validated all bsdfs against preexisting code. materials match except for cubemaps.

src/renderers/shaders/ShaderChunk/bsdfs.glsl

@@ -31,20 +31,14 @@ ReflectedLight BRDF_Add( const in ReflectedLight base, const in ReflectedLight o
 
 vec3 BRDF_Diffuse_Lambert( const in IncidentLight incidentLight, const in GeometricContext geometryContext, const in vec3 diffuseColor ) {
 
-	#if defined( ENERGY_PRESERVING_MONOCHROME ) || defined( ENERGY_PRESERVING_RGB )
+	// factor of 1/PI in BRDF omitted as incoming light intensity is scaled up by PI because it is considered a punctual light source
 
-		return diffuseColor * RECIPROCAL_PI;
+	return diffuseColor;
 
-	#else
-
-		return diffuseColor;
-
-	#endif
-
-}
+} // validated
 
 // this roughness is a different property than specular roughness used in GGX.
-vec3 BRDF_Diffuse_OrenNayar( const in IncidentLight incidentLight, const in GeometricContext geometryContext, const in vec3 diffuse, const in float roughness ) {
+vec3 BRDF_Diffuse_OrenNayar( const in IncidentLight incidentLight, const in GeometricContext geometryContext, const in vec3 diffuseColor, const in float roughness ) {
 
 	vec3 halfDir = normalize( incidentLight.direction + geometryContext.viewDir );
 	float dotVH = saturate( dot( geometryContext.viewDir, halfDir ) );
@@ -56,11 +50,11 @@ vec3 BRDF_Diffuse_OrenNayar( const in IncidentLight incidentLight, const in Geom
 	float Cosri = 2.0 * dotVH - 1.0 - dotNV * dotNL;
 	float termB = 0.45 * m2 / (m2 + 0.09) * Cosri * ( Cosri >= 0.0 ? min( 1.0, dotNL / dotNV ) : dotNL );
 
-	return diffuse * ( RECIPROCAL_PI * ( dotNL * termA + termB ) );
+	return diffuseColor * ( dotNL * termA + termB );
 
 }
 
-vec3 F_Schlick( const in vec3 F0, const in float dotLH ) {
+vec3 F_Schlick( const in vec3 specularColor, const in float dotLH ) {
 
 	// Original approximation by Christophe Schlick '94
 	//;float fresnel = pow( 1.0 - dotLH, 5.0 );
@@ -68,59 +62,72 @@ vec3 F_Schlick( const in vec3 F0, const in float dotLH ) {
 	// Optimized variant (presented by Epic at SIGGRAPH '13)
 	float fresnel = exp2( ( -5.55437 * dotLH - 6.98316 ) * dotLH );
 
-	return F0 + ( 1.0 - F0 ) * fresnel;
+	return ( 1.0 - specularColor ) * fresnel + specularColor;
 
-}
+} // validated
 
 // Microfacet Models for Refraction through Rough Surfaces - equation (34)
 // http://graphicrants.blogspot.com/2013/08/specular-brdf-reference.html
-// roughtness2 is "roughness squared" in Disney’s reparameterization
-float G_SmithSchlick( in float roughtness2, in float dotNL, in float dotNV ) {
+// alpha is "roughness squared" in Disney’s reparameterization
+float G_GGX_Smith( in float alpha, in float dotNL, in float dotNV ) {
+
+	// geometry term = G(l)⋅G(v) / 4(n⋅l)(n⋅v)
 
-	// geometry term = G(l) . G(v) / 4(n . l)(n. v)
+	float a2 = alpha * alpha;
 
-	float a2 = roughtness2 * roughtness2;
 	float gl = dotNL + pow( a2 + ( 1.0 - a2 ) * dotNL * dotNL, 0.5 );
+
 	float gv = dotNV + pow( a2 + ( 1.0 - a2 ) * dotNV * dotNV, 0.5 );
 
 	return 1.0 / ( gl * gv );
 
-}
+} // validated
 
-// useful for clear coat surfaces, use with Distribution_GGX.
-float G_Kelemen( float vDotH ) {
-
-	return 1.0 / ( 4.0 * vDotH * vDotH + 0.0000001 );
-
-}
 
 // Microfacet Models for Refraction through Rough Surfaces - equation (33)
 // http://graphicrants.blogspot.com/2013/08/specular-brdf-reference.html
-// roughtness2 is "roughness squared" in Disney’s reparameterization
-float D_GGX( in float roughtness2, in float dotNH ) {
+// alpha is "roughness squared" in Disney’s reparameterization
+float D_GGX( in float alpha, in float dotNH ) {
+
+	// factor of 1/PI in distribution term omitted as incoming light intensity is scaled up by PI because it is considered a punctual light source
+
+	float a2 = alpha * alpha;
 
-	// factor of 1/PI in distribution term omitted
-	float a2 = roughtness2 * roughtness2;
-	float denom = dotNH * dotNH * ( a2 - 1.0 ) + 1.0; // avoid roughtness2 = 0 with dotNH = 1
+	float denom = dotNH * dotNH * ( a2 - 1.0 ) + 1.0; // avoid alpha = 0 with dotNH = 1
 
 	return a2 / ( denom * denom );
 
