React Native Donkey Kong - Level 1

entities.js

import React from "react";
import { Dimensions } from "react-native";
import Matter from "matter-js";
import Platform from "./platform";
import Mario from "./mario";

//-- Overriding this function because the original references HTMLElement
//-- which will throw an error when running in a React Native context
Matter.Common.isElement = () => false; 

//-- These variable will help us position our entities on the device's screen
const { width, height } = Dimensions.get("window");
const scale = Math.min(width, 430) / 375;
const cx = width / 2;
const cy = height / 2;
const offsetY = (height - 465) / 2 - 35;
const platformWidth = Math.min(width, 430);

export const LevelOne = () => {
    
    //-- We intiate our physics engine and world
    let engine = Matter.Engine.create({ enableSleeping: false });
    let world = engine.world;

    // The origin of our world is in the top-left corner. Hence, the y-axis increases down the screen!
    world.gravity = { x: 0, y: 2 }; 

    //-- Our game entities for level one are below. Notice they all have unique ids (platform1, platform2 etc) and
    //-- we instantiate there components using dedicated function calls (the components can be verbose - 
    //-- so I'm hiding the details here)
    return {
        physics: { engine: engine, world: world },

        platform1: Platform(world, { x: cx, y: offsetY + 35 }, 0, platformWidth * 0.25),
        platform2: Platform(world, { x: cx - 15, y: offsetY + 100 }, 0, platformWidth * 0.8),
        platform3: Platform(world, { x: cx + 15, y: offsetY + 165 }, -0.07, platformWidth * 0.8),
        platform4: Platform(world, { x: cx - 15, y: offsetY + 240 }, 0.07, platformWidth * 0.8),
        platform5: Platform(world, { x: cx + 15, y: offsetY + 315 }, -0.07, platformWidth * 0.8),
        platform6: Platform(world, { x: cx - 15, y: offsetY + 390 }, 0.07, platformWidth * 0.8),
        platform7: Platform(world, { x: cx, y: offsetY + 465 }, 0, platformWidth * 0.9),

        mario: Mario(world, { x: cx, y: offsetY + 465 - 20 / 2 - 20 }),
    };
};