Example #1
0
func (b *VertexBuffer) SetVertices(src []byte, usage Usage) error {
	gl.VertexArray(0).Bind()
	b.bind()
	// set size of buffer and invalidate it
	gl.BufferData(gl.ARRAY_BUFFER, len(src), nil, usage.gl())
	if len(src) > 0 {
		// if unmap returns false, the buffer we wrote to is no longer valid and we
		// need to try again. though, this is apparently uncommon in modern
		// drivers. this means it is not feasible to compute/copy vertices directly
		// into the mapped buffer. however, it would be nice to provide a
		// failure-capable API to do this.
		const maxretries = 5
		retries := 0
		for ; retries < maxretries; retries++ {
			ptr := gl.MapBuffer(gl.ARRAY_BUFFER, gl.WRITE_ONLY)
			slicehdr := reflect.SliceHeader{
				Data: uintptr(ptr),
				Len:  len(src),
				Cap:  len(src),
			}
			dest := *(*[]byte)(unsafe.Pointer(&slicehdr))
			copy(dest, src)
			if gl.UnmapBuffer(gl.ARRAY_BUFFER) {
				break
			}
		}
		if retries == maxretries {
			return errMapBufferFailed
		}
	}
	b.count = len(src) / b.format.Stride()
	return nil
}
Example #2
0
func (t *Texture) ReadTextureFromGPU() []byte {
	t.Bind()
	b := gl.GenBuffer()
	b.Bind(gl.PIXEL_UNPACK_BUFFER)
	gl.BufferData(gl.PIXEL_UNPACK_BUFFER, t.Width()*t.Height()*t.PixelSize(), 0, gl.STREAM_DRAW)
	//gl.GetTexImage(t.target, 0, t.format, buffer)
	b.Bind(gl.PIXEL_UNPACK_BUFFER)

	gl.TexSubImage2D(t.target, 0, 0, 0, t.Width(), t.Height(), t.format, t.typ, unsafe.Pointer(uintptr(0)))
	b.Bind(gl.PIXEL_UNPACK_BUFFER)

	l := t.Width() * t.Height() * t.PixelSize()

	gl.BufferData(gl.PIXEL_UNPACK_BUFFER, t.Width()*t.Height()*t.PixelSize(), 0, gl.STREAM_DRAW)
	ptr := gl.MapBuffer(gl.PIXEL_UNPACK_BUFFER, gl.WRITE_ONLY)

	var x []byte
	s := (*reflect.SliceHeader)(unsafe.Pointer(&x))
	s.Data = uintptr(ptr)
	s.Len = l
	s.Cap = l

	gl.UnmapBuffer(gl.PIXEL_UNPACK_BUFFER)

	return x
}
Example #3
0
func (b *IndexBuffer) setIndices(copyTo func(unsafe.Pointer), usage Usage, size int) error {
	gl.VertexArray(0).Bind()
	b.bind()
	gl.BufferData(gl.ELEMENT_ARRAY_BUFFER, size, nil, usage.gl())
	if size > 0 {
		const maxretries = 5
		retries := 0
		for ; retries < maxretries; retries++ {
			ptr := gl.MapBuffer(gl.ELEMENT_ARRAY_BUFFER, gl.WRITE_ONLY)
			copyTo(ptr)
			if gl.UnmapBuffer(gl.ELEMENT_ARRAY_BUFFER) {
				break
			}
		}
		if retries == maxretries {
			return errMapBufferFailed
		}
	}
	return nil
}