music video renderer web app
deftoku.digi.rip
audio
visualizer
webapp
utils: cleaned up comments
+9
-15
+9
-15
src/visualizers/utils.ts
+9
-15
src/visualizers/utils.ts
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/*
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* - **Ghost-loop prevention** via a `stopped` flag — if the cleanup function
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* is called mid-draw, the loop won't re-schedule itself via the rAF at the
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* end of the tick (which would otherwise keep the old loop running forever
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* and fighting any new preview for the canvas).
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*
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* Returns a cleanup function — call it once to stop the loop and cancel the
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* pending animation frame.
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*/
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// double buffered anim loop: draws offscreen then gets placed to
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// visible canvas in one op
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export function createPreviewLoop(
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const displayCtx = canvas.getContext("2d")!;
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let raf: number;
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// using this prevents ghost-loops; if cleanup is called mid-draw,
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// loop won't re-schedule via rAF at end of tick and prevents
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// old loop running forever and fighting new preview for canvas
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let stopped = false;
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function loop(now: number) {
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if (stopped) return;
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if (now >= nextFrame) {
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// fps limiting: skips rAF callbacks until the next frame deadline
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// then catches up if the callback was delayed (no spiral).
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// then catches up if the callback was delayed
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nextFrame += fixedDt * 1000;
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if (nextFrame < now) nextFrame = now + fixedDt * 1000;
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render(offscreen, fixedDt);
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}
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raf = requestAnimationFrame(loop);
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// cleanup function: called once to stop loop and cancel pending animation
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return () => {
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stopped = true;
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cancelAnimationFrame(raf);
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};
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}
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/**
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* Fills a Uint8Array with synthetic frequency data (animated sine wave).
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* Used by previews that don't have real audio data.
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*/
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// generates Uint8Array with an animated sine wave
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// useful for previews that need real audio data placeholder
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export function generateSyntheticFreq(
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freq: Uint8Array,
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phase: number,