--description--

As the player moves through the game, you will need to clear the canvas before rendering the next frame of the animation.

You can use the <dfn>clearRect()</dfn> Web API to accomplish this. It takes in an x, y, width, and height arguments.

Below your requestAnimationFrame, call the clearRect() method on the ctx variable and pass in 0, 0, canvas.width, canvas.height as the arguments.

--hints--

You should call the clearRect() method on the ctx variable.

assert.match(code, /\s*ctx\s*\.\s*clearRect\s*\([^)]*\)\s*;?/);

You should pass in 0, 0, canvas.width, canvas.height for the arguments of the clearRect() method.

assert.match(code, /\s*ctx\s*\.\s*clearRect\s*\(\s*0\s*,\s*0\s*,\s*canvas\s*\.\s*width\s*,\s*canvas\s*\.\s*height\s*\)\s*;?/);

--seed--

--seed-contents--

html

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Learn Intermediate OOP by Building a Platformer Game</title>
    <link rel="stylesheet" href="./styles.css" />
  </head>
  <body>
    <div class="start-screen">
      <h1 class="main-title">freeCodeCamp Code Warrior</h1>
      <p class="instructions">
        Help the main player navigate to the yellow checkpoints.
      </p>
      <p class="instructions">
        Use the keyboard arrows to move the player around.
      </p>
      <p class="instructions">You can also use the spacebar to jump.</p>

      <div class="btn-container">
        <button class="btn" id="start-btn">Start Game</button>
      </div>
    </div>

    <div class="checkpoint-screen">
      <h2>Congrats!</h2>
      <p>You reached the last checkpoint.</p>
    </div>

    <canvas id="canvas"></canvas>

    <script src="./script.js"></script>
  </body>
</html>

css

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  --main-bg-color: #0a0a23;
  --section-bg-color: #ffffff;
  --golden-yellow: #feac32;
}

body {
  background-color: var(--main-bg-color);
}

.start-screen {
  background-color: var(--section-bg-color);
  width: 100%;
  position: absolute;
  top: 50%;
  left: 50%;
  margin-right: -50%;
  transform: translate(-50%, -50%);
  border-radius: 30px;
  padding: 20px;
  padding-bottom: 5px;
}

.main-title {
  text-align: center;
}

.instructions {
  text-align: center;
  font-size: 1.2rem;
  margin: 15px;
  line-height: 2rem;
}

.btn {
  cursor: pointer;
  width: 100px;
  margin: 10px;
  color: #0a0a23;
  font-size: 18px;
  background-color: var(--golden-yellow);
  background-image: linear-gradient(#fecc4c, #ffac33);
  border-color: var(--golden-yellow);
  border-width: 3px;
}

.btn:hover {
  background-image: linear-gradient(#ffcc4c, #f89808);
}

.btn-container {
  display: flex;
  align-items: center;
  justify-content: center;
}

.checkpoint-screen {
  position: absolute;
  left: 0;
  right: 0;
  margin-left: auto;
  margin-right: auto;
  width: 100%;
  text-align: center;
  background-color: var(--section-bg-color);
  border-radius: 20px;
  padding: 10px;
  display: none;
}

#canvas {
  display: none;
}

@media (min-width: 768px) {
  .start-screen {
    width: 60%;
    max-width: 700px;
  }

  .checkpoint-screen {
    max-width: 300px;
  }
}

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

const player = new Player();

--fcc-editable-region--

const animate = () => {
  requestAnimationFrame(animate);

}

--fcc-editable-region--

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

startBtn.addEventListener("click", startGame);

Step 42

--description--

--hints--

--seed--

--seed-contents--