Clean up Common.hlsl

ScriptableRenderPipeline/Core/ShaderLibrary/Common.hlsl

     return (x < 1.0) ? poly : HALF_PI - poly;
 }
 
+// TODO: this intrinsic is unavailable outside compute. This is a Unity shader compiler bug.
+#if (SHADER_TARGET >= 50) && (SHADER_STAGE_COMPUTE != 0)
+uint FastLog2(uint x)
+{
+    return firstbithigh(x) – 1u;
+}
+#endif
+
 // 4 VGPR, 16 FR (12 FR, 1 QR), 2 scalar
 // input [-infinity, infinity] and output [-PI/2, PI/2]
 float FastATan(float x)
 }
-
-// Same as smoothstep except it assume 0, 1 interval for x
-float Smoothstep01(float x)
-{
-    return x * x * (3.0 - (2.0 * x));
-}
-
-static const float3x3 k_identity3x3 = {1.0, 0.0, 0.0,
-                                       0.0, 1.0, 0.0,
-                                       0.0, 0.0, 1.0};
-
-static const float4x4 k_identity4x4 = {1.0, 0.0, 0.0, 0.0,
-                                       0.0, 1.0, 0.0, 0.0,
-                                       0.0, 0.0, 1.0, 0.0,
-                                       0.0, 0.0, 0.0, 1.0};
 
 // Using pow often result to a warning like this
 // "pow(f, e) will not work for negative f, use abs(f) or conditionally handle negative values if you expect them"
 float3 Orthonormalize(float3 tangent, float3 normal)
 {
     return normalize(tangent - dot(tangent, normal) * normal);
+}
+
+// Same as smoothstep except it assume 0, 1 interval for x
+float Smoothstep01(float x)
+{
+    return x * x * (3.0 - (2.0 * x));
 }
 
 // ----------------------------------------------------------------------------
 // ----------------------------------------------------------------------------
 // Space transformations
 // ----------------------------------------------------------------------------
+
+static const float3x3 k_identity3x3 = {1, 0, 0,
+                                       0, 1, 0,
+                                       0, 0, 1};
+
+static const float4x4 k_identity4x4 = {1, 0, 0, 0,
+                                       0, 1, 0, 0,
+                                       0, 0, 1, 0,
+                                       0, 0, 0, 1};
 
 // Use case examples:
 // (position = positionCS) => (clipSpaceTransform = use default)

ScriptableRenderPipeline/Core/ShaderLibrary/Hammersley.hlsl

 // Ref: http://holger.dammertz.org/stuff/notes_HammersleyOnHemisphere.html
 uint ReverseBits32(uint bits)
 {
-#if 1 // Shader model 5
+// TODO: this intrinsic is unavailable outside compute. This is a Unity shader compiler bug.
+#if (SHADER_TARGET >= 50) && (SHADER_STAGE_COMPUTE != 0)
     return reversebits(bits);
 #else
     bits = (bits << 16) | (bits >> 16);