mirror of
https://github.com/bspeice/speice.io
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39 lines
870 B
TypeScript
39 lines
870 B
TypeScript
export function camera(
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x: number,
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y: number,
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width: number,
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height: number,
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scale: number,
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zoom: number,
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rotate: number,
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offsetX: number,
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offsetY: number,
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): [number, number] {
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const zoomFactor = Math.pow(2, zoom);
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// Zoom, offset, and rotation are
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// applied in IFS coordinates
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[x, y] = [
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(x - offsetX) * zoomFactor,
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(y - offsetY) * zoomFactor,
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];
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[x, y] = [
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x * Math.cos(rotate) -
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y * Math.sin(rotate),
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x * Math.sin(rotate) +
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y * Math.cos(rotate),
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]
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// Scale is applied to pixel
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// coordinates. Shift by half
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// the image width and height
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// to compensate for the
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// IFS coordinates being symmetric
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// around the origin
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return [
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Math.floor(x * scale + width / 2),
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Math.floor(y * scale + height / 2)
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];
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}
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