更新
问题已经找到，我也发现Box2D for web在每一方面都有泄漏 :/
为了展示这个问题，我制作了一个简单的圆在一个静态多边形中移动，并在一段时间后得出了以下结果。
注意，以下项目正在泄漏，因为我没有创建任何主体或以任何方式改变世界:
- b2Vec2
- 特征
- b2ManifoldPoint
- b2ContactID
- b2Manifold
- b2ContactEdge
- b2PolyAndCircleContact
- 阵列
- ...
原帖
我有一个问题，因为我正在分析我的游戏，但垃圾回收器没有删除我的主体、联系人和其他东西。然后我看了看它们从GC保留了什么，发现是Box2D自身。这可能导致两种选择：我的错还是Box2D泄漏了。我认为是我的原因。
究竟是什么让它保持不变？
- contact.m_nodeA.other似乎是最常用的保留来自GC的东西。
- 其他时候：在联系人中的m_fixtureB...请参见图片
您可以看到该主体具有__destroyed属性。在使用world.DestroyBody(body)手动删除之前，将其手动设置。
当我销毁一个主体时，我在调用世界上的step方法之后调用它。
从Box2D方法中可以看出，它不会摆脱其他变量，也不会将其更改为另一个主体，因此我的主体没有进行垃圾回收。
这里我错过了什么想法吗？
现在只有在未运行world.Step时才能解决问题：
var gravity = new Box2D.Vec2(0, 0);
var doSleep = true;
var world = new Box2D.World(gravity, doSleep);
var step = false;
var fixtureDef = new Box2D.FixtureDef();
fixtureDef.density = 1.0;
fixtureDef.friction = 0.5;
fixtureDef.restitution = 0.2;
fixtureDef.shape = new Box2D.PolygonShape();
fixtureDef.shape.SetAsBox(1, 1);
var bodyDef = new Box2D.BodyDef;
bodyDef.type = Box2D.Body.b2_dynamicBody;
bodyDef.position.x = 0.4;
bodyDef.position.y = 0.4;
var bodies = []
var fix = [];
window.c = function(){
for(var i = 0; i < 100; i++){
var body = world.CreateBody(bodyDef);
body._id = i;
fix.push(body.CreateFixture(fixtureDef));
bodies.push(body);
}
if(step){world.Step(1/60, 3, 3); world.ClearForces();}
console.log('Created', bodies)
fixtureDef = null;
bodyDef = null;
}
window.d = function(){
_.each(bodies, function(body, i){
body.DestroyFixture(fix[i]);
world.DestroyBody(body);
fix[i] = null;
bodies[i] = null;
})
if(step){world.Step(1/60, 3, 3); world.ClearForces();}
bodies = null;
fix = null;
}
将步骤更改为true，内存泄漏问题再次出现。
复现内存泄漏问题：
您的文件中的代码：
var gravity = new Box2D.Vec2(0, 0);
var doSleep = true;
var world = new Box2D.World(gravity, doSleep);
var bodies = []
window.c = function(){
for(var i = 0; i < 100; i++){
var bodyDef = new Box2D.BodyDef();
bodyDef.type = 2;
var shape = new Box2D.PolygonShape();
shape.SetAsBox(1, 1);
var fixtureDef = new Box2D.FixtureDef();
fixtureDef.shape = shape;
var body = world.CreateBody(bodyDef);
body._id = i;
body.CreateFixture(fixtureDef);
bodies.push(body);
}
world.Step(0.3, 3, 3);
console.log('Created', bodies)
}
window.d = function(){
_.each(bodies, function(body, i){
world.DestroyBody(body);
bodies[i] = null;
})
world.Step(0.3, 3, 3);
bodies = null;
}
打开 Google Chrome：
- 然后打开您的个人资料并拍摄快照。
- 现在在控制台中运行 c() 方法以创建 100 个物体。
- 现在拍摄第二个快照。
- 在快照中搜索 b2Body，您将找到 100 个对象计数。
- 现在运行 d() 方法以删除所有物体；
- 通过单击垃圾桶来强制进行垃圾回收。
- 拍摄快照 3。
- 搜索 b2Body，您还会发现 100 个对象计数。
在最后一步，应该只有 0 个对象，因为它们已被销毁。但实际上你会发现这个：
现在您可以看到有许多来自 b2ContactEdge 的引用。如果您删除代码中的 world.Step 部分，则只会看到对该物体的 2 个引用。
如果您删除此行
body.CreateFixture(fixtureDef);
或将身体静止不再泄漏。
我的游戏循环
...gameLoop = function(o){
// used a lot here
var world = o.world;
// calculate the new positions
var worldStepSeconds = o.worldStepMs / 1000;
// step world
world.Step(worldStepSeconds, o.velocityIterations, o.positionIterations)
// render debug
if(o.renderDebug){
world.DrawDebugData();
}
// always to not accumulate forces, maybe some bug occurs
world.ClearForces();
// tick all ticking entities
_.each(o.getTickEntitiesFn(), function(actor){
if(!actor) return;
actor.tick(o.worldStepMs, o.lastFrameMs);
})
// update PIXI entities
var body = world.GetBodyList();
var worldScale = world.SCALE;
var destroyBody = world.DestroyBody.bind(world);
