binaryfoundry · March 12, 2025 08:46 · Mar 12, 2025 · Feb 10, 2021 · Feb 8, 2021 · Feb 7, 2021
diff --git a/ShaderLabPBR.shader b/ShaderLabPBR.shader
@@ -143,7 +143,7 @@ Shader "CustomPBRShader"
 
                 float3 f0 = max(_Albedo.rgb * _Metalness, 0.04);
 
-                float3 diffuse = diffuse_img(n) * (1.0 / 3.142) * (1.0 - _Metalness);
+                float3 diffuse = diffuse_img(n) * (1.0 - _Metalness);
                 float3 specular = specular_img(n, v);
 
                 float3 c = lerp(diffuse, specular, EnvBRDFApprox(f0, NoV, _Roughness));

diff --git a/ShaderLabPBR.shader b/ShaderLabPBR.shader
@@ -143,7 +143,7 @@ Shader "CustomPBRShader"
 
                 float3 f0 = max(_Albedo.rgb * _Metalness, 0.04);
 
-                float3 diffuse = diffuse_img(n) * (1.0 - _Metalness);
+                float3 diffuse = diffuse_img(n) * (1.0 / 3.142) * (1.0 - _Metalness);
                 float3 specular = specular_img(n, v);
 
                 float3 c = lerp(diffuse, specular, EnvBRDFApprox(f0, NoV, _Roughness));

diff --git a/ShaderLabPBR.shader b/ShaderLabPBR.shader
@@ -106,7 +106,7 @@ Shader "CustomPBRShader"
             // https://google.github.io/filament/Filament.md.html#toc5.3.4.1
             float3 diffuse_img(float3 n)
             {
-                return texCUBE(_IrradianceMap, n).rgb;
+                return _Albedo.rgb * texCUBE(_IrradianceMap, n).rgb;
             }
 
             // https://github.com/EpicGames/UnrealEngine/blob/release/Engine/Shaders/Private/ReflectionEnvironmentShared.ush

diff --git a/ShaderLabPBR.shader b/ShaderLabPBR.shader
@@ -120,7 +120,9 @@ Shader "CustomPBRShader"
             //    half LevelFrom1x1 = REFLECTION_CAPTURE_ROUGHEST_MIP - REFLECTION_CAPTURE_ROUGHNESS_MIP_SCALE * log2(Roughness);
             //    return CubemapMaxMip - 1 - LevelFrom1x1;
             //}
-
+            // Diffuse albedo must be divided by pi to be energy conserving.
+            // https://www.scratchapixel.com/lessons/3d-basic-rendering/introduction-to-shading/diffuse-lambertian-shading
+
             // Sample offline generated convolved environment map. MipLevels
             // should match the number of images output.
             // https://google.github.io/filament/Filament.md.html#toc5.3.4.4
@@ -133,9 +135,6 @@ Shader "CustomPBRShader"
                 return texCUBElod(_RadianceMap, float4(r, _Roughness * MipLevels)).rgb;
             }
 
-            // Diffuse albedo must be divided by pi to be energy conserving.
-            // https://www.scratchapixel.com/lessons/3d-basic-rendering/introduction-to-shading/diffuse-lambertian-shading
-
             fixed4 frag (v2f i) : SV_Target
             {
                 float3 n = normalize(i.normal);
@@ -144,7 +143,7 @@ Shader "CustomPBRShader"
 
                 float3 f0 = max(_Albedo.rgb * _Metalness, 0.04);
 
-                float3 diffuse = diffuse_img(n) * (_Albedo.rgb / 3.1415926535) * (1.0 - _Metalness);
+                float3 diffuse = diffuse_img(n) * (1.0 - _Metalness);
                 float3 specular = specular_img(n, v);
 
                 float3 c = lerp(diffuse, specular, EnvBRDFApprox(f0, NoV, _Roughness));

diff --git a/ShaderLabPBR.shader b/ShaderLabPBR.shader
@@ -127,8 +127,9 @@ Shader "CustomPBRShader"
             // If not using a pre-convolved environment map, but instead one rendered
             // at runtime use UE4 heuristic mapping to calculate mip level above. This
             // mimics the offline convolution by biasing the mip level.
-            float3 specular_img(float3 n, float3 v, float3 r)
+            float3 specular_img(float3 n, float3 v)
             {
+                float3 r = reflect(v, n);
                 return texCUBElod(_RadianceMap, float4(r, _Roughness * MipLevels)).rgb;
             }
 
