func newTexture(file string) (uint32, error) {
imgFile, err := os.Open(file)
if err != nil {
return 0, err
}
img, _, err := image.Decode(imgFile)
if err != nil {
return 0, err
}
rgba := image.NewRGBA(img.Bounds())
if rgba.Stride != rgba.Rect.Size().X*4 {
return 0, 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.TEXTURE0)
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.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))
return texture, nil
}
// LoadDictionary reads a gobbed Dictionary object from r, registers its atlas texture with opengl,
// and returns a Dictionary that is ready to render text.
func LoadDictionary(r io.Reader) (*Dictionary, error) {
errChan := make(chan error)
initOnce.Do(func() {
render.Queue(func() {
// errChan <- render.RegisterShader("glop.font", []byte(font_vertex_shader), []byte(font_fragment_shader))
errChan <- render.RegisterShader("glop.font", []byte(font_vshader), []byte(font_fshader))
})
})
err := <-errChan
if err != nil {
return nil, err
}
var dict Dictionary
dec := gob.NewDecoder(r)
err = dec.Decode(&dict)
if err != nil {
return nil, err
}
render.Queue(func() {
// Create the gl texture for the atlas
gl.GenTextures(1, &dict.atlas.texture)
glerr := gl.GetError()
if glerr != 0 {
errChan <- fmt.Errorf("Gl Error on gl.GenTextures: %v", glerr)
return
}
// Send the atlas to opengl
gl.BindTexture(gl.TEXTURE_2D, dict.atlas.texture)
gl.PixelStorei(gl.UNPACK_ALIGNMENT, 1)
gl.TexImage2D(
gl.TEXTURE_2D,
0,
gl.RED,
dict.Dx,
dict.Dy,
0,
gl.RED,
gl.UNSIGNED_BYTE,
gl.Ptr(&dict.Pix[0]))
glerr = gl.GetError()
if glerr != 0 {
errChan <- fmt.Errorf("Gl Error on creating texture: %v", glerr)
return
}
// Create the atlas sampler and set the parameters we want for it
gl.GenSamplers(1, &dict.atlas.sampler)
gl.SamplerParameteri(dict.atlas.sampler, gl.TEXTURE_MIN_FILTER, gl.LINEAR)
gl.SamplerParameteri(dict.atlas.sampler, gl.TEXTURE_MAG_FILTER, gl.LINEAR)
gl.SamplerParameteri(dict.atlas.sampler, gl.TEXTURE_WRAP_S, gl.REPEAT)
gl.SamplerParameteri(dict.atlas.sampler, gl.TEXTURE_WRAP_T, gl.REPEAT)
glerr = gl.GetError()
if glerr != 0 {
errChan <- fmt.Errorf("Gl Error on creating sampler: %v", glerr)
return
}
errChan <- nil
})
err = <-errChan
if err != nil {
return nil, err
}
return &dict, nil
}