[Mesa-dev] [PATCH 02/14] i965: Allocate binding table space for shader images.

[Kenneth Graunke]

On Friday, February 06, 2015 07:23:16 PM Francisco Jerez wrote:
> Reviewed-by: Paul Berry <stereotype441 at gmail.com>
> ---
>  src/mesa/drivers/dri/i965/brw_context.h  | 5 +++++
>  src/mesa/drivers/dri/i965/brw_shader.cpp | 7 +++++++
>  2 files changed, 12 insertions(+)
> 
> diff --git a/src/mesa/drivers/dri/i965/brw_context.h b/src/mesa/drivers/dri/i965/brw_context.h
> index bebb0be..e28c65d 100644
> --- a/src/mesa/drivers/dri/i965/brw_context.h
> +++ b/src/mesa/drivers/dri/i965/brw_context.h
> @@ -341,6 +341,7 @@ struct brw_stage_prog_data {
>        uint32_t gather_texture_start;
>        uint32_t ubo_start;
>        uint32_t abo_start;
> +      uint32_t image_start;
>        uint32_t shader_time_start;
>        /** @} */
>     } binding_table;
> @@ -621,6 +622,9 @@ struct brw_vs_prog_data {
>  /** Max number of atomic counter buffer objects in a shader */
>  #define BRW_MAX_ABO 16
>  
> +/** Max number of image units in a shader */
> +#define BRW_MAX_IMAGES 16
> +

Out of curiosity, why 16?  The Windows driver and Nvidia both seem to
use 8, while AMD offers 32:

http://delphigl.de/glcapsviewer/gl_stats_caps_single.php?listreportsbycap=GL_MAX_IMAGE_UNITS

We have 32 texture units on Haswell these days (though honestly, it's
pretty arbitrary...we could have more if we wanted...)

That's not an objection - I'm just curious.  As is,
Reviewed-by: Kenneth Graunke <kenneth at whitecape.org>

>  /**
>   * Max number of binding table entries used for stream output.
>   *
> @@ -653,6 +657,7 @@ struct brw_vs_prog_data {
>                              BRW_MAX_TEX_UNIT * 2 + /* normal, gather */ \
>                              12 + /* ubo */                              \
>                              BRW_MAX_ABO +                               \
> +                            BRW_MAX_IMAGES +                            \
>                              2 /* shader time, pull constants */)
>  
>  #define SURF_INDEX_GEN6_SOL_BINDING(t) (t)
> diff --git a/src/mesa/drivers/dri/i965/brw_shader.cpp b/src/mesa/drivers/dri/i965/brw_shader.cpp
> index 67d8de4..5c8f3d5 100644
> --- a/src/mesa/drivers/dri/i965/brw_shader.cpp
> +++ b/src/mesa/drivers/dri/i965/brw_shader.cpp
> @@ -1116,6 +1116,13 @@ backend_visitor::assign_common_binding_table_offsets(uint32_t next_binding_table
>        stage_prog_data->binding_table.abo_start = 0xd0d0d0d0;
>     }
>  
> +   if (shader && shader->base.NumImages) {
> +      stage_prog_data->binding_table.image_start = next_binding_table_offset;
> +      next_binding_table_offset += shader->base.NumImages;
> +   } else {
> +      stage_prog_data->binding_table.image_start = 0xd0d0d0d0;
> +   }
> +
>     /* This may or may not be used depending on how the compile goes. */
>     stage_prog_data->binding_table.pull_constants_start = next_binding_table_offset;
>     next_binding_table_offset++;
> 
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