[Mesa-dev] [PATCH 11/11] i965: Use nir_lower_tex for texture coordinate lowering

Iago Toral itoral at igalia.com
Mon Nov 16 23:56:18 PST 2015


On Mon, 2015-11-16 at 07:55 -0800, Jason Ekstrand wrote:
> On Mon, Nov 16, 2015 at 6:27 AM, Iago Toral <itoral at igalia.com> wrote:
> > On Mon, 2015-11-16 at 11:33 +0100, Iago Toral wrote:
> >> On Wed, 2015-11-11 at 17:26 -0800, Jason Ekstrand wrote:
> >> > Previously, we had a rescale_texcoords helper in the FS backend for
> >> > handling rescaling of texture coordinates.  Now that we can do variants in
> >> > NIR, we can use nir_lower_tex to do the rescaling for us.  This allows us
> >> > to delete the i965-specific code and gives us proper TEXTURE_RECTANGLE and
> >> > GL_CLAMP handling in vertex and geometry shaders.
> >> > ---
> >> >  src/mesa/drivers/dri/i965/brw_fs.cpp              |   2 +
> >> >  src/mesa/drivers/dri/i965/brw_fs.h                |   3 -
> >> >  src/mesa/drivers/dri/i965/brw_fs_nir.cpp          |   4 +-
> >> >  src/mesa/drivers/dri/i965/brw_fs_visitor.cpp      | 125 ----------------------
> >> >  src/mesa/drivers/dri/i965/brw_nir.c               |  23 ++++
> >> >  src/mesa/drivers/dri/i965/brw_nir.h               |   6 ++
> >> >  src/mesa/drivers/dri/i965/brw_vec4.cpp            |   2 +
> >> >  src/mesa/drivers/dri/i965/brw_vec4_gs_visitor.cpp |   2 +
> >> >  8 files changed, 36 insertions(+), 131 deletions(-)
> >> >
> >> > diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp
> >> > index b8713ab..c56cafe 100644
> >> > --- a/src/mesa/drivers/dri/i965/brw_fs.cpp
> >> > +++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
> >> > @@ -5468,6 +5468,7 @@ brw_compile_fs(const struct brw_compiler *compiler, void *log_data,
> >> >                 char **error_str)
> >> >  {
> >> >     nir_shader *shader = nir_shader_clone(mem_ctx, src_shader);
> >> > +   brw_nir_apply_sampler_key(shader, compiler->devinfo, &key->tex, true);
> >>
> >> This looks like it is part of the post-processing process. In fact, you
> >> call this right before brw_postprocess_nir() for every stage. Why not
> >> just add a key parameter to brw_postprocess_nir() and call
> >> brw_nir_apply_sampler_key from there instead?
> 
> Well, right now, brw_nir_apply_sampler_key is used for all stages.
> However, if we do more variant stuff in NIR, we'll need to have
> brw_nir_apply_vs_key, brw_nir_apply_fs_key, etc. and we can't put it
> in postprocess_nir.  I didn't want to join it prematurely.

Oh right, that makes sense.

> >> Either way,
> >> Reviewed-by: Iago Toral Quiroga <itoral at igalia.com>
> 
> Thanks!
