Learn Intermediate OOP by Building a Platformer Game - Step 98

[YoungStallion602]

Tell us what’s happening:

I can't seem to figure this out , What is it am I missng.

### Your code so far

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const startBtn = document.getElementById("start-btn");
const canvas = document.getElementById("canvas");
const startScreen = document.querySelector(".start-screen");
const checkpointScreen = document.querySelector(".checkpoint-screen");
const checkpointMessage = document.querySelector(".checkpoint-screen > p");
const ctx = canvas.getContext("2d");
canvas.width = innerWidth;
canvas.height = innerHeight;
const gravity = 0.5;
let isCheckpointCollisionDetectionActive = true;

const proportionalSize = (size) => {
  return innerHeight < 500 ? Math.ceil((size / 500) * innerHeight) : size;
}

class Player {
  constructor() {
    this.position = {
      x: proportionalSize(10),
      y: proportionalSize(400),
    };
    this.velocity = {
      x: 0,
      y: 0,
    };
    this.width = proportionalSize(40);
    this.height = proportionalSize(40);
  }
  draw() {
    ctx.fillStyle = "#99c9ff";
    ctx.fillRect(this.position.x, this.position.y, this.width, this.height);
  }
  
  update() {
    this.draw();
    this.position.x += this.velocity.x;
    this.position.y += this.velocity.y;

    if (this.position.y + this.height + this.velocity.y <= canvas.height) {
      if (this.position.y < 0) {
        this.position.y = 0;
        this.velocity.y = gravity;
      }
      this.velocity.y += gravity;
    } else {
      this.velocity.y = 0;
    }

    if (this.position.x < this.width) {
      this.position.x = this.width;
    }

    if (this.position.x >= canvas.width - 2 * this.width) {
      this.position.x = canvas.width - 2 * this.width;
    }
  }
}

class Platform {
  constructor(x, y) {
    this.position = {
      x,
      y,
    };
    this.width = 200;
    this.height = proportionalSize(40);
  }
  draw() {
    ctx.fillStyle = "#acd157";
    ctx.fillRect(this.position.x, this.position.y, this.width, this.height);
  }
}


class CheckPoint {
  constructor(x, y, width, height) {
    this.x = x;
    this.y = y;
    this.width = width;
    this.height = height;
  }

  draw() {
    fillStyle: "#f1be32";
    fillRect(this.x, this.y, this.width, this.height);
  }
}







const player = new Player();

const platformPositions = [
  { x: 500, y: proportionalSize(450) },
  { x: 700, y: proportionalSize(400) },
  { x: 850, y: proportionalSize(350) },
  { x: 900, y: proportionalSize(350) },
  { x: 1050, y: proportionalSize(150) },
  { x: 2500, y: proportionalSize(450) },
  { x: 2900, y: proportionalSize(400) },
  { x: 3150, y: proportionalSize(350) },
  { x: 3900, y: proportionalSize(450) },
  { x: 4200, y: proportionalSize(400) },
  { x: 4400, y: proportionalSize(200) },
  { x: 4700, y: proportionalSize(150) },
];

const platforms = platformPositions.map(
  (platform) => new Platform(platform.x, platform.y)
);

const animate = () => {
  requestAnimationFrame(animate);
  ctx.clearRect(0, 0, canvas.width, canvas.height);

  platforms.forEach((platform) => {
    platform.draw();
  });

  player.update();

  if (keys.rightKey.pressed && player.position.x < proportionalSize(400)) {
    player.velocity.x = 5;
  } else if (keys.leftKey.pressed && player.position.x > proportionalSize(100)) {
    player.velocity.x = -5;
  } else {
    player.velocity.x = 0;

    if (keys.rightKey.pressed && isCheckpointCollisionDetectionActive) {
      platforms.forEach((platform) => {
        platform.position.x -= 5;
      });
    } else if (keys.leftKey.pressed && isCheckpointCollisionDetectionActive) {
      platforms.forEach((platform) => {
        platform.position.x += 5;
      });
    }
  }

  platforms.forEach((platform) => {
    const collisionDetectionRules = [
      player.position.y + player.height <= platform.position.y,
      player.position.y + player.height + player.velocity.y >= platform.position.y,
      player.position.x >= platform.position.x - player.width / 2,
      player.position.x <=
        platform.position.x + platform.width - player.width / 3,
    ];

    if (collisionDetectionRules.every((rule) => rule)) {
      player.velocity.y = 0;
      return;
    }

    const platformDetectionRules = [
      player.position.x >= platform.position.x - player.width / 2,
      player.position.x <=
        platform.position.x + platform.width - player.width / 3,
      player.position.y + player.height >= platform.position.y,
      player.position.y <= platform.position.y + platform.height,
    ];

    if (platformDetectionRules.every(rule => rule)) {
      player.position.y = platform.position.y + player.height;
      player.velocity.y = gravity;
    };
  });
}


const keys = {
  rightKey: {
    pressed: false
  },
  leftKey: {
    pressed: false
  }
};

const movePlayer = (key, xVelocity, isPressed) => {
  if (!isCheckpointCollisionDetectionActive) {
    player.velocity.x = 0;
    player.velocity.y = 0;
    return;
  }

  switch (key) {
    case "ArrowLeft":
      keys.leftKey.pressed = isPressed;
      if (xVelocity === 0) {
        player.velocity.x = xVelocity;
      }
      player.velocity.x -= xVelocity;
      break;
    case "ArrowUp":
    case " ":
    case "Spacebar":
      player.velocity.y -= 8;
      break;
    case "ArrowRight":
      keys.rightKey.pressed = isPressed;
      if (xVelocity === 0) {
        player.velocity.x = xVelocity;
      }
      player.velocity.x += xVelocity;
  }
}

const startGame = () => {
  canvas.style.display = "block";
  startScreen.style.display = "none";
  animate();
}

startBtn.addEventListener("click", startGame);

window.addEventListener("keydown", ({ key }) => {
  movePlayer(key, 8, true);
});

window.addEventListener("keyup", ({ key }) => {
  movePlayer(key, 0, false);
});

Your browser information:

User Agent is: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/17.2.1 Safari/605.1.15

Challenge Information:

Learn Intermediate OOP by Building a Platformer Game - Step 98

freeCodeCamp.org

[Teller]

Hi @YoungStallion602

Look at the Platform class to guide you on the syntax.

Happy coding