Merge pull request #536 from gkjohnson/fresnel-fix

revert some fresnel changes

Author: gkjohnson

src/shader/bsdf/bsdfSampling.glsl.js

@@ -94,8 +94,10 @@ export const bsdfSamplingGLSL = /* glsl */`
 
 		// TODO: subsurface approx?
 
-		float F = evaluateFresnelWeight( dot( wo, wh ), surf.eta, surf.f0 );
+		// float F = evaluateFresnelWeight( dot( wo, wh ), surf.eta, surf.f0 );
+		float F = disneyFresnel( wo, wi, wh, surf.f0, surf.eta, surf.metalness );
 		color = ( 1.0 - F ) * transFactor * metalFactor * wi.z * surf.color * ( retro + lambert ) / PI;
+
 		return wi.z / PI;
 
 	}
@@ -206,7 +208,8 @@ export const bsdfSamplingGLSL = /* glsl */`
 		color = surf.transmission * surf.color;
 
 		// PDF
-		float F = evaluateFresnelWeight( dot( wo, wh ), surf.eta, surf.f0 );
+		// float F = evaluateFresnelWeight( dot( wo, wh ), surf.eta, surf.f0 );
+		float F = disneyFresnel( wo, wi, wh, surf.f0, surf.eta, surf.metalness );
 		if ( F >= 1.0 ) {
 
 			return 0.0;
@@ -297,7 +300,8 @@ export const bsdfSamplingGLSL = /* glsl */`
 
 		float metalness = surf.metalness;
 		float transmission = surf.transmission;
-		float fEstimate = evaluateFresnelWeight( dot( wo, wh ), surf.eta, surf.f0 );
+		// float fEstimate = evaluateFresnelWeight( dot( wo, wh ), surf.eta, surf.f0 );
+		float fEstimate = disneyFresnel( wo, wi, wh, surf.f0, surf.eta, surf.metalness );
 
 		float transSpecularProb = mix( max( 0.25, fEstimate ), 1.0, metalness );
 		float diffSpecularProb = 0.5 + 0.5 * metalness;

src/shader/common/fresnel.glsl.js

@@ -69,30 +69,36 @@ export const fresnelGLSL = /* glsl */`
 
 	}
 
-	float evaluateFresnelWeight( float cosTheta, float eta, float f0 ) {
+	// TODO: disney fresnel was removed and replaced with this fresnel function to better align with
+	// the glTF but is causing blown out pixels. Should be revisited
+	// float evaluateFresnelWeight( float cosTheta, float eta, float f0 ) {
 
-		if ( totalInternalReflection( cosTheta, eta ) ) {
+	// 	if ( totalInternalReflection( cosTheta, eta ) ) {
 
-			return 1.0;
+	// 		return 1.0;
 
-		}
+	// 	}
 
-		return schlickFresnel( cosTheta, f0 );
+	// 	return schlickFresnel( cosTheta, f0 );
 
-	}
+	// }
 
-	/*
 	// https://schuttejoe.github.io/post/disneybsdf/
 	float disneyFresnel( vec3 wo, vec3 wi, vec3 wh, float f0, float eta, float metalness ) {
 
 		float dotHV = dot( wo, wh );
-		float dotHL = dot( wi, wh );
+		if ( totalInternalReflection( dotHV, eta ) ) {
 
+			return 1.0;
+
+		}
+
+		float dotHL = dot( wi, wh );
 		float dielectricFresnel = dielectricFresnel( abs( dotHV ), eta );
 		float metallicFresnel = schlickFresnel( dotHL, f0 );
 
 		return mix( dielectricFresnel, metallicFresnel, metalness );
 
 	}
-	*/
+
 `;