@@ -139,13 +140,12 @@ Shader "CustomPBRShader"
             {
                 float3 n = normalize(i.normal);
                 float3 v = normalize(_WorldSpaceCameraPos - i.posWorld.xyz);
-                float3 r = reflect(v, n);
                 float NoV = dot(n, v);
 
                 float3 f0 = max(_Albedo.rgb * _Metalness, 0.04);
 
                 float3 diffuse = diffuse_img(n) * (_Albedo.rgb / 3.1415926535) * (1.0 - _Metalness);
-                float3 specular = specular_img(n, v, r);
+                float3 specular = specular_img(n, v);
 
                 float3 c = lerp(diffuse, specular, EnvBRDFApprox(f0, NoV, _Roughness));
 

diff --git a/ShaderLabPBR.shader b/ShaderLabPBR.shader
@@ -54,6 +54,9 @@ Shader "CustomPBRShader"
                 return o;
             }
 
+            // Tone Mapping
+            //https://mynameismjp.wordpress.com/2010/04/30/a-closer-look-at-tone-mapping/
+            //https://github.com/TheRealMJP/BakingLab/blob/master/BakingLab/ACES.hlsl
             static const float3x3 ACESInputMat =
             {
                 {0.59719, 0.35458, 0.04823},

diff --git a/ShaderLabPBR.shader b/ShaderLabPBR.shader
@@ -23,8 +23,6 @@ Shader "CustomPBRShader"
 
             #include "UnityCG.cginc"
 
-            const float pi = 3.141592653589793238462;
-
             float4 _Albedo;
             float _Metalness;
             float _Roughness;
@@ -143,7 +141,7 @@ Shader "CustomPBRShader"
 
                 float3 f0 = max(_Albedo.rgb * _Metalness, 0.04);
 
-                float3 diffuse = diffuse_img(n) * (_Albedo.rgb / pi) * (1.0 - _Metalness);
+                float3 diffuse = diffuse_img(n) * (_Albedo.rgb / 3.1415926535) * (1.0 - _Metalness);
                 float3 specular = specular_img(n, v, r);
 
                 float3 c = lerp(diffuse, specular, EnvBRDFApprox(f0, NoV, _Roughness));

diff --git a/ShaderLabPBR.shader b/ShaderLabPBR.shader
@@ -148,7 +148,7 @@ Shader "CustomPBRShader"
 
                 float3 c = lerp(diffuse, specular, EnvBRDFApprox(f0, NoV, _Roughness));
 
-                return float4(toneMapACES(c * exposure), _Albedo.a);
+                return float4(toneMapACES(c * Exposure), _Albedo.a);
             }
             ENDCG
         }

diff --git a/ShaderLabPBR.shader b/ShaderLabPBR.shader
@@ -125,7 +125,7 @@ Shader "CustomPBRShader"
             // https://google.github.io/filament/Filament.md.html#toc5.3.4.4
             // If not using a pre-convolved environment map, but instead one rendered
             // at runtime use UE4 heuristic mapping to calculate mip level above. This
-            // mimics the offline convolution vy biasing the mip level.
+            // mimics the offline convolution by biasing the mip level.
             float3 specular_img(float3 n, float3 v, float3 r)
             {
                 return texCUBElod(_RadianceMap, float4(r, _Roughness * MipLevels)).rgb;

diff --git a/ShaderLabPBR.shader b/ShaderLabPBR.shader
@@ -125,7 +125,7 @@ Shader "CustomPBRShader"
             // https://google.github.io/filament/Filament.md.html#toc5.3.4.4
             // If not using a pre-convolved environment map, but instead one rendered
             // at runtime use UE4 heuristic mapping to calculate mip level above. This
-            // heuristically mimics the offline convolution.
+            // mimics the offline convolution vy biasing the mip level.
             float3 specular_img(float3 n, float3 v, float3 r)
             {
                 return texCUBElod(_RadianceMap, float4(r, _Roughness * MipLevels)).rgb;

diff --git a/ShaderLabPBR.shader b/ShaderLabPBR.shader
@@ -123,8 +123,9 @@ Shader "CustomPBRShader"
             // Sample offline generated convolved environment map. MipLevels
             // should match the number of images output.
             // https://google.github.io/filament/Filament.md.html#toc5.3.4.4
-            // If not using a pre-convolved environment map which was rendered
-            // at runtime use UE4 heuristic mapping to calculate mip level above.
+            // If not using a pre-convolved environment map, but instead one rendered
+            // at runtime use UE4 heuristic mapping to calculate mip level above. This
+            // heuristically mimics the offline convolution.
             float3 specular_img(float3 n, float3 v, float3 r)
             {
                 return texCUBElod(_RadianceMap, float4(r, _Roughness * MipLevels)).rgb;

diff --git a/ShaderLabPBR.shader b/ShaderLabPBR.shader
@@ -23,6 +23,8 @@ Shader "CustomPBRShader"
 
