handle emissive color conversions in gamma space and with specific Un…

…ity shaders better
KhronosGroup · Sep 5, 2023 · 0fdc0e4 · 0fdc0e4
1 parent cacb3ec
commit 0fdc0e4
Show file tree

Hide file tree

Showing 3 changed files with 27 additions and 2 deletions.
diff --git a/Runtime/Scripts/Extensions/SchemaExtensions.cs b/Runtime/Scripts/Extensions/SchemaExtensions.cs
@@ -334,6 +334,12 @@ public static UnityEngine.Color ToUnityColorLinear(this GLTF.Math.Color color)
 			var c = new UnityEngine.Color(color.R, color.G, color.B, color.A);
 			return c;
 		}
+
+		public static UnityEngine.Color ToUnityColorGamma(this GLTF.Math.Color color)
+		{
+			var c = new UnityEngine.Color(color.R, color.G, color.B, color.A).linear;
+			return c;
+		}
 
 		public static GLTF.Math.Color ToNumericsColorRaw(this UnityEngine.Color color)
 		{
@@ -346,6 +352,12 @@ public static GLTF.Math.Color ToNumericsColorLinear(this UnityEngine.Color color
 			var lc = color.linear;
 			return new GLTF.Math.Color(lc.r, lc.g, lc.b, lc.a);
 		}
+
+		public static GLTF.Math.Color ToNumericsColorGamma(this UnityEngine.Color color)
+		{
+			var lc = color.gamma;
+			return new GLTF.Math.Color(lc.r, lc.g, lc.b, lc.a);
+		}
 
 		public static GLTF.Math.Color[] ToNumericsColorLinear(this UnityEngine.Color[] inColorArr)
 		{

diff --git a/Runtime/Scripts/SceneExporter/ExporterMaterials.cs b/Runtime/Scripts/SceneExporter/ExporterMaterials.cs
@@ -163,11 +163,24 @@ public MaterialId ExportMaterial(Material materialObj)
 
 			if (materialObj.IsKeywordEnabled("_EMISSION") || materialObj.IsKeywordEnabled("EMISSION") || materialObj.HasProperty("emissiveTexture") || materialObj.HasProperty("_EmissiveTexture"))
 			{
+				// In Gamma space, some materials treat their emissive color inputs differently than in Linear space.
+				// This is super confusing when converting materials, but we also need to handle it correctly here.
+				var isUnityMaterialWithWeirdColorspaceHandling = QualitySettings.activeColorSpace == ColorSpace.Gamma &&
+					(materialObj.shader.name == "Standard" || materialObj.shader.name == "Standard (Specular setup)" ||
+					materialObj.shader.name == "Standard (Roughness setup)" ||
+					materialObj.shader.name == "Universal Render Pipeline/Lit" ||
+					materialObj.shader.name == "Universal Render Pipeline/Simple Lit" ||
+					materialObj.shader.name == "Universal Render Pipeline/Unlit");
+
 				if (materialObj.HasProperty("_EmissionColor") || materialObj.HasProperty("emissiveFactor") || materialObj.HasProperty("_EmissiveFactor"))
 				{
 					var c = materialObj.HasProperty("_EmissionColor") ? materialObj.GetColor("_EmissionColor") : materialObj.HasProperty("emissiveFactor") ? materialObj.GetColor("emissiveFactor") : materialObj.GetColor("_EmissiveFactor");
 					DecomposeEmissionColor(c, out var emissiveAmount, out var maxEmissiveAmount);
-					material.EmissiveFactor = emissiveAmount.ToNumericsColorRaw();
+
+					if (isUnityMaterialWithWeirdColorspaceHandling)
+						material.EmissiveFactor = emissiveAmount.ToNumericsColorRaw();
+					else
+						material.EmissiveFactor = emissiveAmount.ToNumericsColorGamma();
 
 					if(maxEmissiveAmount > 1)
 					{

diff --git a/Runtime/Scripts/SceneImporter/ImporterMaterials.cs b/Runtime/Scripts/SceneImporter/ImporterMaterials.cs
@@ -641,7 +641,7 @@ void SetTransformKeyword()
 					}
 				}
 
-				uniformMapper.EmissiveFactor = QualitySettings.activeColorSpace == ColorSpace.Linear ? def.EmissiveFactor.ToUnityColorLinear() : def.EmissiveFactor.ToUnityColorRaw();
+				uniformMapper.EmissiveFactor = QualitySettings.activeColorSpace == ColorSpace.Linear ? def.EmissiveFactor.ToUnityColorLinear() : def.EmissiveFactor.ToUnityColorLinear();
 
 				var emissiveExt = GetEmissiveStrength(def);
 				if (emissiveExt != null)