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Game crashes when I try to destroy a b2Body, what should I do?

开发者 https://www.devze.com 2023-03-14 22:03 出处:网络
\"Assertion failed: (m_bodyCount < m_bodyCapacity), function Add, file libs/Box2D/Dynamics/b2Island.h, line 65.\"
"Assertion failed: (m_bodyCount < m_bodyCapacity), function Add, file libs/Box2D/Dynamics/b2Island.h, line 65." 

That is what it the crash leaves in the console.

[self removeChild:(CCSprite*)body->GetUserData() cleanup:YES];

body->SetTransform(b2Vec2(30, 30), 0); //moving the body out of the scene so it doesnt collide anymore!

 world->DestroyBody(body);

I think im doing the right stuff..

@property (nonatomic, assign) b2Body *body;

Here is how i "make it" a property

I dont understand why it doesnt work, "body" is a proper pointer because I can retrieve infromation from the bodys UserData like tags that are set in the creatin of the body, so that shouldnt be a problem.. Do anyone know whats wrong with my code?

Thank you.

Edited in:

-(void) tick: (ccTime) dt //Main loop
{

if (ballFired) {
    Magnet *aMagnet = [magnetArray objectAtIndex:0];

    world->DestroyBody(aMagnet.body); //It crashes here!
}



int32 velocityIterations = 8;
int32 positionIterations = 1;

// Instruct the world to perform a single step of simulation. It is
// generally best to keep 开发者_如何学JAVAthe time step and iterations fixed.
world->Step(dt, velocityIterations, positionIterations);


//Iterate over the bodies in the physics world
for (b = world->GetBodyList(); b; b = b->GetNext())
{
    if (b->GetUserData() != NULL) {
        //Synchronize the AtlasSprites position and rotation with the corresponding body
        CCSprite *myActor = (CCSprite*)b->GetUserData();
        myActor.position = CGPointMake( b->GetPosition().x * PTM_RATIO, b>GetPosition().y * PTM_RATIO);
        myActor.rotation = -1 * CC_RADIANS_TO_DEGREES(b->GetAngle());
    }   
    }




}

Isnt this outside the world step?

Edit 2:

        ContactListener::ContactListener(){};

         void ContactListener::BeginContact(b2Contact* contact)
        {
        // Box2d objects that collided
       b2Fixture* fixtureA = contact->GetFixtureA();


       b2Fixture* fixtureB = contact->GetFixtureB();
       CCSprite* actorA = (CCSprite*) fixtureA->GetBody()->GetUserData();
       CCSprite* actorB = (CCSprite*)  fixtureB->GetBody()->GetUserData();



      if(actorA == nil || actorB == nil) return;

    b2WorldManifold* worldManifold = new b2WorldManifold();
    contact->GetWorldManifold(worldManifold);


      Kollisjon *kollisjon = [Kollisjon sharedKollisjon];

     if (actorA.tag == 1) {

    NSLog(@"OK1");

    kollisjon.kollidertBody = fixtureB->GetBody();

    kollisjon.world->DestroyBody(kollisjon.kollidertBody); //Isnt this ok?

    }

    else if (actorB.tag == 1) {

       NSLog(@"OK2");


       kollisjon.kollidertBody = fixtureA->GetBody();

       kollisjon.world->DestroyBody(kollisjon.kollidertBody); //Isnt this ok?

    } 


    }

Is it not outside the timestep? Please help me here...

Thank you


You must scan for contacts, store all contacts in an array, and then AFTER all contacts have been checked, you remove your bodies.

Checking for contacts:

std::vector<MyContact>::iterator pos;
for(pos = _contactListener->_contacts.begin(); 
    pos != _contactListener->_contacts.end(); ++pos) 
{
    MyContact contact = *pos;

    b2Body *bodyA = contact.fixtureA->GetBody();
    b2Body *bodyB = contact.fixtureB->GetBody();

    // Rocket explosion rect
    if(bodyA->GetUserData() == NULL)
    {
        NSLog(@"NULL collision detected. (BODY A)");

        hasDoneRocketCollisions = YES;

        CCSprite *sprite = (CCSprite*) bodyB->GetUserData();

        if(sprite.visible == NO) continue;

        if(sprite.tag >= 200 && sprite.tag < 300)
        {
            index = sprite.tag - 200;
            if([spriteTracker containsObject:sprite]) continue;
            [spriteTracker addObject:sprite];
            bodiesToKill[counter] = bodyB;
            [enemyChargerIsAlive replaceObjectAtIndex:(int)(sprite.tag-200) withObject:[NSNumber numberWithInt:0]];
            [ParticleController spawnExplosion:sprite.position inParent:currentDefaultNode];
        }
        else if(sprite.tag >= 300 && sprite.tag < 400)
        {
            index = sprite.tag - 300;
            if([spriteTracker containsObject:sprite]) continue;
            [spriteTracker addObject:sprite];
            bodiesToKill[counter] = bodyB;
            [enemyShooterIsAlive replaceObjectAtIndex:(int)(sprite.tag-300) withObject:[NSNumber numberWithInt:0]];
            [ParticleController spawnExplosion:sprite.position inParent:currentDefaultNode];
            counter++;
        }
    }
}

Later in your method after all contacts have been checked:

b2Body *dyingBody;

for(int i = 0; i < counter; i++)
{
    CCSprite *dyingSprite;
    dyingSprite = [spriteTracker objectAtIndex:i];
    dyingSprite.visible = NO;

    // Is player projectile
    if(dyingSprite.tag >= 100 && dyingSprite.tag < 200)
    {
        CCParticleSystemQuad *dyingParticle;
        dyingParticle  = [particlesToKill objectAtIndex:particleIndex];
        particleIndex++;
        [dyingParticle stopSystem];

        dyingBody = bodiesToKill[i];
        dyingBody->SetActive(false);

        [ParticleController spawnExplosion:dyingSprite.position inParent:currentDefaultNode];
        [AudioController playExplosion];

        dyingSprite.visible = NO;

        if([_player currentShotType] == 1)
        {
            rocketHitBody->SetTransform(b2Vec2(dyingSprite.position.x/PTM_RATIO, dyingSprite.position.y/PTM_RATIO), 0.0);
            rocketHitBody->SetActive(true);
        }
    }
}

Take note that these are just random chunks of code I have copy and pasted in. They are for example only and may only confuse you if you try to read them as exact instructions.

The point here is: You can not remove a body while it is being accessed by the step or contact listener. Finish using the contact listener and then remove your bodies.

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