Best practice for a mass of Bullets/Enemies. SPImage or SPSprite

seriousGeorge

What's the best practice to add (masses) of Bullets and enemies? At the moment I set up my Bullet- and enemyfactories to spit their childrens out as SPImages. So far I have no problems performance-, memory- and collision-detection-wise with about 100 Displayobjects.

I was just wondering if I'm doing that correctly. My Player has animations - so I'm using RCAnimatedSprite here.

What would be the benefit of SPPrite other than assigning animations and grouping things together? Would it reduce draw calls? And I'm using a spritesheet of course.

Forgive me if that's a stupid question. But I'm still in the transitioning from AS3 (I used ND2D there) 😉

Daniel

Here's an article that might help:

http://wiki.sparrow-framework.org/manual/performance_optimization

My recommendation: use the "SPQuadBatch" class for the bullets. I suppose you've got masses of bullets that don't need to do any collision detection or other fancy stuff. That class will render them as fast as possible! (The particle system uses that class, as well!)

For the enemies, a conventional display object is probably better, because it gives you more control. That can be a sprite or your RCAnimatedSprite.

I hope that helps!! =)

seriousGeorge

Hi Daniel,

sorry to bring this up again. But actually I do need collision detection for each and every bullet around... it's kind of a bullet hell shooter (yawn again 😉

Right now I went for subclassing SPImage which seems fine. Tough when having around 100-200 bullets and also some enemies and seeker missiles things will slow down a bit. But thats just my hardcore test-scenario to see where the limits are.

Daniel

It's probably not the rendering of the object that slows things down, but the collision detection code. These things tend to grow exponentially.

Analyze your code in instruments to find out where the time is spent. If it's really the collision detection, maybe there's some way of optimizing the code.

seriousGeorge

Yes, thats one factor. I did it like I saw it in one of your tutorials... distacne & radius first, bounding box second. As everything is happening very quick I went for distance & radius only. Seems to work fine and reduced lag.

I have some sort of logic- and therefore performance error left. I'm currently checking for bullets every frame for different enemy-categories and the player. That's crap 😉 I'm about now to move that stuff in one global function.

And besides... I was very temped to drop Sparrow for SpriteKit (as my job will demand anyway somewhere in the future) - but - I just like sparrow and the community and you can't compare that to the - somewhat - anonymous apple boards.

So, if I haven't done that in the past, here's my bow to you. You're somewhat like a Grant-Skinner for gamecoding in the obj-c world and I'm very very thankful for your work 🙂

Daniel

I don't know if I mentioned it in the blog article: when you make the distance-check, you can avoid the square root by checking comparing the *squared* distance. That does the trick just as well, and you avoid the somewhat expensive "sqrt" call.

Thanks for this HUGE compliment! That means a lot to me -- I really appreciate it. 😃

I'd be sorry to see you go to SpriteKit, but I can understand the reasoning, of course. If you do, I'd be happy about any feedback after you've used it for a while -- what you like better than Sparrow, and what it lacks.