geforce 2 mx400 32bit X resolution unatainable?

kraylus · l33t Joined: 07 Jun 2002 Posts: 648 Location: ft.worth.tx

NOTE TO Moderator: perhaps this should go in the desktop forum, but i figured it was more of a hardware compatibility issue than a desktop or gui issue.

i know in win2k my geforce2 mx400 can do 16, 24, and 32 bit. it can also do so at 1024x768 (probably a bit higher, but i havent tried).

in linux, it's either 16 or 24 bit. it won't do 32 bit. i know, however that it CAN do 32bit in linux because i read an article where an editor had theirs set to some insane res (using the same exact hardware) on 32bit colour.

so my question is... how do i use 32bit? when i set my xf86conf file to 32 it complains that it's not supported. is it a drawback of the driver? what's the deal?

ryan
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I used gentoo BEFORE it was cool.

drakonite · l33t Joined: 02 Nov 2002 Posts: 768 Location: Lincoln, NE

Do you know what 32bit is? It's nothing special. The color is no different than 24bit.

The reason 32bit exists is that sometimes it is faster to work with 32bits of information than just 24bits. It gets rid of a couple of operations so there is a slight speed increase, but it wastes more memory.

FYI, the speed increase is small. It might mean a few fps more in a 32bit optimized game, otherwise I doubt you'll ever notice a difference.

kraylus · l33t Joined: 07 Jun 2002 Posts: 648 Location: ft.worth.tx

the problem with that is that it's not fixed. sure, in alot of things i can't really tell the difference between 32 and 24 bit but on some things i can. like gradients for example. it's always easy to tell the difference when looking at gradients.

reguardless, even if i *can't* tell the difference, there's something not working right. i dunno know about you, but when something doesn't work right, it bothers me

does anyone know what could be the matter?

ryan
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I used gentoo BEFORE it was cool.

drakonite · l33t Joined: 02 Nov 2002 Posts: 768 Location: Lincoln, NE

CasimirEffect · Posted: Sun Jan 19, 2003 12:55 am Post subject:

Here's a quick lesson for both of you.
Colors on a computer screen are made up of various combinations of red, green, and blue (RGB). The bit depth specifies how many different levels of each color there are. 24bit color depth gives you 8bits per color channel (8*3=24). This gives you ~16.7 million total colors to choose from. 32bit color adds another 8bit channel to the mix. This is called alpha and is used to for transparency. As you can see the number of colors 32bits are able to display is exactly the same as with 24bits. The only difference is the alpha channel, which is not directly supported by X-windows. That is why 32bit color is not an option in your XF86Config file.
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