speice.io/blog/2024-11-15-playing-with-fire/3-log-density/chaosGameHistogram.ts

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// hidden-start
import {randomBiUnit} from "../src/randomBiUnit";
import {randomChoice} from "../src/randomChoice";
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import {Props as ChaosGameFinalProps} from "../2-transforms/chaosGameFinal";
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import {camera, histIndex} from "../src/camera";
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const quality = 10;
const step = 100_000;
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// hidden-end
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export type Props = ChaosGameFinalProps & {
paint: (width: number, height: number, histogram: number[]) => ImageData;
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}
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export function* chaosGameHistogram({width, height, transforms, final, paint}: Props) {
let iterations = quality * width * height;
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// highlight-start
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const histogram = Array<number>(width * height).fill(0);
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// highlight-end
let [x, y] = [randomBiUnit(), randomBiUnit()];
for (let i = 0; i < iterations; i++) {
const [_, transform] = randomChoice(transforms);
[x, y] = transform(x, y);
const [finalX, finalY] = final(x, y);
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if (i > 20) {
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// highlight-start
const [pixelX, pixelY] = camera(finalX, finalY, width);
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const hIndex = histIndex(pixelX, pixelY, width, 1);
if (hIndex < 0 || hIndex >= histogram.length) {
continue;
}
histogram[hIndex] += 1;
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// highlight-end
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}
if (i % step === 0)
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yield paint(width, height, histogram);
}
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yield paint(width, height, histogram);
}