3D Graphics: possible optimization?

sandruzzo · 24 February 2016, 09:06

Hi,

I'was thinking about how we handle 3d polygon. We get used to use polygon that range from + to - with differente degree. Like x = -50.0 y = -10.0 and on.

But if we map our world and object from -1 to +1 and scale them after all trasformation, maybe we can have less bit for fixed math and have a lot of precalcuated value since we have fixed range.

Maybe we'll have less "bigger" world, but a lot more velocity, since we can put on table a lot of calc, like x*cos, y*sin and on.

What do you think?

Cylon · 24 February 2016, 19:34

This sounds like the usual 'normalization' already done in 3d engines?

sandruzzo · 26 February 2016, 07:40

Quote:

Originally Posted by Cylon

This sounds like the usual 'normalization' already done in 3d engines?

never seen applicated on an 3d engine, and I've a good experience about it. Maybe we this simple trick, we can use only 16 bit to describe objects and world so we can use a lot of table to speed up the engine.

Samurai_Crow · 26 February 2016, 08:01

16 bit coordinates make good fixed point references since doing a word to word unsigned multiply will leave a scaled screen coordinate in the upper word of the result. Fixed point has not been commonly used for 3d since before Quake 1, though.

24 February 2016, 09:06	#1
sandruzzo Registered User Join Date: Feb 2011 Location: Italy/Rome Posts: 2,281	3D Graphics: possible optimization? Hi, I'was thinking about how we handle 3d polygon. We get used to use polygon that range from + to - with differente degree. Like x = -50.0 y = -10.0 and on. But if we map our world and object from -1 to +1 and scale them after all trasformation, maybe we can have less bit for fixed math and have a lot of precalcuated value since we have fixed range. Maybe we'll have less "bigger" world, but a lot more velocity, since we can put on table a lot of calc, like xcos, ysin and on. What do you think?

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24 February 2016, 19:34	#2
Cylon Registered User Join Date: Oct 2014 Location: Europe Posts: 470	This sounds like the usual 'normalization' already done in 3d engines?

26 February 2016, 08:01	#4
Samurai_Crow Total Chaos forever! Join Date: Aug 2007 Location: Waterville, MN, USA Age: 49 Posts: 2,186	16 bit coordinates make good fixed point references since doing a word to word unsigned multiply will leave a scaled screen coordinate in the upper word of the result. Fixed point has not been commonly used for 3d since before Quake 1, though.

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