while(body){
var actor = null;
var visualEntity = null;
var box2DEntity = o.getBox2DEntityByIdFn(body.GetUserData());
if(box2DEntity){
visualEntity = o.getVisualEntityByIdFn(box2DEntity.getVisualEntityId());
if(box2DEntity.isDestroying()){
// optimization
body.__destroyed = true;
world.DestroyBody(body);
box2DEntity.completeDestroy();
}
}
if(visualEntity){
if(visualEntity.isDestroying()){
visualEntity.completeDestroy();
}else{
var inverseY = true;
var bodyDetails = Utils.getScreenPositionAndRotationOfBody(world, body, inverseY);
visualEntity.updateSprite(bodyDetails.x, bodyDetails.y, bodyDetails.rotation);
}
}
// this delegates out functionality for each body processed
if(o.triggersFn.eachBody) o.triggersFn.eachBody(world, body, visualEntity);
body = body.GetNext();
}
// when a joint is created is then also created it's visual counterpart and then set to userData.
var joint = world.GetJointList();
while(joint){
var pixiGraphics = joint.GetUserData();
if(pixiGraphics){
// In order to draw a distance joint we need to know the start and end positions.
// The joint saves the global (yes) anchor positions for each body.
// After that we need to scale to our screen and invert y axis.
var anchorA = joint.GetAnchorA();
var anchorB = joint.GetAnchorB();
var screenPositionA = anchorA.Copy();
var screenPositionB = anchorB.Copy();
// scale
screenPositionA.Multiply(world.SCALE);
screenPositionB.Multiply(world.SCALE);
// invert y
screenPositionA.y = world.CANVAS_HEIGHT - screenPositionA.y
screenPositionB.y = world.CANVAS_HEIGHT - screenPositionB.y
// draw a black line
pixiGraphics.clear();
pixiGraphics.lineStyle(1, 0x000000, 0.7);
pixiGraphics.moveTo(screenPositionA.x, screenPositionA.y);
pixiGraphics.lineTo(screenPositionB.x, screenPositionB.y);
}
joint = joint.GetNext();
}
// render the PIXI scene
if(o.renderPixi){
o.renderer.render(o.stage)
}
// render next frame
requestAnimFrame(o.requestAnimFrameFn);
}
来自Box2d的代码：
b2ContactManager.prototype.Destroy = function (c) {
var fixtureA = c.GetFixtureA();
var fixtureB = c.GetFixtureB();
var bodyA = fixtureA.GetBody();
var bodyB = fixtureB.GetBody();
if (c.IsTouching()) {
this.m_contactListener.EndContact(c);
}
if (c.m_prev) {
c.m_prev.m_next = c.m_next;
}
if (c.m_next) {
c.m_next.m_prev = c.m_prev;
}
if (c == this.m_world.m_contactList) {
this.m_world.m_contactList = c.m_next;
}
if (c.m_nodeA.prev) {
c.m_nodeA.prev.next = c.m_nodeA.next;
}
if (c.m_nodeA.next) {
c.m_nodeA.next.prev = c.m_nodeA.prev;
}
if (c.m_nodeA == bodyA.m_contactList) {
bodyA.m_contactList = c.m_nodeA.next;
}
if (c.m_nodeB.prev) {
c.m_nodeB.prev.next = c.m_nodeB.next;
}
if (c.m_nodeB.next) {
c.m_nodeB.next.prev = c.m_nodeB.prev;
}
if (c.m_nodeB == bodyB.m_contactList) {
bodyB.m_contactList = c.m_nodeB.next;
}
this.m_contactFactory.Destroy(c);
--this.m_contactCount;
}
b2ContactFactory.prototype.Destroy = function (contact) {
if (contact.m_manifold.m_pointCount > 0) {
contact.m_fixtureA.m_body.SetAwake(true);
contact.m_fixtureB.m_body.SetAwake(true);
}
var type1 = parseInt(contact.m_fixtureA.GetType());
var type2 = parseInt(contact.m_fixtureB.GetType());
var reg = this.m_registers[type1][type2];
if (true) {
reg.poolCount++;
contact.m_next = reg.pool;
reg.pool = contact;
}
var destroyFcn = reg.destroyFcn;
destroyFcn(contact, this.m_allocator);
}