47 lines
1.5 KiB
JavaScript
47 lines
1.5 KiB
JavaScript
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"use strict";
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// Shade.ts -> Shade.js
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// Constants
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const SHADOW_UPDATE_INTERVAL = 4;
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const SHADOW_BLUR_RADIUS = 5;
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const SHADOW_INTENSITY = 128;
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// Canvases
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let shadowCanvas1;
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let shadowCanvasCtx1;
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let shadowCanvas2;
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let shadowCanvasCtx2;
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function initializeShade() {
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shadowCanvas1 = new OffscreenCanvas(width + 1, height + 1);
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shadowCanvasCtx1 = shadowCanvas1.getContext('2d');
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shadowCanvas2 = new OffscreenCanvas(width + 1, height + 1);
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shadowCanvasCtx2 = shadowCanvas2.getContext("2d");
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}
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function updateShadows() {
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if (pixelTicks % SHADOW_UPDATE_INTERVAL !== 0)
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return;
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const shadowCanvasImageData1 = shadowCanvasCtx1.createImageData(width + 1, height + 1);
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const shadowCanvasData1 = shadowCanvasImageData1.data;
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for (let pixel of currentPixels) {
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const exposed = getNeighbors(pixel).length !== 4;
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const alphaIndex = (pixel.y * (width + 1) + pixel.x) * 4 + 3;
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shadowCanvasData1[alphaIndex] = exposed ? 0 : SHADOW_INTENSITY;
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}
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shadowCanvasCtx1.putImageData(shadowCanvasImageData1, 0, 0);
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// Blur the shadows
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shadowCanvasCtx2.clearRect(0, 0, shadowCanvas2.width, shadowCanvas2.height);
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shadowCanvasCtx2.filter = `blur(${SHADOW_BLUR_RADIUS}px)`;
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shadowCanvasCtx2.drawImage(shadowCanvas1, 0, 0, shadowCanvas2.width, shadowCanvas2.height);
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shadowCanvasCtx2.filter = "none";
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}
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function drawShadows(ctx) {
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ctx.globalAlpha = 1.0;
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ctx.drawImage(shadowCanvas2, 0, 0, canvas.width, canvas.height);
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}
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// Hooks
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runAfterReset(initializeShade);
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runEveryTick(updateShadows);
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renderPostPixel(drawShadows);
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