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[#1091] new Detector class to be instantiated by each physic world instance to detect and solve collisions
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‎CHANGELOG.md

+4
Original file line numberDiff line numberDiff line change
@@ -4,6 +4,10 @@
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### Changed
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- General: further code revamping to make melonJS more modular and allow instantiation of different app/games
7+
- Physic: new `Detector` class instantiated by each physic world instance to detect and solve collisions
8+
9+
### Fixed
10+
- Doc: fix `fps` type in the World class
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## [14.2.0] (melonJS 2) - _2022-12-26_
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‎src/physics/collision.js

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Original file line numberDiff line numberDiff line change
@@ -1,4 +1,4 @@
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import { rayCast } from "./detector.js";
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import { game } from "../index.js";
22

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/**
44
* Collision detection (and projection-based collision response) of 2D shapes.<br>
@@ -117,7 +117,7 @@ var collision = {
117117
* // ...
118118
* }
119119
*/
120-
rayCast(line, result) { return rayCast(line, result); }
120+
rayCast(line, result) { return game.world.rayCast(line, result); }
121121
};
122122

123123
export default collision;

‎src/physics/detector.js

+172-145
Original file line numberDiff line numberDiff line change
@@ -1,10 +1,8 @@
11
import * as SAT from "./sat.js";
22
import ResponseObject from "./response.js";
33
import Vector2d from "./../math/vector2.js";
4-
import { game } from "../index.js";
54
import Bounds from "./bounds.js";
65

7-
86
// a dummy object when using Line for raycasting
97
let dummyObj = {
108
pos : new Vector2d(0, 0),
@@ -16,167 +14,196 @@ let dummyObj = {
1614
}
1715
};
1816

17+
// some cache bounds object used for collision detection
1918
let boundsA = new Bounds();
2019
let boundsB = new Bounds();
2120

22-
// the global response object used for collisions
23-
let globalResponse = new ResponseObject();
24-
2521
/**
26-
* a function used to determine if two objects should collide (based on both respective objects collision mask and type).<br>
27-
* you can redefine this function if you need any specific rules over what should collide with what.
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* @ignore
29-
* @param {Renderable} a - a reference to the object A.
30-
* @param {Renderable} b - a reference to the object B.
31-
* @returns {boolean} true if they should collide, false otherwise
22+
* the Detector class contains methods for detecting collisions between bodies using a broadphase algorithm.
3223
*/
33-
function shouldCollide(a, b) {
34-
var bodyA = a.body,
35-
bodyB = b.body;
36-
return (
37-
a !== b &&
38-
a.isKinematic !== true && b.isKinematic !== true &&
39-
typeof bodyA === "object" && typeof bodyB === "object" &&
40-
bodyA.shapes.length > 0 && bodyB.shapes.length > 0 &&
41-
!(bodyA.isStatic === true && bodyB.isStatic === true) &&
42-
(bodyA.collisionMask & bodyB.collisionType) !== 0 &&
43-
(bodyA.collisionType & bodyB.collisionMask) !== 0
44-
);
45-
}
46-
47-
48-
49-
/**
50-
* find all the collisions for the specified object
51-
* @ignore
52-
* @param {Renderable} objA - object to be tested for collision
53-
* @param {ResponseObject} [response] - a user defined response object that will be populated if they intersect.
54-
* @returns {boolean} in case of collision, false otherwise
55-
*/
56-
export function collisionCheck(objA, response = globalResponse) {
57-
var collisionCounter = 0;
58-
// retreive a list of potential colliding objects from the game world
59-
var candidates = game.world.broadphase.retrieve(objA);
24+
export default class Detector {
25+
/**
26+
* @param {Container} world - the physic world this detector is bind to
27+
*/
28+
constructor(world) {
29+
// @ignore
30+
this.world = world;
31+
32+
/**
33+
* the default response object used for collisions
34+
* (will be automatically populated by the collides functions)
35+
* @type {ResponseObject}
36+
*/
37+
this.response = new ResponseObject();
38+
}
6039

61-
boundsA.addBounds(objA.getBounds(), true);
62-
boundsA.addBounds(objA.body.getBounds());
40+
/**
41+
* determine if two objects should collide (based on both respective objects body collision mask and type).<br>
42+
* you can redefine this function if you need any specific rules over what should collide with what.
43+
* @param {Renderable} a - a reference to the object A.
44+
* @param {Renderable} b - a reference to the object B.
45+
* @returns {boolean} true if they should collide, false otherwise
46+
*/
47+
shouldCollide(a, b) {
48+
var bodyA = a.body,
49+
bodyB = b.body;
50+
return (
51+
(typeof bodyA === "object" && typeof bodyB === "object") &&
52+
a !== b &&
53+
a.isKinematic !== true && b.isKinematic !== true &&
54+
bodyA.shapes.length > 0 && bodyB.shapes.length > 0 &&
55+
!(bodyA.isStatic === true && bodyB.isStatic === true) &&
56+
(bodyA.collisionMask & bodyB.collisionType) !== 0 &&
57+
(bodyA.collisionType & bodyB.collisionMask) !== 0
58+
);
59+
}
6360

