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

/**** 
* Classes
****/ 
// Obstacle class (tree or rock)
var Obstacle = Container.expand(function () {
	var self = Container.call(this);
	self.type = Math.random() < 0.6 ? 'tree' : 'rock';
	var assetId = self.type === 'tree' ? 'tree' : 'rock';
	var obs = self.attachAsset(assetId, {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.radius = obs.width * 0.45;
	self.speed = 0; // Set by game
	return self;
});
// Powerup class (shield or boost)
var Powerup = Container.expand(function () {
	var self = Container.call(this);
	self.kind = Math.random() < 0.5 ? 'shield' : 'boost';
	var assetId = self.kind === 'shield' ? 'shield' : 'boost';
	var pu = self.attachAsset(assetId, {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.radius = pu.width * 0.45;
	self.speed = 0; // Set by game
	return self;
});
// Snowboarder (player) class
var Snowboarder = Container.expand(function () {
	var self = Container.call(this);
	var sb = self.attachAsset('snowboarder', {
		anchorX: 0.5,
		anchorY: 0.5
	});
	self.radius = sb.width * 0.45; // For collision
	self.hasShield = false;
	self.shieldNode = null;
	// Show shield visual if active
	self.setShield = function (active) {
		self.hasShield = active;
		if (active && !self.shieldNode) {
			self.shieldNode = self.attachAsset('shield', {
				anchorX: 0.5,
				anchorY: 0.5,
				scaleX: 1.3,
				scaleY: 1.3,
				alpha: 0.5
			});
		} else if (!active && self.shieldNode) {
			self.shieldNode.destroy();
			self.shieldNode = null;
		}
	};
	return self;
});

/**** 
* Initialize Game
****/ 
var game = new LK.Game({
	backgroundColor: 0xffffff // White for snow
});

/**** 
* Game Code
****/ 
// Game constants
// Snowboarder (player)
// Tree obstacle
// Rock obstacle
// Shield powerup
// Speed boost powerup
var GAME_WIDTH = 2048;
var GAME_HEIGHT = 2732;
var PLAY_AREA_MARGIN = 120; // px, left/right margin for obstacles
var OBSTACLE_MIN_Y_DIST = 400; // Minimum vertical distance between obstacles
var OBSTACLE_MAX_Y_DIST = 700;
var OBSTACLE_MIN_X = PLAY_AREA_MARGIN;
var OBSTACLE_MAX_X = GAME_WIDTH - PLAY_AREA_MARGIN;
var POWERUP_CHANCE = 0.12; // Chance to spawn a powerup instead of obstacle
// Intensity increase after 1000 points
var INTENSITY_SCORE_THRESHOLD = 1000;
var INTENSE_OBSTACLE_MIN_Y_DIST = 220;
var INTENSE_OBSTACLE_MAX_Y_DIST = 400;
var INTENSE_POWERUP_CHANCE = 0.16;
// Game state
var snowboarder;
var obstacles = [];
var powerups = [];
var dragNode = null;
var dragOffsetX = 0;
var dragStartX = 0;
var dragStartSnowboarderX = 0;
var lastObstacleY = 0;
var speed = 18; // Initial speed (pixels per frame)
var maxSpeed = 48;
var speedIncreaseEvery = 600; // Increase speed every N ticks
var ticksSinceStart = 0;
var distance = 0; // Distance traveled (score)
var scoreTxt;
var shieldTimer = 0;
var boostTimer = 0;
var isBoosting = false;
// Add tree images to both sides of the screen as static background elements
var leftTrees = [];
var rightTrees = [];
var treeSpacingY = 320;
var treeY = 0;
while (treeY < GAME_HEIGHT + 200) {
	// Left side
	var leftTree = LK.getAsset('tree', {
		anchorX: 0.5,
		anchorY: 0.5,
		x: PLAY_AREA_MARGIN / 2,
		y: treeY
	});
	game.addChild(leftTree);
	leftTrees.push(leftTree);
	// Right side
	var rightTree = LK.getAsset('tree', {
		anchorX: 0.5,
		anchorY: 0.5,
		x: GAME_WIDTH - PLAY_AREA_MARGIN / 2,
		y: treeY
	});
	game.addChild(rightTree);
	rightTrees.push(rightTree);
	treeY += treeSpacingY;
}
// GUI: Score
scoreTxt = new Text2('0', {
	size: 120,
	fill: "#222"
});
scoreTxt.anchor.set(0.5, 0);
LK.gui.top.addChild(scoreTxt);
// Initialize player
snowboarder = new Snowboarder();
game.addChild(snowboarder);
snowboarder.x = GAME_WIDTH / 2;
snowboarder.y = GAME_HEIGHT * 0.12;
// Helper: Clamp value
function clamp(val, min, max) {
	return Math.max(min, Math.min(max, val));
}
// Helper: Distance between two objects
function dist(a, b) {
	var dx = a.x - b.x;
	var dy = a.y - b.y;
