On Tue, 2018-11-20 at 10:08 +0100, Erik Faye-Lund wrote: > On Tue, 2018-11-20 at 01:21 -0500, Marek Olšák wrote: > > I'd like to keep ARB_texture_float enabled on drivers that don't > > support linear interpolation. ARB_texture_float is required by DX9, > > which doesn't require linear interpolation. > > This logic sounds circular. Since ARB_texture_float *does* require > linear interpolation, are you sure DX9 requires ARB_texture_float? > How > would DirectX even require a GL extension? > > Are you talking about Gallium Nine or something like that? If so, it > should probably require some combination of OES_texture_half_float > and > OES_texture_float instead, no? > > FWIW, I can't find any refreences to ARB_texture_float in Gallium > Nine... > > What exactly are you talking about? >
OK, I think perhaps I've figured it out; you're probably referring to Wine's emulation. And the problem is that OES_texture_half_float / OES_texture_float are only available (outside of mesa) from OpenGL ES. A state-tracker has enough information, but not an application. It looks a bit to me like there's simply no OpenGL extension that matches the DX9 behavior. I find this surprising, because ATI had a bunch of floating-point texturing demos for Radeon 9600 etc. Even ATI_texture_float doesn't seem to diallow filtering either... This also brings up another problem. We expose ATI_texture_float if ARB_texture_float is supported. But this seems like a bad choice; ATI_texture_float defines a *different* 16-bit floating point format than ARB_texture_float. From the ATI_texture_float spec: "There are no NAN or infinity values for 16 bit floating-point." However, the ARB_texture_float-extension defines both NAN and infinity values... Especially NAN-propagation has been problematic with cross-API emulation in the past. Since the ATI_texture_float and ARB_texture_float enums have the same values, I doubt there's little to do here apart from either accepting this problem, or stop advertising ATI_texture_float (which probably leads to problems with old applications that doesn't care about NAN / infinity)... But perhaps we should at least document problems like these somewhere? _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-dev
