Separate hat functions

src/hats.js

@@ -0,0 +1,100 @@
+import Layer from "./animation/layer.js";
+import { PALETTE } from "./animation/sprites.js";
+import { getLayerPixels } from "./shared.js";
+
+const HAT = {
+	TOP_HAT: 'top-hat'
+};
+
+/**
+ * @param {string[][]} spriteSheet 
+ * @returns {{ base: Layer[], down: Layer[] }}
+ */
+export function createHatLayers(spriteSheet) {
+	const hatLayers = {
+		base: [],
+		down: []
+	};
+	for (const hatName in HAT) {
+		const hatKey = HAT[hatName];
+		const hatLayer = buildHatLayer(spriteSheet, hatKey, false);
+		const downHatLayer = buildHatLayer(spriteSheet, hatKey, false, 1);
+		hatLayers.base.push(hatLayer);
+		hatLayers.down.push(downHatLayer);
+	}
+	return hatLayers;
+}
+
+/**
+ * @param {string[][]} spriteSheet 
+ * @param {string} hatName 
+ * @param {boolean} [outlineBottom=false]
+ * @param {number} [yOffset=0]
+ * @returns {Layer}
+ */
+function buildHatLayer(spriteSheet, hatName, outlineBottom = false, yOffset = 0) {
+	const LEFT_PADDING = 6;
+	const RIGHT_PADDING = 14;
+	const TOP_PADDING = 4 + yOffset;
+	const BOTTOM_PADDING = Math.max(0, 16 - yOffset);
+
+	const hatPixels = getLayerPixels(spriteSheet, 0, 12);
+	const paddedHatPixels = [];
+
+	// Top padding
+	for (let y = 0; y < TOP_PADDING; y++) {
+		paddedHatPixels.push(Array(hatPixels[0].length + LEFT_PADDING + RIGHT_PADDING)
+			.fill(PALETTE.TRANSPARENT)
+		);
+	}
+	// Left and right padding
+	for (let y = 0; y < hatPixels.length; y++) {
+		const row = [];
+		for (let x = 0; x < LEFT_PADDING; x++) {
+			row.push(PALETTE.TRANSPARENT);
+		}
+
+		for (let x = 0; x < hatPixels[y].length; x++) {
+			row.push(hatPixels[y][x]);
+		}
+
+		for (let x = 0; x < RIGHT_PADDING; x++) {
+			row.push(PALETTE.TRANSPARENT);
+		}
+
+		paddedHatPixels.push(row);
+	}
+	// Bottom padding
+	for (let y = 0; y < BOTTOM_PADDING; y++) {
+		paddedHatPixels.push(Array(hatPixels[0].length + LEFT_PADDING + RIGHT_PADDING)
+			.fill(PALETTE.TRANSPARENT)
+		);
+	}
+
+	// Add outline
+	let neighborOffsets = [
+		[-1, 0],
+		[1, 0],
+		[0, -1],
+		[-1, -1],
+		[1, -1],
+	];
+	if (outlineBottom) {
+		neighborOffsets.push([0, 1], [-1, 1], [1, 1]);
+	}
+	for (let y = 0; y < paddedHatPixels.length; y++) {
+		for (let x = 0; x < paddedHatPixels[y].length; x++) {
+			const pixel = paddedHatPixels[y][x];
+			if (pixel !== PALETTE.TRANSPARENT && pixel !== PALETTE.BORDER) {
+				for (let [dx, dy] of neighborOffsets) {
+					const newX = x + dx;
+					const newY = y + dy;
+					if (newY >= 0 && newY < paddedHatPixels.length && newX >= 0 && newX < paddedHatPixels[newY].length && paddedHatPixels[newY][newX] === PALETTE.TRANSPARENT) {
+						paddedHatPixels[newY][newX] = PALETTE.BORDER;
+					}
+				}
+			}
+		}
+	}
+	return new Layer(paddedHatPixels);
+}