 }
 
-vec3 BRDF_Specular_GGX( const in IncidentLight incidentLight, const in GeometricContext geometry, const in vec3 specularColor, const in float roughness2 ) {
+// GGX Distribution, Schlick Fresnel, GGX-Smith Visibility
+vec3 BRDF_Specular_GGX( const in IncidentLight incidentLight, const in GeometricContext geometry, const in vec3 specularColor, const in float roughness ) {
 	
+	// factor of 1/PI in BRDF omitted (normally it is in D_GGX) as incoming light intensity is scaled up by PI because it is considered a punctual light source
+
+	float alpha = roughness * roughness; // UE4's roughness
+
 	vec3 halfDir = normalize( incidentLight.direction + geometry.viewDir );
-	float dotNH = saturate( dot( geometry.normal, halfDir ) );
-	float dotLH = saturate( dot( incidentLight.direction, halfDir ) );
+
 	float dotNL = saturate( dot( geometry.normal, incidentLight.direction ) );
 	float dotNV = saturate( dot( geometry.normal, geometry.viewDir ) );
+	float dotNH = saturate( dot( geometry.normal, halfDir ) );
+	float dotLH = saturate( dot( incidentLight.direction, halfDir ) );
 
 	vec3 F = F_Schlick( specularColor, dotLH );
-	float G = G_SmithSchlick( roughness2, dotNL, dotNV );
-	float D = D_GGX( roughness2, dotNH );
+
+	float G = G_GGX_Smith( alpha, dotNL, dotNV );
+
+	float D = D_GGX( alpha, dotNH );
 
 	return F * ( G * D );
 
+} // validated
+
+// useful for clear coat surfaces, use with Distribution_GGX.
+float G_Kelemen( float vDotH ) {
+
+	return 1.0 / ( 4.0 * vDotH * vDotH + 0.0000001 );
+
 }
 
 #define DIELECTRIC_SPECULAR_F0 0.20
@@ -149,14 +156,18 @@ vec3 BRDF_Specular_GGX_Environment( const in IncidentLight incidentLight, const
 	float dotNV = saturate( dot( geometry.normal, geometry.viewDir ) );
 
 	const vec4 c0 = vec4( - 1, - 0.0275, - 0.572, 0.022 );
+
 	const vec4 c1 = vec4( 1, 0.0425, 1.04, - 0.04 );
+
 	vec4 r = roughness * c0 + c1;
+
 	float a004 = min( r.x * r.x, exp2( - 9.28 * dotNV ) ) * r.x + r.y;
+
 	vec2 AB = vec2( -1.04, 1.04 ) * a004 + r.zw;
 
 	return specularColor * AB.x + AB.y;
 
-}
+} // validated
 
 
 float G_BlinnPhong_Implicit( /* in float dotNL, in float dotNV */ ) {
@@ -168,21 +179,29 @@ float G_BlinnPhong_Implicit( /* in float dotNL, in float dotNV */ ) {
 
 float D_BlinnPhong( const in float shininess, const in float dotNH ) {
 
-	// factor of 1/PI in distribution term omitted ???
+	// factor of 1/PI in distribution term omitted as incoming light intensity is scaled up by PI because it is considered a punctual light source
+
 	return ( shininess * 0.5 + 1.0 ) * pow( dotNH, shininess );
 
 }
 
 vec3 BRDF_Specular_BlinnPhong( const in IncidentLight incidentLight, const in GeometricContext geometry, const in vec3 specularColor, const in float shininess ) {
 
+	// factor of 1/PI in BRDF omitted (normally it is in D_BlinnPhong) as incoming light intensity is scaled up by PI because it is considered a punctual light source
+
 	vec3 halfDir = normalize( incidentLight.direction + geometry.viewDir );
+
+	//float dotNL = saturate( dot( geometry.normal, incidentLight.direction ) );
+	//float dotNV = saturate( dot( geometry.normal, geometry.viewDir ) );
 	float dotNH = saturate( dot( geometry.normal, halfDir ) );
 	float dotLH = saturate( dot( incidentLight.direction, halfDir ) );
 
 	vec3 F = F_Schlick( specularColor, dotLH );
+
 	float G = G_BlinnPhong_Implicit( /* dotNL, dotNV */ );
+
 	float D = D_BlinnPhong( shininess, dotNH );
 
 	return F * ( G * D );
 
-}
+} // validated

src/renderers/shaders/ShaderChunk/lights_phong_pars_fragment.glsl

@@ -40,6 +40,6 @@ void BlinnPhongMaterial_RE_IndirectLight( const in IncidentLight indirectLight,
 
 }
 
-#define Material_RE_DiffuseIndirectLight    BlinnPhongMaterial_RE_IndirectLight
+#define Material_RE_IndirectDiffuseLight    BlinnPhongMaterial_RE_IndirectLight
 
 #define Material_LightProbeLOD( material )   (0)