Build system
- Add a single hand-written Makefile (GNU make + gcc, pure C). Builds
raylib from vendored source and links rspektrum with no premake/lua.
Targets: all/run/test/bench/clean; release default, DEBUG=1 for debug;
ARCH overridable (defaults to -march=x86-64-v3).
- Remove premake entirely: rspektrum.make, raylib.make, build/premake5*
binaries, build/premake5.lua, build/ecc/*. The generated top-level
Makefile was gitignored, so hand-edits to it were silently lost.
- Vendor raylib src/ into the repo (was gitignored -> fresh clones could
not build). Commit only src/ (~16MB); examples/projects stay local.
Verified: a build from the git-tracked tree alone succeeds offline.
- Release flags bumped to -O3 -ffast-math with a portable arch baseline
(x86-64-v3 = AVX2+FMA on x64, SSE2 on x86). Confirmed FMA/AVX codegen
in fft.o.
FFT optimization (src/fft.c)
- Precompute twiddle factors and the bit-reversal permutation once per
size, cached as a small plan table (FFTW's idea, lightweight). Removes
the per-butterfly cexpf() and per-element bit-twiddling that dominated.
- 3.6x faster on the mlnl_samples.wav STFT workload (2048-pt, -O2 same
flags both sides): 81us -> 22us per FFT. With the new -O3/-ffast-math/
AVX2 release flags stacked: ~15us (5.5x vs the old -O2 baseline).
- Verified vs a double-precision reference DFT: 1e-6 relative error,
round-trip 2.4e-7. Drop-in: same FFT() signature.
Tests/bench (bench/)
- fft_verify.c: FFT vs reference DFT + round-trip check (make test).
- fft_bench.c: times the real STFT workload (make bench).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
