/**** 
* Plugins
****/ 
var tween = LK.import("@upit/tween.v1");

/**** 
* Classes
****/ 
// Block class: falling piano key
var Block = Container.expand(function () {
	var self = Container.call(this);
	// Attach block asset
	var blockAsset = self.attachAsset('block', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	// Track if block has been hit or missed
	self.hit = false;
	self.missed = false;
	// For hit effect
	self.showHitEffect = function () {
		var effect = LK.getAsset('hitEffect', {
			anchorX: 0.5,
			anchorY: 0.5,
			x: 0,
			y: 0
		});
		self.addChild(effect);
		tween(effect, {
			alpha: 0
		}, {
			duration: 300,
			easing: tween.linear,
			onFinish: function onFinish() {
				effect.destroy();
			}
		});
	};
	return self;
});

/**** 
* Initialize Game
****/ 
var game = new LK.Game({
	backgroundColor: 0x181818
});

/**** 
* Game Code
****/ 
// Piano note sounds for each lane (C, D, E, G as example)
// Music (looping, but we will play it once per game)
// Sound for miss
// Sound for block hit
// Block hit effect
// Target line
// Falling block (piano key)
// --- GAME CONSTANTS ---
var NUM_LANES = 4;
var LANE_WIDTH = 400; // 2048/4 = 512, but leave some margin
var BLOCK_WIDTH = 300;
var BLOCK_HEIGHT = 120;
var BLOCK_SPEED_START = 12; // px per frame (60fps)
var BLOCK_SPEED_MAX = 32;
var BLOCK_SPEED_INCREMENT = 0.5; // per level
var BLOCK_SPAWN_INTERVAL = 48; // frames between blocks (will decrease as tempo increases)
var BLOCK_SPAWN_INTERVAL_MIN = 18;
var TARGET_LINE_Y = 2732 - 320; // 320px from bottom
var HIT_WINDOW = 80; // px window for perfect hit
var MISS_WINDOW = 120; // px window for miss
// --- GAME STATE ---
var blocks = [];
var score = 0;
var combo = 0;
var bestCombo = 0;
var blockSpeed = BLOCK_SPEED_START;
var blockSpawnInterval = BLOCK_SPAWN_INTERVAL;
var ticksSinceLastBlock = 0;
var isPlaying = false;
var songTicks = 0;
var songLengthTicks = 60 * 60; // 60 seconds at 60fps (will end game if song ends)
var nextTempoIncrease = 600; // every 10 seconds
// --- LANE POSITIONS ---
var laneXs = [];
for (var i = 0; i < NUM_LANES; i++) {
	// Center blocks in each lane
	laneXs[i] = LANE_WIDTH / 2 + i * LANE_WIDTH + (2048 - NUM_LANES * LANE_WIDTH) / 2;
}
// --- GUI ELEMENTS ---
// Score text
var scoreTxt = new Text2('0', {
	size: 120,
	fill: 0xFFFFFF
});
scoreTxt.anchor.set(0.5, 0);
LK.gui.top.addChild(scoreTxt);
// Combo text
var comboTxt = new Text2('', {
	size: 80,
	fill: 0xFFE066
});
comboTxt.anchor.set(0.5, 0);
LK.gui.top.addChild(comboTxt);
comboTxt.y = 130;
// Best combo text
var bestComboTxt = new Text2('', {
	size: 60,
	fill: 0xCCCCCC
});
bestComboTxt.anchor.set(0.5, 0);
LK.gui.top.addChild(bestComboTxt);
bestComboTxt.y = 210;
// --- TARGET LINE ---
var targetLine = LK.getAsset('targetLine', {
	anchorX: 0.5,
	anchorY: 0.5,
	x: 2048 / 2,
	y: TARGET_LINE_Y
});
game.addChild(targetLine);
// --- GAME START ---
function startGame() {
	// Reset state
	for (var i = blocks.length - 1; i >= 0; i--) {
		blocks[i].destroy();
		blocks.splice(i, 1);
	}
	score = 0;
	combo = 0;
	bestCombo = 0;
	blockSpeed = BLOCK_SPEED_START;
	blockSpawnInterval = BLOCK_SPAWN_INTERVAL;
	ticksSinceLastBlock = 0;
	isPlaying = true;
	songTicks = 0;
	nextTempoIncrease = 600;
	scoreTxt.setText('0');
	comboTxt.setText('');
	bestComboTxt.setText('');
	// Start music
	LK.playMusic('pianoTrack', {
		loop: false
	});
}
startGame();
// --- BLOCK SCHEDULING ---
// For MVP, blocks are spawned randomly in lanes, but now in sync with the music beat using LK.music.getBeat API
function spawnBlock() {
	var lane = Math.floor(Math.random() * NUM_LANES);
	var block = new Block();
	block.x = laneXs[lane];
	block.y = -BLOCK_HEIGHT / 2;
	block.lane = lane;
	block.hit = false;
	block.missed = false;
	blocks.push(block);
	game.addChild(block);
}
// --- BEAT SYNC SCHEDULING ---
var lastBeat = -1;
// --- GAME UPDATE ---
game.update = function () {
	if (!isPlaying) return;
	songTicks++;
	ticksSinceLastBlock++;
	// Increase tempo every 10 seconds
	if (songTicks >= nextTempoIncrease) {
		if (blockSpeed < BLOCK_SPEED_MAX) blockSpeed += BLOCK_SPEED_INCREMENT;
		if (blockSpawnInterval > BLOCK_SPAWN_INTERVAL_MIN) blockSpawnInterval--;
		nextTempoIncrease += 600;
	}
	// Spawn new block on beat using LK.music.getBeat for beat-synced block drops
	var currentBeat = LK.music.getBeat && LK.music.getBeat('pianoTrack');
	if (typeof currentBeat === "number" && currentBeat !== lastBeat) {
		spawnBlock();
		lastBeat = currentBeat;
		ticksSinceLastBlock = 0;
	}
	// Move blocks
	for (var i = blocks.length - 1; i >= 0; i--) {
		var block = blocks[i];
		if (block.hit || block.missed) continue;
		block.y += blockSpeed;
		// Missed block (passed target line + window)
		if (block.y - TARGET_LINE_Y > MISS_WINDOW) {
			block.missed = true;
			combo = 0;
			comboTxt.setText('');
			LK.getSound('miss').play();
			// Flash screen red
			LK.effects.flashScreen(0xff0000, 600);
			// End game
			isPlaying = false;
			LK.stopMusic();
			LK.showGameOver();
			break;
		}
	}
	// End game if song ends
	if (songTicks > songLengthTicks) {
		isPlaying = false;
		LK.stopMusic();
		LK.showYouWin();
	}
};
// --- INPUT HANDLING ---
// Tap/click on falling block at the right time
game.down = function (x, y, obj) {
	if (!isPlaying) return;
	// Only allow taps below the target line (to avoid accidental taps)
	if (y < TARGET_LINE_Y - BLOCK_HEIGHT) return;
	// Find the block closest to the target line in each lane
	var tapped = false;
	for (var i = 0; i < NUM_LANES; i++) {
		// Check if tap is in this lane
		var laneLeft = laneXs[i] - LANE_WIDTH / 2;
		var laneRight = laneXs[i] + LANE_WIDTH / 2;
		if (x >= laneLeft && x < laneRight) {
			// Find the first block in this lane within the hit window
			var bestBlock = null;
			var bestDist = 9999;
			for (var j = 0; j < blocks.length; j++) {
				var block = blocks[j];
				if (block.lane !== i || block.hit || block.missed) continue;
				var dist = Math.abs(block.y - TARGET_LINE_Y);
				if (dist < HIT_WINDOW && dist < bestDist) {
					bestBlock = block;
					bestDist = dist;
				}
			}
			if (bestBlock) {
				// Hit!
				bestBlock.hit = true;
				tapped = true;
				score += 1;
				combo += 1;
				if (combo > bestCombo) bestCombo = combo;
				scoreTxt.setText(score + '');
				comboTxt.setText(combo > 1 ? combo + ' combo!' : '');
				bestComboTxt.setText('Best: ' + bestCombo);
				bestBlock.showHitEffect();
				// Play a different piano note sound for each lane
				var noteId = 'piano_note_' + bestBlock.lane;
				if (LK.hasSound && LK.hasSound(noteId)) {
					LK.getSound(noteId).play();
				} else {
					LK.getSound('hit').play();
				}
				// Animate block fade out
				tween(bestBlock, {
					alpha: 0
				}, {
					duration: 180,
					onFinish: function onFinish() {
						bestBlock.destroy();
					}
				});
			}
			break;
		}
	}
	if (!tapped) {
		// Missed tap (tapped empty lane or wrong time)
		combo = 0;
		comboTxt.setText('');
		LK.getSound('miss').play();
		LK.effects.flashScreen(0xff0000, 400);
		isPlaying = false;
		LK.stopMusic();
		LK.showGameOver();
	}
};
// --- GAME OVER / WIN HANDLING ---
// (Handled by LK engine, game will be reset automatically)
// --- MUSIC RESTART ON GAME RESET ---
LK.on('gameReset', function () {
	startGame();
});

