如何在遊戲中發射時同步去除b2bodies

Question

在我的遊戲中，我有一些怪物和我的英雄。當我火了一些子彈我刪除碰撞或者與怪物或接地體機構，並還增加了一個定時器事件刪除子彈作爲

-(void) removeProjectile:(CCPhysicsSprite*)projectile{ 
     dispatch_time_t removeProjectile = dispatch_time(DISPATCH_TIME_NOW, (int64_t)(1* NSEC_PER_SEC)); 
    dispatch_after(removeProjectile, dispatch_get_main_queue(), ^(void){ 
     int i; 

     for(i=0;i<deadBodyCount;i++) 
     { 
      if(deadBodies[i] == projectile.b2Body) 
      { 
       break; 
      } 
     } 
     if(i==deadBodyCount) 
     { 
      deadBodies[deadBodyCount]=projectile.b2Body; 
      deadBodyCount++; 
     } 
    }); 
} 

，但會發生什麼我的代碼崩潰，不知道。請幫幫我。如果你有任何方法來做到這一點。 我在

-(void)removeDeadBodies{ 
for (int i=0; i<deadBodyCount; i++) { 
    if(deadBodies[i]){ 
     if([self getPSTag:deadBodies[i]]==3){ 
      CCPhysicsSprite *temp=(CCPhysicsSprite *)deadBodies[i]->GetUserData(); 
      NSLog(@"%@",temp); 
      [[self getChildByTag:kTagParentNode]removeChild:temp cleanup:YES]; 
     } 
     else if([self getPSTag:deadBodies[i]]==2){ 
      for (int j=0; j<monsterCount; j++) { 
       if (monsters[j].b2Body==deadBodies[i]) { 
        [[self getChildByTag:kTagParentNode]removeChild:monsters[j] cleanup:YES]; 
        monsters[j]=NULL; 
       } 
      } 
     } 
     _world->DestroyBody(deadBodies[i]); 
     deadBodies[i]=NULL;} 
    } 
    deadBodyCount=0; 
    } 

-(int)getPSTag:(b2Body *)body{ //physics sprite tag value from a b2Body 
CCPhysicsSprite *sprite=(CCPhysicsSprite*)body->GetUserData(); 
//Here is the error------------------------------------ 
if(sprite) 
    return (int)sprite.tag; 
else 
    return 0; 
} 

去除deadbodies，這是我開始接觸方法

-(void)beginContact:(b2Contact *)contact{ 
b2Body *bodyA=contact->GetFixtureA()->GetBody(); 
b2Body *bodyB=contact->GetFixtureB()->GetBody(); 
int collideCheck=[self checkForCollisionGroups:bodyA And:bodyB]; 
if(!collideCheck) 
    return; 
switch (collideCheck) { 
    case 1: 
     for (int i=0; i<monsterCount; i++) { 
      if(monsters[i].isVisible){ 
       //Checking if Projectile hitting the monster 
       //bodyA is monster and bodyB is projectile 
       if([self getPSTag:bodyA]==2&&[self getPSTag:bodyB]==3){ 
        [monsters[i] monsterHit]; 
        [self doExplosionAtPoint:monsters[i].position]; 

        deadBodies[deadBodyCount++]=monsters[i].b2Body; 

        CCPhysicsSprite *x=(CCPhysicsSprite *)bodyB->GetUserData(); 
        for (int i=0; i<10; i++) { 
         if(deadBodies[i]==x.b2Body) 
          return; 
        } 
        deadBodies[deadBodyCount++]=x.b2Body; 

        [self.top updateScore:100]; 
       }//bodyA is Projectile and bodyB is Monster 
       else if([self getPSTag:bodyA]==3&&[self getPSTag:bodyB]==2){//if one of the   body is projectile 
        [monsters[i] monsterHit]; 
        [self doExplosionAtPoint:monsters[i].position]; 

        CCPhysicsSprite *x=(CCPhysicsSprite *)bodyA->GetUserData(); 
        for (int i=0; i<10; i++) { 
         if(deadBodies[i]==x.b2Body) 
          return; 
        } 
        deadBodies[deadBodyCount++]=x.b2Body; 

        deadBodies[deadBodyCount++]=monsters[i].b2Body; 

        [self.top updateScore:100]; 
       } 
      } 
     } 
     break; 
    case 2: 
     if (jumping==YES) { 
      jumping=NO; 
     } 
     break; 
    case 3: //bullet hitting with any object 
     if([self getPSTag:bodyA]==3){//if one of the body is projectile 
      CCPhysicsSprite *x=(CCPhysicsSprite *)bodyA->GetUserData(); 
      for (int i=0; i<10; i++) { 
       if(deadBodies[i]==x.b2Body) 
        return; 
      } 
      deadBodies[deadBodyCount++]=x.b2Body; 
     } 
     else if ([self getPSTag:bodyB]==3){ 
      CCPhysicsSprite *x=(CCPhysicsSprite *)bodyB->GetUserData(); 
      for (int i=0; i<10; i++) { 
       if(deadBodies[i]==x.b2Body) 
        return; 
      } 
      deadBodies[deadBodyCount++]=x.b2Body; 
     } 
     break; 
    case 4: 
     for (int i=0; i<monsterCount; i++) { 
      if(monsters[i].isVisible){ 
       if((bodyA==monsters[i].b2Body&&bodyB==_heroBody)||(bodyA==_heroBody&&bodyB==monsters[i].b2Body)) { 
        _heroBody->SetLinearVelocity(b2Vec2(-3*hero.scaleX, 5)); 
        lifeCount=[_top updateHealthMeterWithDamage:10]; 
        NSLog(@"collide"); 
        moving=false; 
       } 
      } 
     } 
     break; 
    /*case 6:if([self getPSTag:bodyA]==33){ 
     movingTile.position=((CCSprite*)bodyA->GetUserData()).position; 
      } 
     else 
      movingTile.position=((CCSprite*)bodyB->GetUserData()).position;*/ 
    default: 
     break; 
    } 
} 

Answer 1

我看着你的代碼。我不明白使用removeProjectile：CCPhysicsSprite *）射彈{}方法，而您間接地將這些射彈添加到beginContact（）中的deadBodies []中。所以我想在這裏你有兩個指向同一個身體的指針。當你運行removeDeadBodies（）for循環時，它實際上首先刪除了body，然後在下一次迭代中，當它再次得到沒有body的懸掛指針時，它會崩潰。

我評論了這一行[self removeProjectile：projectile];在createProjectileAt（）方法中。現在一切正常。

我知道實現它可能遲了，但建議，爲了更好地控制你的b2body並安全地從世界刪除，你可以將一個帶數據成員的struct數據類型作爲Sprite和BOOL變量，如isDelete。並使用這個結構作爲body的userdata。所以現在你可以在beginContact（）回調中將這個bool變量設置爲YES。在你更新後：tick方法在world-> step結束之後只是遍歷整個body的世界並檢查可以被刪除的BOOL var。你可以安全地刪除屍體。不需要維護一個deadBody數組等，因此不會有任何同步問題。