	return Math.sqrt(dx * dx + dy * dy);
}
// Spawn an obstacle or powerup
function spawnObstacleOrPowerup(y) {
	// Determine if intensity should be increased
	var scoreVal = Math.floor(distance / 10);
	var minYDist = OBSTACLE_MIN_Y_DIST;
	var maxYDist = OBSTACLE_MAX_Y_DIST;
	var powerupChance = POWERUP_CHANCE;
	if (scoreVal >= INTENSITY_SCORE_THRESHOLD) {
		minYDist = INTENSE_OBSTACLE_MIN_Y_DIST;
		maxYDist = INTENSE_OBSTACLE_MAX_Y_DIST;
		powerupChance = INTENSE_POWERUP_CHANCE;
	}
	if (Math.random() < powerupChance) {
		// Powerup
		var pu = new Powerup();
		pu.x = Math.random() * (OBSTACLE_MAX_X - OBSTACLE_MIN_X) + OBSTACLE_MIN_X;
		pu.y = y;
		pu.speed = speed;
		powerups.push(pu);
		game.addChild(pu);
	} else {
		// Obstacle
		var obs = new Obstacle();
		obs.x = Math.random() * (OBSTACLE_MAX_X - OBSTACLE_MIN_X) + OBSTACLE_MIN_X;
		obs.y = y;
		obs.speed = speed;
		obstacles.push(obs);
		game.addChild(obs);
	}
}
// Initial obstacles
lastObstacleY = snowboarder.y - 600;
for (var i = 0; i < 6; i++) {
	lastObstacleY -= Math.random() * (OBSTACLE_MAX_Y_DIST - OBSTACLE_MIN_Y_DIST) + OBSTACLE_MIN_Y_DIST;
	spawnObstacleOrPowerup(lastObstacleY);
}
// Touch/drag controls
game.down = function (x, y, obj) {
	// Only allow drag if touch is on lower 2/3 of screen (to avoid top menu)
	if (y > GAME_HEIGHT * 0.2) {
		dragNode = snowboarder;
		dragStartX = x;
		dragStartSnowboarderX = snowboarder.x;
	}
};
game.move = function (x, y, obj) {
	if (dragNode === snowboarder) {
		var dx = x - dragStartX;
		var newX = clamp(dragStartSnowboarderX + dx, OBSTACLE_MIN_X, OBSTACLE_MAX_X);
		snowboarder.x = newX;
	}
};
game.up = function (x, y, obj) {
	dragNode = null;
};
// Main game loop
game.update = function () {
	ticksSinceStart++;
	// Increase speed over time
	if (ticksSinceStart % speedIncreaseEvery === 0 && speed < maxSpeed) {
		speed += 2;
	}
	// Speed scaling: increase by 20% for each 1000 points after the first 1000 points
	var scoreVal = Math.floor(distance / 10);
	if (scoreVal >= 1000) {
		// Number of 1000-point steps after the first 1000
		var speedSteps = Math.floor((scoreVal - 1000) / 1000) + 1;
		var scaledSpeed = speed * Math.pow(1.2, speedSteps);
		// Clamp to maxSpeed if needed
		if (scaledSpeed > maxSpeed) {
			scaledSpeed = maxSpeed;
		}
		speed = scaledSpeed;
	}
	// If boosting, increase speed temporarily
	var currentSpeed = isBoosting ? speed * 1.7 : speed;
	// Move side trees up (reverse flow)
	for (var i = 0; i < leftTrees.length; i++) {
		leftTrees[i].y -= currentSpeed;
		// If tree goes off top, move it to bottom
		if (leftTrees[i].y < -200) {
			leftTrees[i].y += treeSpacingY * leftTrees.length;
		}
	}
	for (var i = 0; i < rightTrees.length; i++) {
		rightTrees[i].y -= currentSpeed;
		if (rightTrees[i].y < -200) {
			rightTrees[i].y += treeSpacingY * rightTrees.length;
		}
	}
	// Move obstacles and powerups up (reverse flow)
	for (var i = obstacles.length - 1; i >= 0; i--) {
		var obs = obstacles[i];
		obs.y -= currentSpeed;
		obs.speed = currentSpeed;
		// Remove if off screen (now above screen)
		if (obs.y + obs.height / 2 < -100) {
			obs.destroy();
			obstacles.splice(i, 1);
		}
	}
	for (var i = powerups.length - 1; i >= 0; i--) {
		var pu = powerups[i];
		pu.y -= currentSpeed;
		pu.speed = currentSpeed;
		// Remove if off screen (now above screen)
		if (pu.y + pu.height / 2 < -100) {
			pu.destroy();
			powerups.splice(i, 1);
		}
	}
	// Continuously spawn obstacles and powerups as the player progresses (now below player)
	while (lastObstacleY < snowboarder.y + 3000) {
		// Use more intense spawn distances after threshold
		var scoreVal = Math.floor(distance / 10);
		var minYDist = OBSTACLE_MIN_Y_DIST;
		var maxYDist = OBSTACLE_MAX_Y_DIST;
		if (scoreVal >= INTENSITY_SCORE_THRESHOLD) {
			minYDist = INTENSE_OBSTACLE_MIN_Y_DIST;
			maxYDist = INTENSE_OBSTACLE_MAX_Y_DIST;
		}
		lastObstacleY += Math.random() * (maxYDist - minYDist) + minYDist;
