[Mesa-dev] [PATCH v3 2/5] i965: Faking the ETC2 compression on Gen < 8 GPUs using two miptrees.

Nanley Chery nanleychery at gmail.com
Fri Feb 8 20:30:18 UTC 2019


On Thu, Feb 07, 2019 at 06:00:19PM +0200, Eleni Maria Stea wrote:
> GPUs Gen < 8 cannot sample ETC2 formats. So far, they converted the
> compressed EAC/ETC2 images to non-compressed RGBA images. When
> GetCompressed* functions were called, the pixels were returned in this
> RGBA format and not the compressed format that was expected.
> 
> Trying to fix this problem, we use a secondary shadow miptree to store the
> decompressed data for the rendering and the main miptree to store the
> compressed for the Get functions to work. Each time that the main miptree
> is written with compressed data, we decompress them to RGB and update the
> shadow. Then we use the shadow for rendering.
> 
> v2:
>    - Fixes in the commit message (Nanley Chery)
>    - Reversed the changes in brw_get_texture_swizzle and swapped the b, g
>    values at the time that we decompress the data in the function:
>    intel_miptree_update_etc_shadow of intel_mipmap_tree.c (Nanley Chery)
>    - Simplified the format checks in the miptree_create function of the
>    intel_mipmap_tree.c and reserved the call of the
>    intel_lower_compressed_format for the case that we are faking the ETC
>    support (Nanley Chery)
>    - Removed the check for the auxiliary usage for the shadow miptree at
>    creation (miptree_create of intel_mipmap_tree.c) as we won't use
>    auxiliary buffers with these types of trees (Nanley Chery)
>    - Set the etc_format of the non-ETC miptrees to MESA_FORMAT_NONE and
>    removed the unecessary checks (Nanley Chery)
>    - Fixed an unrelated indentation change (Nanley Chery)
>    - Modified the function intel_miptree_finish_write to set the
>    mt->shadow_needs_update to true to catch all the cases when we need to
>    update the miptree (Nanley Chery)
>    - In order to update the shadow miptree during the unmap of the
>    main and always map the main (Nanley Chery) the following change was
>    necessary: Splitted the previous update function that was updating all
>    the mipmap levels and use two functions instead: one that updates one
>    level and one that updates all of them. Used the first during unmap
>    and the second before the rendering.
>    - Removed the BRW_MAP_ETC_BIT flag and the mechanism to decide which
>    miptree should be mapped each time and reversed all the changes in the
>    higher level texture functions that upload data to textures as they
>    aren't needed anymore.
>    - Replaced the boolean needs_fake_etc with an inline function that
>    checks when we need to fake the ETC compression (Nanley Chery)
>    - Removed the initialization of the strides in the update function as
>    the values will be overwritten by the intel_miptree_map call (Nanley
>    Chery)
>    - Used minify instead of division in the new update function
>    intel_miptree_update_etc_shadow_levels in intel_mipmap_tree.c (Nanley
>    Chery)
>    - Removed the depth from the calculation of the number of slices in
>    the new update function (intel_miptree_update_etc_shadow_levels of
>    intel_mipmap_tree.c) as we don't need to support 3D ETC images.
