func (a *Atlas) unbind(release bool) error {
if !gl.Object(a.gltex).IsTexture() {
return nil
}
a.gltex.Unbind(gl.TEXTURE_2D)
if release {
a.gltex.Delete()
}
a.gltex = gl.Texture(gl.FALSE)
return checkGlError()
}
// bind the given atlas to the current GL context
//
// the current implementation is very stupid, since it will
// upload the texture every single call.
//
// later, improve this to upload only if there is a real need for it
func (a *Atlas) bind() error {
// discard any possible error
if err := checkGlError(); err != nil {
return err
}
if gl.Object(a.gltex).IsTexture() {
a.gltex = gl.GenTexture()
}
a.gltex.Bind(gl.TEXTURE_2D)
gl.TexImage2D(gl.TEXTURE_2D, 0, gl.RGBA, a.data.Bounds().Dx(), a.data.Bounds().Dy(), 0, gl.RGBA, gl.UNSIGNED_BYTE, a.data.Pix)
if err := checkGlError(gl.OUT_OF_MEMORY, gl.INVALID_OPERATION); err != nil {
return err
}
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.REPEAT)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.REPEAT)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR)
gl.TexParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR_MIPMAP_LINEAR)
gl.GenerateMipmap(gl.TEXTURE_2D)
panicGlError()
return nil
}