src/Collisions.mjs
import BVH from './modules/BVH.mjs';
import Circle from './modules/Circle.mjs';
import Polygon from './modules/Polygon.mjs';
import Point from './modules/Point.mjs';
import Result from './modules/Result.mjs';
import SAT from './modules/SAT.mjs';
/**
* A collision system used to track bodies in order to improve collision detection performance
* @class
*/
class Collisions {
/**
* @constructor
*/
constructor() {
/** @private */
this._bvh = new BVH();
}
/**
* Creates a {@link Circle} and inserts it into the collision system
* @param {Number} [x = 0] The starting X coordinate
* @param {Number} [y = 0] The starting Y coordinate
* @param {Number} [radius = 0] The radius
* @param {Number} [scale = 1] The scale
* @param {Number} [padding = 0] The amount to pad the bounding volume when testing for potential collisions
* @returns {Circle}
*/
createCircle(x = 0, y = 0, radius = 0, scale = 1, padding = 0) {
const body = new Circle(x, y, radius, scale, padding);
this._bvh.insert(body);
return body;
}
/**
* Creates a {@link Polygon} and inserts it into the collision system
* @param {Number} [x = 0] The starting X coordinate
* @param {Number} [y = 0] The starting Y coordinate
* @param {Array<Number[]>} [points = []] An array of coordinate pairs making up the polygon - [[x1, y1], [x2, y2], ...]
* @param {Number} [angle = 0] The starting rotation in radians
* @param {Number} [scale_x = 1] The starting scale along the X axis
* @param {Number} [scale_y = 1] The starting scale long the Y axis
* @param {Number} [padding = 0] The amount to pad the bounding volume when testing for potential collisions
* @returns {Polygon}
*/
createPolygon(x = 0, y = 0, points = [[0, 0]], angle = 0, scale_x = 1, scale_y = 1, padding = 0) {
const body = new Polygon(x, y, points, angle, scale_x, scale_y, padding);
this._bvh.insert(body);
return body;
}
/**
* Creates a {@link Point} and inserts it into the collision system
* @param {Number} [x = 0] The starting X coordinate
* @param {Number} [y = 0] The starting Y coordinate
* @param {Number} [padding = 0] The amount to pad the bounding volume when testing for potential collisions
* @returns {Point}
*/
createPoint(x = 0, y = 0, padding = 0) {
const body = new Point(x, y, padding);
this._bvh.insert(body);
return body;
}
/**
* Creates a {@link Result} used to collect the detailed results of a collision test
*/
createResult() {
return new Result();
}
/**
* Creates a Result used to collect the detailed results of a collision test
*/
static createResult() {
return new Result();
}
/**
* Inserts bodies into the collision system
* @param {...Circle|...Polygon|...Point} bodies
*/
insert(...bodies) {
for(const body of bodies) {
this._bvh.insert(body, false);
}
return this;
}
/**
* Removes bodies from the collision system
* @param {...Circle|...Polygon|...Point} bodies
*/
remove(...bodies) {
for(const body of bodies) {
this._bvh.remove(body, false);
}
return this;
}
/**
* Updates the collision system. This should be called before any collisions are tested.
*/
update() {
this._bvh.update();
return this;
}
/**
* Draws the bodies within the system to a CanvasRenderingContext2D's current path
* @param {CanvasRenderingContext2D} context The context to draw to
*/
draw(context) {
return this._bvh.draw(context);
}
/**
* Draws the system's BVH to a CanvasRenderingContext2D's current path. This is useful for testing out different padding values for bodies.
* @param {CanvasRenderingContext2D} context The context to draw to
*/
drawBVH(context) {
return this._bvh.drawBVH(context);
}
/**
* Returns a list of potential collisions for a body
* @param {Circle|Polygon|Point} body The body to test for potential collisions against
* @returns {Array<Body>}
*/
potentials(body) {
return this._bvh.potentials(body);
}
/**
* Determines if two bodies are colliding
* @param {Circle|Polygon|Point} target The target body to test against
* @param {Result} [result = null] A Result object on which to store information about the collision
* @param {Boolean} [aabb = true] Set to false to skip the AABB test (useful if you use your own potential collision heuristic)
* @returns {Boolean}
*/
collides(source, target, result = null, aabb = true) {
return SAT(source, target, result, aabb);
}
};
export {
Collisions as default,
Collisions,
Result,
Circle,
Polygon,
Point,
};
