Golang gl.VertexAttribPointer函数代码示例

func (shape *StaticShape) Draw(shader Shader, camera Camera) {
	gl.BindBuffer(gl.ARRAY_BUFFER, shape.VBO)
	stride := shape.Stride()

	gl.EnableVertexAttribArray(shader.Attrib("vertCoord"))
	gl.VertexAttribPointer(shader.Attrib("vertCoord"), vertexDim, gl.FLOAT, false, stride, 0)

	if len(shape.normals) > 0 {
		gl.EnableVertexAttribArray(shader.Attrib("vertNormal"))
		gl.VertexAttribPointer(shader.Attrib("vertNormal"), normalDim, gl.FLOAT, false, stride, vertexDim*vecSize)
	}
	// TODO: texture

	if len(shape.indices) > 0 {
		gl.BindBuffer(gl.ELEMENT_ARRAY_BUFFER, shape.IBO)
		gl.DrawElements(gl.TRIANGLES, len(shape.indices), gl.UNSIGNED_BYTE, 0)
	} else {
		gl.DrawArrays(gl.TRIANGLES, 0, shape.Len())
	}

	gl.DisableVertexAttribArray(shader.Attrib("vertCoord"))
	if len(shape.normals) > 0 {
		gl.DisableVertexAttribArray(shader.Attrib("vertNormal"))
	}
	// TODO: texture
}

func (w *windowImpl) Draw(src2dst f64.Aff3, src screen.Texture, sr image.Rectangle, op draw.Op, opts *screen.DrawOptions) {
	t := src.(*textureImpl)
	a := w.vertexAff3(sr)

	gl.UseProgram(w.s.texture.program)
	writeAff3(w.s.texture.mvp, mul(a, src2dst))

	// OpenGL's fragment shaders' UV coordinates run from (0,0)-(1,1),
	// unlike vertex shaders' XY coordinates running from (-1,+1)-(+1,-1).
	//
	// We are drawing a rectangle PQRS, defined by two of its
	// corners, onto the entire texture. The two quads may actually
	// be equal, but in the general case, PQRS can be smaller.
	//
	//	(0,0) +---------------+ (1,0)
	//	      |  P +-----+ Q  |
	//	      |    |     |    |
	//	      |  S +-----+ R  |
	//	(0,1) +---------------+ (1,1)
	//
	// The PQRS quad is always axis-aligned. First of all, convert
	// from pixel space to texture space.
	tw := float64(t.size.X)
	th := float64(t.size.Y)
	px := float64(sr.Min.X-0) / tw
	py := float64(sr.Min.Y-0) / th
	qx := float64(sr.Max.X-0) / tw
	sy := float64(sr.Max.Y-0) / th
	// Due to axis alignment, qy = py and sx = px.
	//
	// The simultaneous equations are:
	//	  0 +   0 + a02 = px
	//	  0 +   0 + a12 = py
	//	a00 +   0 + a02 = qx
	//	a10 +   0 + a12 = qy = py
	//	  0 + a01 + a02 = sx = px
	//	  0 + a11 + a12 = sy
	writeAff3(w.s.texture.uvp, f64.Aff3{
		qx - px, 0, px,
		0, sy - py, py,
	})

	gl.ActiveTexture(gl.TEXTURE0)
	gl.BindTexture(gl.TEXTURE_2D, t.id)
	gl.Uniform1i(w.s.texture.sample, 0)

	gl.BindBuffer(gl.ARRAY_BUFFER, w.s.texture.quadXY)
	gl.EnableVertexAttribArray(w.s.texture.pos)
	gl.VertexAttribPointer(w.s.texture.pos, 2, gl.FLOAT, false, 0, 0)

	gl.BindBuffer(gl.ARRAY_BUFFER, w.s.texture.quadUV)
	gl.EnableVertexAttribArray(w.s.texture.inUV)
	gl.VertexAttribPointer(w.s.texture.inUV, 2, gl.FLOAT, false, 0, 0)

