make things move in direction when edges touched of canvas. so, player moves and canvas follows player through obstacle platforms jumpings. output only new functions or what to modify exactly, without full original code output.: const canvas=document.getElementById("game-canvas");const context=canvas.getContext("2d");canvas.width=800;canvas.height=600;const GRAVITY=80;const ENEMY_RADIUS=10;const PLAYER_RADIUS=10;const TRACTION=.9999;const OBSTACLE_COUNT=5;const OBSTACLE_GAP=5;let playerX=50;let playerY=250;let isPlayerAlive=true;let enemyX=400;let enemyY=100;let enemySpeedX=0;let enemySpeedY=0;let enemyMultiplier=0;let playerSpeedX=0;let playerSpeedY=0;let playerIsOnGround=false;let lasers=[];let shootingTimer=0;let obstacles=[];const obstacleWidth=200;const obstacleHeight=10;let offsetY=0;let scrollSpeed=1;function applyGravity(){if(!playerIsOnGround){playerSpeedY+=GRAVITY/60}}function applyTraction(){playerSpeedX*=TRACTION}function movePlayer(){if(!isPlayerAlive)return;playerX+=playerSpeedX;playerY+=playerSpeedY;if(playerX<0){playerX=0}if(playerX+PLAYER_RADIUS*2>canvas.width){playerX=canvas.width-PLAYER_RADIUS*2}context.fillStyle="pink";context.fillRect(playerX,playerY-offsetY,PLAYER_RADIUS*2,PLAYER_RADIUS*2)}function moveEnemy(){if(!isPlayerAlive)return;const targetIndex=findNearestObstacle(playerX,playerY);const targetX=obstacles[targetIndex].x+obstacleWidth/2;const targetY=obstacles[targetIndex].y+obstacleHeight/2;const epsilon=.2;if(Math.abs(enemyX-targetX)>epsilon||Math.abs(enemyY-targetY)>epsilon){const angle=Math.atan2(targetY-enemyY,targetX-enemyX);enemySpeedX=Math.cos(angle)*2;enemySpeedY=Math.sin(angle)*2}else{enemySpeedX=0;enemySpeedY=0}enemyX+=enemySpeedX;enemyY+=enemySpeedY;if(shootingTimer<=0){shootLaser();shootingTimer=1}shootingTimer-=1e-4;context.fillStyle="cyan";context.fillRect(enemyX-ENEMY_RADIUS,enemyY-ENEMY_RADIUS,ENEMY_RADIUS*2,ENEMY_RADIUS*2)}function findNearestObstacle(x,y){let minIndex=0;let minDistance=Number.MAX_VALUE;for(let i=0;i<obstacles.length;i++){const dx=x-(obstacles[i].x+obstacleWidth/2);const dy=y-(obstacles[i].y+obstacleHeight/2);const distance=Math.sqrt(dx*dx+dy*dy);if(distance<minDistance){minDistance=distance;minIndex=i}}return minIndex}function isColliding(x,y,width,height){for(const obstacle of obstacles){if(x<obstacle.x+obstacle.width&&x+width>obstacle.x&&y<obstacle.y+obstacle.height&&y+height>obstacle.y){return true}}return false}function checkCollision(){if(isColliding(playerX,playerY,PLAYER_RADIUS*2,PLAYER_RADIUS*2)){playerY-=playerSpeedY;offsetY-=playerSpeedY;playerSpeedY=0;playerIsOnGround=true}else{playerIsOnGround=false}}function detectObstacleCollision(){for(const obstacle of obstacles){if(playerX+PLAYER_RADIUS*2>obstacle.x&&playerX<obstacle.x+obstacle.width&&playerY+PLAYER_RADIUS*2>obstacle.y&&playerY<obstacle.y+obstacle.height){if(playerX+PLAYER_RADIUS*2<obstacle.x+5){playerX=obstacle.x-PLAYER_RADIUS*2}else if(playerX>obstacle.x+obstacle.width-5){playerX=obstacle.x+obstacle.width}else{if(playerY+PLAYER_RADIUS*2<obstacle.y+5){playerY=obstacle.y-PLAYER_RADIUS*2;playerIsOnGround=true}if(playerY>obstacle.y+obstacle.height-5){playerY=obstacle.y+obstacle.height;playerSpeedY=0}}}if(enemyX+ENEMY_RADIUS*2>obstacle.x&&enemyX<obstacle.x+obstacle.width&&enemyY+ENEMY_RADIUS*2>obstacle.y&&enemyY<obstacle.y+obstacle.height){if(enemyX+ENEMY_RADIUS*2<obstacle.x+5){enemyX=obstacle.x-ENEMY_RADIUS*2}else if(enemyX>obstacle.x+obstacle.width-5){enemyX=obstacle.x+obstacle.width}else{if(enemyY+ENEMY_RADIUS*2<obstacle.y+5){enemyY=obstacle.y-ENEMY_RADIUS*2}else