Some animations

lib/Animation.ts

@@ -0,0 +1,38 @@
+import { drawSprite, type Sprite } from "#/lib/Sprite.ts";
+
+export type Animation = {
+	xIndex: number;
+	yIndex: number;
+	frameTime: number;
+	frameDelta: number;
+};
+
+export function createAnimation(yIndex: number, frameTime: number): Animation {
+	return {
+		xIndex: 0,
+		yIndex,
+		frameTime,
+		frameDelta: 0,
+	};
+}
+
+export function animateSprite(
+	ctx: CanvasRenderingContext2D,
+	sprite: Sprite,
+	animation: Animation,
+	x: number,
+	y: number,
+	delta: number,
+): void {
+	drawSprite(ctx, sprite, animation.xIndex, animation.yIndex, x, y);
+
+	animation.frameDelta += delta;
+	if (animation.frameDelta >= animation.frameTime) {
+		animation.frameDelta = animation.frameDelta - animation.frameTime;
+
+		animation.xIndex += 1;
+		if (animation.xIndex >= sprite.xFrames) {
+			animation.xIndex = 0;
+		}
+	}
+}