[Mesa-dev] [PATCH 26/29] intel/blorp: Add support for more format bitcasting

Pohjolainen, Topi topi.pohjolainen at gmail.com
Wed Mar 7 13:08:37 UTC 2018


On Fri, Jan 26, 2018 at 05:59:55PM -0800, Jason Ekstrand wrote:
> By making use of the NIR helper for uint vector casts, we should now be
> able to bitcast between any two uint formats so long as their channels
> are in RGBA order (possibly with channels missing).  In order to do this
> we need to rework the key a bit to pass the actual formats instead of
> just the number of bits in each.
> ---
>  src/intel/blorp/blorp_blit.c | 105 +++++++++++++++++++++++++++++++++++--------
>  src/intel/blorp/blorp_priv.h |  13 +++---
>  2 files changed, 95 insertions(+), 23 deletions(-)
> 
> diff --git a/src/intel/blorp/blorp_blit.c b/src/intel/blorp/blorp_blit.c
> index ea0687f..321b3e3 100644
> --- a/src/intel/blorp/blorp_blit.c
> +++ b/src/intel/blorp/blorp_blit.c
> @@ -871,17 +871,71 @@ bit_cast_color(struct nir_builder *b, nir_ssa_def *color,
>  {
>     assert(key->texture_data_type == nir_type_uint);
>  
> -   /* We don't actually know how many source channels we have and NIR will
> -    * assert if the number of destination channels ends up being more than 4.
> -    * Choose the largest number of source channels that won't over-fill a
> -    * destination vec4.
> -    */
> -   const unsigned src_channels =
> -      MIN2(4, (4 * key->dst_bpc) / key->src_bpc);
> -   color = nir_channels(b, color, (1 << src_channels) - 1);
> +   if (key->src_format == key->dst_format)
> +      return color;
>  
> -   color = nir_format_bitcast_uint_vec_unmasked(b, color, key->src_bpc,
> -                                                key->dst_bpc);
> +   const struct isl_format_layout *src_fmtl =
> +      isl_format_get_layout(key->src_format);
> +   const struct isl_format_layout *dst_fmtl =
> +      isl_format_get_layout(key->dst_format);
> +
> +   /* They must be uint formats with the same bit size */
> +   assert(src_fmtl->bpb == dst_fmtl->bpb);
> +   assert(src_fmtl->channels.r.type == ISL_UINT);
> +   assert(dst_fmtl->channels.r.type == ISL_UINT);
> +
> +   /* They must be in regular color formats (no luminance or alpha) */
> +   assert(src_fmtl->channels.r.bits > 0);
> +   assert(dst_fmtl->channels.r.bits > 0);
> +
> +   /* They must be in RGBA order (possibly with channels missing) */
> +   assert(src_fmtl->channels.r.start_bit == 0);
> +   assert(dst_fmtl->channels.r.start_bit == 0);
> +
> +   if (src_fmtl->bpb <= 32) {
> +      const unsigned src_channels =
> +         isl_format_get_num_channels(key->src_format);
> +      const unsigned src_bits[4] = {
> +         src_fmtl->channels.r.bits,
> +         src_fmtl->channels.g.bits,
> +         src_fmtl->channels.b.bits,
> +         src_fmtl->channels.a.bits,
> +      };
> +      const unsigned dst_channels =
> +         isl_format_get_num_channels(key->dst_format);
> +      const unsigned dst_bits[4] = {
> +         dst_fmtl->channels.r.bits,
> +         dst_fmtl->channels.g.bits,
> +         dst_fmtl->channels.b.bits,
> +         dst_fmtl->channels.a.bits,
> +      };
> +      nir_ssa_def *packed =
> +         nir_format_pack_uint_unmasked(b, color, src_bits, src_channels);
> +      color = nir_format_unpack_uint(b, packed, dst_bits, dst_channels);

I tried to think why nir_format_bitcast_uint_vec_unmasked() can't handle
these cases (src_fmtl->bpb <= 32). At this point it still does, right? Using
nir_format_pack_uint_unmasked()/nir_format_unpack_uint() already here is
preparing for cases where src or dst is ISL_FORMAT_R11G11B10_FLOAT and which
nir_format_bitcast_uint_vec_unmasked() can't handle anymore?

