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#include "gltf_loader.h"
#include "spdlog/spdlog.h"
#include <concepts>
enum class SceneFileType {
GLTF,
GLB,
UNKNOWN,
};
bool load_gltf(const std::string_view path, iris::Scene &scene) {
tinygltf::Model model;
tinygltf::TinyGLTF loader;
std::string error;
std::string warning;
SceneFileType file_type = [&path] {
if (path.find_last_of(".") != std::string::npos) {
std::string_view extension = path.substr(path.find_last_of(".") + 1);
if (extension == "glb") {
return SceneFileType::GLB;
} else if (extension == "gltf") {
return SceneFileType::GLTF;
}
}
return SceneFileType::UNKNOWN;
}();
switch (file_type) {
case SceneFileType::GLTF:
if (!loader.LoadASCIIFromFile(&model, &error, &warning, path.data())) {
spdlog::error("Failed to load glTF file: {}", error);
return false;
}
break;
case SceneFileType::GLB:
if (!loader.LoadBinaryFromFile(&model, &error, &warning, path.data())) {
spdlog::error("Failed to load glTF file: {}", error);
return false;
}
break;
case SceneFileType::UNKNOWN:
spdlog::error("Unknown file type: {}", path);
return false;
}
spdlog::info("loaded glTF file {} has:\n"
"{} accessors\n"
"{} animations\n"
"{} buffers\n"
"{} bufferViews\n"
"{} materials\n"
"{} meshes\n"
"{} nodes\n"
"{} textures\n"
"{} images\n"
"{} skins\n"
"{} samplers\n"
"{} cameras\n"
"{} scenes\n"
"{} lights",
path,
model.accessors.size(),
model.animations.size(),
model.buffers.size(),
model.bufferViews.size(),
model.materials.size(),
model.meshes.size(),
model.nodes.size(),
model.textures.size(),
model.images.size(),
model.skins.size(),
model.samplers.size(),
model.cameras.size(),
model.scenes.size(),
model.lights.size());
for (const auto &mesh : model.meshes) {
iris::Mesh iris_mesh {
.name = mesh.name,
.vertices = {},
.indices = {},
};
for (const auto &primitive : mesh.primitives) {
const auto &index_accessor = model.accessors[primitive.indices];
const auto &index_buffer_view = model.bufferViews[index_accessor.bufferView];
const auto &index_buffer = model.buffers[index_buffer_view.buffer];
const uint8_t *index_data_ptr = index_buffer.data.data() + index_buffer_view.byteOffset + index_accessor.byteOffset;
auto extract_index = [&index_data_ptr]<typename T>() -> T requires std::integral<T> {
const T *index_data = reinterpret_cast<const T *>(index_data_ptr);
index_data_ptr += sizeof(T);
return *index_data;
};
switch (index_accessor.componentType) {
case TINYGLTF_COMPONENT_TYPE_BYTE:
for (size_t i = 0; i < index_accessor.count; i++) {
iris_mesh.indices.push_back(extract_index.operator()<int8_t>());
}
break;
case TINYGLTF_COMPONENT_TYPE_UNSIGNED_BYTE:
for (size_t i = 0; i < index_accessor.count; i++) {
iris_mesh.indices.push_back(extract_index.operator()<uint8_t>());
}
break;
case TINYGLTF_COMPONENT_TYPE_SHORT:
for (size_t i = 0; i < index_accessor.count; i++) {
iris_mesh.indices.push_back(extract_index.operator()<int16_t>());
}
break;
case TINYGLTF_COMPONENT_TYPE_UNSIGNED_SHORT:
for (size_t i = 0; i < index_accessor.count; i++) {
iris_mesh.indices.push_back(extract_index.operator()<uint16_t>());
}
break;
case TINYGLTF_COMPONENT_TYPE_INT:
for (size_t i = 0; i < index_accessor.count; i++) {
iris_mesh.indices.push_back(extract_index.operator()<int32_t>());
}
break;
case TINYGLTF_COMPONENT_TYPE_UNSIGNED_INT:
for (size_t i = 0; i < index_accessor.count; i++) {
iris_mesh.indices.push_back(extract_index.operator()<uint32_t>());
}
break;
default:
spdlog::error("Unsupported index component type: {}", index_accessor.componentType);
return false;
}
switch (primitive.mode) {
case TINYGLTF_MODE_TRIANGLES: {
// All float ?
for (const auto &[attrib_name, accessor_index] : primitive.attributes) {
const auto &accessor = model.accessors[accessor_index];
const auto &buffer_view = model.bufferViews[accessor.bufferView];
const auto &buffer = model.buffers[buffer_view.buffer];
const float *data = reinterpret_cast<const float *>(buffer.data.data() + buffer_view.byteOffset + accessor.byteOffset);
// TODO: support other types. Currently only float3 is supported
if (accessor.type != TINYGLTF_TYPE_VEC3 || accessor.componentType != TINYGLTF_COMPONENT_TYPE_FLOAT) {
spdlog::error("Unsupported POSITION type: {}, {}", accessor.type, accessor.componentType);
return false;
}
// spdlog::info("attribute: {}, count: {}", attrib_name, accessor.count);
if (attrib_name == "POSITION") {
spdlog::info("loading POSITION, count {}", accessor.count);
for (size_t i = 0; i < accessor.count; i++) {
iris_mesh.vertices.push_back(data[i * 3 + 0]);
iris_mesh.vertices.push_back(data[i * 3 + 1]);
iris_mesh.vertices.push_back(data[i * 3 + 2]);
}
} else if (attrib_name == "NORMAL") {
spdlog::info("loading NORMAL, count {}", accessor.count);
for (size_t i = 0; i < accessor.count; i++) {
iris_mesh.vertices.push_back(data[i * 3 + 0]);
iris_mesh.vertices.push_back(data[i * 3 + 1]);
iris_mesh.vertices.push_back(data[i * 3 + 2]);
}
// TODO reorder normals correctly
} else if (attrib_name == "TEXCOORD_0") {
spdlog::info("loading TEXCOORD_0, count {}", accessor.count);
for (size_t i = 0; i < accessor.count; i++) {
iris_mesh.vertices.push_back(data[i * 2 + 0]);
iris_mesh.vertices.push_back(data[i * 2 + 1]);
}
} else {
spdlog::warn("Unsupported attribute: {}", attrib_name);
}
}
}
// TODO add support for other modes
default:
spdlog::error("Unsupported primitive mode: {}", primitive.mode);
return false;
}
}
scene.meshes.push_back(iris_mesh);
}
return true;
}
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