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Assets/Alloy/Shaders/Feature/DirectionalBlend.cginc

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+// Alloy Physical Shader Framework
+// Copyright 2013-2017 RUST LLC.
+// http://www.alloy.rustltd.com/
+
+/////////////////////////////////////////////////////////////////////////////////
+/// @file DirectionalBlend.cginc
+/// @brief Allows blending based how much a normal faces a given direction.
+/////////////////////////////////////////////////////////////////////////////////
+
+#ifndef ALLOY_SHADERS_FEATURE_DIRECTIONAL_BLEND_CGINC
+#define ALLOY_SHADERS_FEATURE_DIRECTIONAL_BLEND_CGINC
+
+#ifdef A_DIRECTIONAL_BLEND_ON
+    #ifndef _DIRECTIONALBLENDMODE_WORLD
+        #ifdef A_DIRECTIONAL_BLEND_MODE_OFF
+            #define _DIRECTIONALBLENDMODE_WORLD
+        #else
+            #define A_WORLD_TO_OBJECT_ON
+        #endif
+    #endif
+
+    #ifndef A_NORMAL_WORLD_ON
+        #define A_NORMAL_WORLD_ON
+    #endif
+#endif
+
+#include "Assets/Alloy/Shaders/Framework/Feature.cginc"
+
+#ifdef A_DIRECTIONAL_BLEND_ON
+    /// Direction around which the blending occurs.
+    /// Expects a normalized direction vector.
+    half3 _DirectionalBlendDirection;
+    
+    /// Directional Blend weight.
+    /// Expects values in the range [0,1].
+    half _OrientedScale;
+    
+    /// Hemispherical cutoff where blend begins.
+    /// Expects values in the range [0,1].
+    half _OrientedCutoff;
+    
+    /// Offset from cutoff where smooth blending occurs.
+    /// Expects values in the range [0.0001,1].
+    half _OrientedBlend;
+
+    /// Controls how much the vertex color alpha influences the cutoff.
+    /// Expects values in the range [0,1].
+    half _DirectionalBlendAlphaVertexTint;
+#endif
+
+void aDirectionalBlend(
+    inout ASurface s)
+{
+#ifdef A_DIRECTIONAL_BLEND_ON    
+    #ifdef _DIRECTIONALBLENDMODE_WORLD
+        half3 normal = s.normalWorld;
+    #else
+        half3 normal = UnityWorldToObjectDir(s.normalWorld);
+    #endif	
+
+    // Convert [-1,1] -> [1,0] to flip direction for free.
+    half mask = dot(normal, _DirectionalBlendDirection) * -0.5h + 0.5h;
+    aBlendRangeMask(s, mask, _OrientedScale, _OrientedCutoff, _OrientedBlend, _DirectionalBlendAlphaVertexTint);
+#endif
+}
+
+#endif // ALLOY_SHADERS_FEATURE_DIRECTIONAL_BLEND_CGINC