planck-js/example/BasicSliderCrank.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.
 */

// A basic slider crank created for GDC tutorial: Understanding Constraints
planck.testbed('BasicSliderCrank', function(testbed) {
  var pl = planck, Vec2 = pl.Vec2;
  var world = new pl.World(Vec2(0, -10));

  var ground = world.createBody(Vec2(0.0, 17.0));

  // Define crank.
  var crank = world.createDynamicBody(Vec2(-8.0, 20.0));
  crank.createFixture(pl.Box(4.0, 1.0), 2.0);
  world.createJoint(pl.RevoluteJoint({}, ground, crank, Vec2(-12.0, 20.0)));

  // Define connecting rod
  var rod = world.createDynamicBody(Vec2(4.0, 20.0));
  rod.createFixture(pl.Box(8.0, 1.0), 2.0);
  world.createJoint(pl.RevoluteJoint({}, crank, rod, Vec2(-4.0, 20.0)));

  // Define piston
  var piston = world.createDynamicBody({
    fixedRotation : true,
    position : Vec2(12.0, 20.0)
  });
  piston.createFixture(pl.Box(3.0, 3.0), 2.0);
  world.createJoint(pl.RevoluteJoint({}, rod, piston, Vec2(12.0, 20.0)));
  world.createJoint(pl.PrismaticJoint({}, ground, piston, Vec2(12.0, 17.0), Vec2(1.0, 0.0)));

  return world;
});