	gl.DrawArrays(gl.TRIANGLE_STRIP, 0, 4)

	gl.DisableVertexAttribArray(w.s.texture.pos)
	gl.DisableVertexAttribArray(w.s.texture.inUV)
}

func (e *Engine) Draw(c size.Event) {

	gl.Enable(gl.DEPTH_TEST)
	gl.DepthFunc(gl.LESS)

	gl.ClearColor(0.2, 0.2, 0.2, 1)
	gl.Clear(gl.COLOR_BUFFER_BIT)
	gl.Clear(gl.DEPTH_BUFFER_BIT)

	gl.UseProgram(e.shader.program)

	m := mgl32.Perspective(0.785, float32(c.WidthPt/c.HeightPt), 0.1, 10.0)
	gl.UniformMatrix4fv(e.shader.projection, m[:])

	eye := mgl32.Vec3{0, 0, 8}
	center := mgl32.Vec3{0, 0, 0}
	up := mgl32.Vec3{0, 1, 0}

	m = mgl32.LookAtV(eye, center, up)
	gl.UniformMatrix4fv(e.shader.view, m[:])

	m = mgl32.HomogRotate3D(float32(e.touchLoc.X/c.WidthPt-0.5)*3.14*2, mgl32.Vec3{0, 1, 0})
	gl.UniformMatrix4fv(e.shader.modelx, m[:])

	m = mgl32.HomogRotate3D(float32(e.touchLoc.Y/c.HeightPt-0.5)*3.14, mgl32.Vec3{1, 0, 0})
	gl.UniformMatrix4fv(e.shader.modely, m[:])

	coordsPerVertex := 3
	for _, obj := range e.shape.Objs {
		gl.BindBuffer(gl.ARRAY_BUFFER, obj.coord)
		gl.EnableVertexAttribArray(e.shader.vertCoord)

		gl.VertexAttribPointer(e.shader.vertCoord, coordsPerVertex, gl.FLOAT, false, 12, 0)

		if obj.useuv == true {
			gl.Uniform1i(e.shader.useuv, 1)
			texCoordsPerVertex := 2
			gl.BindBuffer(gl.ARRAY_BUFFER, obj.uvcoord)
			gl.EnableVertexAttribArray(e.shader.vertTexCoord)
			gl.VertexAttribPointer(e.shader.vertTexCoord, texCoordsPerVertex, gl.FLOAT, false, 8, 0)

			gl.BindTexture(gl.TEXTURE_2D, obj.tex)
		} else {
			gl.Uniform1i(e.shader.useuv, 0)
			gl.Uniform4f(e.shader.color, obj.color[0], obj.color[1], obj.color[2], obj.color[3])
		}
		gl.DrawArrays(gl.TRIANGLES, 0, obj.vcount)
		if obj.useuv {
			gl.DisableVertexAttribArray(e.shader.vertTexCoord)
		}
		gl.DisableVertexAttribArray(e.shader.vertCoord)
	}

	debug.DrawFPS(c)
}

func (e *Engine) Draw(c size.Event) {

	gl.Enable(gl.DEPTH_TEST)
	gl.DepthFunc(gl.LESS)

	gl.ClearColor(0.5, 0.8, 0.8, 1)
	gl.Clear(gl.COLOR_BUFFER_BIT)
	gl.Clear(gl.DEPTH_BUFFER_BIT)

	gl.UseProgram(e.shader.program)

	gl.Uniform3fv(e.shader.lightdir, []float32{0.5, 0.6, 0.7})

	m := mgl32.Perspective(1.3, float32(c.WidthPt/c.HeightPt), 0.1, 10.0)
	gl.UniformMatrix4fv(e.shader.projectionmatrix, m[:])

	eye := mgl32.Vec3{0, 0, 0.2}
	center := mgl32.Vec3{0, 0, 0}
	up := mgl32.Vec3{0, 1, 0}

	m = mgl32.LookAtV(eye, center, up)
	gl.UniformMatrix4fv(e.shader.viewmatrix, m[:])

