From 21e35a988af61520b491e7d7ae53286bb9dbfcd0 Mon Sep 17 00:00:00 2001
From: lisyarus <lisyarus@gmail.com>
Date: Wed, 29 Mar 2023 23:53:09 +0300
Subject: [PATCH] Parse emission texture & KHR_materials_emissive_strength from
 glTF

---
 libs/gfx/include/psemek/gfx/gltf_parser.hpp |  1 +
 libs/gfx/source/gltf_parser.cpp             | 17 +++++++++++++++++
 2 files changed, 18 insertions(+)

diff --git a/libs/gfx/include/psemek/gfx/gltf_parser.hpp b/libs/gfx/include/psemek/gfx/gltf_parser.hpp
index 64d13c22..25145d0f 100644
--- a/libs/gfx/include/psemek/gfx/gltf_parser.hpp
+++ b/libs/gfx/include/psemek/gfx/gltf_parser.hpp
@@ -56,6 +56,7 @@ namespace psemek::gfx
 			std::optional<color_4f> albedo;
 			std::optional<std::size_t> texture;
 			std::optional<color_3f> emission;
+			std::optional<std::size_t> emission_texture;
 			std::optional<std::size_t> material_texture;
 		};
 
diff --git a/libs/gfx/source/gltf_parser.cpp b/libs/gfx/source/gltf_parser.cpp
index 553155d1..d725a9d0 100644
--- a/libs/gfx/source/gltf_parser.cpp
+++ b/libs/gfx/source/gltf_parser.cpp
@@ -70,6 +70,7 @@ namespace psemek::gfx
 		static std::unordered_set<std::string> supported_extensions =
 		{
 			"KHR_lights_punctual",
+			"KHR_materials_emissive_strength"
 		};
 
 	}
@@ -207,6 +208,22 @@ namespace psemek::gfx
 				for (std::size_t i = 0; i < 3; ++i)
 					target_emission[i] = emission[i].GetFloat();
 			}
+
+			if (material.HasMember("emissiveTexture"))
+			{
+				target.emission_texture = document["textures"].GetArray()[material["emissiveTexture"]["index"].GetUint64()]["source"].GetInt64();
+			}
+
+			if (material.HasMember("extensions"))
+			{
+				auto const & extensions = material["extensions"];
+				if (extensions.HasMember("KHR_materials_emissive_strength"))
+				{
+					if (!target.emission)
+						target.emission = {1.f, 1.f, 1.f};
+					*target.emission *= extensions["KHR_materials_emissive_strength"]["emissiveStrength"].GetFloat();
+				}
+			}
 		}
 
 		if (document.HasMember("images")) for (auto const & image : document["images"].GetArray())