Collision detection in Cocos2d?

Question

I try to detect Collision of two sprites as follows ... but when I try to start the game, no collisions occur .... what am I possibly mistaken?

- (void)update:(ccTime)dt { CGRect projectileRect = CGRectMake(projectile.position.x - (projectile.contentSize.width/2), projectile.position.y - (projectile.contentSize.height/2), projectile.contentSize.width, projectile.contentSize.height); //CGRectMake(0,220,320,50); CGRect targetRects = CGRectMake(_monkey.position.x - (_monkey.contentSize.width/2), _monkey.position.y - (_monkey.contentSize.height/2), _monkey.contentSize.width, _monkey.contentSize.height); if (CGRectIntersectsRect(projectileRect, targetRects)) { NSLog(@"ha ha Collision detected"); } 

}

The projectile sprite is animated from the top of the screen and the monkey sprite is animated from left to right at the bottom, the projectile goes through the monkey, but the log does not work out caused ???

 - (void)update:(ccTime)dt { CGRect projectileRect = [projectile boundingBox]; CGRect targetRects = [_monkey boundingBox]; if (CGRectIntersectsRect(projectileRect, targetRects)) { NSLog(@"ha ha Collision detected"); } CGRect projectileRects = CGRectMake(projectile.position.x - (projectile.contentSize.width/2), projectile.position.y - (projectile.contentSize.height/2), projectile.contentSize.width, projectile.contentSize.height); CGRect targetRect = CGRectMake(_monkey.position.x - (_monkey.contentSize.width/2), _monkey.position.y - (_monkey.contentSize.height/2), _monkey.contentSize.width, _monkey.contentSize.height); if (CGRectIntersectsRect(projectileRects, targetRect)) { NSLog(@"@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); } 

}

- (void) spriteMoveFinished: (id) sender {

 //NSLog(@"spriteMoveFinished"); CCSprite *sprite = (CCSprite *)sender; [self removeChild:sprite cleanup:YES]; if (sprite.tag == 1) { [_targets removeObject:sprite]; } else if (sprite.tag == 2) { [_projectiles removeObject:sprite]; } 

}

- (void) addTarget {

 projectile = [CCSprite spriteWithFile:@"egg.png" rect:CGRectMake(0, 0, 10, 10)]; projectile.position = ccp(_bear.position.x,_bear.position.y-20); projectile.tag=2; [self addChild:projectile]; CGPoint realDest = ccp(_bear.position.x, _bear.position.y - 380); int minDuration = 2.0; int maxDuration = 4.0; int rangeDuration = maxDuration - minDuration; int actualDuration = (arc4random() % rangeDuration) + minDuration; // Move projectile to actual endpoint [projectile runAction:[CCSequence actions: [CCMoveTo actionWithDuration:actualDuration position:realDest], [CCCallFuncN actionWithTarget:self selector:@selector(spriteMoveFinished:)], nil]]; // Add to projectiles array projectile.tag = 2; [_projectiles addObject:projectile]; 

}

 -(void) registerWithTouchDispatcher { [[CCTouchDispatcher sharedDispatcher] addTargetedDelegate:self priority:0 swallowsTouches:YES]; } 

- (BOOL) ccTouchBegan: (UITouch *) touch withEvent: (UIEvent *) event {

 CGPoint touchLocation = [self convertTouchToNodeSpace:touch]; if(CGRectContainsPoint(CGRectMake(0,0,320,50),touchLocation)) { if (![_walkMonkey isDone]) { [_monkey runAction:_walkMonkey]; } } else { } return YES; 

}

- (void) ccTouchEnded: (UITouch *) touch withEvent: (UIEvent *) event {

 CGPoint touchLocation = [self convertTouchToNodeSpace:touch]; if(CGRectContainsPoint(CGRectMake(0,0,320,50),touchLocation)) { [_monkey stopAction:_walkMonkey]; } 

}

 - (void)ccTouchMoved:(UITouch *)touch withEvent:(UIEvent *)event { CGPoint touchLocation = [self convertTouchToNodeSpace:touch]; CGPoint oldTouchLocation = [touch previousLocationInView:touch.view]; oldTouchLocation = [[CCDirector sharedDirector] convertToGL:oldTouchLocation]; oldTouchLocation = [self convertToNodeSpace:oldTouchLocation]; CGPoint translation = ccpSub(touchLocation, oldTouchLocation); if (translation.x > 3) { _monkey.flipX=YES; } else if (translation.x < -3){ _monkey.flipX=NO; } if(CGRectContainsPoint(CGRectMake(40,0,240,50),touchLocation)) { CGPoint newPos = ccpAdd(translation,_monkey.position); if(newPos.x >= 320 || newPos.x <= 20) { NSLog(@"monkey not walking"); } else { newPos.y = 100; _monkey.position = newPos; } } } 

Answer 1

You should use the built-in functions:

 CGRect projectileRect = [projectile boundingBox]; CGRect targetRects = [_monkey boundingBox]; if (CGRectIntersectsRect(projectileRect, targetRects)) { NSLog(@"ha ha Collision detected"); } 

The boundingBox method takes into account a few more things, for example, if a node is located relative to its parent.

Also note that underscoring variable prefixes is considered bad practice in Objective-C. Apple reserves variable names with leading underscores for its internal libraries. If you really need to classify instance variables, one common way is to suffix them with underscores.