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seen Aug 25 '11 at 14:51

Jul
22
awarded  Yearling
Feb
19
awarded  Nice Answer
Nov
6
awarded  Nice Question
Jul
22
awarded  Yearling
Jan
4
awarded  Popular Question
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3
awarded  Enlightened
Oct
3
awarded  Nice Answer
Jul
22
awarded  Yearling
Jul
12
awarded  Nice Answer
Feb
17
awarded  Good Answer
Aug
20
comment Data structures in older games
MeDataBase - you copy the last active object to the slot that was occupied by a coin that became inactive (ie, if you have 10 coins, coin 5 becomes inactive, copy coin 10 to slot 5 and decrease numactive coins) you can just iterate up to numCoins and update all those elements. You wouldn't need the 'if'. Of course this only works if inactive coins don't need to maintain state and if order of update is not important (the state could be maintained if the array stores pointers to coins and not actual coins, but then you get scattered cache behaviour which is likely worse than the 'if')
Aug
20
awarded  Scholar
Aug
20
accepted Quaternions and rotation around world axis
Aug
20
comment Quaternions and rotation around world axis
Ah, now it makes sense. I didn't know (ouch, that woulda been in FAQs) that quaternion multiplication was associative, so indeed the rotation and it's inverse cancel eachother out, giving me the insight I needed, one has the local rotation on the right and one on the left which basically say 'apply rotation in parent space' or 'apply rotation in local space'....no different than matrices. Pretty elementary once you see it! Thanks!
Aug
20
awarded  Student
Aug
20
asked Quaternions and rotation around world axis
Jul
23
awarded  Yearling
Feb
24
awarded  Good Answer
Sep
16
comment Why do we use physics engines for collision testing or raycasting?
Hmmm, from his/her question I assumed he was asking 'if I only need raycasting or coldet', say for object picking or some sort of collection game, or heck a shooter where every collision if fatal. In that case no physics are needed at all, although in many instances, if you can't get away with sphere/sphere I'd opt to abuse a physics engine for that anyhow.
Sep
15
comment Why do we use physics engines for collision testing or raycasting?
This is a bold statement, and not true. If you need raycasting and collision testing you need a collision detection engine. If you want the to simulate rigid bodies that respond to collisions you need a physics engine. The only reason people use physics engines for collision testing is that (a)you can have it resolve collisions for you to prevent penetrations and (b) since collision detection is such a huge and important part of any physics simulation the implementation is likely more optimal than something you could whip up yourself.