Add filament-style clearcoat

7 files changed, 311 insertions, 65 deletions

diff --git a/Editor/tooner.cs b/Editor/tooner.cs
index adc0fca..2c02896 100644
--- a/Editor/tooner.cs
+++ b/Editor/tooner.cs
@@ -98,6 +98,24 @@ public class ToonerGUI : ShaderGUI {
       SetKeyword("_ROUGHNESS_MAP", bct.textureValue);
   }
 
+  void DoClearcoat() {
+    MaterialProperty bc;
+    bc = FindProperty("_Clearcoat_Enabled");
+    bool enabled = bc.floatValue > 1E-6;
+    EditorGUI.BeginChangeCheck();
+    enabled = EditorGUILayout.Toggle("Enable clearcoat", enabled);
+    EditorGUI.EndChangeCheck();
+    bc.floatValue = enabled ? 1.0f : 0.0f;
+    SetKeyword("_CLEARCOAT", enabled);
+
+    if (enabled) {
+        bc = FindProperty("_Clearcoat_Strength");
+        editor.RangeProperty(bc, "Strength");
+        bc = FindProperty("_Clearcoat_Roughness");
+        editor.RangeProperty(bc, "Roughness");
+    }
+  }
+
   enum PbrAlbedoMixMode {
     AlphaBlend,
     Add,
@@ -1028,55 +1046,9 @@ public class ToonerGUI : ShaderGUI {
 
   void DoMochieParams() {
     MaterialProperty bc;
-    GUILayout.Label("SSS", EditorStyles.boldLabel);
-    {
-      EditorGUI.indentLevel += 1;
-      bc = FindProperty("_ScatterDist");
-      editor.FloatProperty(bc, "Distance");
-      bc = FindProperty("_ScatterPow");
-      editor.FloatProperty(bc, "Power");
-      bc = FindProperty("_ScatterIntensity");
-      editor.FloatProperty(bc, "Intensity");
-      bc = FindProperty("_ScatterAmbient");
-      editor.FloatProperty(bc, "Ambient");
-      EditorGUI.indentLevel -= 1;
-    }
-    GUILayout.Label("SSR", EditorStyles.boldLabel);
-    {
-      EditorGUI.indentLevel += 1;
-
-      bc = FindProperty("_Enable_SSR");
-      bool enabled = (bc.floatValue != 0.0);
-      EditorGUI.BeginChangeCheck();
-      enabled = EditorGUILayout.Toggle("Enable SSR", enabled);
-      EditorGUI.EndChangeCheck();
-      bc.floatValue = enabled ? 1.0f : 0.0f;
-      SetKeyword("SSR_ENABLED", enabled);
-
-      if (enabled) {
-        bc = FindProperty("_SSRStrength");
-        editor.FloatProperty(bc, "Strength");
-        bc = FindProperty("_SSRHeight");
-        editor.FloatProperty(bc, "Height");
-        bc = FindProperty("_EdgeFade");
-        editor.FloatProperty(bc, "Edge fade");
-      }
 
-      EditorGUI.indentLevel -= 1;
-    }
-    GUILayout.Label("GSAA", EditorStyles.boldLabel);
-    {
-      EditorGUI.indentLevel += 1;
-      bc = FindProperty("_GSAA");
-      editor.FloatProperty(bc, "Enable");
-      bc = FindProperty("_GSAAStrength");
-      editor.FloatProperty(bc, "Strength");
-      EditorGUI.indentLevel -= 1;
-    }
     bc = FindProperty("_WrappingFactor");
     editor.FloatProperty(bc, "Wrapping factor");
-    bc = FindProperty("_Subsurface");
-    editor.FloatProperty(bc, "Subsurface");
     bc = FindProperty("_SpecularStrength");
     editor.FloatProperty(bc, "Specular strength");
     bc = FindProperty("_FresnelStrength");
@@ -1085,23 +1057,6 @@ public class ToonerGUI : ShaderGUI {
     editor.FloatProperty(bc, "Use fresnel");
     bc = FindProperty("_ReflectionStrength");
     editor.FloatProperty(bc, "Reflection strength");
-    /*
-float _ScatterDist;
-float _ScatterPow;
-float _ScatterIntensity;
-float _ScatterAmbient;
-float _GSAA;
-float _GSAAStrength;
-float _WrappingFactor;
-float _Subsurface;
-float _SpecularStrength;
-float _FresnelStrength;
-float _UseFresnel;
-float _ReflectionStrength;
-float3 shadowedReflections;
-float3 _ReflShadows;
-float3 _ReflShadowStrength;
-*/
   }
 
   enum RenderingMode {
@@ -1300,6 +1255,11 @@ float3 _ReflShadowStrength;
 
     DoPBROverlay();
 
+    GUILayout.Label("Clearcoat", EditorStyles.boldLabel);
+    EditorGUI.indentLevel += 1;
+    DoClearcoat();
+    EditorGUI.indentLevel -= 1;
+
     DoDecal();
 
     GUILayout.Label("Lighting", EditorStyles.boldLabel);
diff --git a/MochieStandardBRDF.cginc b/MochieStandardBRDF.cginc
index 795bbee..90f5df5 100644
--- a/MochieStandardBRDF.cginc
+++ b/MochieStandardBRDF.cginc
@@ -1,6 +1,9 @@
 #ifndef MOCHIE_STANDARD_BRDF_INCLUDED
 #define MOCHIE_STANDARD_BRDF_INCLUDED
 
