26 lines
1.1 KiB
Markdown
26 lines
1.1 KiB
Markdown
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# RTVolume
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WebGPU software ray tracing of **procedural (AABB) geometry** with an
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**any-hit** cut-out — the two features added for issue #13.
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A 3×3×3 grid of unit boxes is registered as an AABB BLAS
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(`Mesh::BuildProcedural`, the WebGPU analog of `VK_GEOMETRY_TYPE_AABBS_KHR`).
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The hit group is a `RTShaderGroupType::ProceduralHitGroup` carrying:
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- `intersection.wgsl` — analytic ray–sphere test that turns each box into a
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radius-1 sphere (runs in TRACE, once per box the ray enters);
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- `anyhit.wgsl` — returns `RT_ANYHIT_IGNORE` for half the cells of a
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spherical checkerboard, so the ray passes through and the background /
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spheres behind show through (the visible proof any-hit runs);
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- `closesthit.wgsl` — normal-based Lambert shading, tinted per instance.
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The geometry is registered **non-opaque** and the instances clear their
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force-opaque flag, which is what lets the any-hit shader run. Flip the
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instance flag to `kRTGeometryInstanceForceOpaque` (or build the mesh with
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`opaque = true`) to skip any-hit and see solid spheres.
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WebGPU/DOM only:
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```
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crafter-build --target=wasm32-wasip1 -r
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```
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