From 7ad2c92d31ac894b77d1fda9cee31c217e95e362 Mon Sep 17 00:00:00 2001
From: lisyarus <lisyarus@gmail.com>
Date: Thu, 30 Mar 2023 10:48:54 +0300
Subject: [PATCH] Parse blender extras in glTF

---
 libs/gfx/include/psemek/gfx/gltf_parser.hpp |  9 ++++
 libs/gfx/source/gltf_parser.cpp             | 49 +++++++++++++++++++++
 2 files changed, 58 insertions(+)

diff --git a/libs/gfx/include/psemek/gfx/gltf_parser.hpp b/libs/gfx/include/psemek/gfx/gltf_parser.hpp
index 25145d0f..d086c262 100644
--- a/libs/gfx/include/psemek/gfx/gltf_parser.hpp
+++ b/libs/gfx/include/psemek/gfx/gltf_parser.hpp
@@ -18,6 +18,9 @@ namespace psemek::gfx
 
 	struct gltf_asset
 	{
+		using extra = std::variant<float, std::vector<float>, std::string>;
+		using extras_map = std::unordered_map<std::string, extra>;
+
 		struct node
 		{
 			std::string name;
@@ -31,6 +34,8 @@ namespace psemek::gfx
 			geom::quaternion<float> rotation;
 			geom::vector<float, 3> scale;
 			geom::affine_transform<float, 3, 3> transform;
+
+			extras_map extras;
 		};
 
 		struct mesh
@@ -58,6 +63,8 @@ namespace psemek::gfx
 			std::optional<color_3f> emission;
 			std::optional<std::size_t> emission_texture;
 			std::optional<std::size_t> material_texture;
+
+			extras_map extras;
 		};
 
 		struct texture
@@ -146,6 +153,8 @@ namespace psemek::gfx
 			float intensity;
 			float range;
 			geom::interval<float> cone_angle;
+
+			extras_map extras;
 		};
 
 		std::vector<node> nodes;
diff --git a/libs/gfx/source/gltf_parser.cpp b/libs/gfx/source/gltf_parser.cpp
index d725a9d0..5511aac9 100644
--- a/libs/gfx/source/gltf_parser.cpp
+++ b/libs/gfx/source/gltf_parser.cpp
@@ -3,6 +3,7 @@
 #include <psemek/geom/rotation.hpp>
 #include <psemek/geom/translation.hpp>
 #include <psemek/util/to_string.hpp>
+#include <psemek/log/log.hpp>
 
 #include <boost/preprocessor/stringize.hpp>
 
@@ -73,6 +74,48 @@ namespace psemek::gfx
 			"KHR_materials_emissive_strength"
 		};
 
+		gltf_asset::extras_map parse_extras(rapidjson::GenericValue<rapidjson::UTF8<>> const & value)
+		{
+			gltf_asset::extras_map result;
+
+			if (value.HasMember("extras"))
+			{
+				for (auto const & extra : value["extras"].GetObject())
+				{
+					std::string name = extra.name.GetString();
+					gltf_asset::extra value;
+
+					bool error = false;
+
+					if (extra.value.IsNumber())
+						value = extra.value.GetFloat();
+					else if (extra.value.IsString())
+						value = extra.value.GetString();
+					else if (extra.value.IsArray())
+					{
+						std::vector<float> v;
+						for (auto const & val : extra.value.GetArray())
+						{
+							if (!val.IsNumber())
+								error = true;
+							else
+								v.push_back(val.GetFloat());
+						}
+						value = std::move(v);
+					}
+					else
+						error = true;
+
+					if (error)
+						log::warning() << "every 'extras' value must be either a number, an array of numbers, or a string (while parting glTF)";
+					else
+						result[name] = std::move(value);
+				}
+			}
+
+			return result;
+		}
+
 	}
 
 	gltf_asset parse_gltf(io::istream && stream)
@@ -144,6 +187,8 @@ namespace psemek::gfx
 						target.light = extension.value["light"].GetUint64();
 					}
 				}
+
+			target.extras = parse_extras(node);
 		}
 
 		if (document.HasMember("meshes")) for (auto const & mesh : document["meshes"].GetArray())
@@ -224,6 +269,8 @@ namespace psemek::gfx
 					*target.emission *= extensions["KHR_materials_emissive_strength"]["emissiveStrength"].GetFloat();
 				}
 			}
+
+			target.extras = parse_extras(material);
 		}
 
 		if (document.HasMember("images")) for (auto const & image : document["images"].GetArray())
@@ -367,6 +414,8 @@ namespace psemek::gfx
 						if (spot.HasMember("outerConeAngle"))
 							target.cone_angle.max = spot["outerConeAngle"].GetFloat();
 					}
+
+					target.extras = parse_extras(light);
 				}
 			}
 		}