[Mesa-dev] [PATCH 4/5] gallium: add a cull distance semantic

[Brian Paul]

On 06/10/2013 08:31 AM, Zack Rusin wrote:
> cull distance is analogous to clip distance. If a register is
> given this semantic, then the values in it are assumed to be a
> float32 distance to a plane. Primitives will be completely
> discarded if the plane distance for all of the vertices in
> the primitive are < 0.
>
> Signed-off-by: Zack Rusin <zackr at vmware.com>
> ---
>   src/gallium/auxiliary/tgsi/tgsi_scan.c     |    4 ++++
>   src/gallium/auxiliary/tgsi/tgsi_scan.h     |    1 +
>   src/gallium/auxiliary/tgsi/tgsi_strings.c  |    3 ++-
>   src/gallium/include/pipe/p_shader_tokens.h |    3 ++-
>   4 files changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/src/gallium/auxiliary/tgsi/tgsi_scan.c b/src/gallium/auxiliary/tgsi/tgsi_scan.c
> index 872e4ff..2a37b38 100644
> --- a/src/gallium/auxiliary/tgsi/tgsi_scan.c
> +++ b/src/gallium/auxiliary/tgsi/tgsi_scan.c
> @@ -200,6 +200,10 @@ tgsi_scan_shader(const struct tgsi_token *tokens,
>                         fulldecl->Semantic.Name == TGSI_SEMANTIC_CLIPDIST) {
>                        info->num_written_clipdistance += util_bitcount(fulldecl->Declaration.UsageMask);
>                     }
> +                  if ((procType == TGSI_PROCESSOR_VERTEX || procType == TGSI_PROCESSOR_GEOMETRY) &&
> +                      fulldecl->Semantic.Name == TGSI_SEMANTIC_CULLDIST) {
> +                     info->num_written_culldistance += util_bitcount(fulldecl->Declaration.UsageMask);
> +                  }
>                     /* extra info for special outputs */
>                     if (procType == TGSI_PROCESSOR_FRAGMENT &&
>                         fulldecl->Semantic.Name == TGSI_SEMANTIC_POSITION)
> diff --git a/src/gallium/auxiliary/tgsi/tgsi_scan.h b/src/gallium/auxiliary/tgsi/tgsi_scan.h
> index a5b7024..91eef67 100644
> --- a/src/gallium/auxiliary/tgsi/tgsi_scan.h
> +++ b/src/gallium/auxiliary/tgsi/tgsi_scan.h
> @@ -78,6 +78,7 @@ struct tgsi_shader_info
>      boolean writes_viewport_index;
>      boolean writes_layer;
>
> +   unsigned num_written_culldistance;
>      unsigned num_written_clipdistance;
>      /**
>       * Bitmask indicating which register files are accessed with
> diff --git a/src/gallium/auxiliary/tgsi/tgsi_strings.c b/src/gallium/auxiliary/tgsi/tgsi_strings.c
> index 2785676..6f244e5 100644
> --- a/src/gallium/auxiliary/tgsi/tgsi_strings.c
> +++ b/src/gallium/auxiliary/tgsi/tgsi_strings.c
> @@ -80,7 +80,8 @@ const char *tgsi_semantic_names[TGSI_SEMANTIC_COUNT] =
>      "TEXCOORD",
>      "PCOORD",
>      "VIEWPORT_INDEX",
> -   "LAYER"
> +   "LAYER",
> +   "CULLDIST"
>   };
>
>   const char *tgsi_texture_names[TGSI_TEXTURE_COUNT] =
> diff --git a/src/gallium/include/pipe/p_shader_tokens.h b/src/gallium/include/pipe/p_shader_tokens.h
> index c984d50..4a6a57f 100644
> --- a/src/gallium/include/pipe/p_shader_tokens.h
> +++ b/src/gallium/include/pipe/p_shader_tokens.h
> @@ -166,7 +166,8 @@ struct tgsi_declaration_interp
>   #define TGSI_SEMANTIC_PCOORD     20 /**< point sprite coordinate */
>   #define TGSI_SEMANTIC_VIEWPORT_INDEX 21 /**< viewport index */
>   #define TGSI_SEMANTIC_LAYER      22 /**< layer (rendertarget index) */
> -#define TGSI_SEMANTIC_COUNT      23 /**< number of semantic values */
> +#define TGSI_SEMANTIC_CULLDIST   23
> +#define TGSI_SEMANTIC_COUNT      24 /**< number of semantic values */
>
>   struct tgsi_declaration_semantic
>   {
>

Reviewed-by: Brian Paul <brianp at vmware.com>