Webleb - UI Elements - Ragdoll Physics Playground

// script.js

// Get HTML elements
const canvas = document.getElementById('world');
const spawnRagdollBtn = document.getElementById('spawnRagdollBtn');
const spawnObjectBtn = document.getElementById('spawnObjectBtn');
const spawnWeaponBtn = document.getElementById('spawnWeaponBtn');
const mapSelect = document.getElementById('mapSelect');
const changeMapBtn = document.getElementById('changeMapBtn');

// Matter.js module aliases
const Engine = Matter.Engine,
      Render = Matter.Render,
      World = Matter.World,
      Bodies = Matter.Bodies,
      Body = Matter.Body,
      Constraint = Matter.Constraint,
      Composites = Matter.Composites,
      Composite = Matter.Composite,
      Mouse = Matter.Mouse,
      MouseConstraint = Matter.MouseConstraint;

// Engine and world
const engine = Engine.create();
const world = engine.world;

// Canvas size
const WIDTH = 900, HEIGHT = 600;

// Renderer
const render = Render.create({
    canvas: canvas,
    engine: engine,
    options: {
        width: WIDTH,
        height: HEIGHT,
        wireframes: false,
        background: '#e0f7fa',
        pixelRatio: window.devicePixelRatio,
        showAngleIndicator: false,
    }
});

// Store current map objects to remove on map change
let currentMapObjs = [];

// Utility: random color for objects
function randomColor() {
    const colors = ['#6ec6ff','#ffb74d','#9575cd','#26a69a','#ec407a','#ffd54f','#8d6e63'];
    return colors[Math.floor(Math.random() * colors.length)];
}

// Ragdoll builder
function spawnRagdoll(x = 200, y = 100) {
    // Limbs and body parts
    const head = Bodies.circle(x, y, 22, { render: { fillStyle: '#ffd54f' }, density: 0.002 });
    const torso = Bodies.rectangle(x, y+45, 25, 60, { render: { fillStyle: '#90caf9' }, density: 0.003 });
    const leftArm = Bodies.rectangle(x-30, y+45, 15, 48, { render: { fillStyle: '#b0bec5' }, density: 0.002 });
    const rightArm = Bodies.rectangle(x+30, y+45, 15, 48, { render: { fillStyle: '#b0bec5' }, density: 0.002 });
    const leftLeg = Bodies.rectangle(x-10, y+110, 16, 50, { render: { fillStyle: '#bcaaa4' }, density: 0.002 });
    const rightLeg = Bodies.rectangle(x+10, y+110, 16, 50, { render: { fillStyle: '#bcaaa4' }, density: 0.002 });

// Joints
    const constraints = [
        Constraint.create({ bodyA: head, pointA: {x:0, y:22}, bodyB: torso, pointB: {x:0, y:-30}, stiffness: 0.8 }),
        Constraint.create({ bodyA: leftArm, pointA: {x:0, y:-24}, bodyB: torso, pointB: {x:-13, y:-24}, stiffness: 0.7 }),
        Constraint.create({ bodyA: rightArm, pointA: {x:0, y:-24}, bodyB: torso, pointB: {x:13, y:-24}, stiffness: 0.7 }),
        Constraint.create({ bodyA: leftLeg, pointA: {x:0, y:-25}, bodyB: torso, pointB: {x:-8, y:30}, stiffness: 0.8 }),
        Constraint.create({ bodyA: rightLeg, pointA: {x:0, y:-25}, bodyB: torso, pointB: {x:8, y:30}, stiffness: 0.8 }),
    ];

const ragdoll = Composite.create();
    Composite.add(ragdoll, [head, torso, leftArm, rightArm, leftLeg, rightLeg, ...constraints]);
    World.add(world, ragdoll);
}

// Object spawner: crates, balls, etc
function spawnObject(x = 100 + Math.random()*700, y = 50) {
    const shape = Math.random() > 0.5 ? 'box' : 'circle';
    if (shape === 'box') {
        const box = Bodies.rectangle(x, y, 40, 40, {
            restitution: 0.4, 
            render: { fillStyle: randomColor() }
        });
        World.add(world, box);
    } else {
        const ball = Bodies.circle(x, y, 22, {
            restitution: 0.7, 
            render: { fillStyle: randomColor() }
        });
        World.add(world, ball);
    }
}

