Traktor: Refactored PBR lighting shaders.

code/World/Editor/IrradianceGridAsset.cpp

@@ -1,6 +1,6 @@
 /*
  * TRAKTOR
- * Copyright (c) 2022 Anders Pistol.
+ * Copyright (c) 2022-2024 Anders Pistol.
  *
  * This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
@@ -14,7 +14,7 @@
 namespace traktor::world
 {
 
-T_IMPLEMENT_RTTI_EDIT_CLASS(L"traktor.world.IrradianceGridAsset", 2, IrradianceGridAsset, editor::Asset)
+T_IMPLEMENT_RTTI_EDIT_CLASS(L"traktor.world.IrradianceGridAsset", 3, IrradianceGridAsset, editor::Asset)
 
 void IrradianceGridAsset::serialize(ISerializer& s)
 {
@@ -23,6 +23,9 @@ void IrradianceGridAsset::serialize(ISerializer& s)
 	if (s.getVersion< IrradianceGridAsset >() >= 1)
 		s >> Member< float >(L"intensity", m_intensity, AttributeUnit(UnitType::Percent));
 
+	if (s.getVersion< IrradianceGridAsset >() >= 3)
+		s >> Member< float >(L"saturation", m_saturation, AttributeUnit(UnitType::Percent));
+
 	if (s.getVersion< IrradianceGridAsset >() >= 2)
 		s >> Member< bool >(L"cancelSun", m_cancelSun);
 }

code/World/Editor/IrradianceGridAsset.h

@@ -1,6 +1,6 @@
 /*
  * TRAKTOR
- * Copyright (c) 2022 Anders Pistol.
+ * Copyright (c) 2022-2024 Anders Pistol.
  *
  * This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
@@ -33,10 +33,13 @@ class T_DLLCLASS IrradianceGridAsset : public editor::Asset
 
 	float getIntensity() const { return m_intensity; }
 
+	float getSaturation() const { return m_saturation; }
+
 	bool shouldCancelSun() const { return m_cancelSun; }
 
 private:
 	float m_intensity = 1.0f;
+	float m_saturation = 1.0f;
 	bool m_cancelSun = true;
 };
 

code/World/Editor/IrradianceGridPipeline.cpp

@@ -1,6 +1,6 @@
 /*
  * TRAKTOR
- * Copyright (c) 2022-2023 Anders Pistol.
+ * Copyright (c) 2022-2024 Anders Pistol.
  *
  * This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
@@ -193,9 +193,12 @@ bool IrradianceGridPipeline::buildOutput(
 	{
 		// No asset specified; use dynamic sky.
 		const Scalar intensity(asset->getIntensity());
+		const Scalar saturation(asset->getSaturation());
 
 		WrappedSHFunction shFunction([&] (const Vector4& unit) -> Vector4 {
 			Color4f cl(0.0f, 0.0f, 0.0f, 0.0f);
+
+			// Sample over hemisphere.
 			for (int32_t i = 0; i < 1000; ++i)
 			{
 				const Vector2 uv = Quasirandom::hammersley(i, 1000);
@@ -213,6 +216,11 @@ bool IrradianceGridPipeline::buildOutput(
 				col += clamp((0.1_simd - direction.y()) * 10.0_simd, 0.0_simd, 1.0_simd) * Vector4(0.0f, 0.1f, 0.2f, 0.0f);
 				cl += Color4f(col * w);
 			}
+
+			// Apply saturation.
+			const Scalar bw = dot3(cl, Vector4(1.0f, 1.0f, 1.0f)) / 3.0_simd;
+			cl = Color4f(lerp(Vector4(bw, bw, bw, 0.0f), cl, saturation));
+
 			return (cl * intensity * 2.0_simd) / 1000.0_simd;
 		});
 