>    (Nanley Chery)
> 
> v3:
>   - Renamed the rgba_fmt in function miptree_create
>   (intel_mipmap_tree.c) to decomp_format as the format is not always in
>   rgba order. (Nanley Chery)
>   - Documented the new usage for the shadow miptree in the comment above
>   the field in the intel_miptree struct in intel_mipmap_tree.h (Nanley
>   Chery)
>   - Removed the redundant flags from the mapping of the miptrees in
>   intel_miptree_update_etc_shadow of intel_mipmap_tree.c (Nanley Chery)
>   - Fixed the switch from surface's logical level to physical level in
>   the intel_miptree_update_etc_shadow_levels of intel_mipmap_tree.c
>   (Nanley Chery)
>   - Excluded the Baytrail GPUs from the check for the ETC emulation as
>   they support the ETC formats natively. (Nanley Chery)
>   - Simplified the check if the format is BGRA in
>   intel_miptree_update_etc_shadow of intel_mipmap_tree.c (Nanley Chery)
> ---
>  .../drivers/dri/i965/brw_wm_surface_state.c   |   5 +-
>  src/mesa/drivers/dri/i965/intel_mipmap_tree.c | 130 ++++++++++++++++--
>  src/mesa/drivers/dri/i965/intel_mipmap_tree.h |  24 ++++
>  3 files changed, 149 insertions(+), 10 deletions(-)
> 
> diff --git a/src/mesa/drivers/dri/i965/brw_wm_surface_state.c b/src/mesa/drivers/dri/i965/brw_wm_surface_state.c
> index 618e2ab35bc..c2cf34aee71 100644
> --- a/src/mesa/drivers/dri/i965/brw_wm_surface_state.c
> +++ b/src/mesa/drivers/dri/i965/brw_wm_surface_state.c
> @@ -521,7 +521,7 @@ static void brw_update_texture_surface(struct gl_context *ctx,
>            */
>           mesa_fmt = mt->format;
>        } else if (mt->etc_format != MESA_FORMAT_NONE) {
> -         mesa_fmt = mt->format;
> +         mesa_fmt = mt->shadow_mt->format;
>        } else if (plane > 0) {
>           mesa_fmt = mt->format;
>        } else {
> @@ -581,6 +581,9 @@ static void brw_update_texture_surface(struct gl_context *ctx,
>           assert(mt->shadow_mt && !mt->shadow_needs_update);
>           mt = mt->shadow_mt;
>           format = ISL_FORMAT_R8_UINT;
> +      } else if (intel_miptree_needs_fake_etc(brw, mt)) {
> +         assert(mt->shadow_mt);
> +         mt = mt->shadow_mt;
>        }
>  
>        const int surf_index = surf_offset - &brw->wm.base.surf_offset[0];
> diff --git a/src/mesa/drivers/dri/i965/intel_mipmap_tree.c b/src/mesa/drivers/dri/i965/intel_mipmap_tree.c
> index 479188fd1c8..c7367fc385f 100644
> --- a/src/mesa/drivers/dri/i965/intel_mipmap_tree.c
> +++ b/src/mesa/drivers/dri/i965/intel_mipmap_tree.c
> @@ -57,6 +57,11 @@ static void *intel_miptree_map_raw(struct brw_context *brw,
>                                     GLbitfield mode);
>  
>  static void intel_miptree_unmap_raw(struct intel_mipmap_tree *mt);
> +static void intel_miptree_update_etc_shadow(struct brw_context *brw,
> +                                            struct intel_mipmap_tree *mt,
> +                                            unsigned int level,
> +                                            unsigned int slice,
> +                                            int level_w, int level_h);
>  
>  static bool
>  intel_miptree_supports_mcs(struct brw_context *brw,
> @@ -687,10 +692,8 @@ miptree_create(struct brw_context *brw,
>     if (devinfo->gen < 6 && _mesa_is_format_color_format(format))
>        tiling_flags &= ~ISL_TILING_Y0_BIT;
>  
> -   mesa_format mt_fmt;
> -   if (_mesa_is_format_color_format(format)) {
> -      mt_fmt = intel_lower_compressed_format(brw, format);
> -   } else {
> +   mesa_format mt_fmt = format;
> +   if (!_mesa_is_format_color_format(format)) {
>        /* Fix up the Z miptree format for how we're splitting out separate
>         * stencil. Gen7 expects there to be no stencil bits in its depth buffer.
>         */
> @@ -707,6 +710,25 @@ miptree_create(struct brw_context *brw,
>     if (mt == NULL)
>        return NULL;
>  
> +   if (intel_miptree_needs_fake_etc(brw, mt)) {
> +      mesa_format decomp_format = intel_lower_compressed_format(brw, format);
> +      mt->etc_format = format;
> +      mt->shadow_mt = make_surface(brw, target, decomp_format, first_level,
> +                                   last_level, width0, height0, depth0,
> +                                   num_samples, tiling_flags,
> +                                   mt_surf_usage(mt_fmt),
> +                                   alloc_flags, 0, NULL);
> +
> +      if (mt->shadow_mt == NULL) {
> +         intel_miptree_release(&mt);
> +         return NULL;
> +      }
> +
> +      mt->shadow_mt->etc_format = MESA_FORMAT_NONE;
> +   } else {
> +      mt->etc_format = MESA_FORMAT_NONE;
> +   }
> +
>     if (needs_separate_stencil(brw, mt, format)) {
>        mt->stencil_mt =
>           make_surface(brw, target, MESA_FORMAT_S_UINT8, first_level, last_level,
> @@ -719,9 +741,6 @@ miptree_create(struct brw_context *brw,
>        }
>     }
>  
> -   mt->etc_format = (_mesa_is_format_color_format(format) && mt_fmt != format) ?
