From e59529d3f55b9128f798a7f02a7288f96bdaf9a4 Mon Sep 17 00:00:00 2001
From: Chuyan Zhang <chuyan@ucsb.edu>
Date: Thu, 3 Oct 2024 19:49:47 -0700
Subject: use xmake build & scene load wip

---
 src/gltf_loader.cpp | 96 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 96 insertions(+)
 create mode 100644 src/gltf_loader.cpp

(limited to 'src/gltf_loader.cpp')

diff --git a/src/gltf_loader.cpp b/src/gltf_loader.cpp
new file mode 100644
index 0000000..2b3818f
--- /dev/null
+++ b/src/gltf_loader.cpp
@@ -0,0 +1,96 @@
+#include "gltf_loader.h"
+#include "spdlog/spdlog.h"
+
+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<float> iris_mesh;
+        for (const auto &primitive : mesh.primitives) {
+            const auto &position_accessor = model.accessors[primitive.attributes.at("POSITION")];
+            const auto &position_buffer_view = model.bufferViews[position_accessor.bufferView];
+            const auto &position_buffer = model.buffers[position_buffer_view.buffer];
+            const auto &position_data = reinterpret_cast<const float *>(position_buffer.data.data() + position_buffer_view.byteOffset + position_accessor.byteOffset);
+
+            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 auto &index_data = reinterpret_cast<const uint32_t *>(index_buffer.data.data() + index_buffer_view.byteOffset + index_accessor.byteOffset);
+
+            iris_mesh.vertices.insert(iris_mesh.vertices.end(), position_data, position_data + position_accessor.count * 3);
+            iris_mesh.indices.insert(iris_mesh.indices.end(), index_data, index_data + index_accessor.count);
+        }
+        scene.meshes.push_back(iris_mesh);
+    }
+    return true;
+}
\ No newline at end of file
-- 
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