planck-js/example/ConveyorBelt.js

2D JavaScript physics engine for cross-platform HTML5 game development

/*
 * MIT License
 * Copyright (c) 2019 Erin Catto
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

planck.testbed('ConveyorBelt', function(testbed) {
  var pl = planck, Vec2 = pl.Vec2;
  var world = new pl.World(Vec2(0, -10));

  // Ground
  var ground = world.createBody();
  ground.createFixture(pl.Edge(Vec2(-20.0, 0.0), Vec2(20.0, 0.0)), 0.0);

  // Platform
  var platform = world
    .createBody(Vec2(-5.0, 5.0))
    .createFixture(pl.Box(10.0, 0.5), {friction : 0.8});

  // Boxes
  for (var i = 0; i < 5; ++i) {
    world.createDynamicBody(Vec2(-10.0 + 2.0 * i, 7.0))
      .createFixture(pl.Box(0.5, 0.5), 20.0);
  }

  world.on('pre-solve', function(contact, oldManifold) {
    var fixtureA = contact.getFixtureA();
    var fixtureB = contact.getFixtureB();

    if (fixtureA == platform) {
      contact.setTangentSpeed(5.0);
    }

    if (fixtureB == platform) {
      contact.setTangentSpeed(-5.0);
    }
  });

  return world;
});