spectrogram.c was ~2950 lines holding everything. Break it into cohesive
translation units; spectrogram.c keeps only globals + the main frame loop.
New modules:
- spectrogram_types.h shared types, constants, extern globals, inline math
- fft.c/.h FFT, bit-reverse, twiddle (standalone, no app deps)
- stft.c/.h STFT compute, adaptive resolution, FFT-size LRU cache
- audio.c/.h WAV/ffmpeg load, FreeSignal, bandpass, playback
- render.c/.h UI scaling, colormaps, texture gen, on-screen drawing
- ui.c/.h file browser, sidebar, sliders, PNG export
Also:
- utils.c now includes utils.h instead of re-typedef'ing AudioSignal/
SignalStats (they had to be hand-synced before).
- Remove dead code: ApplyHannWindow and ComputeSTFTHighResRange were never
called (the live high-res path is ComputeNextHighResChunk).
- Delete the unused raylib-template main.c.
- rspektrum.make: build the new units. premake5.lua: glob src/**.c so a
future regen stays correct.
Pure code movement otherwise; no behavior change. Builds clean (-Wshadow).
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
