Add back hdri distortion (#2049)

Unity-Technologies · Sep 29, 2020 · cd7c840 · cd7c840
1 parent 9963ae2
commit cd7c840
Showing 1 changed file with 29 additions and 0 deletions.
diff --git a/com.unity.render-pipelines.high-definition/Runtime/Sky/HDRISky/HDRISky.shader b/com.unity.render-pipelines.high-definition/Runtime/Sky/HDRISky/HDRISky.shader
@@ -184,6 +184,35 @@ Shader "Hidden/HDRP/Sky/HDRISky"
 
     float3 GetSkyColor(float3 dir)
     {
+#if SKY_MOTION
+        if (dir.y >= 0 || !_UpperHemisphere)
+        {
+            float2 alpha = frac(float2(_ScrollFactor, _ScrollFactor + 0.5)) - 0.5;
+
+#ifdef USE_FLOWMAP
+            float3 tangent = normalize(cross(dir, float3(0.0, 1.0, 0.0)));
+            float3 bitangent = cross(tangent, dir);
+
+            float3 windDir = RotationUp(dir, _ScrollDirection);
+            float2 flow = SAMPLE_TEXTURE2D_LOD(_Flowmap, sampler_Flowmap, GetLatLongCoords(windDir, _UpperHemisphere), 0).rg * 2.0 - 1.0;
+
+            float3 dd = flow.x * tangent + flow.y * bitangent;
+#else
+            float3 windDir = RotationUp(float3(0, 0, 1), _ScrollDirection);
+            windDir.x *= -1.0;
+            float3 dd = windDir*sin(dir.y*PI*0.5);
+#endif
+
+            // Sample twice
+            float3 color1 = SAMPLE_TEXTURECUBE_LOD(_Cubemap, sampler_Cubemap, dir - alpha.x*dd, 0).rgb;
+            float3 color2 = SAMPLE_TEXTURECUBE_LOD(_Cubemap, sampler_Cubemap, dir - alpha.y*dd, 0).rgb;
+
+            // Blend color samples
+            return lerp(color1, color2, abs(2.0 * alpha.x));
+        }
+        else
+#endif
+
         return SAMPLE_TEXTURECUBE_LOD(_Cubemap, sampler_Cubemap, dir, 0).rgb;
     }