPointer(position, coordsPerVertex, gl.FLOAT, false, 0, 0) //导入position缓存
	glctx.DrawArrays(gl.TRIANGLES, 0, vertexCount)

	glctx.BindBuffer(gl.ARRAY_BUFFER, colorbuf)
	glctx.EnableVertexAttribArray(color)
	defer glctx.DisableVertexAttribArray(color)//必须全部缓存导入完成后再关闭
	glctx.VertexAttribPointer(color, colorsPerVertex, gl.FLOAT, false, 0, 0) //导入color缓存
	glctx.DrawArrays(gl.TRIANGLES, 0, vertexCount)



	fps.Draw(sz)
}

// PaintKey will paint the key 1) its own color or 2) red if they key is pressed.
func (k *PianoKey) PaintKey(glctx gl.Context, frameData util.FrameData) {
	glctx.BindBuffer(gl.ARRAY_BUFFER, k.glBuf)
	glctx.VertexAttribPointer(frameData.Position, coordsPerVertex, gl.FLOAT, false, 0, 0)
	if k.pressed {
		// Paint Red if pressed
		glctx.Uniform4f(frameData.Color, 1, 0, 0, 1)
	} else {
		// Paint white if not pressed
		glctx.Uniform4f(frameData.Color, k.keyColor.Red, k.keyColor.Green, k.keyColor.Blue, 1)
	}
	if frameData.Orientation == util.Portrait {
		glctx.DrawArrays(gl.TRIANGLES, 6, vertexCount)
	} else if frameData.Orientation == util.Landscape {
		glctx.DrawArrays(gl.TRIANGLES, 0, vertexCount)
	}
}

func (wf *Waveform) Paint(ctx gl.Context, xps, yps, width, height float32) {
	// TODO this is racey and samples can be in the middle of changing
	// move the slice copy to Prepare and sync with playback, or feed over chan
	// TODO assumes mono

	var (
		xstep float32 = width / float32(len(wf.samples))
		xpos  float32 = xps
	)

	for i, x := range wf.samples {
		// clip
		if x > 1 {
			x = 1
		} else if x < -1 {
			x = -1
		}

		wf.verts[i*3] = float32(xpos)
		wf.verts[i*3+1] = yps + (height * float32((x+1)/2))
		wf.verts[i*3+2] = 0
		xpos += xstep
	}

	for i, x := range wf.verts {
		u := math.Float32bits(x)
		wf.data[4*i+0] = byte(u >> 0)
		wf.data[4*i+1] = byte(u >> 8)
		wf.data[4*i+2] = byte(u >> 16)
		wf.data[4*i+3] = byte(u >> 24)
	}

	ctx.UseProgram(wf.program)
	ctx.Uniform4f(wf.color, 1, 1, 1, 1)

	// update hw buf and draw
	ctx.BindBuffer(gl.ARRAY_BUFFER, wf.buf)
	ctx.EnableVertexAttribArray(wf.position)
	ctx.VertexAttribPointer(wf.position, 3, gl.FLOAT, false, 0, 0)
	ctx.BufferSubData(gl.ARRAY_BUFFER, 0, wf.data)
	ctx.DrawArrays(gl.LINE_STRIP, 0, len(wf.samples))
	ctx.DisableVertexAttribArray(wf.position)
}

func onPaint(glctx gl.Context, sz size.Event) {

	glctx.Viewport(0, 0, sz.WidthPx, sz.HeightPx)
	glctx.ClearColor(0.5, 0.5, 0.5, 1)
	glctx.Clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT)

	glctx.UseProgram(program)

	projectionMtx = mgl32.Perspective(45, float32(width)/float32(height), 0.1, 100)

	arcBallMtx := arcball.getMtx()

	glctx.UniformMatrix4fv(projection, projectionMtx[:])

	glctx.UniformMatrix4fv(view, arcBallMtx[:])

	glctx.BindBuffer(gl.ARRAY_BUFFER, triBuf)
	glctx.EnableVertexAttribArray(position)
	glctx.EnableVertexAttribArray(color)
	glctx.EnableVertexAttribArray(normals)

	vertSize := 4 * (coordsPerVertex + colorPerVertex + normalsPerVertex)

	glctx.VertexAttribPointer(position, coordsPerVertex, gl.FLOAT, false, vertSize, 0)
	glctx.VertexAttribPointer(color, colorPerVertex, gl.FLOAT, false, vertSize, 4*coordsPerVertex)
	glctx.VertexAttribPointer(normals, normalsPerVertex, gl.FLOAT, false, vertSize, 4*(coordsPerVertex+colorPerVertex))

	glctx.DepthMask(true)

	glctx.Uniform3fv(lightPos, light.Pos[:])
	glctx.Uniform3fv(lightIntensity, light.Intensities[:])

	for _, k := range piano.Keys {
		glctx.Uniform4fv(tint, k.Color[:])

		mtx := k.GetMtx()
		normMat := mtx.Mat3().Inv().Transpose()
		glctx.UniformMatrix3fv(normalMatrix, normMat[:])
		glctx.UniformMatrix4fv(model, mtx[:])
		glctx.DrawArrays(gl.TRIANGLES, 0, len(triangleData)/vertSize)
	}

	modelMtx := mgl32.Ident4()
	modelMtx = modelMtx.Mul4(mgl32.Translate3D(worldPos.X(), worldPos.Y(), worldPos.Z()))
	modelMtx = modelMtx.Mul4(mgl32.Scale3D(0.5, 0.5, 0.5))

	/*
		glctx.Uniform4fv(tint, red[:])
		// Disable depthmask so we dont get the pixel depth of the cursor cube
		glctx.DepthMask(false)
		glctx.UniformMatrix4fv(model, modelMtx[:])
		glctx.DepthMask(true)
	*/

	glctx.DisableVertexAttribArray(position)
	glctx.DisableVertexAttribArray(color)
	glctx.DisableVertexAttribArray(normals)

	fps.Draw(sz)
}

// This is the main rendering call that updates the current scene and all children in the scene
func appPaint(glctx gl.Context, sz size.Event, delta float32) {
	glctx.ClearColor(currentScene.BGColor.R, currentScene.BGColor.G, currentScene.BGColor.B, currentScene.BGColor.A)
	glctx.Clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT)
	for _, child := range currentScene.Children {
		child.act(delta)
		child.draw(tempBatch, 1.0)
		if len(InputChannel) > 0 {
			for e := range InputChannel {
				if child.Input != nil {
					child.Input(child, e)
				}
				if len(InputChannel) == 0 {
					break
				}
			}
		}
	}

	glctx.UseProgram(program)

	green += 0.01
	if green > 1 {
		green = 0
	}
	glctx.Uniform4f(color, 0, green, 0, 1)

	glctx.Uniform2f(offset, touchX/float32(sz.WidthPx), touchY/float32(sz.HeightPx))

	glctx.BindBuffer(gl.ARRAY_BUFFER, buf)
	glctx.EnableVertexAttribArray(position)
	glctx.VertexAttribPointer(position, coordsPerVertex, gl.FLOAT, false, 0, 0)
	glctx.DrawArrays(gl.TRIANGLES, 0, vertexCount)
	glctx.DisableVertexAttribArray(position)

	fps.Draw(sz)
}

// TODO an Attrib type that describes it's format would be useful here
func (prg Program) Pointer(ctx gl.Context, a gl.Attrib, size int) {
	ctx.EnableVertexAttribArray(a)
	ctx.VertexAttribPointer(a, size, gl.FLOAT, false, 0, 0)
}