public void LoadShader(OpenGLBaseShaderID id, string vertexShader, string fragmentShader)
        {
            if (d_shaders.ContainsKey(id))
            {
                return;
            }

            d_shaders[id] = new OpenGLBaseShader(vertexShader, fragmentShader, d_glStateChanger);
            d_shaders[id].Link();
        }
        // TODO:
        //virtual ~OpenGLBaseShaderManager()
        //{
        //	deinitialiseShaders();
        //	d_shadersInitialised = false;
        //}

        public OpenGLBaseShader GetShader(OpenGLBaseShaderID id)
        {
            return(d_shaders.ContainsKey(id)
                                       ? d_shaders[id]
                                       : null);
        }