From Zanshins' GlQuake Dojo comes an explanation of why 32 bit color may run so fast, it looks like trilinear filtering is not "free". If this is true then ATI has some serious issues to deal with
planetquake.com
Eric
Pulled from Zanshin's article:
"I finally got my hands on a Rage 128 through a friend.. I'd been following the comdex reports closely, and then reading the other web p1mp's breakdowns on the card with interest.. I mean hell, with hardware DVD alone, combined with TNT-like peformance and image quality.. It might be worth my while to bug someone at ATI to get me one of these bad boys for personal use. But then I got an email from a friend of mine who had been at Comdex
He had been able to see the demo of Quake 2 running on the Rage 128, and it did indeed seem to demonstrate TNT-like in speed. Image quality, he said, wasn't QUITE as good as TNT.. It was somewhere between V2 and TNT. There were noticeable filtering artifacts. But then when he got a minute at the console of the demo machine by means of stealth and flattery, he noticed something odd.. gl_texturemode was set to gl_linear_mipmap_nearest. Hrm.. That's not trilinear. No wonder the artifacts. When the ATI rep saw him messing with the console, he was immediately removed from the booth.
Well, I got a chance to play with this bad boy via another friend this weekend. I dropped it into my PII-450, and lo and behold, it actually didn't suck. 2d image quality was good, (Anand, I don't know WHAT you've been smoking, but my TNT and the ATI cards look FINE at 1600x1200 on a Viewsonic P815. Better than my old Millenium II even.) and flames didn't shoot out of my computer from demonic forces imbued into the chip by ATI.
What I DID find out though, was that my friend was dead-on.. Looking back through ATI's charts and the press releases, I noticed they very carefully when comparing to TNT and voodoo2 avoid the subject of single-pass trilinear filtering. See, when you turn trilinear on via gl_texturemode GL_LINEAR_MIPMAP_LINEAR in Quake II, suddenly you don't peform NEARLY as well as TNT. In most cases, a 30% cut in performance across the board. So, apparently unlike TNT, Trilinear ain't "free". |