	m = mgl32.HomogRotate3D((e.touchx/float32(c.WidthPt)-0.5)*6.28, mgl32.Vec3{0, 1, 0})
	gl.UniformMatrix4fv(e.shader.modelmatrix, m[:])

	m = mgl32.HomogRotate3D((e.touchx/float32(c.WidthPt)-0.5)*6.28, mgl32.Vec3{0, -1, 0})
	gl.UniformMatrix4fv(e.shader.lightmatrix, m[:])

	coordsPerVertex := 3
	for _, obj := range e.shape.Objs {
		gl.BindBuffer(gl.ARRAY_BUFFER, obj.coord)
		gl.EnableVertexAttribArray(e.shader.vertCoord)
		gl.VertexAttribPointer(e.shader.vertCoord, coordsPerVertex, gl.FLOAT, false, 12, 0)

		texCoordsPerVertex := 2
		gl.BindBuffer(gl.ARRAY_BUFFER, obj.uvcoord)
		gl.EnableVertexAttribArray(e.shader.texcoord)
		gl.VertexAttribPointer(e.shader.texcoord, texCoordsPerVertex, gl.FLOAT, false, 8, 0)

		gl.BindBuffer(gl.ARRAY_BUFFER, obj.normal)
		gl.EnableVertexAttribArray(e.shader.normal)
		gl.VertexAttribPointer(e.shader.normal, 3, gl.FLOAT, false, 12, 0)

		gl.BindTexture(gl.TEXTURE_2D, obj.tex)

		gl.DrawArrays(gl.TRIANGLES, 0, obj.vcount)

		gl.DisableVertexAttribArray(e.shader.texcoord)
		gl.DisableVertexAttribArray(e.shader.normal)
		gl.DisableVertexAttribArray(e.shader.vertCoord)
	}

	debug.DrawFPS(c)
}

func onPaint(sz size.Event) {
	gl.ClearColor(rgb(156), rgb(39), rgb(176), 1)
	gl.Clear(gl.COLOR_BUFFER_BIT)

	var rotationMatrix = []float32{
		f32.Cos(-alpha), -f32.Sin(-alpha), 0.0,
		f32.Sin(-alpha), f32.Cos(-alpha), 0.0,
		0.0, 0.0, 1.0,
	}

	gl.UseProgram(program)
	// setting color
	gl.Uniform4f(color, rgb(255), rgb(255), rgb(255), 1)
	gl.UniformMatrix3fv(matrixId, rotationMatrix)
	gl.Uniform1f(resolutionId, resIndex)

	gl.BindBuffer(gl.ARRAY_BUFFER, swasBuffer)

	gl.EnableVertexAttribArray(position)
	gl.VertexAttribPointer(position, 3, gl.FLOAT, false, 0, 0)
	gl.DrawArrays(gl.LINES, 0, 16)
	gl.DisableVertexAttribArray(position)

	gl.UseProgram(texProgram)
	// setting color
	gl.Uniform4f(color2, rgb(130), rgb(50), rgb(80), 1)
	gl.Uniform1f(resolutionId2, resIndex)
	gl.UniformMatrix3fv(matrixId2, rotationMatrix)

	gl.BindBuffer(gl.ARRAY_BUFFER, quadBuffer)
	gl.EnableVertexAttribArray(position2)
	gl.VertexAttribPointer(position2, 3, gl.FLOAT, false, 0, 0)

	gl.BindBuffer(gl.ARRAY_BUFFER, quadTexBuffer)
	gl.EnableVertexAttribArray(textureCoords)
	gl.VertexAttribPointer(textureCoords, 2, gl.FLOAT, false, 0, 0)

	gl.Uniform1i(gl.GetUniformLocation(texProgram, "myTexture"), 0)
	gl.ActiveTexture(gl.TEXTURE0)
	gl.BindTexture(gl.TEXTURE_2D, textureId)

