Add better version of occlusion.js

mods/shade.js

@@ -0,0 +1,46 @@
+"use strict";
+// Shade.ts -> Shade.js
+// Constants
+const SHADOW_UPDATE_INTERVAL = 4;
+const SHADOW_BLUR_RADIUS = 5;
+const SHADOW_INTENSITY = 128;
+// Canvases
+let shadowCanvas1;
+let shadowCanvasCtx1;
+let shadowCanvas2;
+let shadowCanvasCtx2;
+
+function initializeShade() {
+	shadowCanvas1 = new OffscreenCanvas(width + 1, height + 1);
+	shadowCanvasCtx1 = shadowCanvas1.getContext('2d');
+	shadowCanvas2 = new OffscreenCanvas(width + 1, height + 1);
+	shadowCanvasCtx2 = shadowCanvas2.getContext("2d");
+}
+
+function updateShadows() {
+	if (pixelTicks % SHADOW_UPDATE_INTERVAL !== 0)
+		return;
+	const shadowCanvasImageData1 = shadowCanvasCtx1.createImageData(width + 1, height + 1);
+	const shadowCanvasData1 = shadowCanvasImageData1.data;
+	for (let pixel of currentPixels) {
+		const exposed = getNeighbors(pixel).length !== 4;
+		const alphaIndex = (pixel.y * (width + 1) + pixel.x) * 4 + 3;
+		shadowCanvasData1[alphaIndex] = exposed ? 0 : SHADOW_INTENSITY;
+	}
+	shadowCanvasCtx1.putImageData(shadowCanvasImageData1, 0, 0);
+	// Blur the shadows
+	shadowCanvasCtx2.clearRect(0, 0, shadowCanvas2.width, shadowCanvas2.height);
+	shadowCanvasCtx2.filter = `blur(${SHADOW_BLUR_RADIUS}px)`;
+	shadowCanvasCtx2.drawImage(shadowCanvas1, 0, 0, shadowCanvas2.width, shadowCanvas2.height);
+	shadowCanvasCtx2.filter = "none";
+}
+
+function drawShadows(ctx) {
+	ctx.globalAlpha = 1.0;
+	ctx.drawImage(shadowCanvas2, 0, 0, canvas.width, canvas.height);
+}
+
+// Hooks
+runAfterReset(initializeShade);
+runEveryTick(updateShadows);
+renderPostPixel(drawShadows);