Area Light snippet.js

		"#if MAX_AREA_LIGHTS > 0",

			"for( int i = 0; i < MAX_AREA_LIGHTS; i ++ ) {",

				"vec3 lPosition = ( viewMatrix * vec4( areaLightPosition[ i ], 1.0 ) ).xyz;",
				//"vec3 lVector = lPosition.xyz + vViewPosition.xyz;",

				"vec3 width = areaLightWidth[ i ];",
				"vec3 height = areaLightHeight[ i ];",
				"vec3 up = normalize( ( viewMatrix * vec4( height, 0.0 ) ).xyz );",
				"vec3 right = normalize( ( viewMatrix * vec4( width, 0.0 ) ).xyz );",
				"vec3 pnormal = normalize( cross( right, up ) );",

				"float widthScalar = length( width );",
				"float heightScalar = length( height );",

				//project onto plane and calculate direction from center to the projection.
				"vec3 projection = projectOnPlane( -vViewPosition.xyz, lPosition, pnormal );",  // projection in plane
				"vec3 dir = projection - lPosition;",

				//calculate distance from area:
				"vec2 diagonal = vec2( dot( dir, right ), dot( dir, up ) );",
				"vec2 nearest2D = vec2( clamp( diagonal.x, -widthScalar, widthScalar ), clamp( diagonal.y, -heightScalar, heightScalar ) );",
				"vec3 nearestPointInside = lPosition + ( right *nearest2D.x + up * nearest2D.y );",

				"vec3 lVector = ( nearestPointInside + vViewPosition.xyz );",
				"float distanceAttenuation = calcLightAttenuation( length( lVector ), areaLightDistance[ i ], areaLightDecayExponent[i] );",
				"lVector = normalize( lVector );",

				"vec3 incidentLight = areaLightColor[ i ] * distanceAttenuation * 0.01;", // the 0.01 is the area light intensity scaling.

				"float nDotLDiffuse = saturate( dot( normal, lVector ) );",

		   		"vec3 diff = Diffuse_Lambert() * diffuseColor * widthScalar * heightScalar;",

				"vec3 viewReflection = reflect( viewDirection.xyz, normal );",
				"vec3 reflectionLightPlaneIntersection = linePlaneIntersect( -vViewPosition.xyz, viewReflection, lPosition, pnormal );",

				"float specAngle = dot( viewReflection, pnormal );",

				// && dot( -vViewPosition.xyz - areaLightPosition[ i ], -pnormal ) >= 0.0 
				"if ( specAngle < 0.0 ) {",

					"vec3 dirSpec = reflectionLightPlaneIntersection - lPosition;",
					"vec2 dirSpec2D = vec2( dot( dirSpec, right ), dot( dirSpec, up ) );",
					"vec2 nearestSpec2D = vec2( clamp( dirSpec2D.x, -widthScalar, widthScalar ), clamp( dirSpec2D.y, -heightScalar, heightScalar ) );",
					"lVector = normalize( lPosition + ( right *nearestSpec2D.x + up * nearestSpec2D.y ) + vViewPosition.xyz );",

				"} else { ",

					"lVector = vec3( 0 );",

				"}",

				"vec3 hVector = normalize( viewDirection.xyz + lVector.xyz );",
				"float nDotH = saturate( dot( normal, hVector ) );",
				"float nDotL = saturate( dot( normal, lVector ) );",
				"float hDotV = saturate( dot( hVector, viewDirection ) );",