	gl.DrawArrays(gl.TRIANGLES, 0, 6)
	gl.DisableVertexAttribArray(position2)
	gl.DisableVertexAttribArray(textureCoords)

	if spin == true {
		alpha += 0.1
	}

	if alpha >= 360 {
		alpha = 0.0
	}

}

func (video *Video) initGL() {
	log.Print("Initing")
	video.fpsmanager = gfx.NewFramerate()
	video.fpsmanager.SetFramerate(60)

	gl.ClearColor(0.0, 0.0, 0.0, 1.0)
	gl.Enable(gl.CULL_FACE)
	gl.Enable(gl.DEPTH_TEST)

	log.Print("Creating program")
	video.prog = createProgram(vertShaderSrcDef, fragShaderSrcDef)
	log.Print("Attrib loc 1")
	posAttrib := attribLocation(video.prog, "vPosition")
	log.Print("Attrib loc 2")
	texCoordAttr := attribLocation(video.prog, "vTexCoord")
	log.Print("Uniform loc 1")
	paletteLoc := uniformLocation(video.prog, "palette")
	log.Print("Uniform loc 2")
	video.textureUni = uniformLocation(video.prog, "texture")

	log.Print("Gen Texture")
	video.texture = genTexture()
	gl.ActiveTexture(gl.TEXTURE0)
	gl.BindTexture(gl.TEXTURE_2D, video.texture)

	log.Print("TexParam")
	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST)
	gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST)

	gl.UseProgram(video.prog)
	gl.EnableVertexAttribArray(posAttrib)
	gl.EnableVertexAttribArray(texCoordAttr)

	gl.Uniform3iv(paletteLoc, nes.SPaletteRgb)

	log.Print("VertBO")
	vertVBO := genBuffer()
	checkGLError()
	gl.BindBuffer(gl.ARRAY_BUFFER, vertVBO)
	verts := f32.Bytes(binary.LittleEndian, -1.0, 1.0, -1.0, -1.0, 1.0, -1.0, 1.0, -1.0, 1.0, 1.0, -1.0, 1.0)
	gl.BufferData(gl.ARRAY_BUFFER, verts, gl.STATIC_DRAW)

	textCoorBuf := genBuffer()
	checkGLError()
	gl.BindBuffer(gl.ARRAY_BUFFER, textCoorBuf)
	texVerts := f32.Bytes(binary.LittleEndian, 0.0, 1.0, 0.0, 0.0, 1.0, 0.0, 1.0, 0.0, 1.0, 1.0, 0.0, 1.0)
	gl.BufferData(gl.ARRAY_BUFFER, texVerts, gl.STATIC_DRAW)

	gl.VertexAttribPointer(posAttrib, 2, gl.FLOAT, false, 0, 0)
	gl.VertexAttribPointer(texCoordAttr, 2, gl.FLOAT, false, 0, 0)
	log.Print("Started")
}

func onPaint(c size.Event) {
	//清场
	gl.ClearColor(1, 1, 1, 1) //设置背景颜色
	gl.Clear(gl.COLOR_BUFFER_BIT)

	//使用program
	gl.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)
	gl.UniformMatrix4fv(scan, []float32{
		float32(touchLoc.X/c.WidthPt*4 - 2), 0, 0, 0,
		0, float32(touchLoc.Y/c.HeightPt*4 - 2), 0, 0,
		0, 0, 0, 0,
		0, 0, 0, 1,
	})
	gl.BindBuffer(gl.ARRAY_BUFFER, buf)
	gl.EnableVertexAttribArray(position)
	/*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；
	*/
	gl.VertexAttribPointer(position, coordsPerVertex, gl.FLOAT, false, 0, 0) //更新position值
	gl.DrawArrays(gl.TRIANGLES, 0, vertexCount)
	gl.DisableVertexAttribArray(position)

	debug.DrawFPS(c)
}

func onPaint(c size.Event) {
	gl.ClearColor(0, 0.3, 0.3, 1)
	gl.Clear(gl.COLOR_BUFFER_BIT)

	gl.UseProgram(program)

	green += direction
	if green > 1 {
		green = 1
		direction = -direction
	}
	if green < 0.4 {
		green = 0.4
		direction = -direction
	}
	gl.Uniform4f(color, 0, green, 0, 1)

	gl.Uniform2f(offset, touchX/float32(c.WidthPx), touchY/float32(c.HeightPx))

	gl.BindBuffer(gl.ARRAY_BUFFER, buf)

	gl.BufferData(gl.ARRAY_BUFFER, triangleData, gl.STATIC_DRAW) // ?

