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View Full Version : new drivers: early z-test and texture borders



michagl
03-07-2005, 09:12 AM
first let me say that if people don't like lazy questions like this polluting the board, just say so and i won't ask in the future.

i've basicly recently installed some new drivers, and i'm just curious about this system option call 'early z-test'... were in the pipeline is early and late for that matter? pre/post shader?

also, when i installed these new drivers, my texture borders went funny. it looks like a decision has been made to heavilly inforce texture bordering. in the past a filtered texture with no border would just fill the same colour as the edge pixel. now it uses the 'border colour' were bordered is not specified. i haven't come up with a good solution. for most of my textures it isn't a problem. for the ones were it is, i just hacked them to be repeated textures, so that the filter works agains the opposite side pixels, which just happen to generally be pretty close in my case... but this is definately just a temporary solution.

are there extensions to enable the old style non-bordered filtering? because i really don't want to have go back and start bordering textures... or really even always use bordered textures for that matter.

just for the record, i'm using nvidia drivers, and i figure the old drivers were nvidia as well.

sincerely,

michael

Stephen_H
03-07-2005, 09:29 AM
i've basicly recently installed some new drivers, and i'm just curious about this system option call 'early z-test'... were in the pipeline is early and late for that matter? pre/post shader? The early Z test is not official GL, but something the gfx hardware vendors have added as an optimization. From what Nvidia/ATI have chosen to reveal about this, the early z test occurs pre-fragment shader unless the fragment modifies depth, in which case it is disabled.

ZbuffeR
03-07-2005, 01:07 PM
The border stuff... Maybe related to this control panel option :
"Enable conformant OpenGL texture clamp behavior.Enabling this option activates conformant OpenGL texture clamping. "Texture clamping" refers to how texture coordinates are handled when they fall outside the body of the texture. Texture coordinates can be clamped to the edge or within the image."
Try to switch it on or off.
Your programs should work properly with the conformant behavior though.
Use GL_CLAMP_TO_EDGE and not GL_CLAMP.

EDIT: when you speak about drivers, please give the version used in "old" and "new" cases.
"Lastest driver" does not mean much, especially with unofficial/developper versions.

michagl
03-07-2005, 03:09 PM
that seems to have done the trick. so i take it 0.0 and or 1.0 are considered outside the body of the texture then?

thanks a lot btw!

sincerely,

michael

edit: never mind, i take it without CLAMP_TO_EDGE outside the ajacent pixel is just considered to be off the image. thanks again btw! -michael

zed
03-07-2005, 05:45 PM
system option call 'early z-test'... were in the pipeline is early and late for that matter? pre/post shader?exactly where does it say this under "global driver" 70.90 doesnt show anything there

also as others have mentioned for years nvidia treated GL_CLAMP as GL_CLAMP_TO_EDGE (incorrect behaviour) thus everyone got used to writing GL_CLAMP insuring certain apps went up a certain creek

M/\dm/\n
03-07-2005, 11:59 PM
I think it wasn't that simple with early-z. Blending must be off too, and wastn't there something about stenciling too???