public void SetPickingColor(IPickable pickable, ShaderProgram shader)
{
var color = new Vector4(
((pickingIndex >> 16) & 0xFF),
((pickingIndex >> 8) & 0xFF),
(pickingIndex & 0xFF),
((pickingIndex++ >> 24) & 0xFF)
);
color = new Vector4(color.X, color.Y, color.Z, color.W);
var key = BitConverter.ToUInt32(new byte[] {
(byte)color.X, (byte)color.Y,
(byte)color.Z, (byte)color.W
}, 0);
ColorPassIDs.Add(key, pickable);
var input = color / 255.0f;
shader.SetVector4("color", input);
}