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

  var ground = world.createBody();

  var groundFD = {
    filterCategoryBits: 2,
    filterMaskBits: 0xFFFF,
    filterGroupIndex: 0,
  };
  ground.createFixture(pl.Edge(Vec2(-40.0, 0.0), Vec2(40.0, 0.0)), groundFD);

  var rotator = world.createDynamicBody(Vec2(-10.0, 20.0));
  rotator.createFixture(pl.Circle(0.5), 5.0);

  var w = 100.0;
  rotator.setAngularVelocity(w);
  rotator.setLinearVelocity(Vec2(-8.0 * w, 0.0));

  var joint = world.createJoint(pl.RevoluteJoint({
    motorSpeed: 1.0 * Math.PI,
    maxMotorTorque: 10000.0,
    enableMotor: true,
    lowerAngle: -0.25 * Math.PI,
    upperAngle: 0.5 * Math.PI,
    enableLimit: false,
    collideConnected: true,
  }, ground, rotator, Vec2(-10.0, 12.0)));

  var ball = world.createDynamicBody(Vec2(5.0, 30.0));
  ball.createFixture(pl.Circle(3.0), {
    density: 5.0,
    // filterMaskBits: 1,
  });

  var platform = world.createBody({
    position: Vec2(20.0, 10.0),
    type: 'dynamic',
    bullet: true,
  });
  platform.createFixture(pl.Box(10.0, 0.2, Vec2(-10.0, 0.0), 0.0), 2.0);

  world.createJoint(pl.RevoluteJoint({
    lowerAngle: -0.25 * Math.PI,
    upperAngle: 0.0 * Math.PI,
    enableLimit: true,
  }, ground, platform, Vec2(20.0, 10.0)));

  // Tests mass computation of a small object far from the origin
  var triangle = world.createDynamicBody();

  triangle.createFixture(pl.Polygon([
    Vec2(17.63, 36.31),
    Vec2(17.52, 36.69),
    Vec2(17.19, 36.36)
  ]), 1); // assertion hits inside here

  testbed.keydown = function(code, char) {
    switch (char) {
    case 'Z':
      joint.enableLimit(!joint.isLimitEnabled());
      break;

    case 'X':
      joint.enableMotor(!joint.isMotorEnabled());
      break;
    }
  };

  testbed.step = function(settings) {
    // if (stepCount++ == 360) {
    //   ball.setTransform(Vec2(0.0, 0.5), 0.0);
    // }

    testbed.status('Motor Torque', joint.getMotorTorque(testbed.hz));
    // testbed.status('Motor Force', joint.getMaxForce());
  };

  testbed.info('Z: Limits, X: Motor');

  return world;
});