On Wed, Apr 28, 2010 at 12:09 PM, Roland Scheidegger <srol...@vmware.com> wrote: > On 27.04.2010 18:29, José Fonseca wrote: >> On Tue, 2010-04-27 at 08:59 -0700, Roland Scheidegger wrote: >>> On 27.04.2010 17:32, Roland Scheidegger wrote: >>>> On 27.04.2010 13:13, Dave Airlie wrote: >>>>> Another trying to figure out gallium patch from me, >>>>> >>>>> This is in theory EXT_texture_swizzle support, r300g passes the glean >>>>> test with this now. >>>>> >>>>> Some caveats in the patch (i.e. I'm not sure what exactly is correct >>>>> state tracker behaviour wrt sampler views). >>>> Dave, >>>> >>>> Basically looks good but I have some concerns. First, I think the >>>> extension should not be announced unconditionally but rather based on a >>>> cap bit. There's hw we care about which can't do this (i965, svga) and >>>> it seems unreasonable to expect them to do workarounds just so this >>>> extension can be always exposed. >>>> Also, I think it won't work correctly if the pipe format itself has a >>>> swizzle (which is different to rgba). There are really two swizzles >>>> here, one coming from the extension the other inherited from the format, >>>> and they need to be combined. Either in the driver or the state tracker, >>>> I think it's underspecified right now but I think the swizzle parameter >>>> should express the hardware view, hence the combining should take place >>>> in the state tracker. (Also, for depth textures it should also take the >>>> depth texture mode into account, but that might be out of the scope of >>>> what you're trying to do.) >>>> >>>> Roland >>> Actually right now the swizzle seems to represent only the "GL swizzle", >>> not the format one (looking at the u_sampler_view_default_template). Not >>> sure though if that's really the right design. In this case the driver >>> would need to combine the format and extension swizzle. >> >> I think it is worthwhile to keep the format swizzle orthogonal to the >> sampler view swizzles. It is actually more complex trying to describe >> swizzles in terms of the packed vector, since they not always have >> unambiguous meaning (bitmasks, subsampled formats, compressed textures). >> >> Jose > > ok. Can we still express depth texture mode though in the sampler view > swizzle? I guess it's not unreasonable to let drivers handle combining > the swizzles, if necessary could use some util code (for the normal > formats at least).
The main reason I'm doing EXT_texture_swizzle was to add depth texturing using the sampler view afterwards, I just wanted to add this extension while I was in the area. so hopefully it works after I work this out. Dave. > > Roland > _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
