[Mesa-dev] [PATCH 1/2] Revert "i965: Implement guardband clipping on Sandybridge."

[Oliver McFadden]

On Tue, Oct 02, 2012 at 01:20:42PM +0200, Andreas Boll wrote:
> 2012/10/2 Oliver McFadden <oliver.mcfadden at linux.intel.com>:
> > This reverts commit 85cd30406ff8414bc6ac6de1064d059a4c564160.
> >
> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=55523
> 
> You should probably add the following note to both patches:
> 
> NOTE: This is a candidate for the 9.0 branch.

Done, thanks!

> 
> > Signed-off-by: Oliver McFadden <oliver.mcfadden at linux.intel.com>
> > CC: Kenneth Graunke <kenneth at whitecape.org>
> > ---
> >  src/mesa/drivers/dri/i965/gen6_clip_state.c     |    1 -
> >  src/mesa/drivers/dri/i965/gen6_viewport_state.c |   24 +++++++++-------------
> >  2 files changed, 10 insertions(+), 15 deletions(-)
> >
> > diff --git a/src/mesa/drivers/dri/i965/gen6_clip_state.c b/src/mesa/drivers/dri/i965/gen6_clip_state.c
> > index c34d87e..fc8a2d9 100644
> > --- a/src/mesa/drivers/dri/i965/gen6_clip_state.c
> > +++ b/src/mesa/drivers/dri/i965/gen6_clip_state.c
> > @@ -74,7 +74,6 @@ upload_clip_state(struct brw_context *brw)
> >              GEN6_CLIP_MODE_NORMAL |
> >               nonperspective_barycentric_enable_flag |
> >              GEN6_CLIP_XY_TEST |
> > -            GEN6_CLIP_GB_TEST |
> >              userclip << GEN6_USER_CLIP_CLIP_DISTANCES_SHIFT |
> >              depth_clamp |
> >              provoking);
> > diff --git a/src/mesa/drivers/dri/i965/gen6_viewport_state.c b/src/mesa/drivers/dri/i965/gen6_viewport_state.c
> > index 95243f0..f787ac7 100644
> > --- a/src/mesa/drivers/dri/i965/gen6_viewport_state.c
> > +++ b/src/mesa/drivers/dri/i965/gen6_viewport_state.c
> > @@ -33,35 +33,31 @@
> >
> >  /* The clip VP defines the guardband region where expensive clipping is skipped
> >   * and fragments are allowed to be generated and clipped out cheaply by the SF.
> > + *
> > + * By setting it to NDC bounds of [-1,1], we don't do GB clipping.  It's
> > + * supposed to cause seams to become visible in apps due to shared edges taking
> > + * different clip/no clip paths depending on whether the rest of the prim ends
> > + * up in the guardband or not.
> >   */
> >  static void
> >  gen6_upload_clip_vp(struct brw_context *brw)
> >  {
> > -   struct gl_context *ctx = &brw->intel.ctx;
> >     struct brw_clipper_viewport *vp;
> >
> >     vp = brw_state_batch(brw, AUB_TRACE_CLIP_VP_STATE,
> >                         sizeof(*vp), 32, &brw->clip.vp_offset);
> >
> > -   /* According to the Sandybridge PRM, Volume 2, Part 1, Section 6.3.8
> > -    * "Vertex X,Y Clamping and Quantization", the screen-aligned 2D
> > -    * bounding-box of an object must not exceed 16K pixels in either X or Y.
> > -    */
> > -   const float maximum_post_clamp_delta = 16384;
> > -   float gbx = maximum_post_clamp_delta / (float) ctx->Viewport.Width;
> > -   float gby = maximum_post_clamp_delta / (float) ctx->Viewport.Height;
> > -
> > -   vp->xmin = -gbx;
> > -   vp->xmax = gbx;
> > -   vp->ymin = -gby;
> > -   vp->ymax = gby;
> > +   vp->xmin = -1.0;
> > +   vp->xmax = 1.0;
> > +   vp->ymin = -1.0;
> > +   vp->ymax = 1.0;
> >
> >     brw->state.dirty.cache |= CACHE_NEW_CLIP_VP;
> >  }
> >
> >  const struct brw_tracked_state gen6_clip_vp = {
> >     .dirty = {
> > -      .mesa = _NEW_VIEWPORT,
> > +      .mesa = 0,
> >        .brw = BRW_NEW_BATCH,
> >        .cache = 0,
> >     },
> > --
> > 1.7.8.6
> >
> > _______________________________________________
> > mesa-dev mailing list
> > mesa-dev at lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/mesa-dev

-- 
Oliver McFadden.