planck-js/example/CollisionFiltering.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('CollisionFiltering', function(testbed) {
  // This is a test of collision filtering.
  // There is a triangle, a box, and a circle.
  // There are 6 shapes. 3 large and 3 small.
  // The 3 small ones always collide.
  // The 3 large ones never collide.
  // The boxes don't collide with triangles (except if both are small).
  var SMALL_GROUP = 1;
  var LARGE_GROUP = -1;

  var TRIANGLE_CATEGORY = 0x0002;
  var BOX_Category = 0x0004;
  var CIRCLE_CATEGORY = 0x0008;

  var TRIANGLE_MASK = 0xFFFF;
  var BOX_MASK = 0xFFFF ^ TRIANGLE_CATEGORY;
  var CIRCLE_MAX = 0xFFFF;

  var pl = planck, Vec2 = pl.Vec2;
  var world = pl.World(Vec2(0, -10));

  // Ground body
  var ground = world.createBody();
  ground.createFixture(pl.Edge(Vec2(-40.0, 0.0), Vec2(40.0, 0.0)), {friction : 0.3});

  var triangleShapeDef = {};
  triangleShapeDef.density = 1.0;

  // Small triangle
  triangleShapeDef.filterGroupIndex = SMALL_GROUP;
  triangleShapeDef.filterCategoryBits = TRIANGLE_CATEGORY;
  triangleShapeDef.filterMaskBits = TRIANGLE_MASK;

  var body1 = world.createBody({
    type : 'dynamic',
    position : Vec2(-5.0, 2.0)
  });
  body1.createFixture(pl.Polygon([
    Vec2(-1.0, 0.0),
    Vec2(1.0, 0.0),
    Vec2(0.0, 2.0)
  ]), triangleShapeDef);

  // Large triangle (recycle definitions)
  triangleShapeDef.filterGroupIndex = LARGE_GROUP;

  var body2 = world.createBody({
    type : 'dynamic',
    position : Vec2(-5.0, 6.0),
    fixedRotation : true // look at me!
  });
  body2.createFixture(pl.Polygon([
    Vec2(-2.0, 0.0),
    Vec2(2.0, 0.0),
    Vec2(0.0, 4.0)
  ]), triangleShapeDef);

  var body = world.createDynamicBody(Vec2(-5.0, 10.0));
  body.createFixture(pl.Box(0.5, 1.0), 1.0);

  world.createJoint(pl.PrismaticJoint({
    enableLimit : true,
    localAnchorA : Vec2(0.0, 4.0),
    localAnchorB : Vec2(),
    localAxisA : Vec2(0.0, 1.0),
    lowerTranslation : -1.0,
    upperTranslation : 1.0
  }, body2, body));

  var boxShapeDef = {};
  boxShapeDef.density = 1.0;
  boxShapeDef.restitution = 0.1;

  // Small box
  boxShapeDef.filterGroupIndex = SMALL_GROUP;
  boxShapeDef.filterCategoryBits = BOX_Category;
  boxShapeDef.filterMaskBits = BOX_MASK;

  var body3 = world.createDynamicBody(Vec2(0.0, 2.0));
  body3.createFixture(pl.Box(1.0, 0.5), boxShapeDef);

  // Large box (recycle definitions)
  boxShapeDef.filterGroupIndex = LARGE_GROUP;

  var body4 = world.createDynamicBody(Vec2(0.0, 6.0));
  body4.createFixture(pl.Box(2.0, 1.0), boxShapeDef);

  var circleShapeDef = {};

  // Small circle
  circleShapeDef.density = 1.0;

  circleShapeDef.filterGroupIndex = SMALL_GROUP;
  circleShapeDef.filterCategoryBits = CIRCLE_CATEGORY;
  circleShapeDef.filterMaskBits = CIRCLE_MAX;

  var body5 = world.createDynamicBody(Vec2(5.0, 2.0));
  body5.createFixture(pl.Circle(1.0), circleShapeDef);

  // Large circle
  circleShapeDef.filterGroupIndex = LARGE_GROUP;

  var body6 = world.createDynamicBody(Vec2(5.0, 6.0));
  body6.createFixture(pl.Circle(2.0), circleShapeDef);

  return world;
});