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

	debug.DrawFPS(c)
}

func draw() {
	if program.Value == 0 {
		initGL()
		initCL()
	}
	if numPlatforms == 0 {
		gl.ClearColor(1, 0, 0, 1)
	} else {
		gl.ClearColor(0, 1, 0, 1)
	}
	gl.Clear(gl.COLOR_BUFFER_BIT)

	gl.UseProgram(program)

	blue += 0.01
	if blue > 1 {
		blue = 0
	}
	gl.Uniform4f(color, 0, 0, blue, 1)

	gl.Uniform2f(offset, float32(touchLoc.X/geom.Width), float32(touchLoc.Y/geom.Height))

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

	debug.DrawFPS()
}

func (e *Engine) Start() {
	var err error

	e.shader.program, err = LoadProgram("shader.v.glsl", "shader.f.glsl")
	if err != nil {
		panic(fmt.Sprintln("LoadProgram failed:", err))
	}

	e.shape.buf = gl.CreateBuffer()
	gl.BindBuffer(gl.ARRAY_BUFFER, e.shape.buf)
	gl.BufferData(gl.ARRAY_BUFFER, cubeData, gl.STATIC_DRAW)
	fmt.Println(len(cubeData))
	e.shader.vertCoord = gl.GetAttribLocation(e.shader.program, "vertCoord")
	e.shader.projection = gl.GetUniformLocation(e.shader.program, "projection")
	e.shader.view = gl.GetUniformLocation(e.shader.program, "view")
	e.shader.modelx = gl.GetUniformLocation(e.shader.program, "modelx")
	e.shader.modely = gl.GetUniformLocation(e.shader.program, "modely")

	e.shader.color = gl.GetAttribLocation(e.shader.program, "color")
	e.shape.colorbuf = gl.CreateBuffer()
	gl.BindBuffer(gl.ARRAY_BUFFER, e.shape.colorbuf)
	gl.BufferData(gl.ARRAY_BUFFER, colorData, gl.STATIC_DRAW)
	gl.VertexAttribPointer(e.shader.color, colorsPerVertex, gl.FLOAT, false, 4, 0) //更新color值
	gl.DrawArrays(gl.TRIANGLES, 0, vertexCount)

	e.started = time.Now()
}

func (e *Engine) Draw(c event.Config) {
	since := time.Now().Sub(e.started)

	gl.Enable(gl.DEPTH_TEST)
	gl.DepthFunc(gl.LESS)

	gl.ClearColor(0, 0, 0, 1)
	gl.Clear(gl.COLOR_BUFFER_BIT)
	gl.Clear(gl.DEPTH_BUFFER_BIT)

	gl.UseProgram(e.shader.program)

	// Setup MVP
	var m mgl.Mat4
	m = mgl.Perspective(0.785, float32(c.Width/c.Height), 0.1, 10.0)
	gl.UniformMatrix4fv(e.shader.projection, m[:])

	m = mgl.LookAtV(
		mgl.Vec3{3, 3, 3}, // eye
		mgl.Vec3{0, 0, 0}, // center
		mgl.Vec3{0, 1, 0}, // up
	)
	gl.UniformMatrix4fv(e.shader.view, m[:])

	m = mgl.HomogRotate3D(float32(since.Seconds()), mgl.Vec3{0, 1, 0})
	gl.UniformMatrix4fv(e.shader.model, m[:])

