Fixed a bug where main layer influence would show up even if the main layer blend mask was zero.

ScriptableRenderPipeline/HDRenderPipeline/Material/Lit/LitData.hlsl

     #ifdef SURFACE_GRADIENT
     return normalTS + influenceFactor * mainNormalTS * inputMainLayerMask;
     #else
-    return lerp(normalTS, BlendNormalRNM(normalTS, mainNormalTS), influenceFactor * inputMainLayerMask);
+    return lerp(normalTS, BlendNormalRNM(normalTS, mainNormalTS), influenceFactor * inputMainLayerMask); // Multiply by inputMainLayerMask in order to avoid influence where main layer should never be present
-float3 ComputeMainBaseColorInfluence(float influenceMask, float3 baseColor0, float3 baseColor1, float3 baseColor2, float3 baseColor3, LayerTexCoord layerTexCoord, float weights[_MAX_LAYER])
+float3 ComputeMainBaseColorInfluence(float influenceMask, float3 baseColor0, float3 baseColor1, float3 baseColor2, float3 baseColor3, LayerTexCoord layerTexCoord, float inputMainLayerMask, float weights[_MAX_LAYER])
-    float influenceFactor = BlendLayeredScalar(0.0, _InheritBaseColor1, _InheritBaseColor2, _InheritBaseColor3, weights) * influenceMask;
+    float influenceFactor = BlendLayeredScalar(0.0, _InheritBaseColor1, _InheritBaseColor2, _InheritBaseColor3, weights) * influenceMask * inputMainLayerMask; // Multiply by inputMainLayerMask in order to avoid influence where main layer should never be present
 
     // We want to calculate the mean color of the texture. For this we will sample a low mipmap
     float textureBias = 15.0; // Use maximum bias
 #if defined(_MAIN_LAYER_INFLUENCE_MODE)
     if (influenceMask > 0.0f)
     {
-        surfaceData.baseColor = ComputeMainBaseColorInfluence(influenceMask, surfaceData0.baseColor, surfaceData1.baseColor, surfaceData2.baseColor, surfaceData3.baseColor, layerTexCoord, weights);
+        surfaceData.baseColor = ComputeMainBaseColorInfluence(influenceMask, surfaceData0.baseColor, surfaceData1.baseColor, surfaceData2.baseColor, surfaceData3.baseColor, layerTexCoord, blendMasks.a, weights);
         normalTS = ComputeMainNormalInfluence(influenceMask, input, normalTS0, normalTS1, normalTS2, normalTS3, layerTexCoord, blendMasks.a, weights);
     }
     else