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View Full Version : Maximal recommended texture size?



anuchka
08-03-2008, 01:45 AM
Hi

From your experience - what size (in MB ) of texture would be maximal for rendering terrain?

My original texture map is satellite image in SID format.
I converted it to JPG in order to load it as texture map and I got about 350 MB large JPG.I'm thinking to load all the JPG, then to cut and keep in memory only FOV part of image and load it as texture.Is this good solution? Are there any other options?

Thanks

zeoverlord
08-03-2008, 02:32 AM
You can use whatever size you want if you use some kind of megatexturing or texture paging, id software uses up to 20GB of texture data for each level in rage.
But do use a non destructive texture format like TGA or something.

Zengar
08-03-2008, 09:14 AM
Each card has it's limitation on a maximal texture size, it can be queried (my network is very laggy as I am at a conference in eastern europe, so I can't look up the enums). I think the limits are about 4kx4k texels for modern cards. But as zeoverlord says, you can make this size virtualy unlimited if you use some sort of dynamic caching like megatexturing or clipmaps (are they called clipmaps? please correct me if its something different).

anuchka
08-03-2008, 11:29 PM
Thanks to both of you.
I looked at both - megatexturing(as Zengar suggested seems like it's actually clipmapping) and texture paging which is linked to mipmapping. I'll go with texture paging since it's implementation is well explained while about megatexturing I didn't find much clear technical details.

P.S. Zengar - where can I see the enums you mentioned?
Did you mean GL_MAX_TEXTURE_SIZE?
If I use glGetIntegerv(GL_MAX_TEXTURE_SIZE, &texSize);
in terms of what the size is returned (bytes ?)?

dletozeun
08-04-2008, 12:23 AM
The texture size the texture side size in pixels. You can find it in the gl header or using a tool like opengl extension viewer (http://www.realtech-vr.com/glview/) that works only on windows, but gives many information about what is supported on your current configuration about opengl.

anuchka
08-04-2008, 12:33 AM
Thanks ,but I have to do it in runtime ...

dletozeun
08-04-2008, 01:59 AM
So glGetIntegerv will be perfect.