From 663f7bc5f4c51c62b94bc6331aff26355cfde630 Mon Sep 17 00:00:00 2001
From: lisyarus <lisyarus@gmail.com>
Date: Sat, 16 Mar 2024 17:37:57 +0300
Subject: [PATCH] Support retrieving extra properties & raw mesh from gltf mesh

---
 libs/gfx/include/psemek/gfx/gltf_mesh.hpp   |  5 +++
 libs/gfx/include/psemek/gfx/gltf_parser.hpp |  3 +-
 libs/gfx/source/gltf_mesh.cpp               | 45 +++++++++++++++++++--
 3 files changed, 48 insertions(+), 5 deletions(-)

diff --git a/libs/gfx/include/psemek/gfx/gltf_mesh.hpp b/libs/gfx/include/psemek/gfx/gltf_mesh.hpp
index 5cabbc04..5d004f8b 100644
--- a/libs/gfx/include/psemek/gfx/gltf_mesh.hpp
+++ b/libs/gfx/include/psemek/gfx/gltf_mesh.hpp
@@ -3,6 +3,7 @@
 #include <psemek/gfx/gltf_parser.hpp>
 #include <psemek/gfx/drawable.hpp>
 #include <psemek/gfx/texture.hpp>
+#include <psemek/geom/simplex.hpp>
 #include <psemek/util/span.hpp>
 #include <psemek/util/blob.hpp>
 
@@ -17,11 +18,15 @@ namespace psemek::gfx
 		{
 			gfx::drawable * drawable;
 			std::optional<std::size_t> material;
+
+			util::span<geom::point<float, 3> const> vertices;
+			util::span<geom::triangle<std::uint32_t> const> triangles;
 		};
 
 		virtual gltf_asset::material const & material(std::size_t index) const = 0;
 		virtual gfx::texture_2d const & texture(std::size_t index) const = 0;
 		virtual util::span<primitive const> mesh(std::string_view name) const = 0;
+		virtual gltf_asset::extra const * mesh_property(std::string_view mesh_name, std::string_view property_name) const = 0;
 
 		virtual ~gltf_mesh() {}
 	};
diff --git a/libs/gfx/include/psemek/gfx/gltf_parser.hpp b/libs/gfx/include/psemek/gfx/gltf_parser.hpp
index 08923379..59394afd 100644
--- a/libs/gfx/include/psemek/gfx/gltf_parser.hpp
+++ b/libs/gfx/include/psemek/gfx/gltf_parser.hpp
@@ -6,6 +6,7 @@
 #include <psemek/geom/quaternion.hpp>
 #include <psemek/geom/affine_transform.hpp>
 #include <psemek/geom/easing.hpp>
+#include <psemek/util/hstring.hpp>
 
 #include <vector>
 #include <string>
@@ -19,7 +20,7 @@ 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>;
+		using extras_map = std::unordered_map<util::hstring, extra>;
 
 		struct node
 		{
diff --git a/libs/gfx/source/gltf_mesh.cpp b/libs/gfx/source/gltf_mesh.cpp
index b3d0bbaf..105e7fec 100644
--- a/libs/gfx/source/gltf_mesh.cpp
+++ b/libs/gfx/source/gltf_mesh.cpp
@@ -1,4 +1,5 @@
 #include <psemek/gfx/gltf_mesh.hpp>
+#include <psemek/gfx/gltf_accessor_iterator.hpp>
 #include <psemek/gfx/array.hpp>
 #include <psemek/gfx/buffer.hpp>
 #include <psemek/util/hstring.hpp>
@@ -21,6 +22,9 @@ namespace psemek::gfx
 			std::size_t index_offset;
 			GLenum index_type;
 
+			std::vector<geom::point<float, 3>> vertices;
+			std::vector<geom::triangle<std::uint32_t>> triangles;
+
 			void draw() const override
 			{
 				vao.bind();
@@ -46,16 +50,32 @@ namespace psemek::gfx
 			util::span<primitive const> mesh(std::string_view name) const override
 			{
 				if (auto it = meshes_.find(name); it != meshes_.end())
-					return it->second;
+					return it->second.primitives;
 				return {};
 			}
 
+			gltf_asset::extra const * mesh_property(std::string_view mesh_name, std::string_view property_name) const override
+			{
+				if (auto it = meshes_.find(mesh_name); it != meshes_.end())
+					if (auto jt = it->second.extras.find(property_name); jt != it->second.extras.end())
+						return &(jt->second);
+				return nullptr;
+			}
+
 		private:
+			struct mesh_data
+			{
+				std::vector<primitive> primitives;
+				gltf_asset::extras_map extras;
+				std::vector<geom::point<float, 3>> vertices;
+				std::vector<geom::triangle<std::uint32_t>> triangles;
+			};
+
 			std::vector<gltf_asset::material> materials_;
 			std::vector<gfx::texture_2d> textures_;
 			std::vector<gfx::buffer> buffers_;
 			std::vector<std::unique_ptr<drawable_impl>> drawables_;
-			std::unordered_map<util::hstring, std::vector<primitive>> meshes_;
+			std::unordered_map<util::hstring, mesh_data> meshes_;
 		};
 
 		gltf_mesh_impl::gltf_mesh_impl(gltf_asset const & asset, std::function<util::blob(std::string const &)> uri_loader)
@@ -91,6 +111,7 @@ namespace psemek::gfx
 					continue;
 
 				auto & target_mesh = meshes_[node.name];
+				target_mesh.extras = node.extras;
 
 				auto const & mesh = asset.meshes[*node.mesh];
 
@@ -111,11 +132,12 @@ namespace psemek::gfx
 						drawable.index_count = indices_accessor.count;
 					}
 
-					std::pair<GLuint, std::optional<std::size_t>> attributes[3] =
+					std::pair<GLuint, std::optional<std::size_t>> attributes[] =
 					{
 						{0, primitive.position},
 						{1, primitive.normal},
 						{2, primitive.texcoord},
+						{3, primitive.color},
 					};
 
 					for (auto const & attribute : attributes)
@@ -130,7 +152,22 @@ namespace psemek::gfx
 						gl::VertexAttribPointer(attribute.first, attribute_size(accessor.type), accessor.component_type, accessor.normalized, 0, reinterpret_cast<void const *>(view.offset));
 					}
 
-					target_mesh.push_back({&drawable, primitive.material});
+					{
+						auto indices = accessor_range<std::uint32_t>(asset, primitive.indices);
+						for (auto it = indices.it_begin; it != indices.it_end;)
+						{
+							auto i0 = *it++;
+							auto i1 = *it++;
+							auto i2 = *it++;
+							drawable.triangles.push_back({i0, i1, i2});
+						}
+					}
+
+					if (primitive.position)
+						for (auto const & p : accessor_range<geom::point<float, 3>>(asset, *primitive.position))
+							drawable.vertices.push_back(p);
+
+					target_mesh.primitives.push_back({&drawable, primitive.material, drawable.vertices, drawable.triangles});
 				}
 			}
 		}