 
 #if MAX_SPOT_LIGHTS > 0
 
-	for( int i = 0; i < MAX_SPOT_LIGHTS; i ++ ) {
+	for ( int i = 0; i < MAX_SPOT_LIGHTS; i ++ ) {
 
-		vec4 lPosition = viewMatrix * vec4( spotLightPosition[ i ], 1.0 );
+		vec3 lightColor = spotLightColor[ i ];
+
+		vec3 lightPosition = spotLightPosition[ i ];
+		vec4 lPosition = viewMatrix * vec4( lightPosition, 1.0 );
 		vec3 lVector = lPosition.xyz - mvPosition.xyz;
+		vec3 lightDir = normalize( lVector );
 
-		float spotEffect = dot( spotLightDirection[ i ], normalize( spotLightPosition[ i ] - worldPosition.xyz ) );
+		float spotEffect = dot( spotLightDirection[ i ], normalize( lightPosition - worldPosition.xyz ) );
 
 		if ( spotEffect > spotLightAngleCos[ i ] ) {
 
-			spotEffect = max( pow( max( spotEffect, 0.0 ), spotLightExponent[ i ] ), 0.0 );
+			spotEffect = saturate( pow( saturate( spotEffect ), spotLightExponent[ i ] ) );
+
+			// attenuation
 
 			float attenuation = calcLightAttenuation( length( lVector ), spotLightDistance[ i ], spotLightDecay[ i ] );
 
-			lVector = normalize( lVector );
+			attenuation *= spotEffect;
 
-			float dotProduct = dot( transformedNormal, lVector );
-			vec3 spotLightWeighting = vec3( max( dotProduct, 0.0 ) );
+			// diffuse
+
+			float dotProduct = dot( normal, lightDir );
+
+			vLightFront += lightColor * attenuation * saturate( dotProduct );
 
 			#ifdef DOUBLE_SIDED
 
-				vec3 spotLightWeightingBack = vec3( max( -dotProduct, 0.0 ) );
-
-			#endif
-
-			vLightFront += spotLightColor[ i ] * spotLightWeighting * attenuation * spotEffect;
-
-			#ifdef DOUBLE_SIDED
-
-				vLightBack += spotLightColor[ i ] * spotLightWeightingBack * attenuation * spotEffect;
+				vLightBack += lightColor * attenuation * saturate( - dotProduct );
 
 			#endif
 


#endif

transformedNormal = normalize( transformedNormal );

#if MAX_DIR_LIGHTS > 0

for( int i = 0; i < MAX_DIR_LIGHTS; i ++ ) {

	vec3 dirVector = transformDirection( directionalLightDirection[ i ], viewMatrix );

	float dotProduct = dot( transformedNormal, dirVector );
	vec3 directionalLightWeighting = vec3( max( dotProduct, 0.0 ) );

	#ifdef DOUBLE_SIDED

		vec3 directionalLightWeightingBack = vec3( max( -dotProduct, 0.0 ) );

	#endif

	vLightFront += directionalLightColor[ i ] * directionalLightWeighting;

	#ifdef DOUBLE_SIDED

		vLightBack += directionalLightColor[ i ] * directionalLightWeightingBack;

	#endif

}

#endif

#if MAX_POINT_LIGHTS > 0

	for( int i = 0; i < MAX_POINT_LIGHTS; i ++ ) {

		vec4 lPosition = viewMatrix * vec4( pointLightPosition[ i ], 1.0 );
		vec3 lVector = lPosition.xyz - mvPosition.xyz;

		float attenuation = calcLightAttenuation( length( lVector ), pointLightDistance[ i ], pointLightDecay[ i ] );

		lVector = normalize( lVector );
		float dotProduct = dot( transformedNormal, lVector );

		vec3 pointLightWeighting = vec3( max( dotProduct, 0.0 ) );

		#ifdef DOUBLE_SIDED

			vec3 pointLightWeightingBack = vec3( max( -dotProduct, 0.0 ) );

		#endif

		vLightFront += pointLightColor[ i ] * pointLightWeighting * attenuation;

		#ifdef DOUBLE_SIDED

			vLightBack += pointLightColor[ i ] * pointLightWeightingBack * attenuation;

		#endif



#endif

#if MAX_DIR_LIGHTS > 0

	for ( int i = 0; i < MAX_DIR_LIGHTS; i ++ ) {

		vec3 lightColor = directionalLightColor[ i ];

		vec3 lightDir = transformDirection( directionalLightDirection[ i ], viewMatrix );

		// diffuse

		float dotProduct = dot( normal, lightDir );

		vLightFront += lightColor * saturate( dotProduct );

		#ifdef DOUBLE_SIDED

			vLightBack += lightColor * saturate( - dotProduct );

		#endif

	}

#endif

#if MAX_HEMI_LIGHTS > 0

	for ( int i = 0; i < MAX_HEMI_LIGHTS; i ++ ) {

		vec3 lightDir = transformDirection( hemisphereLightDirection[ i ], viewMatrix );

		// diffuse

		float dotProduct = dot( normal, lightDir );

		float hemiDiffuseWeight = 0.5 * dotProduct + 0.5;

		vLightFront += mix( hemisphereLightGroundColor[ i ], hemisphereLightSkyColor[ i ], hemiDiffuseWeight );

		#ifdef DOUBLE_SIDED

			float hemiDiffuseWeightBack = - 0.5 * dotProduct + 0.5;

			vLightBack += mix( hemisphereLightGroundColor[ i ], hemisphereLightSkyColor[ i ], hemiDiffuseWeightBack );

