math.erfinv(1.0f) returned -infinity and erfinv(-1.0f) returned
+infinity: at value = +-1, w = -log((1-value)(1+value)) = -log(0) =
+infinity, the tail branch's leading coefficient is negative, and
`return p * value` delivered the inverted infinity. erf saturates to
exactly 1.0f at 5.543 sigma, so any interval edge beyond that reaches
this bug in ordinary use.
Guard both edges explicitly before the polynomial runs: erfinv(1) is
now +infinity, erfinv(-1) is -infinity, and anything strictly outside
[-1, 1] (including +-infinity) is NaN, which is the correct answer and
was already the fallthrough behavior. Documented the domain and the
edge behavior in a comment, matching the house style `sign` already
uses at math.cs:84. The approximation itself is unchanged.
Also recorded the true measured accuracy beside erf and erfinv: worst
absolute error 6.621e-7 and 5.066e-7 respectively, both inside the
2e-6 bar this package's tests pin.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Fire control's Gaussian scatter needs erf for a cell's probability mass
and erfinv to draw the lateral offset, both called per shot. Abramowitz-
Stegun 7.1.26 for erf (stated max abs error 1.5e-7), Giles 2010 (GPU
Computing Gems) for erfinv. Neither is an HLSL intrinsic, so there is no
shader-parity obligation.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
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>
Aetheria Cut 8a needs int2(float2), clamp(int, int, int), and
frac(double). Fill them in CultMath as dxc compiles them:
- generate-swizzles.ps1 emits same-size conversion constructors and
math functions between float, int, and bool vectors. dxc lowers
float to int as fptosi (toward zero; NaN and out-of-range undefined),
numeric to bool as != 0 (fcmp une, NaN is true), bool to numeric as
0 or 1. floatN(int) splat keeps floatN(0) from going ambiguous
against floatN(intN).
- Int and int-vector clamp are min(max(x, a), b), matching dxc's
IMin(IMax(x, a), b); inverted bounds return b.
- frac(double) keeps double precision. dxc demotes double frac to
float, as it does exp and lerp; CultMath's existing double overloads
already diverge that way, and design.md now says so.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
dxc lowers double min/max to dx.op.binary.f64 opcodes 36/35 (FMin/FMax),
the same operations as float, so Math.Min/Math.Max (NaN-propagating) was the
wrong rule. Double min/max now use the float formulas, with NaN and signed-zero
assertions beside the float ones. Tracked Unity DLL rebuilt.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
dxc lowers float min/max/clamp to dx.op FMin/FMax (36/35) and saturate to
dx.op Saturate (7). DXIL.rst defines them: FMin(a, b) is a < b ? a : b,
FMax(a, b) is a >= b ? a : b, a NaN operand returns the other, and
Saturate is FMin(1, FMax(0, x)). C# used MathF.Min/Max, which pass NaN
through and order signed zeros, so saturate(NaN) was NaN instead of 0.
Every float overload now follows the spec, normalize uses the same max as
its mirror, and the mirror's saturate spells Saturate's operand order
(which maps -0 to +0, where clamp(x, 0, 1) keeps -0). Non-NaN results
change only in the sign of a zero. design.md records the rules and that
dxc marks float math fast, so GPU NaN results are not guaranteed.
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>
The operator kept the [UnscopedRef] ref this[int] row indexer as is. design.md
and the float2x2/float3x3 indexers now say where m[r][c] = v lands: locals,
array elements, class fields, and ref locals keep the write; a readonly field,
in parameter, property (auto-properties too), or static readonly identity
takes a defensive copy, so the write compiles and is lost. Fix: copy to a
local, write, assign back. Verified by compiling and running each case with
Roslyn against CultMath (no diagnostics; writes land 5, lost 0).
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
dxc 1.9.0.5402 (dxc_2026_07_29, lib_6_3, -HV 2021, -Od) lowers step(e, x) to
fcmp olt x, e; select 0 : 1, so NaN on either side gives 1. The previous
x >= e ? 1 : 0 rule came from prose, not the compiler. math.step and
cultmath_step now use x < e ? 0 : 1 for every overload; the mirror's
cultmath_step compiles to the same fcmp/select as the intrinsic. Unity shader
copy synced; DLL rebuilt and byte-checked by build-unity-package.ps1.
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>
HLSL is now CultMath's semantic authority where it defines one.
- float2/3/4, int2, double2/3, bool2 and quaternion are plain structs with
public mutable fields instead of record structs. Indexers and swizzles
(float2.yx; float3 xy xz yx yz zy xyz xzy yzx zyx; float4 xy xyz xyw yzx)
have setters.
- ==, !=, <, >, <=, >= are component-wise and return bool2/3/4. Equals and
GetHashCode stay value-based so vectors remain dictionary keys.
quaternion is not an HLSL type and keeps a bool ==.
- Scalar/vector arithmetic and comparisons get explicit overloads on both
sides instead of leaning on implicit splat.
- New types: bool3, bool4, int3, int4, float2x2, float3x3 (row-major like
HLSL, _mRC fields, Rotate / RotateX/Y/Z / Euler with math.RotationOrder).
- New intrinsics: mul (matrix-vector both sides, matrix-matrix), any, all,
select (HLSL argument order), log, vector pow/sqrt/sin/cos/acos/atan2,
double min/max, int3/int4/bool3/bool4/float2x2/float3x3 constructor
functions.
- simplex_noise is renamed snoise and gains the Ashima 3D variant; the HLSL
mirror follows as cultmath_snoise(float2/float3).
- Random gains NextFloat3() and NextFloat3(float3 max) on the same draw order.
Tests pin snoise(float3), float3x3.Euler and float2x2.Rotate to
Unity.Mathematics reference values, and an HLSL-shaped source block compiles
under using static CultMath.math.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