             #include "UnityCG.cginc"
 
+            const float pi = 3.141592653589793238462;
+
             float4 _Albedo;
             float _Metalness;
             float _Roughness;
@@ -128,6 +130,9 @@ Shader "CustomPBRShader"
                 return texCUBElod(_RadianceMap, float4(r, _Roughness * MipLevels)).rgb;
             }
 
+            // Diffuse albedo must be divided by pi to be energy conserving.
+            // https://www.scratchapixel.com/lessons/3d-basic-rendering/introduction-to-shading/diffuse-lambertian-shading
+
             fixed4 frag (v2f i) : SV_Target
             {
                 float3 n = normalize(i.normal);
@@ -137,7 +142,7 @@ Shader "CustomPBRShader"
 
                 float3 f0 = max(_Albedo.rgb * _Metalness, 0.04);
 
-                float3 diffuse = diffuse_img(n) * _Albedo.rgb * (1.0 - _Metalness);
+                float3 diffuse = diffuse_img(n) * (_Albedo.rgb / pi) * (1.0 - _Metalness);
                 float3 specular = specular_img(n, v, r);
 
                 float3 c = lerp(diffuse, specular, EnvBRDFApprox(f0, NoV, _Roughness));

diff --git a/ShaderLabPBR.shader b/ShaderLabPBR.shader
@@ -122,7 +122,7 @@ Shader "CustomPBRShader"
             // should match the number of images output.
             // https://google.github.io/filament/Filament.md.html#toc5.3.4.4
             // If not using a pre-convolved environment map which was rendered
-            // at runtime use UE4 heuristic mapping to calculate level above.
+            // at runtime use UE4 heuristic mapping to calculate mip level above.
             float3 specular_img(float3 n, float3 v, float3 r)
             {
                 return texCUBElod(_RadianceMap, float4(r, _Roughness * MipLevels)).rgb;

diff --git a/ShaderLabPBR.shader b/ShaderLabPBR.shader
@@ -106,9 +106,23 @@ Shader "CustomPBRShader"
                 return texCUBE(_IrradianceMap, n).rgb;
             }
 
-            // Sample offline generated blurred environment map. MipLevels
+            // https://github.com/EpicGames/UnrealEngine/blob/release/Engine/Shaders/Private/ReflectionEnvironmentShared.ush
+            // Heuristic that maps roughness to mip level
+            // This is done in a way such that a certain mip level will always have the same roughness, regardless of how many mips are in the texture
+            // Using more mips in the cubemap just allows sharper reflections to be supported
+            //#define REFLECTION_CAPTURE_ROUGHEST_MIP 1
+            //#define REFLECTION_CAPTURE_ROUGHNESS_MIP_SCALE 1.2
+            //half ComputeReflectionCaptureMipFromRoughness(half Roughness, half CubemapMaxMip)
+            //{
+            //    half LevelFrom1x1 = REFLECTION_CAPTURE_ROUGHEST_MIP - REFLECTION_CAPTURE_ROUGHNESS_MIP_SCALE * log2(Roughness);
+            //    return CubemapMaxMip - 1 - LevelFrom1x1;
+            //}
+
+            // Sample offline generated convolved environment map. MipLevels
             // should match the number of images output.
             // https://google.github.io/filament/Filament.md.html#toc5.3.4.4
+            // If not using a pre-convolved environment map which was rendered
+            // at runtime use UE4 heuristic mapping to calculate level above.
             float3 specular_img(float3 n, float3 v, float3 r)
             {
                 return texCUBElod(_RadianceMap, float4(r, _Roughness * MipLevels)).rgb;

diff --git a/ShaderLabPBR.shader b/ShaderLabPBR.shader
@@ -99,6 +99,8 @@ Shader "CustomPBRShader"
                 return f0 * AB.x + AB.y;
             }
 
+            // Diffuse reflection map.
+            // https://google.github.io/filament/Filament.md.html#toc5.3.4.1
             float3 diffuse_img(float3 n)
             {
                 return texCUBE(_IrradianceMap, n).rgb;

diff --git a/ShaderLabPBR.shader b/ShaderLabPBR.shader
@@ -104,6 +104,9 @@ Shader "CustomPBRShader"
                 return texCUBE(_IrradianceMap, n).rgb;
             }
 