	// Draw our shape
	gl.BindBuffer(gl.ARRAY_BUFFER, e.shape.buf)

	gl.EnableVertexAttribArray(e.shader.vertCoord)
	gl.VertexAttribPointer(e.shader.vertCoord, e.shape.coordsPerVertex, gl.FLOAT, false, 20, 0) // 4 bytes in float, 5 values per vertex

	gl.EnableVertexAttribArray(e.shader.vertTexCoord)
	gl.VertexAttribPointer(e.shader.vertTexCoord, e.shape.texCoordsPerVertex, gl.FLOAT, false, 20, 12)

	gl.ActiveTexture(gl.TEXTURE0)
	gl.BindTexture(gl.TEXTURE_2D, e.shape.texture)

	gl.DrawArrays(gl.TRIANGLES, 0, e.shape.vertexCount)

	gl.DisableVertexAttribArray(e.shader.vertCoord)

	//debug.DrawFPS(c)
}

func (emitter *particleEmitter) Draw(shader Shader, camera Camera) {
	gl.BindBuffer(gl.ARRAY_BUFFER, emitter.VBO)

	gl.EnableVertexAttribArray(shader.Attrib("vertCoord"))
	gl.VertexAttribPointer(shader.Attrib("vertCoord"), vertexDim, gl.FLOAT, false, emitter.Stride(), 0)

	gl.DrawArrays(gl.TRIANGLES, 0, emitter.Len()*particleLen/vertexDim)

	gl.DisableVertexAttribArray(shader.Attrib("vertCoord"))
}

func onPaint(c config.Event) {
	gl.ClearColor(1, 1, 1, 1)
	gl.Clear(gl.COLOR_BUFFER_BIT)

	gl.UseProgram(program)

	gl.Uniform4f(color, 0.3, 0.3, 0.3, 1) // color
	// position
	x := float32(touchLoc.X / c.Width)
	y := float32(touchLoc.Y / c.Height)
	gl.Uniform2f(offset, x, y)

	gl.BindBuffer(gl.ARRAY_BUFFER, buf)
	gl.EnableVertexAttribArray(position)
	gl.VertexAttribPointer(position, 2, gl.FLOAT, false, 0, 0)
	gl.DrawArrays(gl.TRIANGLE_STRIP, 0, 4)
	gl.DisableVertexAttribArray(position)
}

func (shape *Line) Draw(camera Camera) {
	shader := shape.shader

	// Set uniforms
	gl.Uniform1f(shader.Uniform("lights[0].intensity"), 2.0)
	gl.Uniform3fv(shader.Uniform("lights[0].position"), shape.position[:])
	gl.Uniform3fv(shader.Uniform("lights[0].color"), []float32{0.4, 0.2, 0.1})

	gl.Uniform3fv(shader.Uniform("material.ambient"), []float32{0.1, 0.15, 0.4})
	//gl.Uniform3fv(shader.Uniform("material.diffuse"), []float32{0.8, 0.6, 0.6})
	//gl.Uniform3fv(shader.Uniform("material.specular"), []float32{1.0, 1.0, 1.0})
	//gl.Uniform1f(shader.Uniform("material.shininess"), 16.0)
	//gl.Uniform1f(shader.Uniform("material.refraction"), 1.0/1.52)

	gl.BindBuffer(gl.ARRAY_BUFFER, shape.VBO)
	stride := shape.Stride()

	gl.EnableVertexAttribArray(shader.Attrib("vertCoord"))
	gl.VertexAttribPointer(shader.Attrib("vertCoord"), vertexDim, gl.FLOAT, false, stride, 0)

	gl.DrawArrays(gl.TRIANGLE_STRIP, 0, shape.Len())
}

func onDraw(c config.Event) {
	gl.ClearColor(1, 0, 0, 1)
	gl.Clear(gl.COLOR_BUFFER_BIT)

	gl.UseProgram(program)

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

	gl.Uniform2f(offset, float32(touchLoc.X/c.Width), float32(touchLoc.Y/c.Height))

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

	debug.DrawFPS(c)
}