feat(ibl): revamp ibl and dalc sh

features/IBL/Shaders/IBL/IBL.hlsli

@@ -10,56 +10,88 @@
 namespace ImageBasedLighting
 {
 #if defined(IBL_DEFERRED)
-	Texture2D<sh2> DiffuseIBLTexture : register(t14);
-	Texture2D<sh2> DiffuseSkyIBLTexture : register(t15);
+	Texture2D<sh2> EnvIBLTexture : register(t14);
+	Texture2D<sh2> SkyIBLTexture : register(t15);
 #else
-	Texture2D<sh2> DiffuseIBLTexture : register(t76);
-	Texture2D<sh2> DiffuseSkyIBLTexture : register(t77);
+	Texture2D<sh2> EnvIBLTexture : register(t76);
+	Texture2D<sh2> SkyIBLTexture : register(t77);
 	TextureCube<float4> StaticDiffuseIBLTexture : register(t78);
 	TextureCube<float4> StaticSpecularIBLTexture : register(t79);
 #endif
-	float3 GetDiffuseIBL(float3 rayDir)
+
+	/// Get Env IBL color from environment cubemap SH (without sky)
+	float3 GetEnvIBL(float3 rayDir)
 	{
-		sh2 shR = DiffuseIBLTexture.Load(int3(0, 0, 0));
-		sh2 shG = DiffuseIBLTexture.Load(int3(1, 0, 0));
-		sh2 shB = DiffuseIBLTexture.Load(int3(2, 0, 0));
+		sh2 shR = EnvIBLTexture.Load(int3(0, 0, 0));
+		sh2 shG = EnvIBLTexture.Load(int3(1, 0, 0));
+		sh2 shB = EnvIBLTexture.Load(int3(2, 0, 0));
 		float colorR = SphericalHarmonics::SHHallucinateZH3Irradiance(shR, rayDir);
 		float colorG = SphericalHarmonics::SHHallucinateZH3Irradiance(shG, rayDir);
 		float colorB = SphericalHarmonics::SHHallucinateZH3Irradiance(shB, rayDir);
 		return float3(colorR, colorG, colorB) / Math::PI;
 	}
 
-	float3 GetSkyDiffuseIBL(float3 rayDir)
+	/// Get Sky-only IBL color from game's native reflections cubemap SH
+	float3 GetSkyIBL(float3 rayDir)
 	{
-		sh2 shR = DiffuseSkyIBLTexture.Load(int3(0, 0, 0));
-		sh2 shG = DiffuseSkyIBLTexture.Load(int3(1, 0, 0));
-		sh2 shB = DiffuseSkyIBLTexture.Load(int3(2, 0, 0));
+		sh2 shR = SkyIBLTexture.Load(int3(0, 0, 0));
+		sh2 shG = SkyIBLTexture.Load(int3(1, 0, 0));
+		sh2 shB = SkyIBLTexture.Load(int3(2, 0, 0));
 		float colorR = SphericalHarmonics::SHHallucinateZH3Irradiance(shR, rayDir);
 		float colorG = SphericalHarmonics::SHHallucinateZH3Irradiance(shG, rayDir);
 		float colorB = SphericalHarmonics::SHHallucinateZH3Irradiance(shB, rayDir);
-		return float3(colorR, colorG, colorB) / Math::PI;
+		return max(0, float3(colorR, colorG, colorB) / Math::PI);
 	}
 