+            // Sample offline generated blurred environment map. MipLevels
+            // should match the number of images output.
+            // https://google.github.io/filament/Filament.md.html#toc5.3.4.4
             float3 specular_img(float3 n, float3 v, float3 r)
             {
                 return texCUBElod(_RadianceMap, float4(r, _Roughness * MipLevels)).rgb;

diff --git a/ShaderLabPBR.shader b/ShaderLabPBR.shader
@@ -75,6 +75,8 @@ Shader "CustomPBRShader"
                 return a / b;
             }
 
+            // Maps real valued output to a suitable range for display on an
+            // 8-bits per channel RGB screen.
             float3 toneMapACES(float3 color)
             {
                 color = mul(ACESInputMat, color);
@@ -84,7 +86,8 @@ Shader "CustomPBRShader"
                 return color;
             }
 
-            // Approximates the DFG lookup table generated offline.
+            // Approximates the roughness/Fresnel lookup table generated offline.
+            // Explained in Filament documentation.
             // https://google.github.io/filament/Filament.md.html#table_texturedfg
             float3 EnvBRDFApprox(float3 f0, float3 NoV, float roughness)
             {

diff --git a/ShaderLabPBR.shader b/ShaderLabPBR.shader
@@ -84,6 +84,8 @@ Shader "CustomPBRShader"
                 return color;
             }
 
+            // Approximates the DFG lookup table generated offline.
+            // https://google.github.io/filament/Filament.md.html#table_texturedfg
             float3 EnvBRDFApprox(float3 f0, float3 NoV, float roughness)
             {
                 float4 c0 = float4(-1.0, -0.0275, -0.572, 0.022);

diff --git a/gistfile1.txt → ShaderLabPBR.shader b/gistfile1.txt → ShaderLabPBR.shader
diff --git a/gistfile1.txt b/gistfile1.txt
@@ -1,12 +1,12 @@
-Shader "Unlit/DemoShader"
+Shader "CustomPBRShader"
 {
     Properties
     {
         [NoScaleOffset] _Albedo("Albedo", Color) = (1.0, 1.0, 1.0, 1.0)
         [NoScaleOffset] _Metalness("Conductivity", Range(0.0, 1.0)) = 0.0
         [NoScaleOffset] _Roughness("Roughness", Range(0.0, 1.0)) = 0.0
-        [NoScaleOffset][HDR][HideInInspector] _RadianceMap("RadianceMap", CUBE) = "" {}
-        [NoScaleOffset][HDR][HideInInspector] _IrradianceMap("IrradianceMap", CUBE) = "" {}
+        [NoScaleOffset][HDR] _RadianceMap("RadianceMap", CUBE) = "" {}
+        [NoScaleOffset][HDR] _IrradianceMap("IrradianceMap", CUBE) = "" {}
     }
     SubShader
     {

diff --git a/gistfile1.txt b/gistfile1.txt
@@ -96,7 +96,7 @@ Shader "Unlit/DemoShader"
 
             float3 diffuse_img(float3 n)
             {
-                return _Albedo.rgb * texCUBE(_IrradianceMap, n).rgb;
+                return texCUBE(_IrradianceMap, n).rgb;
             }
 
             float3 specular_img(float3 n, float3 v, float3 r)
@@ -113,7 +113,7 @@ Shader "Unlit/DemoShader"
 
                 float3 f0 = max(_Albedo.rgb * _Metalness, 0.04);
 
-                float3 diffuse = diffuse_img(n) * (1.0 - _Metalness);
+                float3 diffuse = diffuse_img(n) * _Albedo.rgb * (1.0 - _Metalness);
                 float3 specular = specular_img(n, v, r);
 
                 float3 c = lerp(diffuse, specular, EnvBRDFApprox(f0, NoV, _Roughness));

diff --git a/gistfile1.txt b/gistfile1.txt
@@ -107,7 +107,6 @@ Shader "Unlit/DemoShader"
             fixed4 frag (v2f i) : SV_Target
             {
                 float3 n = normalize(i.normal);
-                float3 l = _WorldSpaceLightPos0.xyz - i.posWorld.xyz * _WorldSpaceLightPos0.w;
                 float3 v = normalize(_WorldSpaceCameraPos - i.posWorld.xyz);
                 float3 r = reflect(v, n);
                 float NoV = dot(n, v);

