Am 25.06.2011 00:22, schrieb Vadim Girlin: > On 06/24/2011 11:38 PM, Jerome Glisse wrote: >> On Fri, Jun 24, 2011 at 12:29 PM, Vadim Girlin<vadimgir...@gmail.com> >> wrote: >>> Fixes https://bugs.freedesktop.org/show_bug.cgi?id=38440 >>> >>> Signed-off-by: Vadim Girlin<vadimgir...@gmail.com> >> >> As discussed previously, there is better to handle this. I think best >> solution is to always add the instruction and to conditionally execute >> them thanks to the boolean constant. If this reveal to have a too big >> impact on shader, other solution i see is adding a cf block with those >> instructions and to enable or disable that block (cf_nop) and reupload >> shader that would avoid a rebuild. > > I know its not optimal to do a full rebuild, but rebuild is needed only > when the application will use the same shader in different clamping > states. It won't be a problem if the application doesn't change clamping > state or if it changes the state but uses each shader in one state only. > So assuming that typical app will not use one shader in both states, it > shouldn't be a problem. Is this assumption wrong? I'm not really sure > because I have no much experience in this. But if it's wrong then it's > probably better for performance to build and cache both versions. I tend to think you're right apps probably don't want to use the same shader both with and without clamping.
> > Also it seems last write to color output components is often done with > op2 instructions, so there is another optimization possible - to find > last op2 writes and set clamp bit instead of using additional > instructions. Probably it's not very hard to implement with this patch. > AFAICS it will be impossible with other suggested solutions. > Such optimization should probably be part of a more generic optimization pass. Roland _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