-#if defined(SKYLIGHTING) && !defined(INTERIOR)
-	float3 GetIBLColor(float3 rayDir, float skylighting)
-#else
-	float3 GetIBLColor(float3 rayDir)
-#endif
+	/// Compute ratio between DALC and IBL for brightness/color matching.
+	/// Mode 0 (Luminance Ratio): scalar ratio from luminance, broadcast to float3 (loses DALC tint).
+	/// Mode 1 (Color Ratio): per-channel ratio, preserves DALC color tint.
+	/// DALCAmount interpolates between 1.0 (no matching) and the computed ratio.
+	float3 GetIBLRatio()
 	{
-		float3 color = 0;
-		if (SharedData::InInterior) {
-			color = GetDiffuseIBL(rayDir);
-		} else
-#if defined(SKYLIGHTING)
-		{
-			color = lerp(GetDiffuseIBL(rayDir), GetSkyDiffuseIBL(rayDir), skylighting);
-		}
-#else
-		{
-			color = GetSkyDiffuseIBL(rayDir);
+		// 0th order DALC (DC term)
+		float3 dalc0 = Color::Ambient(SharedData::GetAmbient(0.f));
+
+		// 0th order IBL SH (DC term from env cubemap)
+		sh2 iblSHR = EnvIBLTexture.Load(int3(0, 0, 0));
+		sh2 iblSHG = EnvIBLTexture.Load(int3(1, 0, 0));
+		sh2 iblSHB = EnvIBLTexture.Load(int3(2, 0, 0));
+
+		float colorR = SphericalHarmonics::SHHallucinateZH3Irradiance(iblSHR, float3(0, 0, 0));
+		float colorG = SphericalHarmonics::SHHallucinateZH3Irradiance(iblSHG, float3(0, 0, 0));
+		float colorB = SphericalHarmonics::SHHallucinateZH3Irradiance(iblSHB, float3(0, 0, 0));
+		float3 ibl0 = max(0, float3(colorR, colorG, colorB) / Math::PI);
+
+		if (SharedData::iblSettings.DALCMode == 1) {
+			// Mode 1: per-channel ratio preserving DALC color tint
+			float3 ratio = dalc0 / max(ibl0, 0.001);
+			return lerp(1.0, ratio, SharedData::iblSettings.DALCAmount);
+		} else {
+			// Mode 0: scalar luminance ratio (default)
+			float dalcLum = Color::RGBToLuminance(dalc0);
+			float iblLum = Color::RGBToLuminance(ibl0);
+			float ratio = (iblLum > 0.001) ? (dalcLum / iblLum) : 1.0;
+			return lerp(1.0, ratio, SharedData::iblSettings.DALCAmount);
 		}
-#endif
-		return color;
+	}
+
+	/// Get Env IBL color with settings applied (saturation, scale, ratio)
+	float3 GetEnvIBLColor(float3 rayDir)
+	{
+		float3 ratio = GetIBLRatio();
+		return Color::Saturation(GetEnvIBL(rayDir), SharedData::iblSettings.EnvIBLSaturation) * SharedData::iblSettings.EnvIBLScale * ratio;
+	}
+
+	/// Get Sky IBL color with settings applied (saturation, scale; no ratio)
+	float3 GetSkyIBLColor(float3 rayDir)
+	{
+		return Color::Saturation(GetSkyIBL(rayDir), SharedData::iblSettings.SkyIBLSaturation) * SharedData::iblSettings.SkyIBLScale;
+	}
+
+	/// Get combined IBL color: Env IBL + Sky IBL (for contexts without skylighting)
+	float3 GetIBLColor(float3 rayDir)
+	{
+		return GetEnvIBLColor(rayDir) + GetSkyIBLColor(rayDir);
 	}
 
 #if defined(LIGHTING)
@@ -71,8 +103,7 @@ namespace ImageBasedLighting
 
 	float3 GetFogIBLColor(float3 fogColor)
 	{
-		float3 directionalAmbientColor = max(0, mul(SharedData::DirectionalAmbient, float4(float3(0, 0, 0), 1.0))).xyz;
-		float3 iblColor = directionalAmbientColor * SharedData::iblSettings.DALCAmount + Color::Saturation(GetSkyDiffuseIBL(float3(0, 0, 0)), SharedData::iblSettings.IBLSaturation) * SharedData::iblSettings.DiffuseIBLScale;
+		float3 iblColor = GetEnvIBLColor(float3(0, 0, 0)) + GetSkyIBLColor(float3(0, 0, 0));
 		if (SharedData::iblSettings.PreserveFogLuminance) {
 			const float fogLuminance = Color::RGBToLuminance(fogColor);
 			const float iblLuminance = Color::RGBToLuminance(iblColor);

