Question

How can I have the same sprite in multiple locations dynamically? I have already seen the other question, but, you can only do that with three sprites. I want to have a dynamic number of sprites. My objective is that I am trying to make, instead of shooting only one bullet, I want it to shoot three or more. I have all of the math done, but, I need to draw the three sprites in a for-loop. Here is what I have so far.

- (void)ccTouchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
    UITouch * touch = [touches anyObject];
    CGPoint pointOne = [touch locationInView:[touch view]];
    CGSize size = [[CCDirector sharedDirector] winSize];
    CGPoint position = turret.position;
    CGFloat degrees = angleBetweenLinesInDegrees(position, pointOne);
    turret.rotation = degrees;
    pointOne.y = size.height-pointOne.y;
    CCSprite *projectile = [CCSprite spriteWithFile:@"projectile.png"];
    projectile.position = turret.position;

    // Determine offset of location to projectile
    int angle = angleBetweenLinesInDegrees(position, pointOne);
    int startAngle = angle-15;

    int shots = 3;

    NSMutableArray *projectiles = [[NSMutableArray alloc] initWithCapacity:shots];

    // Ok to add now - we've double checked position
    for(int i = 0;i<shots;i++) {
        [self addChild:projectile z:1];

        int angleToShoot = angle;

        int x = size.width;
        int y = x*tan(angle);

        CGPoint realDest = ccp(x,y);

        projectile.tag = 2;
        if (paused==0 ) {
            [_projectiles addObject:projectile];
            // Move projectile to actual endpoint
            [projectile runAction:
             [CCSequence actions:
              [CCMoveTo actionWithDuration:1 position:realDest],
              [CCCallBlockN actionWithBlock:^(CCNode *node) {
                 [_projectiles removeObject:node];
                 [node removeFromParentAndCleanup:YES];
             }],
              nil]];
        }
    }
}

This gives me the error: 'NSInternalInconsistencyException', reason: 'child already added. It can't be added again'

Answer 1

you need to create 3 different sprite and add all 3 of them as a child.
usually for doing stuff like this is better to use a CCBatchNode (take a look to the cocos doc).
With a batchnode you get all the childs be drawn in 1 draw call with the only constrain that all the childs of the batchnode needs to have the texture on the same spriteSheet (or in your case if they have the same “filename”)
for just 3 projectiles you wont have performance problems but its the correct way to design it, if you will need to have dozens of projectiles on screen without using a batchnode the game wont run smooth.

to recap:
create a ccbatchnode,
add the batchnode as a child of self (i suppose its ur layer or main node)
create 3 sprites and add them as a child of the batchnode