webgpu sponza

examples/Sponza/README.md

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+# Sponza example
+
+Loads the Sponza atrium as a `.cmesh` + one albedo `.ctex` and renders
+it via ray tracing on both Vulkan (native) and WebGPU (wasm). Same
+`main.cpp`, `#ifdef CRAFTER_GRAPHICS_WINDOW_DOM` selects the backend.
+
+## What this example proves
+
+- `.cmesh` and `.ctex` decompression round-trip on both backends
+  (GPU via `VK_EXT_memory_decompression` on Vulkan, CPU via
+  `Compression::DecompressCPU` on WebGPU).
+- A single texture binding flowing from `Image2D<RGBA8>` through the
+  RT pipeline's closest-hit on both backends. The closest-hit samples
+  at the barycentric attribs as UVs — proof-of-binding, not visually
+  accurate. Per-vertex UV interpolation is the next step.
+
+## Asset fetch
+
+`project.cpp` calls `Crafter::GitFetch(...)` on
+[https://github.com/jimmiebergmann/Sponza](https://github.com/jimmiebergmann/Sponza)
+(pinned to commit `222338979d32f4f4818466291bdbc29f192b86ba`). The
+clone lands in the per-user crafter-build cache; first build pulls
+~280 MB once, subsequent builds reuse it.
+
+`cfg.assets` then picks two files out of that clone:
+
+| Source                                  | Compressed output       |
+|-----------------------------------------|-------------------------|
+| `sponza.obj`                            | `sponza.cmesh`          |
+| `textures/sponza_arch_diff.tga`         | `sponza_arch_diff.ctex` |
+
+Both land flat in the example's bin directory.
+
+## Building
+
+```
+crafter build                          # native Vulkan
+crafter build --target=wasm32-wasip1   # WebGPU / wasm
+```
+
+## License & attribution
+
+Sponza geometry, materials, and textures are licensed under
+[CC BY 3.0](https://creativecommons.org/licenses/by/3.0/).
+
+- **Original model:** Frank Meinl, Crytek (2010).
+- **OBJ packaging / cleanup:** Morgan McGuire, McGuire Computer
+  Graphics Archive — https://casual-effects.com/data.
+- **GitHub mirror used here:** Jimmie Bergmann's roof-material fixup —
+  https://github.com/jimmiebergmann/Sponza.
+
+When redistributing builds of this example that bundle the compressed
+Sponza outputs (`*.cmesh`, `*.ctex`), the CC BY 3.0 attribution
+requirement applies. Quoting the original credit somewhere visible to
+end users (about-screen, credits page, etc.) is enough.
+
+The Crafter.Graphics library code itself is LGPL-3.0; the two
+licenses are compatible for data + code distribution.