Kaj

2,740 reputation

714

bio	website
	location
	age
visits	member for	2 years, 10 months
	seen	Aug 25 '11 at 14:51
stats	profile views	248

	2,740 reputation	bio	website		visits	member for	2 years, 10 months
714 badges		location			seen	Aug 25 '11 at 14:51

summary answers questions tags badges favorites bounties reputation activity

307 Actions

suggestions reviews revisions comments badges posts accepts all

Jan 4	awarded	Popular Question
Oct 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.
Sep 14	comment	Efficient way of drawing outlines around sprites Yes, this is what I wanted to suggest as well. Render the masked sprite 1 pixel to the left, right, top and bottom of the original sprite, under the existing sprite. Many games used this method to outline rendered text, or with only 2 of the 4 positions to create a drop shadow.
Sep 13	comment	What are good, simple action games/action RPGs to emulate? There's 'Adventure' for the Atari 2600, which might be even easier, although I am not sure how satisfying it would be. I fondly remember playing it :o)
Sep 13	comment	What is the purpose of the stencil buffer ? More precisely, what is a stencil in computer graphics? In other words, it basically has the same function as a real life stencil, masking out parts when applying ink.
Sep 13	comment	When learning, nothing is better than practice If you have a MAC then the same applies, just take any XCode sample and start modifying it. Also, in game dev, the right attitude is, "I'll crack it", and the 'meh I don't know.....' is where many people get stranded. I think you're kinda hitting this bump as we speak and I advise you to put doubts aside and just do something, anything is better than being indecisive. Even using the wrong engine will teach you something.