| Intro | Player | Platform | Tube | Block | Goomba | Background |
JS Mario 4-Block
A lesson designed to help you create your own block object for your game
%%html
<style>
#canvas {
margin: 0;
border: 1px solid white;
}
</style>
<canvas id="canvas"></canvas>
<script>
// Create empty canvas
let canvas = document.getElementById('canvas');
let c = canvas.getContext('2d');
// Set the canvas dimensions
canvas.width = 650;
canvas.height = 400;
// Define gravity value
let gravity = 1.5;
// Define the Player class
class Player {
constructor() {
// Initial position and velocity of the player
this.position = {
x: 100,
y: 200
};
this.velocity = {
x: 0,
y: 0
};
// Dimensions of the player
this.width = 30;
this.height = 30;
}
// Method to draw the player on the canvas
draw() {
c.fillStyle = 'red';
c.fillRect(this.position.x, this.position.y, this.width, this.height);
}
// Method to update the player position and velocity
update() {
this.draw();
this.position.y += this.velocity.y;
this.position.x += this.velocity.x;
// Apply gravity if player is not at the bottom
if (this.position.y + this.height + this.velocity.y <= canvas.height)
this.velocity.y += gravity;
else
this.velocity.y = 0;
}
}
// Define the Platform class
class Platform {
constructor(image) {
// Initial position of the platform
this.position = {
x: 0,
y: 300
}
this.image = image;
this.width = 650;
this.height = 100;
}
// Method to draw the platform on the canvas
draw() {
c.drawImage(this.image, this.position.x, this.position.y, this.width, this.height);
}
}
// Define the Tube class
class Tube {
constructor(image) {
// Initial position of the tube
this.position = {
x: 500,
y: 180
}
this.image = image;
this.width = 100;
this.height = 120;
}
// Method to draw the tube on the canvas
draw() {
c.drawImage(this.image, this.position.x, this.position.y, this.width, this.height);
}
}
//--
// NEW CODE - DEFINE BLOCKOBJECT CLASS
//--
class BlockObject {
constructor(image) {
// Initial position of the block object
this.position = {
x: 200,
y: 100
};
this.image = image;
this.width = 158;
this.height = 79;
}
// Method to draw the block object on the canvas
draw() {
c.drawImage(this.image, this.position.x, this.position.y);
}
}
// Load images
let image = new Image();
let imageTube = new Image();
//--
// NEW CODE - ADD IMAGE FOR BLOCK OBJECT
//--
let imageBlock = new Image();
// Load image sources
image.src = 'https://samayass.github.io/samayaCSA/images/platform.png';
imageTube.src = 'https://samayass.github.io/samayaCSA/images/tube.png';
imageBlock.src = 'https://samayass.github.io/samayaCSA/images/box.png';
// Create platform, tube, and block object instances
let platform = new Platform(image);
let tube = new Tube(imageTube);
//--
// CREATE BLOCK OBJECT
//--
let blockObject = new BlockObject(imageBlock);
// Create a player object
player = new Player();
// Define keyboard keys and their states
let keys = {
right: {
pressed: false
},
left: {
pressed: false
}
}
// Animation function to continuously update and render the canvas
function animate() {
requestAnimationFrame(animate);
c.clearRect(0, 0, canvas.width, canvas.height);
// Draw platform, player, tube, and block object
platform.draw();
player.update();
tube.draw();
//--
// DRAW BLOCK OBJECT
//--
blockObject.draw();
//--
// COLLISIONS BETWEEN BLOCK OBJECT AND PLAYER
//--
if (
player.position.y + player.height <= blockObject.position.y &&
player.position.y + player.height + player.velocity.y >= blockObject.position.y &&
player.position.x + player.width >= blockObject.position.x &&
player.position.x <= blockObject.position.x + blockObject.width
)
{
player.velocity.y = 0;
}
// Control player horizontal movement
if (keys.right.pressed && player.position.x + player.width <= canvas.width - 50) {
player.velocity.x = 15;
} else if (keys.left.pressed && player.position.x >= 50) {
player.velocity.x = -15;
} else {
player.velocity.x = 0;
}
// Check for collision between player and platform
if (
player.position.y + player.height <= platform.position.y &&
player.position.y + player.height + player.velocity.y >= platform.position.y &&
player.position.x + player.width >= platform.position.x &&
player.position.x <= platform.position.x + platform.width
) {
player.velocity.y = 0;
}
// Check for collision between player and tube
if (
player.position.y + player.height <= tube.position.y &&
player.position.y + player.height + player.velocity.y >= tube.position.y &&
player.position.x + player.width >= tube.position.x &&
player.position.x <= tube.position.x + tube.width
) {
player.velocity.y = 0;
player.position.y += 0.1;
player.velocity.y = 0.0001;
gravity = 0.2;
}
// Reset gravity and collision when not colliding with tube
if (
player.position.y + player.height == tube.position.y + tube.height ||
player.position.y + player.height <= tube.position.y ||
player.position.x + player.width <= tube.position.x ||
player.position.x >= tube.position.x + tube.width
) {
gravity = 1.5;
}
// Handle collision between player and tube sides
if (
player.position.x + player.width <= tube.position.x &&
player.position.x + player.width + player.velocity.x >= tube.position.x &&
player.position.y + player.height >= tube.position.y &&
player.position.y <= tube.position.y + tube.height
)
{
player.velocity.x = 0;
}
if (
player.position.x >= tube.position.x + tube.width &&
player.position.x + player.velocity.x <= tube.position.x + tube.width &&
player.position.y + player.height >= tube.position.y &&
player.position.y <= tube.position.y + tube.height
)
{
player.velocity.x = 0;
}
if (
player.position.x >= tube.position.x &&
player.position.x + player.velocity.x <= tube.position.x &&
player.position.y + player.height >= tube.position.y &&
player.position.y <= tube.position.y + tube.height
)
{
player.velocity.x = 0;
}
if (
player.position.x + player.width <= tube.position.x + tube.width &&
player.position.x + player.width + player.velocity.x >= tube.position.x + tube.width &&
player.position.y + player.height >= tube.position.y &&
player.position.y <= tube.position.y + tube.height
)
{
player.velocity.x = 0;
}
}
// Start the animation loop
animate();
// Add event listeners for key presses
addEventListener('keydown', ({ keyCode }) => {
switch (keyCode) {
case 65:
console.log('left');
keys.left.pressed = true;
break;
case 83:
console.log('down');
break;
case 68:
console.log('right');
keys.right.pressed = true;
break;
case 87:
console.log('up');
player.velocity.y -= 20;
break;
}
});
// Add event listeners for key releases
addEventListener('keyup', ({ keyCode }) => {
switch (keyCode) {
case 65:
console.log('left');
keys.left.pressed = false;
break;
case 83:
console.log('down');
break;
case 68:
console.log('right');
keys.right.pressed = false;
break;
case 87:
console.log('up');
player.velocity.y = -20;
break;
}
})
</script>
Specific Hacks
- Add side and bottom collisions between the player and block object
- Add more blocks to create alternative pathways
Open Ended Hack
- Add a power-up when the player jumps on the block object