> 
> >> >     brw_postprocess_nir(shader, compiler->devinfo, true);
> >> >
> >> >     /* key->alpha_test_func means simulating alpha testing via discards,
> >> > @@ -5628,6 +5629,7 @@ brw_compile_cs(const struct brw_compiler *compiler, void *log_data,
> >> >                 char **error_str)
> >> >  {
> >> >     nir_shader *shader = nir_shader_clone(mem_ctx, src_shader);
> >> > +   brw_nir_apply_sampler_key(shader, compiler->devinfo, &key->tex, true);
> >> >     brw_postprocess_nir(shader, compiler->devinfo, true);
> >> >
> >> >     prog_data->local_size[0] = shader->info.cs.local_size[0];
> >> > diff --git a/src/mesa/drivers/dri/i965/brw_fs.h b/src/mesa/drivers/dri/i965/brw_fs.h
> >> > index 2dfcab1..8a181d7 100644
> >> > --- a/src/mesa/drivers/dri/i965/brw_fs.h
> >> > +++ b/src/mesa/drivers/dri/i965/brw_fs.h
> >> > @@ -217,8 +217,6 @@ public:
> >> >     void emit_interpolation_setup_gen4();
> >> >     void emit_interpolation_setup_gen6();
> >> >     void compute_sample_position(fs_reg dst, fs_reg int_sample_pos);
> >> > -   fs_reg rescale_texcoord(fs_reg coordinate, int coord_components,
> >> > -                           bool is_rect, uint32_t sampler);
> >> >     void emit_texture(ir_texture_opcode op,
> >> >                       const glsl_type *dest_type,
> >> >                       fs_reg coordinate, int components,
> >> > @@ -229,7 +227,6 @@ public:
> >> >                       fs_reg mcs,
> >> >                       int gather_component,
> >> >                       bool is_cube_array,
> >> > -                     bool is_rect,
> >> >                       uint32_t sampler,
> >> >                       fs_reg sampler_reg);
> >> >     fs_reg emit_mcs_fetch(const fs_reg &coordinate, unsigned components,
> >> > diff --git a/src/mesa/drivers/dri/i965/brw_fs_nir.cpp b/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
> >> > index 02b9f5b..3d83d7c 100644
> >> > --- a/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
> >> > +++ b/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
> >> > @@ -2411,8 +2411,6 @@ fs_visitor::nir_emit_texture(const fs_builder &bld, nir_tex_instr *instr)
> >> >
> >> >     int gather_component = instr->component;
> >> >
> >> > -   bool is_rect = instr->sampler_dim == GLSL_SAMPLER_DIM_RECT;
> >> > -
> >> >     bool is_cube_array = instr->sampler_dim == GLSL_SAMPLER_DIM_CUBE &&
> >> >                          instr->is_array;
> >> >
> >> > @@ -2549,7 +2547,7 @@ fs_visitor::nir_emit_texture(const fs_builder &bld, nir_tex_instr *instr)
> >> >     emit_texture(op, dest_type, coordinate, instr->coord_components,
> >> >                  shadow_comparitor, lod, lod2, lod_components, sample_index,
> >> >                  tex_offset, mcs, gather_component,
> >> > -                is_cube_array, is_rect, sampler, sampler_reg);
> >> > +                is_cube_array, sampler, sampler_reg);
> >> >
> >> >     fs_reg dest = get_nir_dest(instr->dest);
> >> >     dest.type = this->result.type;
> >> > diff --git a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
> >> > index 213c912..faf304c 100644
> >> > --- a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
> >> > +++ b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
> >> > @@ -79,122 +79,6 @@ fs_visitor::emit_vs_system_value(int location)
> >> >     return reg;
> >> >  }
> >> >
> >> > -fs_reg
> >> > -fs_visitor::rescale_texcoord(fs_reg coordinate, int coord_components,
> >> > -                             bool is_rect, uint32_t sampler)
> >> > -{
> >> > -   bool needs_gl_clamp = true;
> >> > -   fs_reg scale_x, scale_y;
> >> > -
> >> > -   /* The 965 requires the EU to do the normalization of GL rectangle
> >> > -    * texture coordinates.  We use the program parameter state
> >> > -    * tracking to get the scaling factor.
> >> > -    */
> >> > -   if (is_rect &&
> >> > -       (devinfo->gen < 6 ||
> >> > -        (devinfo->gen >= 6 && (key_tex->gl_clamp_mask[0] & (1 << sampler) ||
> >> > -                               key_tex->gl_clamp_mask[1] & (1 << sampler))))) {
> >> > -      struct gl_program_parameter_list *params = prog->Parameters;
> >> > -
> >> > -
> >> > -      /* FINISHME: We're failing to recompile our programs when the sampler is
> >> > -       * updated.  This only matters for the texture rectangle scale
> >> > -       * parameters (pre-gen6, or gen6+ with GL_CLAMP).