64-
candidates.forEach((objB) => {
65-
// check if both objects "should" collide
66-
if (shouldCollide(objA, objB)) {
61+
/**
62+
* detect collision between two bodies.
63+
* @param {Body} bodyA - a reference to body A.
64+
* @param {Body} bodyB - a reference to body B.
65+
* @returns {Boolean} true if colliding
66+
*/
67+
collides(bodyA, bodyB, response = this.response) {
68+
// for each shape in body A
69+
for (var indexA = bodyA.shapes.length, shapeA; indexA--, (shapeA = bodyA.shapes[indexA]);) {
70+
// for each shape in body B
71+
for (var indexB = bodyB.shapes.length, shapeB; indexB--, (shapeB = bodyB.shapes[indexB]);) {
72+
// full SAT collision check
73+
if (SAT["test" + shapeA.shapeType + shapeB.shapeType].call(
74+
this,
75+
bodyA.ancestor, // a reference to the object A
76+
shapeA,
77+
bodyB.ancestor, // a reference to the object B
78+
shapeB,
79+
// clear response object before reusing
80+
response.clear()) === true
81+
) {
6782

68-
boundsB.addBounds(objB.getBounds(), true);
69-
boundsB.addBounds(objB.body.getBounds());
83+
// set the shape index
84+
response.indexShapeA = indexA;
85+
response.indexShapeB = indexB;
7086

71-
// fast AABB check if both bounding boxes are overlaping
72-
if (boundsA.overlaps(boundsB)) {
73-
// for each shape in body A
74-
objA.body.shapes.forEach((shapeA, indexA) => {
75-
// for each shape in body B
76-
objB.body.shapes.forEach((shapeB, indexB) => {
77-
// full SAT collision check
78-
if (SAT["test" + shapeA.shapeType + shapeB.shapeType].call(
79-
this,
80-
objA, // a reference to the object A
81-
shapeA,
82-
objB, // a reference to the object B
83-
shapeB,
84-
// clear response object before reusing
85-
response.clear()) === true
86-
) {
87-
// we touched something !
88-
collisionCounter++;
89-
90-
// set the shape index
91-
response.indexShapeA = indexA;
92-
response.indexShapeB = indexB;
93-
94-
// execute the onCollision callback
95-
if (objA.onCollision && objA.onCollision(response, objB) !== false && objA.body.isStatic === false) {
96-
objA.body.respondToCollision.call(objA.body, response);
97-
}
98-
if (objB.onCollision && objB.onCollision(response, objA) !== false && objB.body.isStatic === false) {
99-
objB.body.respondToCollision.call(objB.body, response);
100-
}
101-
}
102-
});
103-
});
87+
return true;
88+
}
10489
}
10590
}
106-
});
107-
// we could return the amount of objects we collided with ?
108-
return collisionCounter > 0;
109-
}
110-
111-
/**
112-
* Checks for object colliding with the given line
113-
* @ignore
114-
* @param {Line} line - line to be tested for collision
115-
* @param {Array.<Renderable>} [result] - a user defined array that will be populated with intersecting physic objects.
116-
* @returns {Array.<Renderable>} an array of intersecting physic objects
117-
* @example
118-
* // define a line accross the viewport
119-
* var ray = new me.Line(
120-
* // absolute position of the line
121-
* 0, 0, [
122-
* // starting point relative to the initial position
123-
* new me.Vector2d(0, 0),
124-
* // ending point
125-
* new me.Vector2d(me.game.viewport.width, me.game.viewport.height)
126-
* ]);
127-
*
128-
* // check for collition
129-
* result = me.collision.rayCast(ray);
130-
*
131-
* if (result.length > 0) {
132-
* // ...
133-
* }
134-
*/
135-
export function rayCast(line, result = []) {
136-
var collisionCounter = 0;
137-
138-
// retrieve a list of potential colliding objects from the game world
139-
var candidates = game.world.broadphase.retrieve(line);
140-
141-
for (var i = candidates.length, objB; i--, (objB = candidates[i]);) {
142-
143-
// fast AABB check if both bounding boxes are overlaping
144-
if (objB.body && line.getBounds().overlaps(objB.getBounds())) {
91+
return false;
92+
}
14593

