Cocos2d. Rotate point around another point without hard math calculations? - cocos2d-iphone

Question

I haven't seen easy examples about rotaion around a specified point. I tried something like this but it doesn't work:
//CCNode *node is declared
//In a function of a subclass of CCSprite
- (void)moveWithCicrlce
{
anchorNode = [CCNode node];
anchorNode.position = ccpSub(self.position, circleCenter);
anchorNode.anchorPoint = circleCenter;
[anchorNode runAction:[CCRotateBy actionWithDuration:1 angle:90]];
[self runAction:[CCRepeatForever actionWithAction:[CCSequence actions:[CCCallFunc actionWithTarget:self selector:#selector(rotate)], [CCDelayTime actionWithDuration:0.1], nil]]];
}
- (void)rotate
{
self.position = ccpAdd(anchorNode.position, anchorNode.anchorPoint);
}

Answer 1

Here's how you can rotate a node (sprite etc) around a certain point P (50,50) with a radius (distance from P) of 100:
CCNode* center = [CCNode node];
center.position = CGPointMake(50, 50);
[self addChild:center];
// node to be rotated is added to center node
CCSprite* rotateMe = [CCSprite spriteWithFile:#"image.png"];
[center addChild:rotateMe];
// offset rotateMe from center by 100 points to the right
rotateMe.position = CGPointMake(100, 0);
// perform rotation of rotateMe around center by rotating center
id rotate = [CCRotateBy actionWithDuration:10 rotation:360];
[center runAction:rotate];

Answer 2

My approximate solution:
#interface Bomb : NSObject {
CCSprite *center;
}
...
#end
and some methods:
- (void)explode
{
BombBullet *bullet = [BombBullet spriteWithFile:#"explosion03.png"];
[[[CCDirector sharedDirector] runningScene] addChild:bullet];
center = [CCSprite spriteWithTexture:bullet.texture];
center.position = explosionPoint;
center.anchorPoint = ccp(-0.5, -0.5);
center.visible = NO;
[[[CCDirector sharedDirector] runningScene] addChild:center];
[center runAction:[CCRotateBy actionWithDuration:1 angle:360]];
CCCallFunc *updateAction = [CCCallFuncN actionWithTarget:self selector:#selector(update:)];
[bullet runAction:[CCRepeatForever actionWithAction:[CCSequence actions:updateAction, [CCDelayTime actionWithDuration:0.01], nil]]];
}
- (void)update:(id)sender
{
BombBullet *bombBullet = (BombBullet *)sender;
bombBullet.rotation = center.rotation;
bombBullet.position = ccpAdd(center.position, center.anchorPointInPoints);
bombBullet.position = ccpAdd(bombBullet.position, ccp(-bombBullet.contentSize.width / 2, -bombBullet.contentSize.height / 2));
bombBullet.position = ccpRotateByAngle(bombBullet.position, center.position, bombBullet.rotation);
}
of course I should add sprite deleting.