Just realized that the texture format table in question is in the TGSI doc page, at the bottom. It really should have its own page.
~ C. On Wed, Sep 29, 2010 at 11:36 PM, Jose Fonseca <jfons...@vmware.com> wrote: > Sorry, I've should have drunk my morning coffee before replying. > > You're refferring to writing and not reading... > > Anyway, my comment for u_format still stands. > > But back to your example, it works because out[0] has position semantic. When > writing to depth textures, their are bound as depth stencil buffer. Not in > the color buffer. And whatever gets written to the z channel of the output > position register will be used as the depth value. > > Jose > > ________________________________________ > From: mesa-dev-bounces+jfonseca=vmware....@lists.freedesktop.org > [mesa-dev-bounces+jfonseca=vmware....@lists.freedesktop.org] On Behalf Of > Jose Fonseca [jfons...@vmware.com] > Sent: Thursday, September 30, 2010 7:28 > To: Dave Airlie; mesa-dev@lists.freedesktop.org > Subject: Re: [Mesa-dev] depth writing and missing something > > There are two things to consider: u_format.csv description for depth stencils > is a bit special for practical reasons, and pipe_sampler_view swizzles. > > Several functions in u_format_xxx.c need to be able to read/write stencil, > and this is why u_format.csv describes depth stencil's swizzles as producing > Z S x x. But the stencil channel will never be present when the texture is > read as RGBA tuple. > > Sampling from a depthstencil texture should always produce Z Z Z 1 or Z 0 0 > 1, even before any sampler swizzles are applied. I think Brian documented > this somewhere in gallium/docs/ but I can't find it now. > > At any rate, provided the first channel has z, then the state tracker will > specify how he wants the other channels to be filled in the > pipe_sampler_view' swizzles. > > Effectively, the gallium spec could say that sampling from depth textures > should match (Z x x x). > > This is my understanding of the current state. We could polish this more a > little. > > Jose > > ________________________________________ > From: mesa-dev-bounces+jfonseca=vmware....@lists.freedesktop.org > [mesa-dev-bounces+jfonseca=vmware....@lists.freedesktop.org] On Behalf Of > Dave Airlie [airl...@gmail.com] > Sent: Thursday, September 30, 2010 2:34 > To: mesa-dev@lists.freedesktop.org > Subject: [Mesa-dev] depth writing and missing something > > So I've been playing with stencil writing on r600, and it lead me to > examine the depth writing. > > So at the moment in gallium if we are writing to depth via DrawPixels, > we construct a fragment program that samples from a texture. > > TEX OUT[0].z, IN[1], SAMP[0], 2D > > Now from what I can see the format we pick to sample from is > Z24_UNORM_S8_USCALED, which from the u_format.csv file seems to say it > will put the results into X and Y components. Now if we sample from > the X and Y components and the texture dest writemask is Z, I can't > see how any value arrives in the right place. It seems to work but I'm > a bit lost where the magic is. > > I'd have expected there to be swizzles in the sampler but I can't see > them being set to anything special either. > > Dave. > _______________________________________________ > mesa-dev mailing list > mesa-dev@lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/mesa-dev > _______________________________________________ > mesa-dev mailing list > mesa-dev@lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/mesa-dev > _______________________________________________ > mesa-dev mailing list > mesa-dev@lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/mesa-dev > -- When the facts change, I change my mind. What do you do, sir? ~ Keynes Corbin Simpson <mostawesomed...@gmail.com> _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
