Normal mapping - Flip normal direction for backfaces

Author: knightcrawler25

src/shaders/common/closest_hit.glsl

@@ -241,7 +241,7 @@ bool ClosestHit(Ray r, inout State state, inout LightSampleRec lightSampleRec)
         vec3 normal = normalize(n0.xyz * bary.x + n1.xyz * bary.y + n2.xyz * bary.z);
 
         state.normal = normalize(transpose(inverse(mat3(transform))) * normal);
-        state.ffnormal = dot(state.normal, r.direction) <= 0.0 ? state.normal : state.normal * -1.0;
+        state.ffnormal = dot(state.normal, r.direction) <= 0.0 ? state.normal : -state.normal;
 
         // Calculate tangent and bitangent
         vec3 deltaPos1 = vert1.xyz - vert0.xyz;

src/shaders/common/pathtrace.glsl

@@ -80,8 +80,9 @@ void GetMaterials(inout State state, in Ray r)
         vec3 texNormal = texture(textureMapsArrayTex, vec3(texUV, texIDs.z)).rgb;
         texNormal = normalize(texNormal * 2.0 - 1.0);
 
-        state.normal = normalize(state.tangent * texNormal.x + state.bitangent * texNormal.y + state.ffnormal * texNormal.z);
-        state.ffnormal = normalize(state.normal);
+        vec3 origNormal = state.normal;
+        state.normal = normalize(state.tangent * texNormal.x + state.bitangent * texNormal.y + state.normal * texNormal.z);
+        state.ffnormal = dot(origNormal, r.direction) <= 0.0 ? state.normal : -state.normal;
     }
 
     // Emission Map