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CultLib/packages/cultmath/THIRD-PARTY-NOTICES.md
Meta Vens 0acc3728ed CultMath: Phacelle port moves into MPL-2.0 files; prune cut pinned by boundary points 
MPL-2.0 is file-level and the Phacelle port sat inside MIT files. phacelle and
CultPhasor now live in math.Phacelle.cs and CultPhasor.cs, and cultmath_phacelle
in CultMath.Phacelle.hlsl (included by CultMath.hlsl, both tracked copies), each
with the MPL header and Johansen / Luke Mitchell attribution. math stays one
partial class, so math.phacelle is called exactly as before. The GameCult.Math
package declares MIT AND MPL-2.0 and packs THIRD-PARTY-NOTICES.md and the new
include; the Unity LICENSE.md points at CultLib; build-unity-package.ps1
requires the new include.

The random sweeps never met a cell whose box bound sits just under the 2.25 cut
while its weight is still nonzero, so cuts of 2.245, 2.24 and 2.2 survived.
Six hard-coded points (found by an offline search) sit next to such cells; the
C# pruned-vs-unpruned test and the HLSL mirror test both use them, with a
witness check that re-derives the property from the hash.

Docs: the prune keeps about 45 of 64 cells (14 is the nonzero-weight count),
the support radius is 1.49998 (d^2 = 2.24995), normalization's range and
saturation, W = 0 only for adversarial hashes, and the support-edge gradient
seam size.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
2026-09-30 00:34:27 +02:00

2 KiB
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Third-Party Notices

2D and 3D Simplex Noise

math.snoise and cultmath_snoise port the textureless 2D and 3D simplex-noise functions by Ian McEwan and Ashima Arts, as distributed by Stefan Gustavson's webgl-noise project and Unity Mathematics.

math.snoise(float3) and cultmath_snoise(float3) follow src/noise3D.glsl and math.snoise(float2) follows src/noise2D.glsl of stegu/webgl-noise at commit 22434e04d7753f7e949e8d724ab3da2864c17a0f (the simplex-boundary fix is 21d9fe23d7, scale ff3b5d34ea, permutation a3e6d57095).

math.snoise_grad/cultmath_snoise_grad (and the fbm_grad/ridged_grad octave sums built on them) follow the analytic-gradient differentiation from the same project's src/noise3Dgrad.glsl, with the same kernel radius, permutation and scale as snoise(float3).

Phacelle Noise

math.phacelle and cultmath_phacelle follow Rune Skovbo Johansen's Phacelle noise (Shadertoy t3dyWl; erosion filter wXcfWn; blog, March 2026), read from the C# port PhacelleNoise in lpmitchell/AdvancedTerrainErosion (AdvancedTerrainErosion.cs, converted to burstable C# by Luke Mitchell, 2026). The cell weight, the phase blend and the normalization follow it. The 3D-cell generalisation, the caller-supplied stripe wave vector, the exact gradient and the exact pruning are new here.

  • Copyright (c) 2025 Rune Skovbo Johansen.
  • Upstream: https://github.com/lpmitchell/AdvancedTerrainErosion
  • License: MPL-2.0 (https://mozilla.org/MPL/2.0/). MPL-2.0 is file-level, so it covers exactly the files that carry the port and nothing else: src/CultMath/math.Phacelle.cs, src/CultMath/CultPhasor.cs, shaders/CultMath.Phacelle.hlsl and the Unity copy of that include. Each carries the MPL-2.0 header and this attribution. The rest of CultMath is MIT, so the GameCult.Math NuGet package declares MIT AND MPL-2.0 and ships this file. The Unity package as a whole is MPL-2.0.