Merge pull request #15557 from horizon-games/features/fix-lambert-hemisphere-shadows

Improved Lambert shadowmaps + Hemisphere light

src/renderers/shaders/ShaderChunk/lights_lambert_vertex.glsl.js

@@ -12,9 +12,11 @@ backGeometry.normal = -geometry.normal;
 backGeometry.viewDir = geometry.viewDir;
 
 vLightFront = vec3( 0.0 );
+vIndirectFront = vec3( 0.0 );
 
 #ifdef DOUBLE_SIDED
 	vLightBack = vec3( 0.0 );
+	vIndirectBack = vec3( 0.0 );
 #endif
 
 IncidentLight directLight;
@@ -103,11 +105,11 @@ vec3 directLightColor_Diffuse;
 	#pragma unroll_loop
 	for ( int i = 0; i < NUM_HEMI_LIGHTS; i ++ ) {
 
-		vLightFront += getHemisphereLightIrradiance( hemisphereLights[ i ], geometry );
+		vIndirectFront += getHemisphereLightIrradiance( hemisphereLights[ i ], geometry );
 
 		#ifdef DOUBLE_SIDED
 
-			vLightBack += getHemisphereLightIrradiance( hemisphereLights[ i ], backGeometry );
+			vIndirectBack += getHemisphereLightIrradiance( hemisphereLights[ i ], backGeometry );
 
 		#endif
 

src/renderers/shaders/ShaderLib/meshlambert_frag.glsl.js

@@ -4,13 +4,14 @@ uniform vec3 emissive;
 uniform float opacity;
 
 varying vec3 vLightFront;
+varying vec3 vIndirectFront;
 
 #ifdef DOUBLE_SIDED
-
 	varying vec3 vLightBack;
-
+	varying vec3 vIndirectBack;
 #endif
 
+
 #include <common>
 #include <packing>
 #include <dithering_pars_fragment>
@@ -51,6 +52,16 @@ void main() {
 	// accumulation
 	reflectedLight.indirectDiffuse = getAmbientLightIrradiance( ambientLightColor );
 
+	#ifdef DOUBLE_SIDED
+
+		reflectedLight.indirectDiffuse += ( gl_FrontFacing ) ? vIndirectFront : vIndirectBack;
+
+	#else
+
+		reflectedLight.indirectDiffuse += vIndirectFront;
+
+	#endif
+
 	#include <lightmap_fragment>
 
 	reflectedLight.indirectDiffuse *= BRDF_Diffuse_Lambert( diffuseColor.rgb );
@@ -81,6 +92,5 @@ void main() {
 	#include <fog_fragment>
 	#include <premultiplied_alpha_fragment>
 	#include <dithering_fragment>
-
 }
 `;

src/renderers/shaders/ShaderLib/meshlambert_vert.glsl.js

@@ -2,11 +2,11 @@ export default /* glsl */`
 #define LAMBERT
 
 varying vec3 vLightFront;
+varying vec3 vIndirectFront;
 
 #ifdef DOUBLE_SIDED
-
 	varying vec3 vLightBack;
-
+	varying vec3 vIndirectBack;
 #endif
 
 #include <common>
@@ -47,6 +47,5 @@ void main() {
 	#include <lights_lambert_vertex>
 	#include <shadowmap_vertex>
 	#include <fog_vertex>
-
 }
 `;