Switch to independent implementations of D/G terms

1 files changed, 1 insertions, 32 deletions

diff --git a/filamented.cginc b/filamented.cginc
index 0e27bbc..fb019cb 100644
--- a/filamented.cginc
+++ b/filamented.cginc
@@ -213,37 +213,6 @@
 #include "UnityCG.cginc"
 #include "UnityImageBasedLightingMinimal.cginc"
 
-#define MIN_PERCEPTUAL_ROUGHNESS 0.045f
-#define MIN_ROUGHNESS 		     0.002025f
-
-float D_GGX(float roughness, float NoH, const float3 h) {
-	// Walter et al. 2007, "Microfacet Models for Refraction through Rough Surfaces"
-
-	// In mediump, there are two problems computing 1.0 - NoH^2
-	// 1) 1.0 - NoH^2 suffers floating point cancellation when NoH^2 is close to 1 (highlights)
-	// 2) NoH doesn't have enough precision around 1.0
-	// Both problem can be fixed by computing 1-NoH^2 in highp and providing NoH in highp as well
-
-	// However, we can do better using Lagrange's identity:
-	//      ||a x b||^2 = ||a||^2 ||b||^2 - (a . b)^2
-	// since N and H are unit vectors: ||N x H||^2 = 1.0 - NoH^2
-	// This computes 1.0 - NoH^2 directly (which is close to zero in the highlights and has
-	// enough precision).
-	// Overall this yields better performance, keeping all computations in mediump
-	// Not available without reworking to pass NxH to the function
-	float oneMinusNoHSquared = 1.0 - NoH * NoH;
-	float a = NoH * roughness;
-	float k = roughness / (oneMinusNoHSquared + a * a);
-	float d = k * k * (1.0 / PI);
-	return d;
-}
-
-float V_SmithGGXCorrelated_Fast(float roughness, float NoV, float NoL) {
-    // Hammon 2017, "PBR Diffuse Lighting for GGX+Smith Microsurfaces"
-    float v = 0.5 / lerp(2.0 * NoL * NoV, NoL + NoV, roughness);
-    return v;
-}
-
 float normalFiltering(float perceptualRoughness, const float3 worldNormal) {
     // Kaplanyan 2016, "Stable specular highlights"
     // Tokuyoshi 2017, "Error Reduction and Simplification for Shading Anti-Aliasing"
@@ -275,7 +244,7 @@ half3 Unity_GlossyEnvironment_local (UNITY_ARGS_TEXCUBE(tex), half4 hdr, Unity_G
 	// Workaround for issue where objects are blurrier than they should be
 	// due to specular AA.
 	float roughnessAdjustment = 1-perceptualRoughness;
-	roughnessAdjustment = MIN_PERCEPTUAL_ROUGHNESS * roughnessAdjustment * roughnessAdjustment;
+	roughnessAdjustment = 1e-6f * roughnessAdjustment * roughnessAdjustment;
 	perceptualRoughness = perceptualRoughness - roughnessAdjustment;
 
 	// Unity derivation