learn-vulkan/vk_loader.cpp

135 lines
4.6 KiB
C++

#include <iostream>
#include "vendor/stb_image.h"
#include <vk_loader.h>
#include "vk_engine.h"
#include "vk_initializers.h"
#include "vk_types.h"
#include <glm/gtx/quaternion.hpp>
#include <fastgltf/glm_element_traits.hpp>
#include <fastgltf/parser.hpp>
#include <fastgltf/tools.hpp>
std::optional<std::vector<std::shared_ptr<MeshAsset>>> loadGltfMeshes(VulkanEngine* engine, std::filesystem::path filePath)
{
//> openmesh
std::cout << "\nLoading GLTF: " << filePath << std::endl;
fastgltf::GltfDataBuffer data;
data.loadFromFile(filePath);
constexpr auto gltfOptions = fastgltf::Options::LoadGLBBuffers
| fastgltf::Options::LoadExternalBuffers;
fastgltf::Asset gltf;
fastgltf::Parser parser {};
auto load = parser.loadBinaryGLTF(&data, filePath.parent_path(), gltfOptions);
if (load) {
gltf = std::move(load.get());
} else {
std::print("Failed to load glTF: {} \n", fastgltf::to_underlying(load.error()));
return {};
}
//< openmesh
//> loadmesh
std::vector<std::shared_ptr<MeshAsset>> meshes;
// use the same vectors for all meshes so that the memory doesnt reallocate as
// often
std::vector<uint32_t> indices;
std::vector<Vertex> vertices;
for (fastgltf::Mesh& mesh : gltf.meshes) {
MeshAsset newmesh;
newmesh.name = mesh.name;
// clear the mesh arrays each mesh, we dont want to merge them by error
indices.clear();
vertices.clear();
for (auto&& p : mesh.primitives) {
GeoSurface newSurface;
newSurface.startIndex = (uint32_t)indices.size();
newSurface.count = (uint32_t)gltf.accessors[p.indicesAccessor.value()].count;
size_t initial_vtx = vertices.size();
// load indexes
{
fastgltf::Accessor& indexaccessor = gltf.accessors[p.indicesAccessor.value()];
indices.reserve(indices.size() + indexaccessor.count);
fastgltf::iterateAccessor<std::uint32_t>(gltf, indexaccessor,
[&](std::uint32_t idx) {
indices.push_back(idx + initial_vtx);
});
}
// load vertex positions
{
fastgltf::Accessor& posAccessor = gltf.accessors[p.findAttribute("POSITION")->second];
vertices.resize(vertices.size() + posAccessor.count);
fastgltf::iterateAccessorWithIndex<glm::vec3>(gltf, posAccessor,
[&](glm::vec3 v, size_t index) {
Vertex newvtx;
newvtx.position = v;
newvtx.normal = { 1, 0, 0 };
newvtx.color = glm::vec4 { 1.f };
newvtx.uv_x = 0;
newvtx.uv_y = 0;
vertices[initial_vtx + index] = newvtx;
});
}
// load vertex normals
auto normals = p.findAttribute("NORMAL");
if (normals != p.attributes.end()) {
fastgltf::iterateAccessorWithIndex<glm::vec3>(gltf, gltf.accessors[(*normals).second],
[&](glm::vec3 v, size_t index) {
vertices[initial_vtx + index].normal = v;
});
}
// load UVs
auto uv = p.findAttribute("TEXCOORD_0");
if (uv != p.attributes.end()) {
fastgltf::iterateAccessorWithIndex<glm::vec2>(gltf, gltf.accessors[(*uv).second],
[&](glm::vec2 v, size_t index) {
vertices[initial_vtx + index].uv_x = v.x;
vertices[initial_vtx + index].uv_y = v.y;
});
}
// load vertex colors
auto colors = p.findAttribute("COLOR_0");
if (colors != p.attributes.end()) {
fastgltf::iterateAccessorWithIndex<glm::vec4>(gltf, gltf.accessors[(*colors).second],
[&](glm::vec4 v, size_t index) {
vertices[initial_vtx + index].color = v;
});
}
newmesh.surfaces.push_back(newSurface);
}
// display the vertex normals
constexpr bool OverrideColors = true;
if (OverrideColors) {
for (Vertex& vtx : vertices) {
vtx.color = glm::vec4(vtx.normal, 1.f);
}
}
newmesh.meshBuffers = engine->uploadMesh(indices, vertices);
meshes.emplace_back(std::make_shared<MeshAsset>(std::move(newmesh)));
}
return meshes;
//< loadmesh
}