planck-js/example/TimeOfImpact.ts

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

/*
 * Copyright (c) Erin Catto
 * Licensed under the MIT license
 */

import {
  World,
  Transform,
  Box,
  TimeOfImpact,
  Sweep,
  TOIInput,
  TOIOutput,
  stats,
  Testbed,
  Vec2Value,
} from "planck";

const world = new World();

const testbed = Testbed.mount();
testbed.width = 80;
testbed.height = 60;
testbed.x = 0;
testbed.y = 0;
testbed.start(world);

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

const shapeB = new Box(2.5, 2.5);
const 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;

const 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;

const 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(stats);

  let vertices: Vec2Value[] = [];

  const transformB = new Transform();

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

  const transformA = new Transform();
  sweepA.getTransform(transformA, 0.0);
  vertices = shapeA.m_vertices.map((v) => Transform.mul(transformA, v));
  testbed.drawPolygon(vertices, testbed.color(0.7, 0.7, 0.7));

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

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

  sweepB.getTransform(transformB, 1.0);
  vertices = shapeB.m_vertices.map((v) => Transform.mul(transformB, v));
  testbed.drawPolygon(vertices, testbed.color(1, 1, 1));
};