cocos2d Generating multiple of the same sprites with velocity - objective-c

Question

I'm pretty new to iOS and cocos2d and I'm having a problem trying to create what I want the code to do. Let me give you the rundown first then i'll show what I've got.
What I got so far is a giant sprite in the middle and when that is touched, I want to have say 2000 of a different sprite generate from the center position and like a particle system, shoot off in all directions.
First off, I tried coding implementing the velocity code (written in Objective-c) over to Cocos2d and that didn't work. -code-
-(void)ccTouchBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
if(CGRectContainsPoint([[self getChildByTag:1] boundingBox], location))
{
for( int i = 0; i < 100; i++)
{
CCSprite *ballGuySprite = [CCSprite spriteWithFile:#"ball.png"];
[self addChild:ballGuySprite z:7];
ballGuySprite.position = ccp(((s.width + i *10) /2), (s.height + i *10) /2);
}
}
}
What that does is when I touch the first sprite, 100 of the other sprites are on top of each other leading to the top right corner.
The velocity code that I used when as followed and when I try to apply it to the sprite nothing happens. - Velocity code -
-(void) checkCollisionWithScreenEdges
{
if(ballGuysRect.origin.x <= 0)
{
ballVelocity.x = abs(ballVelocity.x);
}
if(ballGuysRect.origin.x >= VIEW_WIDTH - GUY_SIZE)
{
ballVelocity.x = -1 * abs(ballVelocity.x);
}
if(ballGuysRect.origin.y <= 0)
{
ballVelocity.y = abs(ballVelocity.y);
}
if(ballGuysRect.origin.y >= VIEW_HEIGHT - GUY_SIZE)
{
ballVelocity.y = -1 * abs(ballVelocity.y);
}
}
-(void) updateModelWithTime:(CFTimeInterval)timestamp
{
if(lastTime == 0.0)
{
lastTime = timestamp;
}
else
{
timeDelta = timestamp - lastTime;
lastTime = timestamp;
ballGuysRect.origin.x += ballVelocity.x * timeDelta;
ballGuysRect.origin.y += ballVelocity.y * timeDelta;
[self checkCollisionWithScreenEdges];
}
}
When I attach that code to the sprite, nothing happen.
I also tried adding a CCParticleExplosion which did do what I wanted but I still want to add a touch function to each individual sprite that's generated and they tend to just fade away.
So again, I'm still fairly new to this and if anyone could give any advice that would be great.
Thanks for your patients and time to read this.

Answer 1

Your code looks good to me, but you never seem to update the position of your sprites. Somewhere in updateModelWithTime I would expect you to set ballGuySprite.position = ballGuysRect.origin plus half of its height or width, respectively.
Also, I don't see how updateModelWithTime can control 100 different sprites. I see only one instance of ballGuysRect here. You will need a ballGuysRect for each sprite, e.g. an array.
Finally, I'd say that you don't really need ballGuysRect, ballVelocity, and the sprite. Ball could be a subclass of CCSprite, including a velocity vector. Then all you need to do is keep an array of Balls and manage those.

Answer 2

I am not sure what version of cocos2d you are using but a few things look a bit odd.
Your first problem appears to be that you are just using the same sprite over and over again.
Since you want so many different sprites shooting away, I would recommend that you use a CCSpriteBatchNode, as this should simplify things and speed things up.
The following code should help you get that set up and move them offscreen with CCMoveTo:
//in your header file:
CCSpriteBatchNode *batch;
//in your init method
batch = [CCSpriteBatchNode batchNodeWithFile:#"ball.png"];
//Then in your ccTouches method
for( int i = 0; i < 100; i++)
{
CCSprite *ballGuySprite = [CCSprite spriteWithFile:#"ball.png"];
[batch addChild:ballGuySprite z:7 tag:0];
ballGuySprite.position = ccp(where-ever the center image is located);
id actionMove = [CCMoveTo actionWithDuration:actualDuration
position:ccp(random off screen location)];
[ballGuySprite runAction:actionMove];
}
Also usually your update method looks something like the following:
-(void)update:(ccTime)delta{
//check for sprites that have moved off screen and disable them.
}
Hope this helps.