p5_bounce/src/lib/player.js

import { WORLD } from "./config.js";

const GRAVITY = 0.32;
const JUMP_VELOCITY = -10.5;
const HORIZONTAL_ACCELERATION = 0.65;
const HORIZONTAL_FRICTION = 0.86;
const MAX_HORIZONTAL_SPEED = 7;

export function createPlayer({ x = 0, y = 0, radius = 18 } = {}) {
    return {
        position: { x, y },
        previousPosition: { x, y },
        velocity: { x: 0, y: 0 },
        radius,
        wasReset: false,
    };
}

export function updatePlayer(player, keys, platforms) {
    player.wasReset = false;
    player.previousPosition.x = player.position.x;
    player.previousPosition.y = player.position.y;

    const xDirection = Number(keys.has("arrowright") || keys.has("d")) - Number(keys.has("arrowleft") || keys.has("a"));

    player.velocity.x += xDirection * HORIZONTAL_ACCELERATION;
    player.velocity.x *= HORIZONTAL_FRICTION;
    player.velocity.x = Math.max(-MAX_HORIZONTAL_SPEED, Math.min(MAX_HORIZONTAL_SPEED, player.velocity.x));
    player.velocity.y += GRAVITY;

    player.position.x += player.velocity.x;
    player.position.y += player.velocity.y;

    wrapPlayerHorizontally(player);
    bounceOnPlatforms(player, platforms);
    resetIfPlayerFalls(player, platforms);
}

export function placePlayerOnPlatform(player, platform) {
    player.position.x = platform.x + platform.width / 2;
    player.position.y = platform.y - player.radius;
    player.previousPosition.x = player.position.x;
    player.previousPosition.y = player.position.y;
    player.velocity.x = 0;
    player.velocity.y = JUMP_VELOCITY;
}

function wrapPlayerHorizontally(player) {
    if (player.position.x < -player.radius) {
        player.position.x = WORLD.width + player.radius;
    }

    if (player.position.x > WORLD.width + player.radius) {
        player.position.x = -player.radius;
    }
}

function bounceOnPlatforms(player, platforms) {
    if (player.velocity.y <= 0) {
        return;
    }

    const previousBottom = player.previousPosition.y + player.radius;
    const currentBottom = player.position.y + player.radius;

    for (const platform of platforms) {
        const isCrossingTop = previousBottom <= platform.y && currentBottom >= platform.y;
        const isOverPlatform = player.position.x + player.radius >= platform.x && player.position.x - player.radius <= platform.x + platform.width;

        if (isCrossingTop && isOverPlatform) {
            player.position.y = platform.y - player.radius;
            player.velocity.y = JUMP_VELOCITY;
            return;
        }
    }
}

function resetIfPlayerFalls(player, platforms) {
    if (player.position.y - player.radius <= WORLD.height) {
        return;
    }

    placePlayerOnPlatform(player, platforms[0]);
    player.wasReset = true;
}

export function drawPlayer(p, player, camera) {
    const localX = player.position.x - camera.x;
    const localY = player.position.y - camera.y;

    p.push();
    p.noStroke();
    p.fill(52, 152, 219);
    p.circle(localX, localY, player.radius * 2);

    p.fill(255);
    p.circle(localX + player.radius * 0.35, localY - player.radius * 0.25, player.radius * 0.35);
    p.pop();
}

export function drawWorldPlayer(p, player, area) {
    p.push();
    p.noStroke();
    p.fill(96, 165, 250);
    p.circle(
        area.x + player.position.x * area.scale,
        area.y + player.position.y * area.scale,
        Math.max(5, player.radius * 2 * area.scale),
    );
    p.pop();
}