internal void UpdateTexture(string filename)
{
// This is the texture that the compute program will write into
var bitmap = new System.Drawing.Bitmap(filename);
var texture = new Texture(TextureTarget.Texture2D, bitmap, new SamplerParameters());
texture.Initialize();
bitmap.Dispose();
Texture old = this.spriteTexture;
this.spriteTexture = texture;
this.SetUniform("sprite_texture", texture);
old.Dispose();
}