func setupGL() int32 {
gl.Disable(gl.DEPTH_TEST)
gl.ClearColor(0.7, 0.7, 0.7, 1)
program, _ := loadResources()
gl.BindFragDataLocation(program, 0, gl.Str("outputColor\x00"))
cameraMatrixUniform := gl.GetUniformLocation(program, gl.Str("cameraMatrix\x00"))
octUniform := gl.GetUniformLocation(program, gl.Str("oct\x00"))
gl.Uniform1i(octUniform, 0)
gl.Viewport(0, 0, winWidth, winHeight)
var vao uint32
gl.GenVertexArrays(1, &vao)
gl.BindVertexArray(vao)
quadVertexBufferData := []float32{
-1, -1, 0,
1, -1, 0,
-1, 1, 0,
-1, 1, 0,
1, -1, 0,
1, 1, 0,
}
var vbo uint32
gl.GenBuffers(1, &vbo)
gl.BindBuffer(gl.ARRAY_BUFFER, vbo)
gl.BufferData(gl.ARRAY_BUFFER, len(quadVertexBufferData)*4, gl.Ptr(quadVertexBufferData), gl.STATIC_DRAW)
vertAttrib := uint32(gl.GetAttribLocation(program, gl.Str("inputPosition\x00")))
gl.EnableVertexAttribArray(vertAttrib)
gl.VertexAttribPointer(vertAttrib, 3, gl.FLOAT, false, 0, gl.PtrOffset(0))
return cameraMatrixUniform
}
func newOctree(file string) (uint32, []uint32, error) {
var (
header pack.OctreeHeader
texture uint32
data []uint32
)
fp, err := os.Open(file)
if err != nil {
return 0, nil, err
}
defer fp.Close()
if err := pack.DecodeHeader(fp, &header); err != nil {
return 0, nil, err
}
if header.Format != pack.MipR8G8B8A8UnpackUI32 {
return 0, nil, errors.New("invalid octree format")
}
nodeSize := uint64(1 + 8)
var maxSize int32
gl.GetIntegerv(gl.MAX_TEXTURE_SIZE, &maxSize)
numInts := header.NumNodes * nodeSize
if maxSize*maxSize < int32(numInts) {
panic("octree does not fit on GPU")
}
var (
height int32
width = maxSize
)
for height < width {
maxSize = width
height = int32(numInts/uint64(width)) + 1
width /= 2
}
fmt.Printf("Octree is loaded in an %vx%v, R32UI, 2D texture.\n", maxSize, height)
textureSize := maxSize * height
data = make([]uint32, textureSize)
for i := uint64(0); i < header.NumNodes; i++ {
start := i * nodeSize
if err := binary.Read(fp, binary.BigEndian, data[start:start+nodeSize]); err != nil {
return 0, nil, err
}
// Recalculate alpha value.
data[start] &= 0xffffff00
for j := uint64(1); j < 9; j++ {
if data[start+j] > 0 {
data[start] |= uint32(0x100) >> j
}
}
}
gl.GenTextures(1, &texture)
gl.ActiveTexture(gl.TEXTURE0)
gl.BindTexture(gl.TEXTURE_2D, texture)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST)
gl.TexImage2D(
gl.TEXTURE_2D,
0,
gl.R32UI,
maxSize,
height,
0,
gl.RED_INTEGER,
gl.UNSIGNED_INT,
gl.Ptr(data))
if glErr := gl.GetError(); glErr != gl.NO_ERROR {
err = fmt.Errorf("GL error, loading octree: %x", glErr)
}
return texture, data, err
}
// BufferData implements the opengl.OpenGl interface.
func (native *OpenGl) BufferData(target uint32, size int, data interface{}, usage uint32) {
gl.BufferData(target, size, gl.Ptr(data), usage)
}
// TexImage2D implements the opengl.OpenGl interface.
func (native *OpenGl) TexImage2D(target uint32, level int32, internalFormat uint32, width int32, height int32,
border int32, format uint32, xtype uint32, pixels interface{}) {
gl.TexImage2D(target, level, int32(internalFormat), width, height, border, format, xtype, gl.Ptr(pixels))
}
// ReadPixels implements the opengl.OpenGl interface.
func (native *OpenGl) ReadPixels(x int32, y int32, width int32, height int32, format uint32, pixelType uint32, pixels interface{}) {
gl.ReadPixels(x, y, width, height, format, pixelType, gl.Ptr(pixels))
}
func NewImage(path string) (retImg image, err error) {
imgFile, err := os.Open(path)
if err != nil {
return image{}, err
}
img, _, err := Image.Decode(imgFile)
if err != nil {
return image{}, err
}
rgba := Image.NewRGBA(img.Bounds())
if rgba.Stride != rgba.Rect.Size().X*4 {
return image{}, fmt.Errorf("unsupported stride")
}
draw.Draw(rgba, rgba.Bounds(), img, Image.Point{0, 0}, draw.Src)
var texture uint32
gl.GenTextures(1, &texture)
// gl.ActiveTexture(gl.TEXTURE1)
gl.BindTexture(gl.TEXTURE_2D, texture)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_R, gl.CLAMP_TO_EDGE)
gl.TexImage2D(gl.TEXTURE_2D, 0, gl.RGBA, int32(rgba.Rect.Size().X), int32(rgba.Rect.Size().Y), 0, gl.RGBA, gl.UNSIGNED_BYTE, gl.Ptr(rgba.Pix))
if gl.GetError() != gl.NO_ERROR {
return image{}, fmt.Errorf("Failed to load texture: " + path)
}
return image{data: &img, textureId: texture, width: rgba.Rect.Size().X, height: rgba.Rect.Size().Y}, nil
}