A Problem With ATI's Drivers In DOOM 3?

KingFish

Recently some information claiming ATI's drivers exhibited some odd behavior in DOOM 3 and that the company might be compromising image quality for performance. What's more, this problem seemed to be specific to DOOM 3, raising the possibility that ATI was guilty of engaging in an application-specific optimization—a practice the firm has forsworn.

The problem with ATI's drivers in DOOM 3 has to do with texture filtering, and it is more visible on some textures than others. Textures with high-contrast patterns on them, like the metal grates in the game's Mars base, tend to show the problem most vividly. There is a clearly visible transition between mip map levels, as if trilinear filtering were not happening as it should. Here's an example. This is in DOOM 3's High Quality mode, where 8X anisotropic filtering and trilinear filtering are both supposed to be active. However, as you can see, there's a mip map transition line running across the middle of the grate on the floor in our example screenshot. This problem is visible throughout the game whenever a similar texture is used on the floor. The screenshot shows the problem, but it's more obvious in motion. Once you've noticed it, it's rather distracting, like the transition lines were with bilinear-only filtering on Voodoo cards back in the Quake 2 days. Having those things track on the floor out in front of me as I moved was annoying.

Source: Tech Report

csimon

Yeah I just read that ...they say the problem should be sorted out in a newer release of the 4.9 bet cats.

GHoosdum

I'm more willing to believe that since Doom is the only game that even uses some of the advanced features of these graphics cards, that it is because of that, rather than application-specific optimization.

//edit: Reading through, it would appear that it is merely a driver-bug, so ATI has not been doing anything underhanded with Doom3 performance:

So all of our tests and our counter-mojo line up to support ATI's explanation for the DOOM 3 image quality problems and performance anomalies we've seen. ATI does have a bug in its Catalyst 4.8 and 4.9 beta drivers currently available to the public, and that bug affects image quality in DOOM 3. However, ATI is not trading off image quality for performance; this is an honest-to-goodness software glitch, and nothing more.