package/Shaders/Common/ShadowSampling.hlsli

@@ -107,17 +107,18 @@ namespace ShadowSampling
 	void ExtractLighting(float3 inputColor, out float3 dirColor, out float3 ambientColor)
 #endif
 	{
-		float3 ambientColorAmb = max(0, mul(SharedData::DirectionalAmbient, float4(0, 0, 1, 1)));
+		float3 ambientColorAmb = max(0, SharedData::GetAmbient(float3(0, 0, 1)));
 
 #if defined(IBL)
-		if (SharedData::iblSettings.EnableDiffuseIBL && (!SharedData::InInterior || SharedData::iblSettings.EnableInterior)) {
-			ambientColorAmb *= SharedData::iblSettings.DALCAmount;
-#	if defined(SKYLIGHTING) && !defined(INTERIOR)
-			float3 iblColor = Color::Saturation(ImageBasedLighting::GetIBLColor(float3(0, 0, -1), skylightingDiffuse), SharedData::iblSettings.IBLSaturation) * SharedData::iblSettings.DiffuseIBLScale;
-#	else
-			float3 iblColor = Color::Saturation(ImageBasedLighting::GetIBLColor(float3(0, 0, -1)), SharedData::iblSettings.IBLSaturation) * SharedData::iblSettings.DiffuseIBLScale;
-#	endif
-			ambientColorAmb += Color::IrradianceToGamma(iblColor);
+		if (SharedData::iblSettings.EnableIBL) {
+			if (SharedData::iblSettings.DALCMode == 2) {
+				// Mode 2: keep vanilla DALC scaled by DALCAmount, add sky IBL overlay
+				ambientColorAmb = ambientColorAmb * SharedData::iblSettings.DALCAmount + Color::IrradianceToGamma(ImageBasedLighting::GetSkyIBLColor(float3(0, 0, -1)));
+			} else {
+				float3 envIBLColor = Color::IrradianceToGamma(ImageBasedLighting::GetEnvIBLColor(float3(0, 0, -1)));
+				float3 skyIBLColor = Color::IrradianceToGamma(ImageBasedLighting::GetSkyIBLColor(float3(0, 0, -1)));
+				ambientColorAmb = envIBLColor + skyIBLColor;
+			}
 		}
 #endif
 

package/Shaders/Common/SharedData.hlsli

@@ -2,6 +2,7 @@
 #define __SHARED_DATA_DEPENDENCY_HLSL__
 
 #include "Common/FrameBuffer.hlsli"
+#include "Common/Spherical Harmonics/SphericalHarmonics.hlsli"
 #include "Common/VR.hlsli"
 
 namespace SharedData
@@ -23,6 +24,10 @@ namespace SharedData
 		bool InMapMenu;   // If the world/local map is open (note that the renderer is still deferred here)
 		bool HideSky;     // HideSky flag in WorldSpace, e.g. Blackreach
 		float MipBias;    // Offset to mip level for TAA sharpness#
+		float pad0;
+		float4 AmbientSHR;
+		float4 AmbientSHG;
+		float4 AmbientSHB;
 	};
 
 	struct GrassLightingSettings
@@ -182,14 +187,17 @@ namespace SharedData
 
 	struct IBLSettings
 	{
-		uint EnableDiffuseIBL;
+		uint EnableIBL;
 		uint PreserveFogLuminance;
 		uint UseStaticIBL;
-		uint EnableInterior;
-		float DiffuseIBLScale;
 		float DALCAmount;
-		float IBLSaturation;
+		float EnvIBLScale;
+		float SkyIBLScale;
+		float EnvIBLSaturation;
+		float SkyIBLSaturation;
 		float FogAmount;
+		uint DALCMode;  // 0: Luminance Ratio, 1: Color Ratio, 2: DALC + Sky
+		float2 pad0;
 	};
 
 	struct ExtendedTranslucencySettings
@@ -325,6 +333,11 @@ namespace SharedData
 		return waterData;
 	}
 