> >> > -       */
> >> > -      int tokens[STATE_LENGTH] = {
> >> > -    STATE_INTERNAL,
> >> > -    STATE_TEXRECT_SCALE,
> >> > -    prog->SamplerUnits[sampler],
> >> > -    0,
> >> > -    0
> >> > -      };
> >> > -
> >> > -      no16("rectangle scale uniform setup not supported on SIMD16\n");
> >> > -      if (dispatch_width == 16) {
> >> > -    return coordinate;
> >> > -      }
> >> > -
> >> > -      GLuint index = _mesa_add_state_reference(params,
> >> > -                                          (gl_state_index *)tokens);
> >> > -      /* Try to find existing copies of the texrect scale uniforms. */
> >> > -      for (unsigned i = 0; i < uniforms; i++) {
> >> > -         if (stage_prog_data->param[i] ==
> >> > -             &prog->Parameters->ParameterValues[index][0]) {
> >> > -            scale_x = fs_reg(UNIFORM, i);
> >> > -            scale_y = fs_reg(UNIFORM, i + 1);
> >> > -            break;
> >> > -         }
> >> > -      }
> >> > -
> >> > -      /* If we didn't already set them up, do so now. */
> >> > -      if (scale_x.file == BAD_FILE) {
> >> > -         scale_x = fs_reg(UNIFORM, uniforms);
> >> > -         scale_y = fs_reg(UNIFORM, uniforms + 1);
> >> > -
> >> > -         stage_prog_data->param[uniforms++] =
> >> > -            &prog->Parameters->ParameterValues[index][0];
> >> > -         stage_prog_data->param[uniforms++] =
> >> > -            &prog->Parameters->ParameterValues[index][1];
> >> > -      }
> >> > -   }
> >> > -
> >> > -   /* The 965 requires the EU to do the normalization of GL rectangle
> >> > -    * texture coordinates.  We use the program parameter state
> >> > -    * tracking to get the scaling factor.
> >> > -    */
> >> > -   if (devinfo->gen < 6 && is_rect) {
> >> > -      fs_reg dst = fs_reg(GRF, alloc.allocate(coord_components));
> >> > -      fs_reg src = coordinate;
> >> > -      coordinate = dst;
> >> > -
> >> > -      bld.MUL(dst, src, scale_x);
> >> > -      dst = offset(dst, bld, 1);
> >> > -      src = offset(src, bld, 1);
> >> > -      bld.MUL(dst, src, scale_y);
> >> > -   } else if (is_rect) {
> >> > -      /* On gen6+, the sampler handles the rectangle coordinates
> >> > -       * natively, without needing rescaling.  But that means we have
> >> > -       * to do GL_CLAMP clamping at the [0, width], [0, height] scale,
> >> > -       * not [0, 1] like the default case below.
> >> > -       */
> >> > -      needs_gl_clamp = false;
> >> > -
> >> > -      for (int i = 0; i < 2; i++) {
> >> > -    if (key_tex->gl_clamp_mask[i] & (1 << sampler)) {
> >> > -       fs_reg chan = coordinate;
> >> > -       chan = offset(chan, bld, i);
> >> > -
> >> > -            set_condmod(BRW_CONDITIONAL_GE,
> >> > -                        bld.emit(BRW_OPCODE_SEL, chan, chan, fs_reg(0.0f)));
> >> > -
> >> > -       /* Our parameter comes in as 1.0/width or 1.0/height,
> >> > -        * because that's what people normally want for doing
> >> > -        * texture rectangle handling.  We need width or height
> >> > -        * for clamping, but we don't care enough to make a new
> >> > -        * parameter type, so just invert back.
