gravity.js

// @ts-check

// Responding to gravity & jumping

// Start kaplay
kaplay();

// Load assets
loadSprite("bean", "/sprites/bean.png");

// Set the gravity acceleration (pixels per second)
setGravity(1600);

// Add player game object
const player = add([
    sprite("bean"),
    pos(center()),
    area(),
    // body() component gives the ability to respond to gravity
    body(),
]);

onKeyPress("space", () => {
    // .isGrounded() is provided by body()
    if (player.isGrounded()) {
        // .jump() is provided by body()
        player.jump();
    }
});

// .onGround() is provided by body(). It registers an event that runs whenever player hits the ground.
player.onGround(() => {
    debug.log("ouch");
});

// Accelerate falling when player holding down arrow key
onKeyDown("down", () => {
    if (!player.isGrounded()) {
        player.vel.y += dt() * 1200;
    }
});

// Jump higher if space is held
onKeyDown("space", () => {
    if (!player.isGrounded() && player.vel.y < 0) {
        player.vel.y -= dt() * 600;
    }
});

// Add a platform to hold the player
add([
    rect(width(), 48),
    outline(4),
    area(),
    pos(0, height() - 48),
    // Give objects a body() component if you don't want other solid objects pass through
    body({ isStatic: true }),
]);

add([
    text("Press space key", { width: width() / 2 }),
    pos(12, 12),
]);

// Check out https://kaplayjs.com/doc/BodyComp for everything body() provides