Rename BRDF visibility functions prefix to V_ from Vis_

Source/Engine/Renderer/Config.h

@@ -102,7 +102,7 @@ GPU_CB_STRUCT(ShaderEnvProbeData {
     Float4 Data2;
     });
 
-// Minimum roughness value used for shading (prevent 0 roughness which causes NaNs in Vis_SmithJointApprox)
+// Minimum roughness value used for shading (prevent 0 roughness which causes NaNs in V_SmithJointApprox)
 #define MIN_ROUGHNESS 0.04f
 
 // Maximum amount of directional light cascades (using CSM technique)

Source/Engine/Renderer/ReflectionsPass.cpp

@@ -61,12 +61,12 @@ namespace PreIntegratedGF
         return Float3(sinTheta * cosf(phi), sinTheta * sinf(phi), cosTheta);
 	}
 
-    float Vis_SmithJointApprox(float roughness, float NoV, float NoL)
+    float V_SmithJointApprox(float roughness, float NoV, float NoL)
 	{
         float a = roughness * roughness;
-        float Vis_SmithV = NoL * (NoV * (1 - a) + a);
-        float Vis_SmithL = NoV * (NoL * (1 - a) + a);
-		return 0.5f / (Vis_SmithV + Vis_SmithL);
+        float V_SmithV = NoL * (NoV * (1 - a) + a);
+        float V_SmithL = NoV * (NoL * (1 - a) + a);
+		return 0.5f / (V_SmithV + V_SmithL);
 	}
 
     Float2 IntegrateBRDF(float roughness, float NoV)
@@ -87,12 +87,12 @@ namespace PreIntegratedGF
 
 			if (NoL > 0)
 			{
-                float Vis = Vis_SmithJointApprox(roughness, NoV, NoL);
-                float NoL_Vis_PDF = NoL * Vis * (4 * VoH / NoH);
+                float Vis = V_SmithJointApprox(roughness, NoV, NoL);
+                float NoL_V_PDF = NoL * Vis * (4 * VoH / NoH);
 
                 float Fc = powf(1 - VoH, 5);
-				a += NoL_Vis_PDF * (1 - Fc);
-				b += NoL_Vis_PDF * Fc;
+				a += NoL_V_PDF * (1 - Fc);
+				b += NoL_V_PDF * Fc;
 			}
 		}
 		return Float2(a, b) / (float)NumSamples;

Source/Shaders/BRDF.hlsl

@@ -20,9 +20,9 @@ float D_GGX(float roughness, float NoH)
     return a2 / (PI * d * d);
 }
 
-// Tuned to match behavior of Vis_Smith
+// Tuned to match behavior of V_Smith
 // [Schlick 1994, "An Inexpensive BRDF Model for Physically-Based Rendering"]
-float Vis_Schlick(float roughness, float NoV, float NoL)
+float V_Schlick(float roughness, float NoV, float NoL)
 {
     float k = Square(roughness) * 0.5;
     float visSchlickV = NoV * (1 - k) + k;
@@ -32,7 +32,7 @@ float Vis_Schlick(float roughness, float NoV, float NoL)
 
 // Smith term for GGX
 // [Smith 1967, "Geometrical shadowing of a random rough surface"]
-float Vis_Smith(float roughness, float NoV, float NoL)
+float V_Smith(float roughness, float NoV, float NoL)
 {
     float a = Square(roughness);
     float a2 = a * a;
@@ -43,7 +43,7 @@ float Vis_Smith(float roughness, float NoV, float NoL)
 
 // Appoximation of joint Smith term for GGX
 // [Heitz 2014, "Understanding the Masking-Shadowing Function in Microfacet-Based BRDFs"]
-float Vis_SmithJointApprox(float roughness, float NoV, float NoL)
+float V_SmithJointApprox(float roughness, float NoV, float NoL)
 {
     float a = Square(roughness);
     float visSmithV = NoL * (NoV * (1 - a) + a);

Source/Shaders/Lighting.hlsl

@@ -35,7 +35,7 @@ LightSample StandardShading(GBufferSample gBuffer, float energy, float3 L, float
     float3 specularColor = GetSpecularColor(gBuffer);
     float3 F = F_Schlick(specularColor, VoH);
     float D = D_GGX(gBuffer.Roughness, NoH) * energy;
-    float Vis = Vis_SmithJointApprox(gBuffer.Roughness, NoV, NoL);
+    float Vis = V_SmithJointApprox(gBuffer.Roughness, NoV, NoL);
     // TODO: apply energy compensation to specular (1.0 + specularColor * (1.0 / PreIntegratedGF.y - 1.0))
     lighting.Specular = (D * Vis) * F;
 #endif