/**
 * This is a template that can be used to light a material, it uses pluggable
 * RenderEquations (RE)for specific lighting scenarios.
 *
 * Instructions for use:
 * - Ensure that both RE_Direct, RE_IndirectDiffuse and RE_IndirectSpecular are defined
 * - If you have defined an RE_IndirectSpecular, you need to also provide a Material_LightProbeLOD. <---- ???
 * - Create a material parameter that is to be passed as the third parameter to your lighting functions.
 *
 * TODO:
 * - Add area light support.
 * - Add sphere light support.
 * - Add diffuse light probe (irradiance cubemap) support.
 */

GeometricContext geometry;

geometry.position = - vViewPosition;
geometry.normal = normal;
geometry.viewDir = normalize( vViewPosition );

IncidentLight directLight;

#if ( NUM_POINT_LIGHTS > 0 ) && defined( RE_Direct )

	PointLight pointLight;

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

		pointLight = pointLights[ i ];

		getPointDirectLightIrradiance( pointLight, geometry, directLight );

		#ifdef USE_SHADOWMAP
		directLight.color *= all( bvec2( pointLight.shadow, directLight.visible ) ) ? getPointShadow( pointShadowMap[ i ], pointLight.shadowMapSize, pointLight.shadowBias, pointLight.shadowRadius, vPointShadowCoord[ i ] ) : 1.0;
		#endif

		RE_Direct( directLight, geometry, material, reflectedLight );

	}

#endif

#if ( NUM_SPOT_LIGHTS > 0 ) && defined( RE_Direct )

	SpotLight spotLight;

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

		spotLight = spotLights[ i ];

		getSpotDirectLightIrradiance( spotLight, geometry, directLight );

		#ifdef USE_SHADOWMAP
		directLight.color *= all( bvec2( spotLight.shadow, directLight.visible ) ) ? getShadow( spotShadowMap[ i ], spotLight.shadowMapSize, spotLight.shadowBias, spotLight.shadowRadius, vSpotShadowCoord[ i ] ) : 1.0;
		#endif

		RE_Direct( directLight, geometry, material, reflectedLight );

	}

#endif

#if ( NUM_DIR_LIGHTS > 0 ) && defined( RE_Direct )

	DirectionalLight directionalLight;

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

		directionalLight = directionalLights[ i ];

		getDirectionalDirectLightIrradiance( directionalLight, geometry, directLight );

		#ifdef USE_SHADOWMAP
		directLight.color *= all( bvec2( directionalLight.shadow, directLight.visible ) ) ? getShadow( directionalShadowMap[ i ], directionalLight.shadowMapSize, directionalLight.shadowBias, directionalLight.shadowRadius, vDirectionalShadowCoord[ i ] ) : 1.0;
		#endif

		RE_Direct( directLight, geometry, material, reflectedLight );

	}

#endif

#if ( NUM_RECT_AREA_LIGHTS > 0 ) && defined( RE_Direct_RectArea )

	RectAreaLight rectAreaLight;

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

		rectAreaLight = rectAreaLights[ i ];
		RE_Direct_RectArea( rectAreaLight, geometry, material, reflectedLight );

	}

#endif

#if defined( RE_IndirectDiffuse )

	vec3 irradiance = getAmbientLightIrradiance( ambientLightColor );

	#ifdef USE_LIGHTMAP

		vec3 lightMapIrradiance = texture2D( lightMap, vUv2 ).xyz * lightMapIntensity;

		#ifndef PHYSICALLY_CORRECT_LIGHTS

			lightMapIrradiance *= PI; // factor of PI should not be present; included here to prevent breakage

		#endif

		irradiance += lightMapIrradiance;

	#endif

	#if ( NUM_HEMI_LIGHTS > 0 )

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

			irradiance += getHemisphereLightIrradiance( hemisphereLights[ i ], geometry );

		}

	#endif

	#if defined( USE_ENVMAP ) && defined( PHYSICAL ) && defined( ENVMAP_TYPE_CUBE_UV )

		// TODO, replace 8 with the real maxMIPLevel
		irradiance += getLightProbeIndirectIrradiance( /*lightProbe,*/ geometry, 8 );

	#endif

	RE_IndirectDiffuse( irradiance, geometry, material, reflectedLight );

#endif

#if defined( USE_ENVMAP ) && defined( RE_IndirectSpecular )

	// TODO, replace 8 with the real maxMIPLevel
	vec3 radiance = getLightProbeIndirectRadiance( /*specularLightProbe,*/ geometry, Material_BlinnShininessExponent( material ), 8 );

	#ifndef STANDARD
		vec3 clearCoatRadiance = getLightProbeIndirectRadiance( /*specularLightProbe,*/ geometry, Material_ClearCoat_BlinnShininessExponent( material ), 8 );
	#else
		vec3 clearCoatRadiance = vec3( 0.0 );
	#endif

	RE_IndirectSpecular( radiance, clearCoatRadiance, geometry, material, reflectedLight );

#endif
