[Mesa-dev] [PATCH 10/13] i965: Make gl_BaseVertex available in a buffer object.

[Ian Romanick]

Reviewed-by: Ian Romanick <ian.d.romanick at intel.com>

On 08/08/2014 12:31 AM, Kenneth Graunke wrote:
> This will be used for GL_ARB_shader_draw_parameters, as well as fixing
> gl_VertexID, which is supposed to include gl_BaseVertex's value.
> 
> For indirect draws, we simply point at the indirect buffer; for normal
> draws, we upload the value via the upload buffer.
> 
> Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>
> ---
>  src/mesa/drivers/dri/i965/brw_context.h     |  7 +++++++
>  src/mesa/drivers/dri/i965/brw_draw.c        | 14 ++++++++++++++
>  src/mesa/drivers/dri/i965/brw_draw_upload.c | 10 ++++++++++
>  3 files changed, 31 insertions(+)
> 
> diff --git a/src/mesa/drivers/dri/i965/brw_context.h b/src/mesa/drivers/dri/i965/brw_context.h
> index eea7938..b5b5e41 100644
> --- a/src/mesa/drivers/dri/i965/brw_context.h
> +++ b/src/mesa/drivers/dri/i965/brw_context.h
> @@ -1063,6 +1063,13 @@ struct brw_context
>  
>        int start_vertex_location;
>        int base_vertex_location;
> +
> +      /**
> +       * Buffer and offset used for GL_ARB_shader_draw_parameters
> +       * (for now, only gl_BaseVertex).
> +       */
> +      drm_intel_bo *draw_params_bo;
> +      uint32_t draw_params_offset;
>     } draw;
>  
>     struct {
> diff --git a/src/mesa/drivers/dri/i965/brw_draw.c b/src/mesa/drivers/dri/i965/brw_draw.c
> index d8e16a7..f0aaec7 100644
> --- a/src/mesa/drivers/dri/i965/brw_draw.c
> +++ b/src/mesa/drivers/dri/i965/brw_draw.c
> @@ -465,6 +465,20 @@ static bool brw_try_draw_prims( struct gl_context *ctx,
>        brw->draw.start_vertex_location = prims[i].start;
>        brw->draw.base_vertex_location = prims[i].basevertex;
>  
> +      if (prims[i].is_indirect) {
> +         /* Point draw_params_bo at the indirect buffer. */
> +         brw->draw.draw_params_bo =
> +            intel_buffer_object(ctx->DrawIndirectBuffer)->buffer;
> +         brw->draw.draw_params_offset =
> +            prims[i].indirect_offset + (prims[i].indexed ? 12 : 8);
> +      } else {
> +         /* Set draw_params_bo to NULL so brw_prepare_vertices knows it
> +          * has to upload gl_BaseVertex and such if they're needed.
> +          */
> +         brw->draw.draw_params_bo = NULL;
> +         brw->draw.draw_params_offset = 0;
> +      }
> +
>        if (brw->gen < 6)
>  	 brw_set_prim(brw, &prims[i]);
>        else
> diff --git a/src/mesa/drivers/dri/i965/brw_draw_upload.c b/src/mesa/drivers/dri/i965/brw_draw_upload.c
> index 38b1087..37a65bc 100644
> --- a/src/mesa/drivers/dri/i965/brw_draw_upload.c
> +++ b/src/mesa/drivers/dri/i965/brw_draw_upload.c
> @@ -607,11 +607,21 @@ brw_prepare_vertices(struct brw_context *brw)
>  void
>  brw_prepare_shader_draw_parameters(struct brw_context *brw)
>  {
> +   int *gl_basevertex_value;
>     if (brw->draw.indexed) {
>        brw->draw.start_vertex_location += brw->ib.start_vertex_offset;
>        brw->draw.base_vertex_location += brw->vb.start_vertex_bias;
> +      gl_basevertex_value = &brw->draw.base_vertex_location;
>     } else {
>        brw->draw.start_vertex_location += brw->vb.start_vertex_bias;
> +      gl_basevertex_value = &brw->draw.start_vertex_location;
> +   }
> +
> +   /* For non-indirect draws, upload gl_BaseVertex. */
> +   if (brw->vs.prog_data->uses_vertexid && brw->draw.draw_params_bo == NULL) {
> +      intel_upload_data(brw, gl_basevertex_value, 4, 4,
> +			&brw->draw.draw_params_bo,
> +                        &brw->draw.draw_params_offset);
>     }
>  }
>  
>