CultMath/docs/design.md

Design

CultMath exists to make renderer math readable in every place it needs to live: Rust hot kernels, C# host code, and HLSL shader code.

Rules

• Keep type names HLSL-shaped: float2, float3, float4, and math.
• Keep Rust as the owner of native hot-path kernels and parity fixtures.
• Keep C#, shader, and scripting surfaces as runtime wrappers, not competing math authorities.
• Implement public shader semantics directly; do not copy Unity.Mathematics.
• Prefer small immutable value types.
• Prefer component-wise overloads over clever generic machinery until the API earns that complexity.
• Keep the first surface boring and exact. Noise, matrices, quaternions, and packing helpers come later.

Non-Goals

• Compiling C# to shaders.
• Replacing System.Numerics for general .NET work.
• Recreating every Unity.Mathematics type because a spreadsheet somewhere says “coverage.” That way lies decorative obesity.