+	float3 GetAmbient(float3 normal)
+	{
+		return SphericalHarmonics::Unproject(AmbientSHR, AmbientSHG, AmbientSHB, normal);
+	}
+
 #endif  // PSHADER
 }
 #endif  // __SHARED_DATA_DEPENDENCY_HLSL__

package/Shaders/DeferredCompositeCS.hlsl

@@ -120,7 +120,7 @@ void SampleSSGISpecular(uint2 pixCoord, sh2 lobe, inout float ao, out float3 il,
 	float3 ssgiIl;
 	SampleSSGI(dispatchID.xy, normalWS, ssgiAo, ssgiIl);
 
-	float3 directionalAmbientColor = Color::Ambient(max(0, mul(SharedData::DirectionalAmbient, float4(normalWS, 1.0))));
+	float3 directionalAmbientColor = Color::Ambient(max(0, SharedData::GetAmbient(normalWS)));
 	directionalAmbientColor *= albedo;
 
 	directionalAmbientColor = Color::RGBToYCoCg(directionalAmbientColor);
@@ -173,26 +173,9 @@ void SampleSSGISpecular(uint2 pixCoord, sh2 lobe, inout float ao, out float3 il,
 
 		float3 finalIrradiance = 0;
 
-		float directionalAmbientColorSpecular = Color::RGBToLuminance(Color::Ambient(max(0, mul(SharedData::DirectionalAmbient, float4(R, 1.0))))) * Color::ReflectionNormalisationScale;
+		float directionalAmbientColorSpecular = Color::RGBToLuminance(Color::Ambient(max(0, SharedData::GetAmbient(R)))) * Color::ReflectionNormalisationScale;
 
-#	if defined(INTERIOR)
-		float3 specularIrradiance = EnvTexture.SampleLevel(LinearSampler, R, level);
-
-		float specularIrradianceLuminance = Color::RGBToLuminance(EnvTexture.SampleLevel(LinearSampler, R, 15));
-
-#		if defined(IBL)
-		float3 iblColor = 0;
-		if (SharedData::iblSettings.EnableDiffuseIBL && SharedData::iblSettings.EnableInterior) {
-			directionalAmbientColorSpecular *= SharedData::iblSettings.DALCAmount;
-			iblColor += Color::Saturation(ImageBasedLighting::GetIBLColor(-R), SharedData::iblSettings.IBLSaturation) * SharedData::iblSettings.DiffuseIBLScale;
-			float iblColorLuminance = Color::RGBToLuminance(Color::IrradianceToGamma(iblColor));
-			directionalAmbientColorSpecular += iblColorLuminance;
-		}
-#		endif
-		specularIrradiance = (specularIrradiance / max(specularIrradianceLuminance, 0.001)) * directionalAmbientColorSpecular;
-
-		finalIrradiance = Color::IrradianceToLinear(specularIrradiance);
-#	elif defined(SKYLIGHTING)
+#	if defined(SKYLIGHTING)
 #		if defined(VR)
 		float3 positionMS = positionWS.xyz + FrameBuffer::CameraPosAdjust[eyeIndex].xyz - FrameBuffer::CameraPosAdjust[0].xyz;
 #		else
@@ -204,64 +187,70 @@ void SampleSSGISpecular(uint2 pixCoord, sh2 lobe, inout float ao, out float3 il,
 		float skylightingSpecular = SphericalHarmonics::FuncProductIntegral(skylighting, specularLobe);
 		skylightingSpecular = saturate(skylightingSpecular);
 		skylightingSpecular = Skylighting::mixSpecular(SharedData::skylightingSettings, skylightingSpecular);
+#	endif
 