> -                    format : MESA_FORMAT_NONE;
> -
>     if (!(flags & MIPTREE_CREATE_NO_AUX))
>        intel_miptree_choose_aux_usage(brw, mt);
>  
> @@ -2426,8 +2445,11 @@ intel_miptree_finish_write(struct brw_context *brw,
>  
>     switch (mt->aux_usage) {
>     case ISL_AUX_USAGE_NONE:
> -      if (mt->format == MESA_FORMAT_S_UINT8 && devinfo->gen <= 7)
> +      if (mt->format == MESA_FORMAT_S_UINT8 && devinfo->gen <= 7) {
> +         mt->shadow_needs_update = true;
> +      } else if (intel_miptree_has_etc_shadow(brw, mt)) {
>           mt->shadow_needs_update = true;
> +      }
>        break;
>  
>     case ISL_AUX_USAGE_MCS:
> @@ -3782,7 +3804,8 @@ intel_miptree_map(struct brw_context *brw,
>     if (mt->format == MESA_FORMAT_S_UINT8) {
>        intel_miptree_map_s8(brw, mt, map, level, slice);
>     } else if (mt->etc_format != MESA_FORMAT_NONE &&
> -              !(mode & BRW_MAP_DIRECT_BIT)) {
> +              !(mode & BRW_MAP_DIRECT_BIT) &&
> +              !(intel_miptree_needs_fake_etc(brw, mt))) {
>        intel_miptree_map_etc(brw, mt, map, level, slice);
>     } else if (mt->stencil_mt && !(mode & BRW_MAP_DIRECT_BIT)) {
>        intel_miptree_map_depthstencil(brw, mt, map, level, slice);
> @@ -3816,6 +3839,7 @@ intel_miptree_unmap(struct brw_context *brw,
>                      unsigned int slice)
>  {
>     struct intel_miptree_map *map = mt->level[level].slice[slice].map;
> +   int level_w, level_h;
>  
>     assert(mt->surf.samples == 1);
>  
> @@ -3825,10 +3849,20 @@ intel_miptree_unmap(struct brw_context *brw,
>     DBG("%s: mt %p (%s) level %d slice %d\n", __func__,
>         mt, _mesa_get_format_name(mt->format), level, slice);
>  
> +   level_w = minify(mt->surf.phys_level0_sa.width,
> +                    level - mt->first_level);
> +   level_h = minify(mt->surf.phys_level0_sa.height,
> +                    level - mt->first_level);
> +

I don't think phys_level0_sa is equivalent to logical_level0_px.

-Nanley

>     if (map->unmap)
>  	   map->unmap(brw, mt, map, level, slice);
>  
>     intel_miptree_release_map(mt, level, slice);
> +
> +   if (intel_miptree_has_etc_shadow(brw, mt) && mt->shadow_needs_update) {
> +      intel_miptree_update_etc_shadow(brw, mt, level, slice, level_w,
> +                                      level_h);
> +   }
>  }
>  
>  enum isl_surf_dim
> @@ -3943,3 +3977,81 @@ intel_miptree_get_clear_color(const struct gen_device_info *devinfo,
>        return mt->fast_clear_color;
>     }
>  }
> +
> +static void
> +intel_miptree_update_etc_shadow(struct brw_context *brw,
> +                                struct intel_mipmap_tree *mt,
> +                                unsigned int level,
> +                                unsigned int slice,
> +                                int level_w,
> +                                int level_h)
> +{
> +   struct intel_mipmap_tree *smt;
> +   ptrdiff_t etc_stride, shadow_stride;
> +   GLbitfield etc_mode, shadow_mode;
> +   void *mptr, *sptr;
> +
> +   assert(intel_miptree_has_etc_shadow(brw, mt));
> +   if (!mt->shadow_needs_update)
> +      return;
> +
> +   mt->shadow_needs_update = false;
> +   smt = mt->shadow_mt;
> +
> +   etc_mode = GL_MAP_READ_BIT;
> +   shadow_mode = GL_MAP_WRITE_BIT | GL_MAP_INVALIDATE_RANGE_BIT;
> +
> +   intel_miptree_map(brw, mt, level, slice, 0, 0, level_w, level_h,
> +                     etc_mode, &mptr, &etc_stride);
> +   intel_miptree_map(brw, smt, level, slice, 0, 0, level_w, level_h,
