Advice on speeding up collision - GameCreators Forum

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Erick G

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Joined: 2nd Oct 2004

Location: Texas, USA

Posted: 18th Jul 2005 17:53

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Hi all, any advice on this would be awsome.

I have written a little shoot em up demo for the community, but I dont want to release it yet, as the app is dog slow when activating collision.

Below is pseudo code of what I am sure the problem is, i dont know of any other way to do this.

for all active bullets
for all active enemies
check collision (dbHitObject(bullet,enemy))
next
next

I call this every frame

so it is understandable why it is so slow.
Can anyone of you guru's point me out to a better solution ?

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Sephnroth

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Joined: 10th Oct 2002

Location: United Kingdom

Posted: 18th Jul 2005 21:24

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One thing I often do is something like that but before hand I check if objects are within a certain distance of anything they would collide against and if not I disable their collision completly to get alot of fps back.

However it is important to do the distance check using a fsqrt (fast square root) function and not the normal sqrt or dbsqrt - both are far too slow.

Theres a fsqrt in my "The DarkSDK Collection" in code snippets - I think.

Also obviously have the fastest collision type set to objects that you can get away with. I would make a big point out of making sure all bullets were set to box collision as they really dont need anymore - the enemies would be spheres generally or in rare cases polygon I guess.

DarkSDK/WinAPI Tutorial

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Erick G

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Joined: 2nd Oct 2004

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Posted: 18th Jul 2005 22:02

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