> >> > -        */
> >> > -       fs_reg limit = vgrf(glsl_type::float_type);
> >> > -            bld.MOV(limit, i == 0 ? scale_x : scale_y);
> >> > -            bld.emit(SHADER_OPCODE_RCP, limit, limit);
> >> > -
> >> > -            set_condmod(BRW_CONDITIONAL_L,
> >> > -                        bld.emit(BRW_OPCODE_SEL, chan, chan, limit));
> >> > -    }
> >> > -      }
> >> > -   }
> >> > -
> >> > -   if (coord_components > 0 && needs_gl_clamp) {
> >> > -      for (int i = 0; i < MIN2(coord_components, 3); i++) {
> >> > -    if (key_tex->gl_clamp_mask[i] & (1 << sampler)) {
> >> > -       fs_reg chan = coordinate;
> >> > -       chan = offset(chan, bld, i);
> >> > -            set_saturate(true, bld.MOV(chan, chan));
> >> > -    }
> >> > -      }
> >> > -   }
> >> > -   return coordinate;
> >> > -}
> >> > -
> >> >  /* Sample from the MCS surface attached to this multisample texture. */
> >> >  fs_reg
> >> >  fs_visitor::emit_mcs_fetch(const fs_reg &coordinate, unsigned components,
> >> > @@ -227,7 +111,6 @@ fs_visitor::emit_texture(ir_texture_opcode op,
> >> >                           fs_reg mcs,
> >> >                           int gather_component,
> >> >                           bool is_cube_array,
> >> > -                         bool is_rect,
> >> >                           uint32_t sampler,
> >> >                           fs_reg sampler_reg)
> >> >  {
> >> > @@ -259,14 +142,6 @@ fs_visitor::emit_texture(ir_texture_opcode op,
> >> >        lod = fs_reg(0u);
> >> >     }
> >> >
> >> > -   if (coordinate.file != BAD_FILE) {
> >> > -      /* FINISHME: Texture coordinate rescaling doesn't work with non-constant
> >> > -       * samplers.  This should only be a problem with GL_CLAMP on Gen7.
> >> > -       */
> >> > -      coordinate = rescale_texcoord(coordinate, coord_components, is_rect,
> >> > -                                    sampler);
> >> > -   }
> >> > -
> >> >     /* Writemasking doesn't eliminate channels on SIMD8 texture
> >> >      * samples, so don't worry about them.
> >> >      */
> >> > diff --git a/src/mesa/drivers/dri/i965/brw_nir.c b/src/mesa/drivers/dri/i965/brw_nir.c
> >> > index 693b9cd..3999a60 100644
> >> > --- a/src/mesa/drivers/dri/i965/brw_nir.c
> >> > +++ b/src/mesa/drivers/dri/i965/brw_nir.c
> >> > @@ -395,6 +395,29 @@ brw_create_nir(struct brw_context *brw,
> >> >     return nir;
> >> >  }
> >> >
> >> > +void
> >> > +brw_nir_apply_sampler_key(nir_shader *nir,
> >> > +                          const struct brw_device_info *devinfo,
> >> > +                          const struct brw_sampler_prog_key_data *key_tex,
> >> > +                          bool is_scalar)
> >> > +{
> >> > +   nir_lower_tex_options tex_options = { 0 };
> >> > +
> >> > +   /* Iron Lake and prior require lowering of all rectangle textures */
> >> > +   if (devinfo->gen < 6)
> >> > +      tex_options.lower_rect = true;
> >> > +
> >> > +   /* Prior to Broadwell, our hardware can't actually do GL_CLAMP */
> >> > +   if (devinfo->gen < 8) {
> >> > +      tex_options.saturate_s = key_tex->gl_clamp_mask[0];
> >> > +      tex_options.saturate_t = key_tex->gl_clamp_mask[1];
> >> > +      tex_options.saturate_r = key_tex->gl_clamp_mask[2];
> >> > +   }
> >> > +
> >> > +   if (nir_lower_tex(nir, &tex_options))
> >> > +      nir_optimize(nir, is_scalar);
> >
> > Based on the code above I guess we only want to execute nir_lower_tex if
> > gen < 8 too.
