CultMath's hash is the shader-style frac(sin(x) * 43758.5453) and
returns float. Unity.Mathematics' hash returned a well-mixed uint, and
seeding from the float hash collapses: a 100x100 position grid gave 1625
distinct values in Aetheria's zone generator.
- math.pcg(uint), pcg3d(int3/float2/float3), and pcg4d(int4/float4)
follow Jarzynski and Olano, "Hash Functions for GPU Rendering"
(JCGT 9(3), 2020). pcg3d and pcg4d are the paper's code from page 32.
pcg is O'Neill's RXS-M-XS 32/32 output over one LCG step, with the
constants checked against pcg-c's pcg_variants.h.
- CultMath has no uint vectors, so pcg3d and pcg4d carry uint bit
patterns in int3/int4. The float overloads hash IEEE-754 bits via the
HLSL intrinsic asuint(float), which is new. pcg3d(float2) holds z at
0, the paper's route for 2 -> N inputs.
- The HLSL mirror gains the same functions, written over scalar uints
so the text compiles both in dxc 1.9.0.5402 (lib_6_3, HV 2021, clean)
and in C#. HlslSourceCompatibilityTests now compares int and uint
arguments and results by value; a wrong shift in the mirror's pcg4d
gives 208 mismatches.
- Known-answer vectors come from an independent Python transcription.
pcg3d separates a 100x100 half-unit grid (the full int3). One
component alone has one birthday collision there, as a 32-bit value
can. The same grid on the integer lattice has none.
- design.md states that the hashes are integer-exact in HLSL and on the
CPU: dxc wraps uint multiply and add modulo 2^32, as C# unchecked does.
- Bump to 0.2.3 and rebuild the tracked Unity DLL and pdb.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
dxc 1.9.0.5402 lowers float2/3/4 normalize(x) to x * Rsqrt(Dot(x, x)),
and DXIL.rst defines Rsqrt as 1 / sqrt(src). A zero vector normalizes
to NaN and a NaN component poisons every component. CultMath divided
by max(length, 1e-20), which returned 0 for a zero vector and a huge
finite component beside a NaN one.
- math.normalize(float2/3/4) is now value * (1 / sqrt(dot(value, value))).
- The HLSL mirror drops cultmath_normalize and its epsilon constant: it
now equals the normalize intrinsic, and nothing consumed it.
- HlslSemanticsTests pins zero and NaN normalize, the rsqrt bit pattern,
and zero length/distance. design.md states the rule and notes that
DXIL.rst's Rsqrt special-value table is a copy of Round's.
- GameCult.Geometry's iso-surface gave degenerate triangles (an inside
vertex on the isovalue) a zero normal through the old epsilon. It now
guards them explicitly, with a test.
- quaternion normalize keeps its identity fallback: quaternion is not
an HLSL type.
- Bump to 0.2.2 and rebuild the tracked Unity DLL and pdb.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Bump the package and assembly version and rebuild the tracked Unity
DLL and pdb from a deterministic build.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
The tracked DLL is committed with its source, so a build that embeds the
commit can never match it. Two places named the commit: the informational
version (0.2.0+<sha>) and Source Link's commit URL in the pdb, whose content
id the DLL also carries. The csproj drops the revision from the version, and
the Unity build turns Source Link off; NuGet packs keep it.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
tools/generate-swizzles.ps1 writes the checked-in src/CultMath/Swizzles.g.cs
as partial structs plus a partial math: for float2/3/4, int2/3/4 and bool2/3/4
every swizzle of length 2-4 including repeats, in xyzw and rgba naming, with
setters only on non-repeating masks, plus single-component r/g/b/a. double2/3
get lengths 2-3 (there is no double4). Every HLSL mixed constructor
(float4(float2, float2), float4(float, float2, float), copy forms, ...) exists
as a struct constructor and, for float/int/bool, a math function. The
hand-written swizzles and mixed constructors it supersedes are deleted.
Matrices store private rows and return ref float2/float3 from the row
indexer ([UnscopedRef], polyfilled for netstandard2.1), so m[1][2] = s
compiles as in HLSL; _mRC are get/set properties over the rows. Equality and
hashing stay value-based.
Intrinsics follow HLSL: sign returns int/intN and yields 0 for NaN; step is
x >= y ? 1 : 0 so NaN yields 0; any/all accept float and int vectors;
min/max/abs on int vectors return int vectors, and abs(int) returns int.
Strips the UTF-8 BOMs this branch added to math.cs, CultMath.csproj and
HlslSemanticsTests.cs.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
- Bump GameCult.Math and org.gamecult.cultmath to 0.2.0; the CultCache
Unity tools package now depends on cultmath 0.2.0.
- Rebuild the tracked netstandard2.1 CultMath.dll/pdb with the builder's
deterministic command; build-unity-package.ps1 verifies it byte-for-byte.
- Add Runtime/UnityBridge (CultMath.UnityBridge asmdef) with ToCultMath /
ToUnity / ToColor extension methods for Vector2/3/4, Vector2Int/3Int,
Quaternion and Color. C# only admits conversion operators on the source
or target type, and the core DLL stays engine-free.
- The builder admits exactly that one bridge assembly: it must reference
UnityEngine and CultMath.dll, and no core source may be compiled in the
package.
- Sync the Unity copy of CultMath.hlsl and the third-party notice.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