> +                     shadow_mode, &sptr, &shadow_stride);
> +
> +   if (mt->format == MESA_FORMAT_ETC1_RGB8) {
> +      _mesa_etc1_unpack_rgba8888(sptr, shadow_stride, mptr, etc_stride,
> +                                 level_w, level_h);
> +   } else {
> +      /* destination and source images must have the same swizzle */
> +      bool is_bgra = (smt->format == MESA_FORMAT_B8G8R8A8_SRGB);
> +      _mesa_unpack_etc2_format(sptr, shadow_stride, mptr, etc_stride,
> +                               level_w, level_h, mt->format, is_bgra);
> +   }
> +
> +   intel_miptree_unmap(brw, mt, level, slice);
> +   intel_miptree_unmap(brw, smt, level, slice);
> +}
> +
> +void
> +intel_miptree_update_etc_shadow_levels(struct brw_context *brw,
> +                                       struct intel_mipmap_tree *mt)
> +{
> +   struct intel_mipmap_tree *smt;
> +   int num_slices;
> +   int level_w, level_h;
> +
> +   assert(mt);
> +   assert(mt->surf.size_B > 0);
> +
> +   assert(intel_miptree_has_etc_shadow(brw, mt));
> +
> +   smt = mt->shadow_mt;
> +
> +   level_w = smt->surf.logical_level0_px.width;
> +   level_h = smt->surf.logical_level0_px.height;
> +
> +   num_slices = smt->surf.logical_level0_px.array_len;
> +
> +   for (int level = smt->first_level; level <= smt->last_level; level++)
> +   {
> +      for (unsigned int slice = 0; slice < num_slices; slice++) {
> +         intel_miptree_update_etc_shadow(brw, mt, level, slice, level_w,
> +                                         level_h);
> +      }
> +
> +      level_w = minify(mt->surf.logical_level0_px.width,
> +                       level - mt->first_level);
> +      level_h = minify(mt->surf.logical_level0_px.height,
> +                       level - mt->first_level);
> +   }
> +
> +   mt->shadow_needs_update = false;
> +}
> diff --git a/src/mesa/drivers/dri/i965/intel_mipmap_tree.h b/src/mesa/drivers/dri/i965/intel_mipmap_tree.h
> index 1a7507023a1..752aeaaf9b7 100644
> --- a/src/mesa/drivers/dri/i965/intel_mipmap_tree.h
> +++ b/src/mesa/drivers/dri/i965/intel_mipmap_tree.h
> @@ -301,6 +301,8 @@ struct intel_mipmap_tree
>      *
>      * This miptree may be used for:
>      * - Stencil texturing (pre-BDW) as required by GL_ARB_stencil_texturing.
> +    * - To store the decompressed ETC/EAC data in case we emulate the ETC
> +    *   compression on Gen 7 or earlier GPUs.
>      */
>     struct intel_mipmap_tree *shadow_mt;
>     bool shadow_needs_update;
> @@ -730,6 +732,28 @@ isl_memcpy_type
>  intel_miptree_get_memcpy_type(mesa_format tiledFormat, GLenum format, GLenum type,
>                                uint32_t *cpp);
>  
> +static inline bool
> +intel_miptree_needs_fake_etc(struct brw_context *brw,
> +                             struct intel_mipmap_tree *mt)
> +{
> +   const struct gen_device_info *devinfo = &brw->screen->devinfo;
> +   bool is_etc = _mesa_is_format_etc2(mt->format) ||
> +                 (mt->format == MESA_FORMAT_ETC1_RGB8);
> +
> +   return devinfo->gen < 8 && !devinfo->is_baytrail && is_etc;
> +}
> +
> +static inline bool
> +intel_miptree_has_etc_shadow(struct brw_context *brw,
> +                             struct intel_mipmap_tree *mt)
> +{
> +   return intel_miptree_needs_fake_etc(brw, mt) && mt->shadow_mt;
> +}
> +
> +void
> +intel_miptree_update_etc_shadow_levels(struct brw_context *brw,
> +                                       struct intel_mipmap_tree *mt);
> +
>  #ifdef __cplusplus
>  }
>  #endif
> -- 
> 2.20.1
> 


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