Re: [mesa PATCH] nv50: handle VP without inputs

[Marcin Slusarz <marcin.slusarz-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

On Sun, May 06, 2012 at 09:05:21PM +0200, Christoph Bumiller wrote:
> On 06.05.2012 20:53, Marcin Slusarz wrote:
> > Fixes 3 piglit tests:
> > general/pos-array
> > shaders/glsl-novertexdata
> > shaders/glsl-vs-point-size
> > and makes shaders/vp-ignore-input not trigger PGRAPH DATA_ERROR
> > ---
> > It's a bit ugly... If there's a way to fix it properly, I'm open to suggestions.
> > ---
> >  src/gallium/drivers/nv50/nv50_program.c |    7 +++++++
> >  1 files changed, 7 insertions(+), 0 deletions(-)
> >
> > diff --git a/src/gallium/drivers/nv50/nv50_program.c b/src/gallium/drivers/nv50/nv50_program.c
> > index 48e8db3..c44f537 100644
> > --- a/src/gallium/drivers/nv50/nv50_program.c
> > +++ b/src/gallium/drivers/nv50/nv50_program.c
> > @@ -53,6 +53,13 @@ nv50_vertprog_assign_slots(struct nv50_ir_prog_info *info)
> >           if (info->in[i].mask & (1 << c))
> >              info->in[i].slot[c] = n++;
> >     }
> > +
> > +   // Corner case: VP has no inputs, but we will still need to submit data to
> > +   // draw it. HW will shout at us and won't draw anything if we don't enable
> > +   // any input, so let's just pretend it's the first one.
> > +   if (info->numInputs == 0)
> > +      prog->vp.attrs[0] |= 0xf;
> > +
> >     prog->in_nr = info->numInputs;
> >  
> >     for (i = 0; i < info->numSysVals; ++i) {
> Ah thank you, I've been wondering how to make the nv50 draw without any
> inputs (on nvc0 it just works even if you don't enable any).
> 
> 2 issues though:
> - please don't use C++ style comments in here (the style guardians would
> sooner or later patch this up)
> - if InstanceID or VertexID are used, enabling any inputs will move them
> to a different position in input space, they always come after all the
> ordinary vertex attributes; see usage of the "unsigned n" in the code
> directly above & below

Thanks. I hacked glsl-vs-point-size test to use gl_VertexID/gl_InstanceID and
it indeed failed. But patch below works in all cases :).

---
From: Marcin Slusarz <marcin.slusarz-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Subject: [PATCH] nv50: handle VP without inputs

Fixes 3 piglit tests:
general/pos-array
shaders/glsl-novertexdata
shaders/glsl-vs-point-size
and makes shaders/vp-ignore-input not trigger PGRAPH DATA_ERROR
---
 src/gallium/drivers/nv50/nv50_program.c |   11 +++++++++++
 1 files changed, 11 insertions(+), 0 deletions(-)

diff --git a/src/gallium/drivers/nv50/nv50_program.c b/src/gallium/drivers/nv50/nv50_program.c
index 48e8db3..e6f1097 100644
--- a/src/gallium/drivers/nv50/nv50_program.c
+++ b/src/gallium/drivers/nv50/nv50_program.c
@@ -68,6 +68,17 @@ nv50_vertprog_assign_slots(struct nv50_ir_prog_info *info)
          break;
       }
    }
+
+   /*
+    * Corner case: VP has no inputs, but we will still need to submit data to
+    * draw it. HW will shout at us and won't draw anything if we don't enable
+    * any input, so let's just pretend it's the first one.
+    */
+   if (prog->vp.attrs[0] == 0 &&
+         prog->vp.attrs[1] == 0 &&
+         prog->vp.attrs[2] == 0)
+      prog->vp.attrs[0] |= 0xf;
+
    /* VertexID before InstanceID */
    if (info->io.vertexId < info->numSysVals)
       info->sv[info->io.vertexId].slot[0] = n++;
-- 
1.7.8.5