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https://github.com/syoyo/tinygltf.git
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a040827363
web/ compiles the v3 C runtime with emcc (Emscripten SDK from ~/work/emsdk by default) and ships a simple browser demo that loads glTF/GLB files via drag & drop and renders them with three.js: - loader.c: C bridge exporting flattened primitives, materials, textures (bufferView + data-URI paths) and the scene graph to JS - main.js/index.html/style.css: three.js viewer (OrbitControls, PBR materials, textures, node hierarchy, primitive modes) - gen_sample.py: generates a small self-contained textured Cube.glb sample from tracked assets (no large binaries committed) - Makefile: emcc build (MODULARIZE + ES6, no filesystem), sample generation and local http server targets Verified end-to-end: native bridge tests, Node harness exercising the WASM exports (parse, geometry, images, clear) and HTTP serving.
109 lines
4.0 KiB
Python
109 lines
4.0 KiB
Python
#!/usr/bin/env python3
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"""Generate a small self-contained textured cube GLB (web/Cube.glb).
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Uses the tracked Cube assets from models/ (Cube.gltf geometry in Cube.bin)
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plus a tiny checkerboard PNG generated with only the standard library, so
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the demo ships without large binary assets.
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"""
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import base64
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import json
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import struct
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import sys
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import zlib
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from pathlib import Path
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ROOT = Path(__file__).resolve().parent.parent
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BIN = ROOT / "models" / "Cube" / "Cube.bin"
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OUT = Path(__file__).resolve().parent / "Cube.glb"
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def make_png(width=64, height=64, rgb=(230, 140, 60), rgb2=(245, 245, 245)):
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"""Minimal zlib-based RGB PNG writer."""
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def chunk(tag, data):
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c = tag + data
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return struct.pack(">I", len(data)) + c + struct.pack(">I", zlib.crc32(c) & 0xFFFFFFFF)
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ihdr = struct.pack(">IIBBBBB", width, height, 8, 2, 0, 0, 0) # 8-bit RGB
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raw = bytearray()
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for y in range(height):
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raw.append(0) # filter: none
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for x in range(width):
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c = rgb if (x // 8 + y // 8) % 2 == 0 else rgb2
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raw += bytes(c)
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return (
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b"\x89PNG\r\n\x1a\n"
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+ chunk(b"IHDR", ihdr)
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+ chunk(b"IDAT", zlib.compress(bytes(raw), 9))
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+ chunk(b"IEND", b"")
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)
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def main():
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bin_data = BIN.read_bytes()
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png = make_png()
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total = len(bin_data) + len(png)
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j = {
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"asset": {"version": "2.0", "generator": "tinygltf web demo (gen_sample.py)"},
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"scene": 0,
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"scenes": [{"nodes": [0]}],
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"nodes": [{"mesh": 0, "name": "Cube"}],
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"meshes": [{
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"primitives": [{
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"attributes": {
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"POSITION": 1, "NORMAL": 2, "TANGENT": 3, "TEXCOORD_0": 4,
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},
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"indices": 0,
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"material": 0,
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}]
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}],
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"materials": [{
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"name": "checker",
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"pbrMetallicRoughness": {
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"baseColorFactor": [1.0, 1.0, 1.0, 1.0],
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"baseColorTexture": {"index": 0},
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"metallicFactor": 0.0,
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"roughnessFactor": 1.0,
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},
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}],
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"textures": [{"source": 0, "sampler": 0}],
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"images": [{"bufferView": 5, "mimeType": "image/png"}],
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"samplers": [{"magFilter": 9729, "minFilter": 9987, "wrapS": 10497, "wrapT": 10497}],
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"buffers": [{"byteLength": total}],
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"bufferViews": [
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{"buffer": 0, "byteOffset": 0, "byteLength": 72, "target": 34963}, # indices
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{"buffer": 0, "byteOffset": 72, "byteLength": 432, "target": 34962}, # positions
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{"buffer": 0, "byteOffset": 504, "byteLength": 432, "target": 34962}, # normals
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{"buffer": 0, "byteOffset": 936, "byteLength": 576, "target": 34962}, # tangents
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{"buffer": 0, "byteOffset": 1512, "byteLength": 288, "target": 34962}, # uvs
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{"buffer": 0, "byteOffset": len(bin_data), "byteLength": len(png)}, # image
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],
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"accessors": [
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{"bufferView": 0, "componentType": 5123, "count": 36, "type": "SCALAR", "min": [0], "max": [35]},
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{"bufferView": 1, "componentType": 5126, "count": 36, "type": "VEC3", "min": [-1, -1, -1], "max": [1, 1, 1]},
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{"bufferView": 2, "componentType": 5126, "count": 36, "type": "VEC3"},
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{"bufferView": 3, "componentType": 5126, "count": 36, "type": "VEC4"},
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{"bufferView": 4, "componentType": 5126, "count": 36, "type": "VEC2"},
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],
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}
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json_chunk = json.dumps(j, separators=(",", ":")).encode("utf-8")
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json_chunk += b" " * ((4 - len(json_chunk) % 4) % 4)
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bin_chunk = bin_data + png
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bin_chunk += b"\x00" * ((4 - len(bin_chunk) % 4) % 4)
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total_len = 12 + 8 + len(json_chunk) + 8 + len(bin_chunk)
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glb = struct.pack("<4sII", b"glTF", 2, total_len)
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glb += struct.pack("<II", len(json_chunk), 0x4E4F534A) + json_chunk
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glb += struct.pack("<II", len(bin_chunk), 0x004E4942) + bin_chunk
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OUT.write_bytes(glb)
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print(f"wrote {OUT} ({len(glb)} bytes, image {len(png)} bytes)")
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return 0
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if __name__ == "__main__":
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sys.exit(main())
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