Fix orthographic camera detection

Assets/ScriptableRenderPipeline/HDRenderPipeline/ShaderVariables.hlsl

 
 float3 GetCurrentCameraPosition()
 {
-#if SHADERPASS != SHADERPASS_DEPTH_ONLY
+#if defined(SHADERPASS) && (SHADERPASS != SHADERPASS_DEPTH_ONLY)
     return _WorldSpaceCameraPos;
 #else
     // TEMP: this is rather expensive. Then again, we need '_WorldSpaceCameraPos'
     return -viewMat[2].xyz;
 }
 
-// Computes the world space view direction (pointing towards the camera).
-float3 GetWorldSpaceNormalizeViewDir(float3 positionWS)
+// Returns 'true' if the current camera performs a perspective projection.
+bool IsPerspectiveCamera()
-#if SHADERPASS != SHADERPASS_DEPTH_ONLY
-    if (unity_OrthoParams.w == 0)
+#if defined(SHADERPASS) && (SHADERPASS != SHADERPASS_DEPTH_ONLY)
+    return (unity_OrthoParams.w == 0);
-    if (GetWorldToHClipMatrix()[3].x != 0 &&
-        GetWorldToHClipMatrix()[3].y != 0 &&
-        GetWorldToHClipMatrix()[3].z != 0 &&
-        GetWorldToHClipMatrix()[3].w != 1)
+    return (GetWorldToHClipMatrix()[3].x != 0 ||
+            GetWorldToHClipMatrix()[3].y != 0 ||
+            GetWorldToHClipMatrix()[3].z != 0 ||
+            GetWorldToHClipMatrix()[3].w != 1);
+}
+
+// Computes the world space view direction (pointing towards the camera).
+float3 GetWorldSpaceNormalizeViewDir(float3 positionWS)
+{
+    if (IsPerspectiveCamera())
     {
         // Perspective
         float3 V = GetCurrentCameraPosition() - positionWS;