-#		if defined(IBL)
-		float3 iblColor = 0;
-		if (SharedData::iblSettings.EnableDiffuseIBL) {
-			directionalAmbientColorSpecular *= SharedData::iblSettings.DALCAmount;
-			iblColor += Color::Saturation(ImageBasedLighting::GetIBLColor(-R, skylightingSpecular), SharedData::iblSettings.IBLSaturation) * SharedData::iblSettings.DiffuseIBLScale;
-			float iblColorLuminance = Color::RGBToLuminance(Color::IrradianceToGamma(iblColor));
-			directionalAmbientColorSpecular += iblColorLuminance;
-		}
+#	if defined(IBL)
+		if (SharedData::iblSettings.EnableIBL) {
+			float3 envSample = EnvTexture.SampleLevel(LinearSampler, R, level);
+			float3 fullSample = EnvReflectionsTexture.SampleLevel(LinearSampler, R, level);
+			float3 envSpecular, skySpecular;
+
+			if (SharedData::iblSettings.DALCMode == 2) {
+				// Mode 2: DALC-normalized env scaled by DALCAmount + sky overlay
+				float envLum = Color::RGBToLuminance(EnvTexture.SampleLevel(LinearSampler, R, 15));
+				envSpecular = Color::IrradianceToLinear((envSample / max(envLum, 0.001)) * directionalAmbientColorSpecular) * SharedData::iblSettings.DALCAmount;
+				skySpecular = Color::IrradianceToLinear(max(0, fullSample - envSample)) * SharedData::iblSettings.SkyIBLScale;
+#		if defined(SKYLIGHTING)
+				skySpecular *= skylightingSpecular;
+#		elif defined(INTERIOR)
+				skySpecular = 0;
 #		endif
+			} else {
+				// Mode 0/1: IBL ratio-based
+				float3 ratio = ImageBasedLighting::GetIBLRatio();
+				envSpecular = Color::IrradianceToLinear(envSample * ratio) * SharedData::iblSettings.EnvIBLScale;
+				skySpecular = Color::IrradianceToLinear(max(0, fullSample - envSample)) * SharedData::iblSettings.SkyIBLScale;
+#		if defined(SKYLIGHTING)
+				skySpecular *= skylightingSpecular;
+#		elif defined(INTERIOR)
+				skySpecular = 0;
+#		endif
+			}
 
