[Mesa-dev] [PATCH 2/7] i965/gen7: Make primitives_written counting work.

[Kenneth Graunke]

On 12/22/2011 04:54 PM, Eric Anholt wrote:
> The code was relying on gs.prog_data's copy of the
> number-of-verts-per-prim, which segfaulted on gen7 since it doesn't
> make a GS program.  We can easily calculate that value right here.
> ---
>  src/mesa/drivers/dri/i965/brw_draw.c |   33 +++++++++++++++++++++++++++------
>  1 files changed, 27 insertions(+), 6 deletions(-)
> 
> diff --git a/src/mesa/drivers/dri/i965/brw_draw.c b/src/mesa/drivers/dri/i965/brw_draw.c
> index 082bb9a..c116d39 100644
> --- a/src/mesa/drivers/dri/i965/brw_draw.c
> +++ b/src/mesa/drivers/dri/i965/brw_draw.c
> @@ -379,6 +379,30 @@ static void brw_postdraw_set_buffers_need_resolve(struct brw_context *brw)
>     }
>  }
>  
> +static int
> +verts_per_prim(GLenum mode)
> +{
> +   switch (mode) {
> +   case GL_POINTS:
> +      return 1;
> +   case GL_LINE_STRIP:
> +   case GL_LINE_LOOP:
> +   case GL_LINES:
> +      return 2;
> +   case GL_TRIANGLE_STRIP:
> +   case GL_TRIANGLE_FAN:
> +   case GL_POLYGON:
> +   case GL_TRIANGLES:
> +   case GL_QUADS:
> +   case GL_QUAD_STRIP:
> +      return 3;
> +   default:
> +      _mesa_problem(NULL,
> +		    "unknown prim type in transform feedback primitive count");
> +      return 0;
> +   }
> +}
> +
>  /**
>   * Update internal counters based on the the drawing operation described in
>   * prim.
> @@ -397,14 +421,11 @@ brw_update_primitive_count(struct brw_context *brw,
>         * able to reload SVBI 0 with the correct value in case we have to start
>         * a new batch buffer.
>         */
> -      unsigned svbi_postincrement_value =
> -         brw->gs.prog_data->svbi_postincrement_value;
> +      unsigned verts = verts_per_prim(prim->mode);
>        uint32_t space_avail =
> -         (brw->sol.svbi_0_max_index - brw->sol.svbi_0_starting_index)
> -         / svbi_postincrement_value;
> +         (brw->sol.svbi_0_max_index - brw->sol.svbi_0_starting_index) / verts;
>        uint32_t primitives_written = MIN2 (space_avail, count);
> -      brw->sol.svbi_0_starting_index +=
> -         svbi_postincrement_value * primitives_written;
> +      brw->sol.svbi_0_starting_index += verts;

Don't you mean
         brw->sol.svbi_0_starting_index += verts * primitives_written;

>        /* And update the TRANSFORM_FEEDBACK_PRIMITIVES_WRITTEN query. */
>        brw->sol.primitives_written += primitives_written;