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liabru-matter-js/src/collision/Query.js

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JavaScript

/**
* The `Matter.Query` module contains methods for performing collision queries.
*
* See the included usage [examples](https://github.com/liabru/matter-js/tree/master/examples).
*
* @class Query
*/
var Query = {};
module.exports = Query;
var Vector = require('../geometry/Vector');
var Collision = require('./Collision');
var Bounds = require('../geometry/Bounds');
var Bodies = require('../factory/Bodies');
var Vertices = require('../geometry/Vertices');
(function() {
/**
* Returns a list of collisions between `body` and `bodies`.
* @method collides
* @param {body} body
* @param {body[]} bodies
* @return {collision[]} Collisions
*/
Query.collides = function(body, bodies) {
var collisions = [],
bodiesLength = bodies.length,
bounds = body.bounds,
collides = Collision.collides,
overlaps = Bounds.overlaps;
for (var i = 0; i < bodiesLength; i++) {
var bodyA = bodies[i],
partsALength = bodyA.parts.length,
partsAStart = partsALength === 1 ? 0 : 1;
if (overlaps(bodyA.bounds, bounds)) {
for (var j = partsAStart; j < partsALength; j++) {
var part = bodyA.parts[j];
if (overlaps(part.bounds, bounds)) {
var collision = collides(part, body);
if (collision) {
collisions.push(collision);
break;
}
}
}
}
}
return collisions;
};
/**
* Casts a ray segment against a set of bodies and returns all collisions, ray width is optional. Intersection points are not provided.
* @method ray
* @param {body[]} bodies
* @param {vector} startPoint
* @param {vector} endPoint
* @param {number} [rayWidth]
* @return {collision[]} Collisions
*/
Query.ray = function(bodies, startPoint, endPoint, rayWidth) {
rayWidth = rayWidth || 1e-100;
var rayAngle = Vector.angle(startPoint, endPoint),
rayLength = Vector.magnitude(Vector.sub(startPoint, endPoint)),
rayX = (endPoint.x + startPoint.x) * 0.5,
rayY = (endPoint.y + startPoint.y) * 0.5,
ray = Bodies.rectangle(rayX, rayY, rayLength, rayWidth, { angle: rayAngle }),
collisions = Query.collides(ray, bodies);
for (var i = 0; i < collisions.length; i += 1) {
var collision = collisions[i];
collision.body = collision.bodyB = collision.bodyA;
}
return collisions;
};
/**
* Returns all bodies whose bounds are inside (or outside if set) the given set of bounds, from the given set of bodies.
* @method region
* @param {body[]} bodies
* @param {bounds} bounds
* @param {bool} [outside=false]
* @return {body[]} The bodies matching the query
*/
Query.region = function(bodies, bounds, outside) {
var result = [];
for (var i = 0; i < bodies.length; i++) {
var body = bodies[i],
overlaps = Bounds.overlaps(body.bounds, bounds);
if ((overlaps && !outside) || (!overlaps && outside))
result.push(body);
}
return result;
};
/**
* Returns all bodies whose vertices contain the given point, from the given set of bodies.
* @method point
* @param {body[]} bodies
* @param {vector} point
* @return {body[]} The bodies matching the query
*/
Query.point = function(bodies, point) {
var result = [];
for (var i = 0; i < bodies.length; i++) {
var body = bodies[i];
if (Bounds.contains(body.bounds, point)) {
for (var j = body.parts.length === 1 ? 0 : 1; j < body.parts.length; j++) {
var part = body.parts[j];
if (Bounds.contains(part.bounds, point)
&& Vertices.contains(part.vertices, point)) {
result.push(body);
break;
}
}
}
}
return result;
};
})();