-		directionalAmbientColorSpecular = Color::IrradianceToLinear(directionalAmbientColorSpecular);
-		directionalAmbientColorSpecular *= skylightingSpecular;
-		directionalAmbientColorSpecular = Color::IrradianceToGamma(directionalAmbientColorSpecular);
-
-		float3 specularIrradianceReflections = 0.0;
-
-		if (skylightingSpecular > 0.0) {
-			specularIrradianceReflections = EnvReflectionsTexture.SampleLevel(LinearSampler, R, level);
-
-			float specularIrradianceLuminance = Color::RGBToLuminance(EnvReflectionsTexture.SampleLevel(LinearSampler, R, 15));
-
-			specularIrradianceReflections = (specularIrradianceReflections / max(specularIrradianceLuminance, 0.001)) * directionalAmbientColorSpecular;
-
-			specularIrradianceReflections = Color::IrradianceToLinear(specularIrradianceReflections);
-		}
-
-		float3 specularIrradiance = 0.0;
-
-		if (skylightingSpecular < 1.0) {
-			specularIrradiance = EnvTexture.SampleLevel(LinearSampler, R, level);
-
+			finalIrradiance = envSpecular + skySpecular;
+		} else
+#	endif
+		{
+			// Fallback without IBL: normalize-by-luminance with DALC
+#	if defined(INTERIOR)
+			float3 specularIrradiance = EnvTexture.SampleLevel(LinearSampler, R, level);
 			float specularIrradianceLuminance = Color::RGBToLuminance(EnvTexture.SampleLevel(LinearSampler, R, 15));
-
 			specularIrradiance = (specularIrradiance / max(specularIrradianceLuminance, 0.001)) * directionalAmbientColorSpecular;
-
-			specularIrradiance = Color::IrradianceToLinear(specularIrradiance);
-		}
-
-		finalIrradiance = lerp(specularIrradiance, specularIrradianceReflections, skylightingSpecular);
+			finalIrradiance = Color::IrradianceToLinear(specularIrradiance);
+#	elif defined(SKYLIGHTING)
+			float3 specularIrradianceReflections = 0.0;
+			if (skylightingSpecular > 0.0) {
+				specularIrradianceReflections = EnvReflectionsTexture.SampleLevel(LinearSampler, R, level);
+				float lum = Color::RGBToLuminance(EnvReflectionsTexture.SampleLevel(LinearSampler, R, 15));
+				specularIrradianceReflections = (specularIrradianceReflections / max(lum, 0.001)) * directionalAmbientColorSpecular;
+				specularIrradianceReflections = Color::IrradianceToLinear(specularIrradianceReflections);
+			}
+			float3 specularIrradiance = 0.0;
+			if (skylightingSpecular < 1.0) {
+				specularIrradiance = EnvTexture.SampleLevel(LinearSampler, R, level);
+				float lum = Color::RGBToLuminance(EnvTexture.SampleLevel(LinearSampler, R, 15));
+				float dalcScaled = Color::IrradianceToGamma(Color::IrradianceToLinear(directionalAmbientColorSpecular) * skylightingSpecular);
+				specularIrradiance = (specularIrradiance / max(lum, 0.001)) * dalcScaled;
+				specularIrradiance = Color::IrradianceToLinear(specularIrradiance);
+			}
+			finalIrradiance = lerp(specularIrradiance, specularIrradianceReflections, skylightingSpecular);
 #	else
-#		if defined(IBL)
-		float3 iblColor = 0;
-		if (SharedData::iblSettings.EnableDiffuseIBL) {
-			directionalAmbientColorSpecular *= SharedData::iblSettings.DALCAmount;
-			iblColor += Color::Saturation(ImageBasedLighting::GetIBLColor(-R), SharedData::iblSettings.IBLSaturation) * SharedData::iblSettings.DiffuseIBLScale;
-			float iblColorLuminance = Color::RGBToLuminance(Color::IrradianceToGamma(iblColor));
-			directionalAmbientColorSpecular += iblColorLuminance;
-		}
-#		endif
-		float3 specularIrradianceReflections = EnvReflectionsTexture.SampleLevel(LinearSampler, R, level);
-
-		float specularIrradianceReflectionsLuminance = Color::RGBToLuminance(EnvReflectionsTexture.SampleLevel(LinearSampler, R, 15));
-
-		specularIrradianceReflections = (specularIrradianceReflections / max(specularIrradianceReflectionsLuminance, 0.001)) * directionalAmbientColorSpecular;
-
-		finalIrradiance = Color::IrradianceToLinear(specularIrradianceReflections);
+			float3 specularIrradiance = EnvReflectionsTexture.SampleLevel(LinearSampler, R, level);
+			float specularIrradianceLuminance = Color::RGBToLuminance(EnvReflectionsTexture.SampleLevel(LinearSampler, R, 15));
+			specularIrradiance = (specularIrradiance / max(specularIrradianceLuminance, 0.001)) * directionalAmbientColorSpecular;
+			finalIrradiance = Color::IrradianceToLinear(specularIrradiance);
 #	endif
+		}
 
 #	if defined(SSGI)
 		float3 ssgiIlSpecular;