HDRenderPipeline: factor IBL weight function in lightloop

Assets/ScriptableRenderPipeline/HDRenderPipeline/Lighting/TilePass/TilePassLoop.hlsl

 
 #endif // LIGHTLOOP_TILE_PASS
 
+void applyWeigthedIblLighting(float3 localDiffuseLighting, float3 localSpecularLighting, float2 weight, inout float3 iblDiffuseLighting, inout float3 iblSpecularLighting, inout float totalIblWeight)
+{
+    // IBL weights should not exceed 1.
+    float accumulatedWeight = totalIblWeight + weight.y;
+    totalIblWeight = saturate(accumulatedWeight);
+    weight.y -= saturate(accumulatedWeight - totalIblWeight);
+
+    // TODO: We do'nt use ibl diffuse lighting currently, let here in case users want to use it.
+    // iblDiffuseLighting = lerp(iblDiffuseLighting, localDiffuseLighting, weight.x);
+    iblSpecularLighting = lerp(iblSpecularLighting, localSpecularLighting, weight.y);
+}
+
 // bakeDiffuseLighting is part of the prototype so a user is able to implement a "base pass" with GI and multipass direct light (aka old unity rendering path)
 void LightLoop( float3 V, PositionInputs posInput, PreLightData prelightData, BSDFData bsdfData, float3 bakeDiffuseLighting, uint featureFlags,
                 out float3 diffuseLighting,
 
     if (featureFlags & LIGHTFEATUREFLAGS_DIRECTIONAL)
     {
-        for(i = 0; i < _DirectionalLightCount; ++i)
+        for (i = 0; i < _DirectionalLightCount; ++i)
         {
             float3 localDiffuseLighting, localSpecularLighting;
 
         uint punctualLightCount;
         GetCountAndStart(posInput, LIGHTCATEGORY_PUNCTUAL, punctualLightStart, punctualLightCount);
 
-        for(i = 0; i < punctualLightCount; ++i)
+        for (i = 0; i < punctualLightCount; ++i)
         {
             float3 localDiffuseLighting, localSpecularLighting;
 
 
     if (featureFlags & LIGHTFEATUREFLAGS_AREA)
     {
+        float3 localDiffuseLighting, localSpecularLighting;
+
-
-        float3 localDiffuseLighting = float3(0.0, 0.0, 0.0);
-        float3 localSpecularLighting = float3(0.0, 0.0, 0.0);
 
         // COMPILER BEHAVIOR WARNING!
         // If rectangle lights are before line lights, the compiler will duplicate light matrices in VGPR because they are used differently between the two types of lights.
                 lightType = i < areaLightCount ? _LightDatas[areaIndex].lightType : 0xFF;
             }
 
-            while (i < areaLightCount /* && lightType == GPULIGHTTYPE_RECT */) // Rectangle lights are the last area lights so no need to check type (for now)
+            while (i < areaLightCount && lightType == GPULIGHTTYPE_RECTANGLE)
             {
                 EvaluateBSDF_Area(  context, V, posInput, prelightData, _LightDatas[areaIndex], bsdfData, GPULIGHTTYPE_RECTANGLE,
                                     localDiffuseLighting, localSpecularLighting);
 
                 i++;
                 areaIndex = i < areaLightCount ? FetchIndex(areaLightStart, i) : 0;
-               // lightType = i < areaLightCount ? _LightDatas[areaIndex].lightType : 0xFF;
+                lightType = i < areaLightCount ? _LightDatas[areaIndex].lightType : 0xFF;
-        for (; i < _PunctualLightCount + _AreaLightCount; ++i)
+        for (i = _PunctualLightCount; i < _PunctualLightCount + _AreaLightCount; ++i)
-            float3 localDiffuseLighting, localSpecularLighting;
-
             EvaluateBSDF_Area(  context, V, posInput, prelightData, _LightDatas[i], bsdfData, _LightDatas[i].lightType,
                                 localDiffuseLighting, localSpecularLighting);
 
 
     float3 iblDiffuseLighting  = float3(0.0, 0.0, 0.0);
     float3 iblSpecularLighting = float3(0.0, 0.0, 0.0);
-    float  totalIblWeight      = 0; // Max: 1
+    float  totalIblWeight      = 0.0; // Max: 1
-    if(featureFlags & LIGHTFEATUREFLAGS_ENV)
+    if (featureFlags & LIGHTFEATUREFLAGS_ENV)
+        float3 localDiffuseLighting, localSpecularLighting;
+        float2 weight;
+        context.sampleReflection = SINGLE_PASS_CONTEXT_SAMPLE_REFLECTION_PROBES;
+
     #ifdef LIGHTLOOP_TILE_PASS
         uint envLightStart;
         uint envLightCount;
     #endif
 
-        for(i = 0; i < envLightCount && totalIblWeight < 1.0; ++i)
+        // Note: In case of IBL we are sorted from smaller to bigger projected solid angle bounds. We are not sorted by type so we can't do a 'while' approach like for area light.
+        for (i = 0; i < envLightCount && totalIblWeight < 1.0; ++i)
         {
         #ifdef LIGHTLOOP_TILE_PASS
             uint envLightIndex = FetchIndex(envLightStart, i);
-            float3 localDiffuseLighting, localSpecularLighting;
-            float2 weight;
-
-            context.sampleReflection = SINGLE_PASS_CONTEXT_SAMPLE_REFLECTION_PROBES;
-
-            // IBL weights should not exceed 1.
-            float accumulatedWeight = totalIblWeight + weight.y;
-            totalIblWeight          = saturate(accumulatedWeight);
-            weight.y               -= saturate(accumulatedWeight - totalIblWeight);
-
-            iblDiffuseLighting = lerp(iblDiffuseLighting, localDiffuseLighting, weight.x); // Should be remove by the compiler if it is smart as all is constant 0
-            iblSpecularLighting = lerp(iblSpecularLighting, localSpecularLighting, weight.y);
+            applyWeigthedIblLighting(localDiffuseLighting, localSpecularLighting, weight, iblDiffuseLighting, iblSpecularLighting, totalIblWeight);
-    if(featureFlags & LIGHTFEATUREFLAGS_SKY)
+    if (featureFlags & LIGHTFEATUREFLAGS_SKY)
-        if(_EnvLightSkyEnabled && totalIblWeight < 1.0)
+        if (_EnvLightSkyEnabled && totalIblWeight < 1.0)
         {
             float3 localDiffuseLighting, localSpecularLighting;
             float2 weight;
             EnvLightData envLightSky = InitSkyEnvLightData(0); // The sky data are generated on the fly so the compiler can optimize the code
             EvaluateBSDF_Env(context, V, posInput, prelightData, envLightSky, bsdfData, localDiffuseLighting, localSpecularLighting, weight);
-
-            // IBL weights should not exceed 1.
-            float accumulatedWeight = totalIblWeight + weight.y;
-            totalIblWeight          = 1.0;
-            weight.y               -= saturate(accumulatedWeight - totalIblWeight);
-
-            iblDiffuseLighting = lerp(iblDiffuseLighting, localDiffuseLighting, weight.x); // Should be remove by the compiler if it is smart as all is constant 0
-            iblSpecularLighting = lerp(iblSpecularLighting, localSpecularLighting, weight.y);
+            applyWeigthedIblLighting(localDiffuseLighting, localSpecularLighting, weight, iblDiffuseLighting, iblSpecularLighting, totalIblWeight);
         }
     }