92 lines
3.1 KiB
C++
92 lines
3.1 KiB
C++
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#include "vde/foundation/io_gltf.h"
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#include <fstream>
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#include <sstream>
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#include <algorithm>
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#include <cmath>
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namespace vde::foundation {
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namespace {
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std::string vec3_to_json(double x, double y, double z) {
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return "[" + std::to_string(x) + "," + std::to_string(y) + "," + std::to_string(z) + "]";
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}
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} // namespace
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bool write_gltf(const std::string& filepath, const mesh::HalfedgeMesh& mesh) {
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std::ofstream file(filepath);
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if (!file) return false;
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size_t nv = mesh.num_vertices();
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size_t nf = mesh.num_faces();
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// Count total indices (triangles * 3)
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size_t index_count = nf * 3;
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// Build min/max for accessor bounds
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core::AABB3D bounds = mesh.bounds();
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file << "{\n";
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file << " \"asset\": {\"version\": \"2.0\", \"generator\": \"ViewDesignEngine\"},\n";
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file << " \"scene\": 0,\n";
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file << " \"scenes\": [{\"nodes\": [0]}],\n";
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file << " \"nodes\": [{\"mesh\": 0}],\n";
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file << " \"meshes\": [{\n";
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file << " \"primitives\": [{\n";
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file << " \"attributes\": {\"POSITION\": 0},\n";
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file << " \"indices\": 1\n";
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file << " }]\n";
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file << " }],\n";
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// Buffers and bufferViews
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file << " \"buffers\": [{\"uri\": \"data:application/octet-stream;base64,";
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// Write binary data as base64 (simplified: write inline as hex-ish)
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// For simplicity, write a separate .bin file reference
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file << "mesh.bin\",\"byteLength\": " << (nv*12 + index_count*4) << "}],\n";
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file << " \"bufferViews\": [\n";
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file << " {\"buffer\": 0, \"byteOffset\": 0, \"byteLength\": " << (nv*12) << "},\n";
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file << " {\"buffer\": 0, \"byteOffset\": " << (nv*12) << ", \"byteLength\": " << (index_count*4) << "}\n";
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file << " ],\n";
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// Accessors
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file << " \"accessors\": [\n";
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file << " {\"bufferView\": 0, \"componentType\": 5126, \"count\": " << nv
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<< ", \"type\": \"VEC3\", \"max\": " << vec3_to_json(bounds.max().x(),bounds.max().y(),bounds.max().z())
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<< ", \"min\": " << vec3_to_json(bounds.min().x(),bounds.min().y(),bounds.min().z()) << "},\n";
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file << " {\"bufferView\": 1, \"componentType\": 5125, \"count\": " << index_count
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<< ", \"type\": \"SCALAR\"}\n";
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file << " ]\n";
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file << "}\n";
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// Write binary data file
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std::string binpath = filepath;
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size_t dot = binpath.rfind(.);
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if (dot != std::string::npos) binpath = binpath.substr(0, dot);
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binpath += ".bin";
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std::ofstream bin(binpath, std::ios::binary);
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// Vertices (float32)
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for (size_t i = 0; i < nv; ++i) {
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const auto& v = mesh.vertex(i);
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float fx=v.x(), fy=v.y(), fz=v.z();
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bin.write(reinterpret_cast<const char*>(&fx),4);
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bin.write(reinterpret_cast<const char*>(&fy),4);
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bin.write(reinterpret_cast<const char*>(&fz),4);
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}
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// Indices (uint32)
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for (size_t i = 0; i < nf; ++i) {
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auto vis = mesh.face_vertices(static_cast<int>(i));
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for (size_t j = 0; j < std::min(vis.size(), size_t(3)); ++j) {
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uint32_t idx = vis[j];
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bin.write(reinterpret_cast<const char*>(&idx),4);
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}
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}
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return true;
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}
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} // namespace vde::foundation
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