nordisk/facett

facett-map3d-flight/.nornir/assets/scatter-lut-gpu.svg

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  <text x="20" y="30" fill="#e6edf3" font-size="15" font-weight="bold">facett-map3d-flight · GPU scattering-LUT precompute (FLIGHT-SIM #7)</text>

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    <text x="95"  y="92">LutParams</text><text x="95"  y="110" fill="#8fb3c0">h·mu·steps</text>
    <text x="295" y="92">cs_transmittance</text><text x="295" y="110" fill="#8fb3c0">compute · ray-march</text>
    <text x="495" y="92">storage buffer</text><text x="495" y="110" fill="#8fb3c0">array&lt;vec4&lt;f32&gt;&gt;</text>
    <text x="690" y="92">readback + upload</text><text x="690" y="110" fill="#8fb3c0">→ Rgba32Float tex</text>
    <text x="840" y="90">sky.wgsl</text><text x="840" y="106" fill="#8fb3c0">seam</text>
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  <text x="840" y="140" fill="#7f8b98" text-anchor="middle" font-size="10">(deferred wiring)</text>

  <!-- CPU oracle -->
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  <text x="295" y="208" fill="#8fd18f" text-anchor="middle" font-weight="bold">atmos.rs (CPU)</text>
  <text x="295" y="226" fill="#e6edf3" text-anchor="middle">TransmittanceLut</text>
  <text x="295" y="242" fill="#8fb3c0" text-anchor="middle">::precompute — the ORACLE</text>
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  <text x="295" y="165" fill="#8fd18f" text-anchor="middle" font-size="10">same march, same constants</text>

  <!-- parity gate -->
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  <text x="592" y="208" fill="#f2b84b" text-anchor="middle" font-weight="bold">parity_vs(cpu) — GPU-less-safe proof</text>
  <text x="592" y="226" fill="#e6edf3" text-anchor="middle">max_err_upper (μ≥0) &lt; 5e-4 · outliers ≤ h+2</text>
  <text x="592" y="242" fill="#8fb3c0" text-anchor="middle">horizon-tangent knife-edge confined below μ=0</text>
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  <text x="20" y="300" fill="#8fb3c0" font-size="11">no adapter → test self-skips with a recorded sentinel; the CPU oracle stays the render fallback + RED-when-broken check (runs anywhere).</text>
  <text x="20" y="318" fill="#7f8b98" font-size="11">behind the `wgpu` feature · L2 additive: the landed 21-pass pipeline is untouched.</text>
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