[Mesa-dev] [PATCH] draw: don't crash if GS doesn't emit anything

[Chris Forbes]

It's only silly if the GS *never* emits any verts...

On Sun, Apr 28, 2013 at 12:57 AM, Zack Rusin <zackr at vmware.com> wrote:
> Technically it's legal for geometry shader to not emit any
> vertices. It's silly, but perfectly legal, so lets make draw
> stop crashing if it happens.
>
> Signed-off-by: Zack Rusin <zackr at vmware.com>
> ---
>  src/gallium/auxiliary/draw/draw_pt_fetch_shade_pipeline.c     |    9 +++++++++
>  .../auxiliary/draw/draw_pt_fetch_shade_pipeline_llvm.c        |    9 +++++++++
>  2 files changed, 18 insertions(+)
>
> diff --git a/src/gallium/auxiliary/draw/draw_pt_fetch_shade_pipeline.c b/src/gallium/auxiliary/draw/draw_pt_fetch_shade_pipeline.c
> index 7b871c2..8d66c88 100644
> --- a/src/gallium/auxiliary/draw/draw_pt_fetch_shade_pipeline.c
> +++ b/src/gallium/auxiliary/draw/draw_pt_fetch_shade_pipeline.c
> @@ -299,6 +299,15 @@ static void fetch_pipeline_generic( struct draw_pt_middle_end *middle,
>           }
>        }
>     }
> +   if (prim_info->count == 0) {
> +      debug_printf("GS/IA didn't emit any vertices!\n");
> +
> +      FREE(vert_info->verts);
> +      if (free_prim_info) {
> +         FREE(prim_info->primitive_lengths);
> +      }
> +      return;
> +   }
>
>
>     /* Stream output needs to be done before clipping.
> diff --git a/src/gallium/auxiliary/draw/draw_pt_fetch_shade_pipeline_llvm.c b/src/gallium/auxiliary/draw/draw_pt_fetch_shade_pipeline_llvm.c
> index 0873e34..48fb616 100644
> --- a/src/gallium/auxiliary/draw/draw_pt_fetch_shade_pipeline_llvm.c
> +++ b/src/gallium/auxiliary/draw/draw_pt_fetch_shade_pipeline_llvm.c
> @@ -397,6 +397,15 @@ llvm_pipeline_generic( struct draw_pt_middle_end *middle,
>           }
>        }
>     }
> +   if (prim_info->count == 0) {
> +      debug_printf("GS/IA didn't emit any vertices!\n");
> +
> +      FREE(vert_info->verts);
> +      if (free_prim_info) {
> +         FREE(prim_info->primitive_lengths);
> +      }
> +      return;
> +   }
>
>     /* stream output needs to be done before clipping */
>     draw_pt_so_emit( fpme->so_emit, vert_info, prim_info );
> --
> 1.7.10.4
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