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

Jason Ekstrand jason at jlekstrand.net
Tue May 1 21:34:15 UTC 2018


On Wed, Mar 7, 2018 at 5:08 AM, Pohjolainen, Topi <
topi.pohjolainen at gmail.com> wrote:

> 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?
>

Correct.  nir_format_bitcast_uint_vec_unmasked can handle any cast from one
format with a uniform channel size to another so long as the channel sizes
are at least 8 bits.  However, for 1010102 and similar, it falls over.
Maybe I should say that in the commit message.


> > +   } 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
> >
> > _______________________________________________
> > mesa-dev mailing list
> > mesa-dev at lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/mesa-dev
>
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