BasicSliderCrank.js

/*
 * Copyright (c) 2016-2018 Ali Shakiba http://shakiba.me/planck.js
 * Copyright (c) 2006-2014 Erin Catto  http://www.box2d.org
 *
 * This software is provided 'as-is', without any express or implied
 * warranty.  In no event will the authors be held liable for any damages
 * arising from the use of this software.
 * Permission is granted to anyone to use this software for any purpose,
 * including commercial applications, and to alter it and redistribute it
 * freely, subject to the following restrictions:
 * 1. The origin of this software must not be misrepresented; you must not
 * claim that you wrote the original software. If you use this software
 * in a product, an acknowledgment in the product documentation would be
 * appreciated but is not required.
 * 2. Altered source versions must be plainly marked as such, and must not be
 * misrepresented as being the original software.
 * 3. This notice may not be removed or altered from any source distribution.
 */

// 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;
});