		spawnObstacleOrPowerup(lastObstacleY);
	}
	// Obstacles and powerups keep coming endlessly as the player progresses
	// Always ensure obstacles continue to spawn all game, even if the player is not moving
	if (obstacles.length < 8) {
		// If for any reason there are too few obstacles, spawn more to keep the game challenging
		var scoreVal = Math.floor(distance / 10);
		var minYDist = OBSTACLE_MIN_Y_DIST;
		var maxYDist = OBSTACLE_MAX_Y_DIST;
		if (scoreVal >= INTENSITY_SCORE_THRESHOLD) {
			minYDist = INTENSE_OBSTACLE_MIN_Y_DIST;
			maxYDist = INTENSE_OBSTACLE_MAX_Y_DIST;
		}
		lastObstacleY += Math.random() * (maxYDist - minYDist) + minYDist;
		spawnObstacleOrPowerup(lastObstacleY);
	}
	// Collision: obstacles
	var collided = false;
	for (var i = 0; i < obstacles.length; i++) {
		var obs = obstacles[i];
		if (dist(snowboarder, obs) < snowboarder.radius + obs.radius) {
			collided = true;
			break;
		}
	}
	if (collided) {
		if (snowboarder.hasShield) {
			snowboarder.setShield(false);
			// Flash snowboarder
			LK.effects.flashObject(snowboarder, 0xffe066, 600);
		} else {
			// Game over
			LK.effects.flashScreen(0xff0000, 900);
			LK.showGameOver();
			return;
		}
	}
	// Collision: powerups
	for (var i = powerups.length - 1; i >= 0; i--) {
		var pu = powerups[i];
		if (dist(snowboarder, pu) < snowboarder.radius + pu.radius) {
			if (pu.kind === 'shield') {
				snowboarder.setShield(true);
				shieldTimer = 360; // 6 seconds at 60fps
			} else if (pu.kind === 'boost') {
				isBoosting = true;
				boostTimer = 180; // 3 seconds at 60fps
				// Flash snowboarder red for boost
				LK.effects.flashObject(snowboarder, 0xff3b3b, 400);
			}
			pu.destroy();
			powerups.splice(i, 1);
		}
	}
	// Powerup timers
	if (snowboarder.hasShield) {
		shieldTimer--;
		if (shieldTimer <= 0) {
			snowboarder.setShield(false);
		}
	}
	if (isBoosting) {
		boostTimer--;
		if (boostTimer <= 0) {
			isBoosting = false;
		}
	}
	// Snowboarder stays at the top; do not move snowboarder down the screen (reverse flow)
	// snowboarder.y += currentSpeed;
	// Score: distance traveled
	distance += currentSpeed;
	var scoreVal = Math.floor(distance / 10);
	LK.setScore(scoreVal);
	scoreTxt.setText(scoreVal);
	// Endless game: no win condition, continues until hit
};
/* End of game code */

===================================================================
--- original.js
+++ change.js
@@ -107,8 +107,34 @@
 var scoreTxt;
 var shieldTimer = 0;
 var boostTimer = 0;
 var isBoosting = false;
+// Add tree images to both sides of the screen as static background elements
+var leftTrees = [];
+var rightTrees = [];
+var treeSpacingY = 320;
+var treeY = 0;
+while (treeY < GAME_HEIGHT + 200) {
+	// Left side
+	var leftTree = LK.getAsset('tree', {
+		anchorX: 0.5,
+		anchorY: 0.5,
+		x: PLAY_AREA_MARGIN / 2,
+		y: treeY
+	});
+	game.addChild(leftTree);
+	leftTrees.push(leftTree);
+	// Right side
+	var rightTree = LK.getAsset('tree', {
+		anchorX: 0.5,
+		anchorY: 0.5,
+		x: GAME_WIDTH - PLAY_AREA_MARGIN / 2,
+		y: treeY
+	});
+	game.addChild(rightTree);
+	rightTrees.push(rightTree);
+	treeY += treeSpacingY;
+}
 // GUI: Score
 scoreTxt = new Text2('0', {
 	size: 120,
 	fill: "#222"
@@ -205,8 +231,22 @@
 		speed = scaledSpeed;
 	}
 	// If boosting, increase speed temporarily
 	var currentSpeed = isBoosting ? speed * 1.7 : speed;
+	// Move side trees up (reverse flow)
+	for (var i = 0; i < leftTrees.length; i++) {
+		leftTrees[i].y -= currentSpeed;
+		// If tree goes off top, move it to bottom
+		if (leftTrees[i].y < -200) {
+			leftTrees[i].y += treeSpacingY * leftTrees.length;
+		}
+	}
+	for (var i = 0; i < rightTrees.length; i++) {
+		rightTrees[i].y -= currentSpeed;
+		if (rightTrees[i].y < -200) {
+			rightTrees[i].y += treeSpacingY * rightTrees.length;
+		}
+	}
 	// Move obstacles and powerups up (reverse flow)
 	for (var i = obstacles.length - 1; i >= 0; i--) {
 		var obs = obstacles[i];
 		obs.y -= currentSpeed;