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API Reference: Math

Purpose

Feather.Math provides shader-friendly scalar, vector, matrix, swizzle, and helper APIs that can run both in ordinary C# and inside generated GPU code when supported by the lowerer.

Vector Types

Common vector types:

  • float2, float3, float4
  • int2, int3, int4
  • bool2, bool3, bool4

Typical usage:

float3 n = ShaderMath.Normalize(normal);
float lighting = ShaderMath.Clamp(ShaderMath.Dot(n, lightDir), 0.0f, 1.0f);
float4 color = new float4(lighting, lighting, lighting, 1.0f);

Matrix Types

Common matrix types:

  • float2x2
  • float3x3
  • float4x4

Use explicit Feather matrix types in GPU structs and uniforms.

Swizzles

Vector swizzles expose HLSL-style component combinations:

float2 xy = position.XY;
float3 rgb = color.RGB;
float4 rgba = new float4(rgb, 1.0f);

Swizzles are generated as strongly typed properties.

ShaderMath

Important helpers:

Group Examples
Vector algebra Dot, Cross, Length, LengthSquared, Normalize
Trigonometry Sin, Cos, Tan, Sinh, Cosh, Tanh
Exponential Exp, Log, Pow, Sqrt, InverseSqrt
Value ops Abs, Floor, Ceil, Round, Fract
Bounds/interpolation Min, Max, Clamp, Saturate, Lerp, Mix, Step, SmoothStep
Matrix ops Matrix multiplication and transform helpers where defined

Use f suffixes for float literals in shader code.

Hlsl

Hlsl provides alias names for users who prefer HLSL-style spelling. Calls lower by Roslyn symbol identity, not by source text, so supported aliases are stable even if imported through using static.

Host Vs Shader

Most math helpers have CPU implementations so you can use them in host setup code. Inside generated shaders, only the supported subset lowers to FEIR/EasyGPU. Unsupported calls are generator diagnostics.

Lifetime And Errors

Math types are value types and do not own native resources. Unsupported math calls in shader code are generator diagnostics; invalid CPU-only operations such as inverting a singular matrix can still throw normal managed exceptions when run on the host.

Samples And Tests

  • samples/Mandelbrot
  • samples/JuliaSet
  • samples/SdfRenderer
  • samples/SponzaRenderer
  • tests/Feather.Tests/MathSurfaceTests.cs
  • tests/Feather.Integration.Tests/ShaderDslCoverageTests.cs