Add Math.h with HLSL-style vector and matrix types

[jdolan]

Overview

Adds Sources/ObjectivelyGPU/Math.h — a header-only GPU math library with HLSL-compatible type names, replacing the ad-hoc inline matrix math in Hello.c.

Types

Type	Description
float2 / float3 / float4	Single-precision vector types with .x/.y/.z/.w component access, array accessor, and swizzle members (.xy, .xyz, .zw)
float4x4	Column-major 4×4 matrix (m[col][row]); flat .f[16] and .cols[4] accessors

API

Scalar: float_radians, float_degrees, float_clamp, float_saturate, float_lerp, float_smoothstep, float_sign

Vectors: float3_new, _add, _sub, _mul, _scale, _negate, _dot, _cross, _length, _distance, _normalize, _lerp, _reflect, _min, _max, _fma, _equal (same shape for float2 and float4)

Matrix: float4x4_identity, _mul, _translation, _rotation, _scale, _scale3, _perspective, _ortho, _look_at, _inverse, _transform, _transform4

Hello.c cleanup

The three hand-rolled C functions (rotate_matrix, perspective_matrix, multiply_matrix) are replaced:

// Before: 46 lines of raw float[16] arithmetic
// After:
float4x4 mv = float4x4_rotation(angleX, float3_new(1.f, 0.f, 0.f));
mv = float4x4_mul(float4x4_rotation(angleY, float3_new(0.f, 1.f, 0.f)), mv);
mv = float4x4_mul(float4x4_translation(float3_new(0.f, 0.f, -2.5f)), mv);
const float4x4 proj = float4x4_perspective(45.f, aspect, 0.01f, 100.f);
const float4x4 matrixFinal = float4x4_mul(proj, mv);

Notes

• No SDL or Objectively dependency — pure C99 + <math.h>
• Type names match HLSL intrinsics exactly, so the mental model transfers directly between shader and host code
• float_* / float2_* etc. prefixes avoid any collision with <math.h> or future libc additions

[Copilot]

Pull request overview

This PR introduces a header-only math utility (Math.h) providing HLSL-style vector/matrix types and helpers, and updates the Hello example to use the new float4x4 APIs instead of ad-hoc matrix code.

Changes:

• Add Sources/ObjectivelyGPU/Math.h with float2/3/4 and float4x4 types plus scalar/vector/matrix helper functions.
• Export/install the new header via Sources/ObjectivelyGPU/Makefile.am and the umbrella Sources/ObjectivelyGPU.h.
• Refactor Examples/Hello.c to build model-view-projection using float4x4_* helpers and upload the matrix as uniform data.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

File	Description
Sources/ObjectivelyGPU/Math.h	Adds HLSL-style vector/matrix types and inline math helpers for host-side GPU code.
Sources/ObjectivelyGPU/Makefile.am	Installs/exports Math.h as part of the public headers.
Sources/ObjectivelyGPU.h	Exposes Math.h via the umbrella include for consumers.
Examples/Hello.c	Switches the example’s matrix construction to the new float4x4 API and uploads the final matrix.