Improve animation handling

engine/Animation.ts

@@ -0,0 +1,47 @@
+import { drawSprite, type Sprite } from "#/lib/Sprite.ts";
+
+export const spriteMap = new Map<string, Sprite>();
+
+export type Animation = {
+	spriteSrc: string;
+	xIndex: number;
+	yIndex: number;
+	frameTime: number;
+	frameDelta: number;
+};
+
+export function createAnimation(
+	sprite: Sprite,
+	frameTime: number,
+	yIndex: number,
+): Animation {
+	const spriteSrc = sprite.image.src;
+	spriteMap.set(spriteSrc, sprite);
+
+	return {
+		spriteSrc,
+		xIndex: 0,
+		yIndex,
+		frameTime,
+		frameDelta: 0,
+	};
+}
+
+export function playAnimation(
+	ctx: CanvasRenderingContext2D,
+	animation: Animation,
+	x: number,
+	y: number,
+	delta: number,
+): void {
+	const sprite = spriteMap.get(animation.spriteSrc)!;
+
+	if ((animation.frameDelta += delta) > animation.frameTime) {
+		animation.frameDelta = 0;
+		if ((animation.xIndex += 1) >= sprite.xFrames) {
+			animation.xIndex = 0;
+		}
+	}
+
+	drawSprite(ctx, sprite, animation.xIndex, animation.yIndex, x, y);
+}