if(enemyY>obstacle.y+obstacle.height-5){enemyY=obstacle.y+obstacle.height;enemySpeedY=0}}}}}function shootLaser(){const laserSpeed=2;const angle=Math.atan2(playerY-enemyY,playerX-enemyX);const laserSpeedX=Math.cos(angle)*laserSpeed;const laserSpeedY=Math.sin(angle)*laserSpeed;lasers.push({x:enemyX+ENEMY_RADIUS,y:enemyY+ENEMY_RADIUS,speedX:laserSpeedX,speedY:laserSpeedY})}function moveLasers(){let playerHit=false;for(let i=0;i<lasers.length;i++){const laser=lasers[i];laser.x+=laser.speedX;laser.y+=laser.speedY;if(!playerHit&&laser.x>=playerX&&laser.x<=playerX+PLAYER_RADIUS*2&&laser.y>=playerY&&laser.y<=playerY+PLAYER_RADIUS*2){const randomColor="rgb("+Math.floor(Math.random()*256)+","+Math.floor(Math.random()*256)+","+Math.floor(Math.random()*256)+")";context.strokeStyle=randomColor;context.beginPath();context.moveTo(laser.x,laser.y);context.lineTo(laser.x+laser.speedX,laser.y+laser.speedY);context.lineWidth=3;context.stroke();playerHit=true;isPlayerAlive=false}if(laser.x<0||laser.x>canvas.width||laser.y<0||laser.y>canvas.height){lasers.splice(i,1);i}}if(playerHit){playerX=-100;playerY=-100}}function drawLasers(){context.fillStyle="red";for(const laser of lasers){context.beginPath();context.arc(laser.x,laser.y,5,0,Math.PI*2);context.fill()}}function drawObstacles(){context.fillStyle="yellow";for(const obstacle of obstacles){context.fillRect(obstacle.x,obstacle.y,obstacle.width,obstacle.height)}}function createObstacles(){for(let i=0;i<OBSTACLE_COUNT;i++){const obstacleX=Math.random()*(canvas.width-obstacleWidth);const obstacleY=i*(canvas.height/OBSTACLE_COUNT)+OBSTACLE_GAP;obstacles.push({x:obstacleX,y:obstacleY,width:obstacleWidth,height:obstacleHeight})}}function setPlayerStartPosition(){const startingObstacle=obstacles[0];playerX=startingObstacle.x+obstacleWidth/2-PLAYER_RADIUS;playerY=startingObstacle.y-PLAYER_RADIUS*2}function drawObstacles(){context.fillStyle="yellow";for(const obstacle of obstacles){context.fillRect(obstacle.x,obstacle.y-offsetY,obstacle.width,obstacle.height)}}function generateNewObstacle(){obstacles.shift();const obstacleX=Math.random()*(canvas.width-obstacleWidth);const obstacleY=obstacles[obstacles.length-1].y-canvas.height/OBSTACLE_COUNT;obstacles.push({y:obstacleX,x:obstacleY,width:obstacleWidth,height:obstacleHeight})}function checkEnemyDeath(){if(isPlayerAlive&&playerSpeedY>=0&&playerY+PLAYER_RADIUS*2>enemyY-ENEMY_RADIUS&&playerX+PLAYER_RADIUS*2>enemyX-ENEMY_RADIUS&&playerX<enemyX+ENEMY_RADIUS){playerSpeedY=-20;playerIsOnGround=false;enemyY=-100;enemyX=-100;setTimeout(spawnNewEnemy,1e3);enemyMultiplier++}}function spawnNewEnemy(){enemyX=Math.random()*(canvas.width-ENEMY_RADIUS*2);enemyY=Math.random()*(canvas.height-ENEMY_RADIUS*2);for(let i=0;i<enemyMultiplier-1;i++){shootLaser()}}function draw(){context.fillStyle="black";context.fillRect(0,0,canvas.width,canvas.height);applyGravity();applyTraction();movePlayer();moveEnemy();moveLasers();checkCollision();drawLasers();drawObstacles();checkEnemyDeath();offsetY+=scrollSpeed;if(playerY<offsetY+PLAYER_RADIUS*2){offsetY-=canvas.height/OBSTACLE_COUNT;playerY+=canvas.height/OBSTACLE_COUNT;enemyY+=canvas.height/OBSTACLE_COUNT;generateNewObstacle()}detectObstacleCollision();requestAnimationFrame(draw)}createObstacles();setPlayerStartPosition();draw();document.addEventListener("keydown",event=>{if(event.code==="KeyA"){playerSpeedX=-5}if(event.code==="KeyD"){playerSpeedX=5}if(event.code==="KeyW"&&playerIsOnGround){playerSpeedY=-20;playerIsOnGround=false}});document.addEventListener("keyup",event=>{if(event.code==="KeyA"||event.code==="KeyD"){playerSpeedX=0}});