// Weapon spawner: simple rectangle or axe shape
function spawnWeapon(x = 100 + Math.random()*700, y = 30) {
    // Weapon: "axe" is a rectangle with a colored head
    const handle = Bodies.rectangle(x, y, 80, 10, {
        density: 0.004,
        render: { fillStyle: '#795548' }
    });
    const head = Bodies.rectangle(x+32, y, 20, 32, {
        density: 0.007,
        render: { fillStyle: '#b0bec5' }
    });
    const axe = Composite.create();
    Composite.add(axe, [handle, head,
        Constraint.create({
            bodyA: handle,
            pointA: {x:40, y:0},
            bodyB: head,
            pointB: {x:-10, y:0},
            stiffness: 0.9
        })
    ]);
    World.add(world, axe);
}

// MAPS
function clearCurrentMap() {
    for (let obj of currentMapObjs) {
        World.remove(world, obj);
    }
    currentMapObjs = [];
}

// Map: flat ground only
function mapFlat() {
    clearCurrentMap();
    const ground = Bodies.rectangle(WIDTH/2, HEIGHT-25, WIDTH-60, 40, { 
        isStatic: true, 
        render: { fillStyle: '#43a047' }
    });
    currentMapObjs.push(ground);
    World.add(world, ground);
}

// Map: ramps
function mapRamps() {
    clearCurrentMap();
    const ground = Bodies.rectangle(WIDTH/2, HEIGHT-20, WIDTH-60, 30, { isStatic: true, render: { fillStyle: '#43a047' } });
    const ramp1 = Bodies.rectangle(200, HEIGHT-90, 200, 20, { 
        isStatic: true, angle: -Math.PI/7, 
        render: { fillStyle: '#689f38' }
    });
    const ramp2 = Bodies.rectangle(700, HEIGHT-160, 220, 20, { 
        isStatic: true, angle: Math.PI/8, 
        render: { fillStyle: '#33691e' }
    });
    currentMapObjs.push(ground, ramp1, ramp2);
    World.add(world, [ground, ramp1, ramp2]);
}

// Map: obstacles
function mapObstacles() {
    clearCurrentMap();
    const ground = Bodies.rectangle(WIDTH/2, HEIGHT-25, WIDTH-60, 40, { isStatic: true, render: { fillStyle: '#2e7d32' } });
    const box1 = Bodies.rectangle(300, HEIGHT-120, 70, 120, { isStatic: true, render: { fillStyle: '#a1887f' } });
    const box2 = Bodies.rectangle(600, HEIGHT-180, 60, 150, { isStatic: true, render: { fillStyle: '#8d6e63' } });
    const smallPlat = Bodies.rectangle(WIDTH/2, HEIGHT-220, 120, 14, { isStatic: true, render: { fillStyle: '#607d8b' } });
    currentMapObjs.push(ground, box1, box2, smallPlat);
    World.add(world, [ground, box1, box2, smallPlat]);
}

// Map dictionary
const maps = {
    flat: mapFlat,
    ramps: mapRamps,
    obstacles: mapObstacles
};

// Change map
function changeMap() {
    const selected = mapSelect.value;
    if (maps[selected]) maps[selected]();
}

// Button handlers
spawnRagdollBtn.onclick = () => spawnRagdoll(150 + Math.random()*600, 100 + Math.random()*150);
spawnObjectBtn.onclick = () => spawnObject();
spawnWeaponBtn.onclick = () => spawnWeapon();
changeMapBtn.onclick = () => changeMap();

// Mouse drag & drop
const mouse = Mouse.create(render.canvas);
const mouseConstraint = MouseConstraint.create(engine, {
    mouse: mouse,
    constraint: {
        stiffness: 0.2,
        render: { visible: false }
    }
});
World.add(world, mouseConstraint);

render.mouse = mouse;

// Responsive canvas
canvas.width = WIDTH;
canvas.height = HEIGHT;

// Start with flat map
mapFlat();

// Start physics engine and render loop
Engine.run(engine);
Render.run(render);

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