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View Full Version : Choosing between AGP and VRAM for texture



hophop
04-17-2002, 12:08 AM
Hello, i'm not used to choose where i must store my textures. When i stored them i don't exactly know where they are and if it is the best location (AGP memory, video memory ?), I think that the default location is VRAM, but i(m not sure.

So my questions are :

1- Is the location where i must store my texture depending on the image/color/pixel formats ?
2- Is it depending on the size of the texture
(I think it is, but just to make sure...)
3- from what i know about AGP memory allocation, the functions used are 3D Card vendor-specific (one for NVIDIA, an other for ATI, etc...) is there a way to allocate without knowing the vendor of the card ?
4- how much the storing location affects the performances.

sorry for my english, an for such a long question ! ;P

regards

hophop
04-17-2002, 12:09 PM
hello ?

is it such a stupid question ?
if it is please tell me... so that I don't ask again ;-)

it's an important subject I think.

regards

martin_marinov
04-17-2002, 01:01 PM
Hi
your question in not stupid, but it can not be answered easy. At least it is very implementation dependent - the driver chooses where to store them. It depends of the video card memory size, choosed display mode - bbp, resolution, depth buffer and so on. For example bigger screenresolution leaves less memory free, so it is more probably that some textures can not be stored in VRAM. Also it depends on the textures size and so on.
Driver decides...
Also I'm not a specialist in textures, but I don't know an extension which to hints/specify where to store the texture. However there is an extension for texture compression, which may help ...
There is a such thing for the geometry(Nvidia VAR), but I dont know for the textures.

Sorry for the long and uninformational answer, but that's all I can offer on the topic... http://www.opengl.org/discussion_boards/ubb/smile.gif
By the way, why you choose the _linux_ forum...(just asking, I have nothing against it... http://www.opengl.org/discussion_boards/ubb/smile.gif)

Regards
Martin

hophop
04-17-2002, 01:11 PM
Because i'm coding under Linux most of the time.
Thanks for the effort. :-)
It gives me some directions.
I knew about the VAR system and I thought things were the same with textures.

in deed, it would be a good idea to post my question on the Advanced forum... ;-D

Lev
04-18-2002, 06:33 AM
You have absolutely no influence on where the textures are stored (except texture priorities, but they are kind of useless)

Most implementations store texture in the video memory.

-Lev