Function convert_mesh_part

src/resource/mesh_obj.cpp:101–157

See: https://ufbx.github.io/elements/meshes/#example

	/// See: https://ufbx.github.io/elements/meshes/#example
	static size_t convert_mesh_part(Geometry &g, const ufbx_mesh *mesh, const ufbx_mesh_part *part)
	{
		size_t num_triangles = part->num_triangles;

		// Reserve space for the maximum triangle indices.
		size_t num_tri_indices = mesh->max_face_triangles * 3;
		uint32_t *tri_indices = (uint32_t *)calloc(num_tri_indices, sizeof(uint32_t));

		// Iterate over each face using the specific material.
		for (size_t face_ix = 0; face_ix < part->num_faces; face_ix++) {
			ufbx_face face = mesh->faces.data[part->face_indices.data[face_ix]];

			// Triangulate the face into `tri_indices[]`.
			uint32_t num_tris = ufbx_triangulate_face(tri_indices, num_tri_indices, mesh, face);

			// Iterate over each triangle corner contiguously.
			for (size_t i = 0; i < num_tris * 3; i++) {
				uint32_t index = tri_indices[i];

				ufbx_vec3 v = ufbx_get_vertex_vec3(&mesh->vertex_position, index);
				array::push_back(g._positions, (f32)v.x);
				array::push_back(g._positions, (f32)v.y);
				array::push_back(g._positions, (f32)v.z);

				if (mesh->vertex_normal.exists) {
					ufbx_vec3 v = ufbx_get_vertex_vec3(&mesh->vertex_normal, index);
					array::push_back(g._normals, (f32)v.x);
					array::push_back(g._normals, (f32)v.y);
					array::push_back(g._normals, (f32)v.z);
				}

				if (mesh->vertex_tangent.exists) {
					ufbx_vec3 v = ufbx_get_vertex_vec3(&mesh->vertex_tangent, index);
					array::push_back(g._tangents, (f32)v.x);
					array::push_back(g._tangents, (f32)v.y);
					array::push_back(g._tangents, (f32)v.z);
				}

				if (mesh->vertex_bitangent.exists) {
					ufbx_vec3 v = ufbx_get_vertex_vec3(&mesh->vertex_bitangent, index);
					array::push_back(g._bitangents, (f32)v.x);
					array::push_back(g._bitangents, (f32)v.y);
					array::push_back(g._bitangents, (f32)v.z);
				}

				if (mesh->vertex_uv.exists) {
					ufbx_vec2 v = ufbx_get_vertex_vec2(&mesh->vertex_uv, index);
					array::push_back(g._uvs,        (f32)v.x);
					array::push_back(g._uvs, 1.0f - (f32)v.y);
				}
			}
		}

		free(tri_indices);

		return num_triangles * 3;
	}