diff --git a/gistfile1.txt b/gistfile1.txt
@@ -0,0 +1,127 @@
+Shader "Unlit/DemoShader"
+{
+    Properties
+    {
+        [NoScaleOffset] _Albedo("Albedo", Color) = (1.0, 1.0, 1.0, 1.0)
+        [NoScaleOffset] _Metalness("Conductivity", Range(0.0, 1.0)) = 0.0
+        [NoScaleOffset] _Roughness("Roughness", Range(0.0, 1.0)) = 0.0
+        [NoScaleOffset][HDR][HideInInspector] _RadianceMap("RadianceMap", CUBE) = "" {}
+        [NoScaleOffset][HDR][HideInInspector] _IrradianceMap("IrradianceMap", CUBE) = "" {}
+    }
+    SubShader
+    {
+        Tags { "RenderType" = "Transparent" "Queue" = "Geometry" }
+        LOD 100
+
+        Pass
+        {
+            Blend SrcAlpha OneMinusSrcAlpha
+
+            CGPROGRAM
+            #pragma vertex vert
+            #pragma fragment frag
+
+            #include "UnityCG.cginc"
+
+            float4 _Albedo;
+            float _Metalness;
+            float _Roughness;
+            samplerCUBE _RadianceMap;
+            samplerCUBE _IrradianceMap;
+
+            static float MipLevels = 8.0;
+            static float Exposure = 1.5;
+
+            struct appdata
+            {
+                float4 vertex : POSITION;
+                float3 normal : NORMAL;
+            };
+
+            struct v2f
+            {
+                float4 pos : POSITION;
+                float3 normal : NORMAL;
+                float4 posWorld : TEXCOORD1;
+            };
+
+            v2f vert (appdata v)
+            {
+                v2f o;
+                o.posWorld = mul(unity_ObjectToWorld, v.vertex);
+                o.normal = normalize(mul(float4(v.normal, 0.0), unity_WorldToObject).xyz);
+                o.pos = UnityObjectToClipPos(v.vertex);
+                return o;
+            }
+
+            static const float3x3 ACESInputMat =
+            {
+                {0.59719, 0.35458, 0.04823},
+                {0.07600, 0.90834, 0.01566},
+                {0.02840, 0.13383, 0.83777}
+            };
+
+            static const float3x3 ACESOutputMat =
+            {
+                { 1.60475, -0.53108, -0.07367},
+                {-0.10208,  1.10813, -0.00605},
+                {-0.00327, -0.07276,  1.07602}
+            };
+
+            float3 RRTAndODTFit(float3 v)
+            {
+                float3 a = v * (v + 0.0245786f) - 0.000090537f;
+                float3 b = v * (0.983729f * v + 0.4329510f) + 0.238081f;
+                return a / b;
+            }
+
+            float3 toneMapACES(float3 color)
+            {
+                color = mul(ACESInputMat, color);
+                color = RRTAndODTFit(color);
+                color = mul(ACESOutputMat, color);
+                color = saturate(color);
+                return color;
+            }
+
+            float3 EnvBRDFApprox(float3 f0, float3 NoV, float roughness)
+            {
+                float4 c0 = float4(-1.0, -0.0275, -0.572, 0.022);
+                float4 c1 = float4(1.0, 0.0425, 1.04, -0.04);
+                float4 r = roughness * c0 + c1;
+                float a004 = min(r.x * r.x, exp2(-9.28 * NoV)) * r.x + r.y;
+                float2 AB = float2(-1.04, 1.04) * a004 + r.zw;
+                return f0 * AB.x + AB.y;
+            }
+
+            float3 diffuse_img(float3 n)
+            {
+                return _Albedo.rgb * texCUBE(_IrradianceMap, n).rgb;
+            }
+
+            float3 specular_img(float3 n, float3 v, float3 r)
+            {
+                return texCUBElod(_RadianceMap, float4(r, _Roughness * MipLevels)).rgb;
+            }
+
+            fixed4 frag (v2f i) : SV_Target
+            {
+                float3 n = normalize(i.normal);
+                float3 l = _WorldSpaceLightPos0.xyz - i.posWorld.xyz * _WorldSpaceLightPos0.w;
+                float3 v = normalize(_WorldSpaceCameraPos - i.posWorld.xyz);
+                float3 r = reflect(v, n);
+                float NoV = dot(n, v);
+
+                float3 f0 = max(_Albedo.rgb * _Metalness, 0.04);
+
+                float3 diffuse = diffuse_img(n) * (1.0 - _Metalness);
+                float3 specular = specular_img(n, v, r);
+
+                float3 c = lerp(diffuse, specular, EnvBRDFApprox(f0, NoV, _Roughness));
+
+                return float4(toneMapACES(c * exposure), _Albedo.a);
+            }
+            ENDCG
+        }
+    }
+}
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