146-
// go trough all defined shapes in B (if any)
147-
var bLen = objB.body.shapes.length;
148-
if ( objB.body.shapes.length === 0) {
149-
continue;
94+
/**
95+
* find all the collisions for the specified object using a broadphase algorithm
96+
* @ignore
97+
* @param {Renderable} objA - object to be tested for collision
98+
* @returns {boolean} in case of collision, false otherwise
99+
*/
100+
collisions(objA) {
101+
var collisionCounter = 0;
102+
// retreive a list of potential colliding objects from the game world
103+
var candidates = this.world.broadphase.retrieve(objA);
104+
105+
boundsA.addBounds(objA.getBounds(), true);
106+
boundsA.addBounds(objA.body.getBounds());
107+
108+
candidates.forEach((objB) => {
109+
// check if both objects "should" collide
110+
if (this.shouldCollide(objA, objB)) {
111+
112+
boundsB.addBounds(objB.getBounds(), true);
113+
boundsB.addBounds(objB.body.getBounds());
114+
115+
// fast AABB check if both bounding boxes are overlaping
116+
if (boundsA.overlaps(boundsB)) {
117+
118+
if (this.collides(objA.body, objB.body)) {
119+
// we touched something !
120+
collisionCounter++;
121+
122+
// execute the onCollision callback
123+
if (objA.onCollision && objA.onCollision(this.response, objB) !== false && objA.body.isStatic === false) {
124+
objA.body.respondToCollision.call(objA.body, this.response);
125+
}
126+
if (objB.onCollision && objB.onCollision(this.response, objA) !== false && objB.body.isStatic === false) {
127+
objB.body.respondToCollision.call(objB.body, this.response);
128+
}
129+
}
130+
}
150131
}
132+
});
133+
// we could return the amount of objects we collided with ?
134+
return collisionCounter > 0;
135+
}
151136

152-
var shapeA = line;
137+
/**
138+
* Checks for object colliding with the given line
139+
* @ignore
140+
* @param {Line} line - line to be tested for collision
141+
* @param {Array.<Renderable>} [result] - a user defined array that will be populated with intersecting physic objects.
142+
* @returns {Array.<Renderable>} an array of intersecting physic objects
143+
* @example
144+
* // define a line accross the viewport
145+
* var ray = new me.Line(
146+
* // absolute position of the line
147+
* 0, 0, [
148+
* // starting point relative to the initial position
149+
* new me.Vector2d(0, 0),
150+
* // ending point
151+
* new me.Vector2d(me.game.viewport.width, me.game.viewport.height)
152+
* ]);
153+
*
154+
* // check for collition
155+
* result = me.collision.rayCast(ray);
156+
*
157+
* if (result.length > 0) {
158+
* // ...
159+
* }
160+
*/
161+
rayCast(line, result = []) {
162+
var collisionCounter = 0;
163+
164+
// retrieve a list of potential colliding objects from the game world
165+
var candidates = this.world.broadphase.retrieve(line);
166+
167+
for (var i = candidates.length, objB; i--, (objB = candidates[i]);) {
153168

154-
// go through all defined shapes in B
155-
var indexB = 0;
156-
do {
157-
var shapeB = objB.body.getShape(indexB);
169+
// fast AABB check if both bounding boxes are overlaping
170+
if (objB.body && line.getBounds().overlaps(objB.getBounds())) {
158171

159-
// full SAT collision check
160-
if (SAT["test" + shapeA.shapeType + shapeB.shapeType]
161-
.call(
162-
this,
163-
dummyObj, // a reference to the object A
164-
shapeA,
165-
objB, // a reference to the object B
166-
shapeB
167-
)) {
168-
// we touched something !
169-
result[collisionCounter] = objB;
170-
collisionCounter++;
172+
// go trough all defined shapes in B (if any)
173+
var bLen = objB.body.shapes.length;
174+
if ( objB.body.shapes.length === 0) {
175+
continue;
171176
}
172-
indexB++;
173-
} while (indexB < bLen);
177+
178+
var shapeA = line;
179+
180+
// go through all defined shapes in B
181+
var indexB = 0;
182+
do {
183+
var shapeB = objB.body.getShape(indexB);
184+
185+
// full SAT collision check
186+
if (SAT["test" + shapeA.shapeType + shapeB.shapeType]
187+
.call(
188+
this,
189+
dummyObj, // a reference to the object A
190+
shapeA,
191+
objB, // a reference to the object B
192+
shapeB
193+
)) {
194+
// we touched something !
195+
result[collisionCounter] = objB;
196+
collisionCounter++;
197+
}
198+
indexB++;
199+
} while (indexB < bLen);
200+
}
174201
}
175-
}
176202

177-
// cap result in case it was not empty
178-
result.length = collisionCounter;
203+
// cap result in case it was not empty
204+
result.length = collisionCounter;
179205

180-
// return the list of colliding objects
181-
return result;
206+
// return the list of colliding objects
207+
return result;
208+
}
182209
}

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