===================================================================
--- original.js
+++ change.js
@@ -144,9 +144,9 @@
 	});
 }
 startGame();
 // --- BLOCK SCHEDULING ---
-// For MVP, blocks are spawned randomly in lanes, in sync with the beat (every blockSpawnInterval ticks)
+// For MVP, blocks are spawned randomly in lanes, but now in sync with the music beat using LK.music.getBeat API
 function spawnBlock() {
 	var lane = Math.floor(Math.random() * NUM_LANES);
 	var block = new Block();
 	block.x = laneXs[lane];
@@ -156,8 +156,10 @@
 	block.missed = false;
 	blocks.push(block);
 	game.addChild(block);
 }
+// --- BEAT SYNC SCHEDULING ---
+var lastBeat = -1;
 // --- GAME UPDATE ---
 game.update = function () {
 	if (!isPlaying) return;
 	songTicks++;
@@ -167,11 +169,13 @@
 		if (blockSpeed < BLOCK_SPEED_MAX) blockSpeed += BLOCK_SPEED_INCREMENT;
 		if (blockSpawnInterval > BLOCK_SPAWN_INTERVAL_MIN) blockSpawnInterval--;
 		nextTempoIncrease += 600;
 	}
-	// Spawn new block on beat
-	if (ticksSinceLastBlock >= blockSpawnInterval) {
+	// Spawn new block on beat using LK.music.getBeat for beat-synced block drops
+	var currentBeat = LK.music.getBeat && LK.music.getBeat('pianoTrack');
+	if (typeof currentBeat === "number" && currentBeat !== lastBeat) {
 		spawnBlock();
+		lastBeat = currentBeat;
 		ticksSinceLastBlock = 0;
 	}
 	// Move blocks
 	for (var i = blocks.length - 1; i >= 0; i--) {