> +   } else {
> +      const unsigned src_bpc = src_fmtl->channels.r.bits;
> +      const unsigned dst_bpc = dst_fmtl->channels.r.bits;
> +
> +      assert(src_fmtl->channels.g.bits == 0 ||
> +             src_fmtl->channels.g.bits == src_fmtl->channels.r.bits);
> +      assert(src_fmtl->channels.b.bits == 0 ||
> +             src_fmtl->channels.b.bits == src_fmtl->channels.r.bits);
> +      assert(src_fmtl->channels.a.bits == 0 ||
> +             src_fmtl->channels.a.bits == src_fmtl->channels.r.bits);
> +      assert(dst_fmtl->channels.g.bits == 0 ||
> +             dst_fmtl->channels.g.bits == dst_fmtl->channels.r.bits);
> +      assert(dst_fmtl->channels.b.bits == 0 ||
> +             dst_fmtl->channels.b.bits == dst_fmtl->channels.r.bits);
> +      assert(dst_fmtl->channels.a.bits == 0 ||
> +             dst_fmtl->channels.a.bits == dst_fmtl->channels.r.bits);
> +
> +      /* Restrict to only the channels we actually have */
> +      const unsigned src_channels =
> +         isl_format_get_num_channels(key->src_format);
> +      color = nir_channels(b, color, (1 << src_channels) - 1);
> +
> +      color = nir_format_bitcast_uint_vec_unmasked(b, color, src_bpc, dst_bpc);
> +   }
>  
>     /* Blorp likes to assume that colors are vec4s */
>     nir_ssa_def *u = nir_ssa_undef(b, 1, 32);
> @@ -1321,14 +1375,13 @@ brw_blorp_build_nir_shader(struct blorp_context *blorp, void *mem_ctx,
>                              nir_type_int);
>     }
>  
> -   if (key->dst_bpc != key->src_bpc) {
> +   if (key->format_bit_cast) {
>        assert(isl_swizzle_is_identity(key->src_swizzle));
>        assert(isl_swizzle_is_identity(key->dst_swizzle));
>        color = bit_cast_color(&b, color, key);
> -   }
> -
> -   if (key->dst_format)
> +   } else if (key->dst_format) {
>        color = convert_color(&b, color, key);
> +   }
>  
>     if (key->dst_rgb) {
>        /* The destination image is bound as a red texture three times as wide
> @@ -2522,10 +2575,26 @@ blorp_copy(struct blorp_batch *batch,
>                               params.dst.view.format, packed);
>     }
>  
> -   wm_prog_key.src_bpc =
> -      isl_format_get_layout(params.src.view.format)->channels.r.bits;
> -   wm_prog_key.dst_bpc =
> -      isl_format_get_layout(params.dst.view.format)->channels.r.bits;
> +   if (params.src.view.format != params.dst.view.format) {
> +      enum isl_format src_cast_format = params.src.view.format;
> +      enum isl_format dst_cast_format = params.dst.view.format;
> +
> +      /* The BLORP bitcast code gets confused by RGB formats.  Just treat them
> +       * as RGBA and then everything will be happy.  This is perfectly safe
> +       * because BLORP likes to treat things as if they have vec4 colors all
> +       * the time anyway.
> +       */
> +      if (isl_format_is_rgb(src_cast_format))
> +         src_cast_format = isl_format_rgb_to_rgba(src_cast_format);
> +      if (isl_format_is_rgb(dst_cast_format))
> +         dst_cast_format = isl_format_rgb_to_rgba(dst_cast_format);
> +
> +      if (src_cast_format != dst_cast_format) {
> +         wm_prog_key.format_bit_cast = true;
> +         wm_prog_key.src_format = src_cast_format;
> +         wm_prog_key.dst_format = dst_cast_format;
> +      }
> +   }
>  
>     if (src_fmtl->bw > 1 || src_fmtl->bh > 1) {
>        blorp_surf_convert_to_uncompressed(batch->blorp->isl_dev, &params.src,
> diff --git a/src/intel/blorp/blorp_priv.h b/src/intel/blorp/blorp_priv.h
> index 291c0a9..2013c53 100644
> --- a/src/intel/blorp/blorp_priv.h
> +++ b/src/intel/blorp/blorp_priv.h
> @@ -245,8 +245,11 @@ struct brw_blorp_blit_prog_key
>     /* The swizzle to apply to the source in the shader */
>     struct isl_swizzle src_swizzle;
>  
> -   /* Number of bits per channel in the source image. */
> -   uint8_t src_bpc;
> +   /* The format of the source if format-specific workarounds are needed
> +    * and 0 (ISL_FORMAT_R32G32B32A32_FLOAT) if the destination is natively
> +    * renderable.
> +    */
> +   enum isl_format src_format;
>  
>     /* True if the source requires normalized coordinates */
>     bool src_coords_normalized;
> @@ -268,15 +271,15 @@ struct brw_blorp_blit_prog_key
>     /* The swizzle to apply to the destination in the shader */
>     struct isl_swizzle dst_swizzle;
>  
> -   /* Number of bits per channel in the destination image. */
> -   uint8_t dst_bpc;
> -
>     /* The format of the destination if format-specific workarounds are needed
>      * and 0 (ISL_FORMAT_R32G32B32A32_FLOAT) if the destination is natively
>      * renderable.
>      */
>     enum isl_format dst_format;
>  
> +   /* Whether or not the format workarounds are a bitcast operation */
> +   bool format_bit_cast;
> +
>     /* Type of the data to be read from the texture (one of
>      * nir_type_(int|uint|float)).
>      */
> -- 
> 2.5.0.400.gff86faf
> 
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