[Mesa-dev] [PATCH 1/3] gallium/util: add a helper for calculating primitive count from vertex count

[Marek Olšák]

On Sat, Jul 26, 2014 at 3:36 AM, Ilia Mirkin <imirkin at alum.mit.edu> wrote:
> On Fri, Jul 25, 2014 at 9:30 PM, Marek Olšák <maraeo at gmail.com> wrote:
>> From: Marek Olšák <marek.olsak at amd.com>
>>
>> This is needed by the following commit which is a candidate for stable too.
>>
>> Cc: mesa-stable at lists.freedesktop.org
>> ---
>>  src/gallium/auxiliary/util/u_prim.h | 15 +++++++++++++++
>>  1 file changed, 15 insertions(+)
>>
>> diff --git a/src/gallium/auxiliary/util/u_prim.h b/src/gallium/auxiliary/util/u_prim.h
>> index fd95c0b..cf1a18f 100644
>> --- a/src/gallium/auxiliary/util/u_prim.h
>> +++ b/src/gallium/auxiliary/util/u_prim.h
>> @@ -136,6 +136,21 @@ u_prim_vertex_count(unsigned prim)
>>     return (likely(prim < PIPE_PRIM_MAX)) ? &prim_table[prim] : NULL;
>>  }
>>
>> +/**
>> + * Given a vertex count, return the number of primitives.
>> + * For polygons, return the number of triangles.
>> + */
>> +static INLINE unsigned
>> +u_prims_for_vertices(unsigned prim, unsigned num)
>
> This isn't an issue yet, but with PATCH primitives, the number of
> vertices per primitive will be variable. (I guess it depends on the
> stage you're at...) In my patches, I'm passing the number of patch
> vertices via pipe_draw_info -- perhaps it would make sense to just
> take that as an argument?

I'm not really sure. I think tessellation is unrelated to the bug I'm
fixing in the following patch.

Marek