Fix applying AO twice for lighting in Forward shading and use correct specular occlusion on reflections

#3717

Content/Editor/MaterialTemplates/Features/ForwardShading.hlsl

@@ -142,11 +142,11 @@ void PS_Forward(
 #endif
 #endif
 
-	light.rgb += reflections * GetReflectionSpecularLighting(ViewPos, gBuffer) * light.a;	
+	light.rgb += reflections * GetReflectionSpecularLighting(ViewPos, gBuffer) * light.a;
 #endif
 
-	// Add lighting (apply ambient occlusion)
-	output.rgb += light.rgb * gBuffer.AO;
+	// Add lighting
+	output.rgb += light.rgb;
 
 #endif
 

Source/Shaders/Reflections.shader

@@ -79,7 +79,7 @@ float4 PS_CombinePass(Quad_VS2PS input) : SV_Target0
 	// Calculate specular color
 	float3 specularColor = GetSpecularColor(gBuffer);
 
-	// Calculate reflecion color
+	// Calculate reflection color
 	float3 V = normalize(gBufferData.ViewPos - gBuffer.WorldPos);
 	float NoV = saturate(dot(gBuffer.Normal, V));
 	reflections *= EnvBRDF(PreIntegratedGF, specularColor, gBuffer.Roughness, NoV);

Source/Shaders/ReflectionsCommon.hlsl

@@ -48,10 +48,17 @@ float4 SampleReflectionProbe(float3 viewPos, TextureCube probe, ProbeData data,
 // Calculates the reflective environment lighting to multiply the raw reflection color for the specular light (eg. from Env Probe or SSR).
 float3 GetReflectionSpecularLighting(float3 viewPos, GBufferSample gBuffer)
 {
+	// Calculate reflection color
     float3 specularColor = GetSpecularColor(gBuffer);
     float3 V = normalize(viewPos - gBuffer.WorldPos);
     float NoV = saturate(dot(gBuffer.Normal, V));
-    return EnvBRDFApprox(specularColor, gBuffer.Roughness, NoV);
+    float3 reflections = EnvBRDFApprox(specularColor, gBuffer.Roughness, NoV);
+    
+	// Apply specular occlusion
+	float roughnessSq = gBuffer.Roughness * gBuffer.Roughness;
+	reflections *= GetSpecularOcclusion(NoV, roughnessSq, gBuffer.AO);
+
+    return reflections;
 }
 
 #endif