Golang Context.Uniform4f方法代码示例

// 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 onPaint(glctx gl.Context, sz size.Event) {
	glctx.ClearColor(0.5, 0.5, 0.5, 1)
	glctx.Clear(gl.COLOR_BUFFER_BIT)

	glctx.UseProgram(frameData.Program)

	glctx.Uniform4f(frameData.Color, 0.5, 0.5, 0.5, 1)

	// Put ourselves in the +x/+y quadrant (upper right quadrant)
	glctx.Uniform2f(frameData.Offset, 0.0, 1.0)

	glctx.EnableVertexAttribArray(frameData.Position)
	manager.PaintLayers(sz, frameData)
	// End drawing
	glctx.DisableVertexAttribArray(frameData.Position)

}

func onPaint(glctx gl.Context, sz size.Event) {
	glctx.ClearColor(1, 0, 0, 1)
	glctx.Clear(gl.COLOR_BUFFER_BIT)
	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)
}

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)
}

// 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)
}

func (prg Program) U4f(ctx gl.Context, dst gl.Uniform, v0, v1, v2, v3 float32) {
	ctx.Uniform4f(dst, v0, v1, v2, v3)
}