Add support for black and white Bump Maps to compute normals PR

src/materials/pathtracing/PhysicalPathTracingMaterial.js

@@ -112,10 +112,12 @@ export class PhysicalPathTracingMaterial extends MaterialBase {
 			vertexShader: /* glsl */`
 
 				varying vec2 vUv;
+				varying vec3 vViewPosition;
 				void main() {
 
 					vec4 mvPosition = vec4( position, 1.0 );
 					mvPosition = modelViewMatrix * mvPosition;
+					vViewPosition = - mvPosition.xyz;
 					gl_Position = projectionMatrix * mvPosition;
 
 					vUv = uv;
@@ -231,6 +233,7 @@ export class PhysicalPathTracingMaterial extends MaterialBase {
 				uniform float opacity;
 
 				varying vec2 vUv;
+				varying vec3 vViewPosition;
 
 				// globals
 				mat3 envRotation3x3;
@@ -445,7 +448,7 @@ export class PhysicalPathTracingMaterial extends MaterialBase {
 						if (
 							getSurfaceRecord(
 								material, surfaceHit, attributesArray, state.accumulatedRoughness,
-								surf
+								surf, vViewPosition
 							) == SKIP_SURFACE
 						) {
 

src/materials/pathtracing/glsl/get_surface_record_function.glsl.js

@@ -1,12 +1,23 @@
-
-export const get_surface_record_function = /* glsl */`
+export const get_surface_record_function = /* glsl */ `
 
 	#define SKIP_SURFACE 0
 	#define HIT_SURFACE 1
+	vec3 perturbNormalArb( vec3 surf_pos, vec3 surf_norm, vec2 dHdxy, float faceDirection ) {
+		// normalize is done to ensure that the bump map looks the same regardless of the texture's scale
+		vec3 vSigmaX = normalize( dFdx( surf_pos.xyz ) );
+		vec3 vSigmaY = normalize( dFdy( surf_pos.xyz ) );
+		vec3 vN = surf_norm; // normalized
+		vec3 R1 = cross( vSigmaY, vN );
+		vec3 R2 = cross( vN, vSigmaX );
+		float fDet = dot( vSigmaX, R1 ) * faceDirection;
+		vec3 vGrad = sign( fDet ) * ( dHdxy.x * R1 + dHdxy.y * R2 );
+		return normalize( abs( fDet ) * surf_norm - vGrad );
+	}
+
 	int getSurfaceRecord(
 		Material material, SurfaceHit surfaceHit, sampler2DArray attributesArray,
 		float accumulatedRoughness,
-		inout SurfaceRecord surf
+		inout SurfaceRecord surf, vec3 vViewPosition
 	) {
 
 		if ( material.fogVolume ) {
@@ -154,6 +165,38 @@ export const get_surface_record_function = /* glsl */`
 
 			}
 
+		} else if( material.bumpMap != -1) {
+
+			vec4 tangentSample = textureSampleBarycoord(
+				attributesArray,
+				ATTR_TANGENT,
+				surfaceHit.barycoord,
+				surfaceHit.faceIndices.xyz
+			);
+
+			// some provided tangents can be malformed (0, 0, 0) causing the normal to be degenerate
+			// resulting in NaNs and slow path tracing.
+			if ( length( tangentSample.xyz ) > 0.0 ) {
+
+				vec3 tangent = normalize( tangentSample.xyz );
+				vec3 bitangent = normalize( cross( normal, tangent ) * tangentSample.w );
+				mat3 vTBN = mat3( tangent, bitangent, normal );
+
+				vec3 uvPrime = material.bumpMapTransform * vec3( uv, 1 );
+				float bumpScale = material.bumpScale;
+
+				vec2 dSTdx = dFdx( uvPrime.xy );
+				vec2 dSTdy = dFdy( uvPrime.xy );
+
+				float Hll = bumpScale * texture2D( textures, vec3( uvPrime.xy, material.bumpMap ) ).x;
+				float dBx = bumpScale * texture2D( textures, vec3( uvPrime.xy + dSTdx, material.bumpMap ) ).x - Hll;
+				float dBy = bumpScale * texture2D( textures, vec3( uvPrime.xy + dSTdy, material.bumpMap ) ).x - Hll;
+
+				vec2 dHdxy = vec2( dBx, dBy );
+				normal += vTBN * perturbNormalArb( -vViewPosition, (normal * 2.0 - 1.0), dHdxy ,  1.0 );
+
+			}
+
 		}
 
 		normal *= surfaceHit.side;

src/shader/structs/material_struct.glsl.js

@@ -82,6 +82,10 @@ export const material_struct = /* glsl */ `
 		mat3 specularColorMapTransform;
 		mat3 specularIntensityMapTransform;
 
+		int bumpMap;
+		float bumpScale;
+		mat3 bumpMapTransform;
+
 	};
 
 	mat3 readTextureTransform( sampler2D tex, uint index ) {
@@ -101,7 +105,7 @@ export const material_struct = /* glsl */ `
 
 	Material readMaterialInfo( sampler2D tex, uint index ) {
 
-		uint i = index * 45u;
+		uint i = index * 48u;
 
 		vec4 s0 = texelFetch1D( tex, i + 0u );
 		vec4 s1 = texelFetch1D( tex, i + 1u );
@@ -201,6 +205,12 @@ export const material_struct = /* glsl */ `
 		m.specularColorMapTransform = m.specularColorMap == - 1 ? mat3( 1.0 ) : readTextureTransform( tex, firstTextureTransformIdx + 26u );
 		m.specularIntensityMapTransform = m.specularIntensityMap == - 1 ? mat3( 1.0 ) : readTextureTransform( tex, firstTextureTransformIdx + 28u );
 
+		vec4 s15 = texelFetch1D( tex, firstTextureTransformIdx + 30u );
+		m.bumpMap = int( round( s15.r ) );
+		m.bumpScale = s15.g;
+		// s15.b, s15.a are not used
+		m.bumpMapTransform = m.bumpMap == - 1 ? mat3( 1.0 ) : readTextureTransform( tex, firstTextureTransformIdx + 31u );
+
 		return m;
 
 	}

src/uniforms/MaterialsTexture.js

@@ -1,7 +1,7 @@
 import { DataTexture, RGBAFormat, ClampToEdgeWrapping, FloatType, FrontSide, BackSide, DoubleSide, NearestFilter } from 'three';
 import { reduceTexturesToUniqueSources, getTextureHash } from './utils.js';
 
-const MATERIAL_PIXELS = 45;
+const MATERIAL_PIXELS = 48;
 const MATERIAL_STRIDE = MATERIAL_PIXELS * 4;
 
 const MATTE_OFFSET = 14 * 4 + 0; // s14.r
@@ -457,6 +457,17 @@ export class MaterialsTexture extends DataTexture {
 			// specularIntensityMap transform 43
 			index += writeTextureMatrixToArray( m, 'specularIntensityMap', floatArray, index );
 
+			// sample 45
+			// bumpMap texture
+			floatArray[ index ++ ] = getTexture( m, 'bumpMap' );
+			// bumpScale
+			floatArray[ index ++ ] = getField( m, 'bumpScale', 1.0 );
+			// padding 2 index for alignment to 4
+			index ++;
+			index ++;
+			// bumpMap transform 46, 47
+			index += writeTextureMatrixToArray( m, 'bumpMap', floatArray, index );
+
 		}
 
 		this.needsUpdate = true;