HDRenderLoop: use a envLightSky structure to feed sky information

Assets/ScriptableRenderLoop/HDRenderLoop/HDRenderLoop.asset.meta

 fileFormatVersion: 2
 guid: 2400b74f5ce370c4481e5dc417d03703
-timeCreated: 1480265826
+timeCreated: 1480436907
 licenseType: Pro
 NativeFormatImporter:
   userData: 

Assets/ScriptableRenderLoop/HDRenderLoop/Lighting/LightUtilities.hlsl

 #ifndef UNITY_LIGHT_UTILITIES_INCLUDED
 #define UNITY_LIGHT_UTILITIES_INCLUDED
 
+#include "LightDefinition.cs.hlsl"
+
-void InitSkyEnvLightData(int index)
+EnvLightData InitSkyEnvLightData(int envIndex)
-    _EnvLightSky.envShapeType  = ENVSHAPETYPE_SKY;
-    _EnvLightSky.envIndex      = index;
-    _EnvLightSky.forward       = float3(0.0, 0.0, 1.0);
-    _EnvLightSky.up            = float3(0.0, 1.0, 0.0);
-    _EnvLightSky.right         = float3(1.0, 0.0, 0.0);
-    _EnvLightSky.positionWS    = float3(0.0, 0.0, 0.0);
-    _EnvLightSky.offsetLS      = float3(0.0, 0.0, 0.0);
-    _EnvLightSky.innerDistance = float3(0.0, 0.0, 0.0);
-    _EnvLightSky.blendDistance = 1.0;
+    EnvLightData output;
+    output.envShapeType  = ENVSHAPETYPE_SKY;
+    output.envIndex      = envIndex;
+    output.forward       = float3(0.0, 0.0, 1.0);
+    output.up            = float3(0.0, 1.0, 0.0);
+    output.right         = float3(1.0, 0.0, 0.0);
+    output.positionWS    = float3(0.0, 0.0, 0.0);
+    output.offsetLS      = float3(0.0, 0.0, 0.0);
+    output.innerDistance = float3(0.0, 0.0, 0.0);
+    output.blendDistance = 1.0;
+
+    return output;
-#endif // UNITY_LIGHT_UTILITIES_INCLUDED
+#endif // UNITY_LIGHT_UTILITIES_INCLUDED

Assets/ScriptableRenderLoop/HDRenderLoop/Lighting/SinglePass/SinglePass.hlsl

     uint _PunctualLightCount;
     uint _AreaLightCount;
     uint _EnvLightCount;
-    EnvLightData _EnvLightSky;
 	float4 _ShadowMapSize;
     float4 _DirShadowSplitSpheres[4]; // TODO share this max between C# and hlsl
 CBUFFER_END

Assets/ScriptableRenderLoop/HDRenderLoop/Lighting/SinglePass/SinglePassLoop.hlsl

         float3 localDiffuseLighting, localSpecularLighting;
         float2 weight;
         context.sampleReflection = SINGLE_PASS_CONTEXT_SAMPLE_SKY;
-        InitSkyEnvLightData(0);
-        EvaluateBSDF_Env(context, V, positionWS, prelightData, _EnvLightSky, bsdfData, localDiffuseLighting, localSpecularLighting, weight);
+        EnvLightData envLightSky = InitSkyEnvLightData(0);
+        EvaluateBSDF_Env(context, V, positionWS, prelightData, envLightSky, bsdfData, localDiffuseLighting, localSpecularLighting, weight);
         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);
     }