cocos2d for iPhone

A fast, easy to use, free, and community supported 2D game engine

1. 

   moakesy
   Member

   Hey guys,

   I've been using Cocos2D for a while now, plodding along doing things in my own way. I'm coming to the point now where I want to make better games and want to make sure the methods I use are the correct etc.

   First of all bullets. If I have say a side scrolling shooter game where the player controls a ship that can shoot bullets, the way I have done this in the past is created 10 bullet sprites when the layer starts and just keep repositioning them everytime they go off screen, putting them in a queue ready to be fired again. Is this the most memory efficient way of doing things or should I be creating a new sprite each time and kill it afterwards? If so how would I do that?

   Secondly, I'm just getting to grips with using AtlasSprites. One concern I am having with them is knowing when to create them. With sprites in the past I have initialized them in the header file and allocated them when the layer starts, this is because there are a few different functions that will use the sprite, such my collision detections etc. Is it OK to do this with AtlasSprites or should I be doing something different.

   Thanks a lot guys, the forums have been a huge huge help with my game dev, so thanks.

   Moakesy

   Posted 2 years ago #
2. 

   Steve Oldmeadow
   Administrator

   For your bullets I would recommend setting their visibility to NO. The first thing a CocosNode's visit method does is check for visibility and if the node is not visible it bails out so the transform and draw methods are not called. If you position the sprite off screen then the transform and draw methods will be called and an attempt will be made to draw the sprite even though it is off screen.

   I don't really understand what you mean by you initialized your sprites in the header? Maybe you mean you declared them there and then alloc and init them in the Layer init? If so that approach should work fine for AtlasSprites too.

   Posted 2 years ago #
3. 

   moakesy
   Member

   Thats exactly what I mean Steve, thanks a lot for your help. Once again these forums have served me well.

   Posted 2 years ago #
4. 

   zombie
   Member

   For bullets I would use a particle system. 1000 bullets and no performace impact.

   edit: ok collision handling will have an impact. But should be fine for a larger number of bullets. You would have to add the collision hadling somewhere in the step function of the particle system I would guess.

   Posted 2 years ago #
5. 

   natanavra
   Member

   @zombie you could attach the particle system to a cpBody... I'm doing it in my game, looks amazing! way better than those static annoying sprites...

   Posted 2 years ago #
6. 

   jd
   Member

   If you set visibility = NO, chipmunk will still register collisions though right?

   Posted 2 years ago #
7. 

   zombie
   Member

   @natanavra: Sounds interesting, but why are you doing this? Are you using the particle system only for fast drawing of point sprites.

   @jd: If not handled by yourself, Cocos2d properties do not effect chipmunk.

   - zombie

   Posted 2 years ago #
8. 

   JungleBunny
   Member

   Thanks Steve

   Your contribution to this forum has helped me a lot. I was having a reduction in frame rate and my game was down around 40fps. after I turned off the visibility of off screen objects my fps went back to 60. Awesome

   Posted 2 years ago #

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