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- import FunctionNode from '../core/FunctionNode.js';
- export const F_Schlick = new FunctionNode( `
- 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 );
- // Optimized variant (presented by Epic at SIGGRAPH '13)
- // https://cdn2.unrealengine.com/Resources/files/2013SiggraphPresentationsNotes-26915738.pdf
- float fresnel = exp2( ( -5.55473 * dotLH - 6.98316 ) * dotLH );
- return ( 1.0 - specularColor ) * fresnel + specularColor;
- }` ); // validated
- export const G_BlinnPhong_Implicit = new FunctionNode( `
- float G_BlinnPhong_Implicit() {
- // ( const in float dotNL, const in float dotNV )
- // geometry term is (n dot l)(n dot v) / 4(n dot l)(n dot v)
- return 0.25;
- }` ); // validated
- export const D_BlinnPhong = new FunctionNode( `
- float D_BlinnPhong( const in float shininess, const in float dotNH ) {
- return RECIPROCAL_PI * ( shininess * 0.5 + 1.0 ) * pow( dotNH, shininess );
- }` ); // validated
- export const BRDF_Diffuse_Lambert = new FunctionNode( `
- vec3 BRDF_Diffuse_Lambert( const in vec3 diffuseColor ) {
- return RECIPROCAL_PI * diffuseColor;
- }` ); // validated
- export const BRDF_Specular_BlinnPhong = new FunctionNode( `
- vec3 BRDF_Specular_BlinnPhong( vec3 lightDirection, vec3 specularColor, float shininess ) {
- vec3 halfDir = normalize( lightDirection + PositionViewDirection );
- //float dotNL = saturate( dot( NormalView, lightDirection ) );
- //float dotNV = saturate( dot( NormalView, PositionViewDirection ) );
- float dotNH = saturate( dot( NormalView, halfDir ) );
- float dotLH = saturate( dot( lightDirection, halfDir ) );
- vec3 F = F_Schlick( specularColor, dotLH );
- float G = G_BlinnPhong_Implicit( /* dotNL, dotNV */ );
- float D = D_BlinnPhong( shininess, dotNH );
- return F * ( G * D );
- }` ).setIncludes( [ F_Schlick, G_BlinnPhong_Implicit, D_BlinnPhong ] ); // validated
- export const punctualLightIntensityToIrradianceFactor = new FunctionNode( `
- float punctualLightIntensityToIrradianceFactor( float lightDistance, float cutoffDistance, float decayExponent ) {
- #if defined ( PHYSICALLY_CORRECT_LIGHTS )
- // based upon Frostbite 3 Moving to Physically-based Rendering
- // page 32, equation 26: E[window1]
- // https://seblagarde.files.wordpress.com/2015/07/course_notes_moving_frostbite_to_pbr_v32.pdf
- // this is intended to be used on spot and point lights who are represented as luminous intensity
- // but who must be converted to luminous irradiance for surface lighting calculation
- float distanceFalloff = 1.0 / max( pow( lightDistance, decayExponent ), 0.01 );
- if( cutoffDistance > 0.0 ) {
- distanceFalloff *= pow2( saturate( 1.0 - pow4( lightDistance / cutoffDistance ) ) );
- }
- return distanceFalloff;
- #else
- if( cutoffDistance > 0.0 && decayExponent > 0.0 ) {
- return pow( saturate( -lightDistance / cutoffDistance + 1.0 ), decayExponent );
- }
- return 1.0;
- #endif
- }` );
- export const RE_Direct_BlinnPhong = new FunctionNode( `
- void RE_Direct_BlinnPhong( vec3 lightDirection, vec3 lightColor ) {
- float dotNL = saturate( dot( NormalView, lightDirection ) );
- vec3 irradiance = dotNL * lightColor;
- #ifndef PHYSICALLY_CORRECT_LIGHTS
- irradiance *= PI; // punctual light
- #endif
- ReflectedLightDirectDiffuse += irradiance * BRDF_Diffuse_Lambert( MaterialDiffuseColor.rgb );
- ReflectedLightDirectSpecular += irradiance * BRDF_Specular_BlinnPhong( lightDirection, MaterialSpecularColor, MaterialSpecularShininess );
- }` ).setIncludes( [ BRDF_Diffuse_Lambert, BRDF_Specular_BlinnPhong ] );
- export const RE_IndirectDiffuse_BlinnPhong = new FunctionNode( `
- void RE_IndirectDiffuse_BlinnPhong( ) {
- ReflectedLightIndirectDiffuse += Irradiance * BRDF_Diffuse_Lambert( MaterialDiffuseColor.rgb );
- }` ).setIncludes( [ BRDF_Diffuse_Lambert ] );
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