data/Source/System/Shaders/Modules/PBR.xdi

@@ -0,0 +1,97 @@
+<?xml version="1.0" encoding="utf-8"?>
+<object type="traktor.render.ShaderModule">
+	<text>
+	<![CDATA[
+// https://learnopengl.com/PBR/Lighting
+
+vec3 FresnelSchlick(float cosTheta, vec3 F0)
+{
+	cosTheta = max(cosTheta, 0.0f);
+	return F0 + (1.0 - F0) * pow(clamp(1.0 - cosTheta, 0.0, 1.0), 5.0);
+}
+
+float DistributionGGX(vec3 N, vec3 H, float roughness)
+{
+	const float PI = 3.14159265359f;
+
+	const float a = roughness * roughness;
+	const float a2 = a * a;
+	const float NdotH = max(dot(N, H), 0.0f);
+	const float NdotH2 = NdotH * NdotH;
+	
+	const float num = a2;
+	float denom = (NdotH2 * (a2 - 1.0f) + 1.0f);
+	denom = PI * denom * denom;
+	
+	return num / denom;
+}
+
+float GeometrySchlickGGX(float NdotV, float roughness)
+{
+	const float r = (roughness + 1.0f);
+	const float k = (r * r) / 8.0f;
+
+	const float num = NdotV;
+	const float denom = NdotV * (1.0f - k) + k;
+	
+	return num / denom;
+}
+
+float GeometrySmith(vec3 N, vec3 V, vec3 L, float roughness)
+{
+	const float NdotV = max(dot(N, V), 0.0f);
+	const float NdotL = max(dot(N, L), 0.0f);
+	const float ggx2 = GeometrySchlickGGX(NdotV, roughness);
+	const float ggx1 = GeometrySchlickGGX(NdotL, roughness);
+	return ggx1 * ggx2;
+}
+
+vec3 CalculateLighting(vec3 N, vec3 V, vec3 L, vec3 albedo, float metallic, float roughness, vec3 radiance)
+{
+	const float PI = 3.14159265359f;
+	const vec3 H = normalize(V + L);
+	const float NdotL = max(dot(N, L), 0.0f);
+	const float NdotV = max(dot(N, V), 0.0f);
+
+	const vec3 F0 = mix(vec3(0.04), albedo, metallic);
+	const vec3 F = FresnelSchlick(max(dot(H, V), 0.0), F0);
+
+	const float NDF = DistributionGGX(N, H, roughness);
+	const float G = GeometrySmith(N, V, L, roughness);
+
+	const vec3 numerator = NDF * G * F;
+	const float denominator = 4.0f * NdotV * NdotL + 0.0001f;
+	const vec3 specular = numerator / denominator; 
+
+	const vec3 kS = F;
+	const vec3 kD = (vec3(1.0f) - kS) * (1.0f - metallic);
+
+	return (kD * albedo / PI + specular) * radiance * NdotL;
+}
+
+vec3 CalculateReflection(vec3 N, vec3 V, vec3 albedo, float metallic, float roughness)
+{
+	// Use the view reflection vector as light direction.
+	const vec3 L = -reflect(V, N);
+
+	const vec3 H = normalize(V + L);
+	const float NdotL = max(dot(N, L), 0.0f);
+	const float NdotV = max(dot(N, V), 0.0f);
+
+	const vec3 F0 = mix(vec3(0.04), albedo, metallic);
+	const vec3 F = FresnelSchlick(max(dot(H, V), 0.0), F0);
+
+	const float NDF = DistributionGGX(N, H, roughness);
+	const float G = GeometrySmith(N, V, L, roughness);
+
+	const vec3 numerator = NDF * G * F;
+	const float denominator = 4.0f * NdotV * NdotL + 0.0001f;
+	const vec3 specular = numerator / denominator;
+
+	return clamp(specular, 0.0f, 1.0f);
+}
+
+
+	]]>
+	</text>
+</object>

data/Source/System/Shaders/Modules/PBR.xdm

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8"?>
+<object type="traktor.db.LocalInstanceMeta" version="2">
+	<guid>{8541C8B0-4A05-AA42-BFE7-7DBF639AAF8B}</guid>
+	<primaryType>traktor.render.ShaderModule</primaryType>
+	<blobs/>
+</object>

data/Source/System/Weather/Sky/Sky.xdi

@@ -1,6 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
-<object type="traktor.world.IrradianceGridAsset" version="2">
+<object type="traktor.world.IrradianceGridAsset" version="3">
 	<fileName></fileName>
-	<intensity>1</intensity>
+	<intensity>1.5</intensity>
+	<saturation>0.25</saturation>
 	<cancelSun>false</cancelSun>
 </object>