planck-js/example/TimeOfImpact.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('TimeOfImpact', function(testbed) {
  var pl = planck, Vec2 = pl.Vec2, Transform = pl.Transform;

  var Sweep = pl.internal.Sweep;
  var TimeOfImpact = pl.internal.TimeOfImpact;
  var TOIInput = TimeOfImpact.Input;
  var TOIOutput = TimeOfImpact.Output;

  var world = new pl.World();

  testbed.width = 80;
  testbed.height = 60;
  testbed.x = 0;
  testbed.y = 0;

  var shapeA = pl.Box(25.0, 5.0);
  var sweepA = new Sweep();
  sweepA.c0.set(0, 0);
  sweepA.a0 = 0.1;
  sweepA.c.set(sweepA.c0);
  sweepA.a = sweepA.a0;
  sweepA.localCenter.setZero();

  var shapeB = pl.Box(2.5, 2.5);
  var sweepB = new Sweep();
  sweepB.c0.set(20, 20);
  sweepB.a0 = 0.1; // - 162.0 * Math.PI;
  sweepB.c.set(-20, -20);
  sweepB.a = 3.1; // - 162.0 * Math.PI;
  sweepB.localCenter.setZero();

  // sweepB.a0 -= 300.0 * Math.PI;
  // sweepB.a -= 300.0 * Math.PI;

  var input = new TOIInput();
  input.proxyA.set(shapeA, 0);
  input.sweepA.set(sweepA);
  input.proxyB.set(shapeB, 0);
  input.sweepB.set(sweepB);
  input.tMax = 1.0;

  var output = new TOIOutput();

  TimeOfImpact(output, input);

  testbed.step = function() {

    // "max toi iters = %d, max root iters = %d", b2_toiMaxIters, b2_toiMaxRootIters

    testbed.status('toi', output.t);
    testbed.status(pl.internal.stats);

    var vertices = [];

    var transformB = new Transform();

    for (var t = 0.1; t < 1.0; t += 0.1) {
      sweepB.getTransform(transformB, t);
      vertices = shapeB.m_vertices.map(Transform.mulFn(transformB));
      testbed.drawPolygon(vertices, testbed.color(0.2, 0.2, 0.2));
    }

    var transformA = new Transform();
    sweepA.getTransform(transformA, 0.0);
    vertices = shapeA.m_vertices.map(Transform.mulFn(transformA));
    testbed.drawPolygon(vertices, testbed.color(0.7, 0.7, 0.7));

    sweepB.getTransform(transformB, 0.0);
    vertices = shapeB.m_vertices.map(Transform.mulFn(transformB));
    testbed.drawPolygon(vertices, testbed.color(1, 1, 1));

    sweepB.getTransform(transformB, output.t);
    vertices = shapeB.m_vertices.map(Transform.mulFn(transformB));
    testbed.drawPolygon(vertices, testbed.color(1, 0, 0));

    sweepB.getTransform(transformB, 1.0);
    vertices = shapeB.m_vertices.map(Transform.mulFn(transformB));
    testbed.drawPolygon(vertices, testbed.color(1, 1, 1));

  };

  return world;
});