> 
> It's a no-op in that case and returns false so it's not a big deal.
> The second series uses it to do texture swizzle and that we have to do
> on all gens so I didn't see a good reason put it in an if.  I can if
> you'd like.  It would be a tad more efficient.  Or, for that matter,
> we could make nir_lower_tex early-exit if it has nothing interesting
> to do.
> 
> > Iago
> >
> >> > +}
> >> > +
> >> >  enum brw_reg_type
> >> >  brw_type_for_nir_type(nir_alu_type type)
> >> >  {
> >> > diff --git a/src/mesa/drivers/dri/i965/brw_nir.h b/src/mesa/drivers/dri/i965/brw_nir.h
> >> > index 1cdfe00..a399992 100644
> >> > --- a/src/mesa/drivers/dri/i965/brw_nir.h
> >> > +++ b/src/mesa/drivers/dri/i965/brw_nir.h
> >> > @@ -90,6 +90,12 @@ void brw_postprocess_nir(nir_shader *nir,
> >> >                           const struct brw_device_info *devinfo,
> >> >                           bool is_scalar);
> >> >
> >> > +
> >> > +void brw_nir_apply_sampler_key(nir_shader *nir,
> >> > +                               const struct brw_device_info *devinfo,
> >> > +                               const struct brw_sampler_prog_key_data *key,
> >> > +                               bool is_scalar);
> >> > +
> >> >  enum brw_reg_type brw_type_for_nir_type(nir_alu_type type);
> >> >
> >> >  enum glsl_base_type brw_glsl_base_type_for_nir_type(nir_alu_type type);
> >> > diff --git a/src/mesa/drivers/dri/i965/brw_vec4.cpp b/src/mesa/drivers/dri/i965/brw_vec4.cpp
> >> > index 9f75bb6..d207180 100644
> >> > --- a/src/mesa/drivers/dri/i965/brw_vec4.cpp
> >> > +++ b/src/mesa/drivers/dri/i965/brw_vec4.cpp
> >> > @@ -2036,6 +2036,8 @@ brw_compile_vs(const struct brw_compiler *compiler, void *log_data,
> >> >                 char **error_str)
> >> >  {
> >> >     nir_shader *shader = nir_shader_clone(mem_ctx, src_shader);
> >> > +   brw_nir_apply_sampler_key(shader, compiler->devinfo, &key->tex,
> >> > +                             compiler->scalar_vs);
> >> >     brw_postprocess_nir(shader, compiler->devinfo, compiler->scalar_vs);
> >> >
> >> >     const unsigned *assembly = NULL;
> >> > diff --git a/src/mesa/drivers/dri/i965/brw_vec4_gs_visitor.cpp b/src/mesa/drivers/dri/i965/brw_vec4_gs_visitor.cpp
> >> > index 92b15d9..4caf54e 100644
> >> > --- a/src/mesa/drivers/dri/i965/brw_vec4_gs_visitor.cpp
> >> > +++ b/src/mesa/drivers/dri/i965/brw_vec4_gs_visitor.cpp
> >> > @@ -616,6 +616,8 @@ brw_compile_gs(const struct brw_compiler *compiler, void *log_data,
> >> >     c.key = *key;
> >> >
> >> >     nir_shader *shader = nir_shader_clone(mem_ctx, src_shader);
> >> > +   brw_nir_apply_sampler_key(shader, compiler->devinfo, &key->tex,
> >> > +                             compiler->scalar_gs);
> >> >     brw_postprocess_nir(shader, compiler->devinfo, compiler->scalar_gs);
> >> >
> >> >     prog_data->include_primitive_id =
> >>
> >
> >
> 




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