private Texture2D background;
        private Texture2D backgroundNormals;

        private RenderTarget2D colorMapRenderTarget;
        private RenderTarget2D normalMapRenderTarget;
        private RenderTarget2D shadowMapRenderTarget;

        private Color ambientLight = new Color(.1f, .1f, .1f, 1);

        private Effect lightEffect;
        private Effect lightCombinedEffect;

        private EffectParameter lightEffectParameterScreenWidth;
        private EffectParameter lightEffectParameterScreenHeight;
        private EffectParameter lightEffectParameterNormapMap;

        private EffectTechnique lightCombinedEffectTechnique;
        private EffectParameter lightCombinedEffectParamAmbient;
        private EffectParameter lightCombinedEffectParamLightAmbient;
        private EffectParameter lightCombinedEffectParamAmbientColor;
        private EffectParameter lightCombinedEffectParamColorMap;
        private EffectParameter lightCombinedEffectParamNormalMap;
        private EffectParameter lightCombinedEffectParamShadowMap;