+#include "filament_math.cginc"
+#include "globals.cginc"
+
 /*
  * MIT License
  *
@@ -54,7 +57,7 @@ float GSAARoughness(float3 normal, float roughness){
 
 half4 BRDF1_Mochie_PBS (
     half3 diffColor, half3 specColor, half oneMinusReflectivity, half smoothness,
-    half3 normal, half3 viewDir, half3 worldPos, half2 screenUVs, half4 screenPos,
+    half3 normal, half3 mesh_normal, half3 viewDir, half3 worldPos, half2 screenUVs, half4 screenPos,
     half metallic, half thickness, half3 ssColor, half atten, float2 lightmapUV, float3 vertexColor,
     UnityLight light, UnityIndirect gi)
 {
@@ -170,6 +173,17 @@ half4 BRDF1_Mochie_PBS (
   // 	reflCol *= lerp(1, vertexColor, _ReflVertexColor*_ReflVertexColorStrength);
   // #endif
 
+#if defined(_CLEARCOAT)
+  half cc_nh = saturate(dot(mesh_normal, halfDir));
+  float clearcoat = FilamentClearcoat(
+      _Clearcoat_Roughness,
+      _Clearcoat_Strength,
+      cc_nh,
+      lh,
+      halfDir);
+  specCol += clearcoat * saturate(dot(mesh_normal, light.dir)) * 10;
+#endif
+
   return half4(diffCol + specCol + reflCol + subsurfaceCol, 1);
 }
 
diff --git a/feature_macros.cginc b/feature_macros.cginc
index d9de678..8246737 100644
--- a/feature_macros.cginc
+++ b/feature_macros.cginc
@@ -91,7 +91,7 @@
 #pragma shader_feature_local _ _GIMMICK_EYES_00
 #pragma shader_feature_local _ _PIXELLATE
 #pragma shader_feature_local _ _TROCHOID
-#pragma shader_feature_local _ SSR_ENABLED
+#pragma shader_feature_local _ _CLEARCOAT
 
 #endif  // __FEATURE_MACROS_INC
 
diff --git a/filament_math.cginc b/filament_math.cginc
new file mode 100644
index 0000000..38a30e8
--- /dev/null
+++ b/filament_math.cginc
@@ -0,0 +1,261 @@
+#ifndef __FILAMENT_MATH_INC
+#define __FILAMENT_MATH_INC
+
+#define PI 3.1415926535897932384626433832795028841971
+
+/*
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+
+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
+#if defined(TARGET_MOBILE)
+	float3 NxH = cross(shading_normal, h);
+	float oneMinusNoHSquared = dot(NxH, NxH);
+#else
+	float oneMinusNoHSquared = 1.0 - NoH * NoH;
+#endif
+
+	float a = NoH * roughness;
+	float k = roughness / (oneMinusNoHSquared + a * a);
+	float d = k * k * (1.0 / PI);
+	return saturate(d);
+}
+
+float3 F_Schlick(const float3 f0, float VoH) {
+	float f = pow(1.0 - VoH, 5.0);
+	return f + f0 * (1.0 - f);
+}
+
+float V_Kelemen(float LoH) {
+  // Kelemen 2001, "A Microfacet Based Coupled Specular-Matte BRDF Model with
+  // Importance Sampling"
+  return saturate(0.25 / (LoH * LoH));
+}
+
+float FilamentClearcoat(
+    float roughness,
+    float strength,
+    float NoH,
+    float LoH,
+    float3 h) {
+  float Dc = D_GGX(roughness, NoH, h);
+  float Vc = V_Kelemen(LoH);
+  float Fc = F_Schlick(0.04, LoH) * strength;
+  return (Dc * Vc) * Fc;
+}
+
+#endif  // __FILAMENT_MATH_INC
+
diff --git a/globals.cginc b/globals.cginc
index 4aab736..128972b 100644
--- a/globals.cginc
+++ b/globals.cginc
@@ -38,6 +38,12 @@ float3 shadowedReflections;
 float3 _ReflShadows;
 float3 _ReflShadowStrength;
 
+#if defined(_CLEARCOAT)
+float _Clearcoat_Enabled;
+float _Clearcoat_Strength;
+float _Clearcoat_Roughness;
+#endif
+
 #if defined(SSR_ENABLED)
 UNITY_DECLARE_DEPTH_TEXTURE(_CameraDepthTexture);
 sampler2D _GrabTexture; 
diff --git a/pbr.cginc b/pbr.cginc
index 325ff79..7b37d86 100644
--- a/pbr.cginc
+++ b/pbr.cginc
@@ -237,6 +237,7 @@ float4 getLitColor(
       one_minus_reflectivity,
       smoothness,
       normal,
+      i.normal,
       view_dir,
       i.worldPos,
       screenUVs,
diff --git a/tooner.shader b/tooner.shader
index a5cca46..45fa9e2 100644
--- a/tooner.shader
+++ b/tooner.shader
@@ -6,6 +6,10 @@ Shader "yum_food/tooner"
     _Metallic("Metallic", Range(0, 1)) = 0
     _Roughness("Roughness", Range(0, 1)) = 1
 
+    _Clearcoat_Enabled("Clearcoat enabled", Float) = 0
+    _Clearcoat_Strength("Clearcoat strength", Range(0, 1)) = 0
+    _Clearcoat_Roughness("Clearcoat strength", Range(0, 1)) = 0
+
     [NoScaleOffset] _MainTex("Base color", 2D) = "white" {}
     [NoScaleOffset] _NormalTex("Normal", 2D) = "bump" {}
     [NoScaleOffset] _MetallicTex("Metallic", 2D) = "white" {}