Added stencil setup in UTSAPI;

Changed hair shadow length from screen space to world space;

Runtime/Shaders/Includes/Common/UtsCommon.hlsl

@@ -101,6 +101,20 @@ float SimpleNoise(float2 UV, float Scale)
     return t;
 }
 
+float Dither(float In, float4 positionSS)
+{
+    float2 uv = positionSS.xy;
+    float DITHER_THRESHOLDS[16] =
+    {
+        1.0 / 17.0, 9.0 / 17.0, 3.0 / 17.0, 11.0 / 17.0,
+        13.0 / 17.0, 5.0 / 17.0, 15.0 / 17.0, 7.0 / 17.0,
+        4.0 / 17.0, 12.0 / 17.0, 2.0 / 17.0, 10.0 / 17.0,
+        16.0 / 17.0, 8.0 / 17.0, 14.0 / 17.0, 6.0 / 17.0
+    };
+    uint index = (uint(uv.x) % 4) * 4 + uint(uv.y) % 4;
+    return In - DITHER_THRESHOLDS[index];
+}
+
 #define SampleRampSignalLine(texture, u) (SAMPLE_TEXTURE2D_LOD(texture, s_linear_clamp_sampler, float2(u, 0.5), 0))
 
 // Exposure