text: /*
   * Copyright © 2017 Intel Corporation
   *
   * Permission is hereby granted, free of charge, to any person obtaining a
   * copy of this software and associated documentation files (the "Software"),
   * to deal in the Software without restriction, including without limitation
   * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   * and/or sell copies of the Software, and to permit persons to whom the
   * Software is furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice (including the next
   * paragraph) shall be included in all copies or substantial portions of the
   * Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
   * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
   * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
   * IN THE SOFTWARE.
   */
  
  #include "anv_nir.h"
  #include "anv_private.h"
  #include "nir/nir.h"
  #include "nir/nir_builder.h"
  
  struct ycbcr_state {
     nir_builder *builder;
     nir_ssa_def *image_size;
     nir_tex_instr *origin_tex;
     nir_deref_instr *tex_deref;
     struct anv_ycbcr_conversion *conversion;
  };
  
  static nir_ssa_def *
  y_range(nir_builder *b,
          nir_ssa_def *y_channel,
          int bpc,
          VkSamplerYcbcrRange range)
  {
     switch (range) {
     case VK_SAMPLER_YCBCR_RANGE_ITU_FULL:
        return y_channel;
     case VK_SAMPLER_YCBCR_RANGE_ITU_NARROW:
        return nir_fmul(b,
                        nir_fadd(b,
                                 nir_fmul(b, y_channel,
                                          nir_imm_float(b, pow(2, bpc) - 1)),
                                 nir_imm_float(b, -16.0f * pow(2, bpc - 8))),
                        nir_frcp(b, nir_imm_float(b, 219.0f * pow(2, bpc - 8))));
     default:
        unreachable("missing Ycbcr range");
        return NULL;
     }
  }
  
  static nir_ssa_def *
  chroma_range(nir_builder *b,
               nir_ssa_def *chroma_channel,
               int bpc,
               VkSamplerYcbcrRange range)
  {
     switch (range) {
     case VK_SAMPLER_YCBCR_RANGE_ITU_FULL:
        return nir_fadd(b, chroma_channel,
                        nir_imm_float(b, -pow(2, bpc - 1) / (pow(2, bpc) - 1.0f)));
     case VK_SAMPLER_YCBCR_RANGE_ITU_NARROW:
        return nir_fmul(b,
                        nir_fadd(b,
                                 nir_fmul(b, chroma_channel,
                                          nir_imm_float(b, pow(2, bpc) - 1)),
                                 nir_imm_float(b, -128.0f * pow(2, bpc - 8))),
                        nir_frcp(b, nir_imm_float(b, 224.0f * pow(2, bpc - 8))));
     default:
        unreachable("missing Ycbcr range");
        return NULL;
     }
  }
  
  typedef struct nir_const_value_3_4 {
     nir_const_value v[3][4];
  } nir_const_value_3_4;
  
  static const nir_const_value_3_4 *
  ycbcr_model_to_rgb_matrix(VkSamplerYcbcrModelConversion model)
  {
     switch (model) {
     case VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_601: {
        static const nir_const_value_3_4 bt601 = { {
           { { .f32 =  1.402f             }, { .f32 = 1.0f }, { .f32 =  0.0f               }, { .f32 = 0.0f } },
           { { .f32 = -0.714136286201022f }, { .f32 = 1.0f }, { .f32 = -0.344136286201022f }, { .f32 = 0.0f } },
           { { .f32 =  0.0f               }, { .f32 = 1.0f }, { .f32 =  1.772f             }, { .f32 = 0.0f } },
        } };
  
        return &bt601;
     }
     case VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_709: {
        static const nir_const_value_3_4 bt709 = { {
           { { .f32 =  1.5748031496063f   }, { .f32 = 1.0f }, { .f32 =  0.0f               }, { .f32 = 0.0f } },
           { { .f32 = -0.468125209181067f }, { .f32 = 1.0f }, { .f32 = -0.187327487470334f }, { .f32 = 0.0f } },
           { { .f32 =  0.0f               }, { .f32 = 1.0f }, { .f32 =  1.85563184264242f  }, { .f32 = 0.0f } },
        } };
  
        return &bt709;
     }
     case VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_2020: {
        static const nir_const_value_3_4 bt2020 = { {
           { { .f32 =  1.4746f            }, { .f32 = 1.0f }, { .f32 =  0.0f               }, { .f32 = 0.0f } },
           { { .f32 = -0.571353126843658f }, { .f32 = 1.0f }, { .f32 = -0.164553126843658f }, { .f32 = 0.0f } },
           { { .f32 =  0.0f               }, { .f32 = 1.0f }, { .f32 =  1.8814f            }, { .f32 = 0.0f } },
        } };
  
        return &bt2020;
     }
     default:
        unreachable("missing Ycbcr model");
        return NULL;
     }
  }
  
  static nir_ssa_def *
  convert_ycbcr(struct ycbcr_state *state,
                nir_ssa_def *raw_channels,
                uint32_t *bpcs)
  {
     nir_builder *b = state->builder;
     struct anv_ycbcr_conversion *conversion = state->conversion;
  
     nir_ssa_def *expanded_channels =
        nir_vec4(b,
                 chroma_range(b, nir_channel(b, raw_channels, 0),
                              bpcs[0], conversion->ycbcr_range),
                 y_range(b, nir_channel(b, raw_channels, 1),
                         bpcs[1], conversion->ycbcr_range),
                 chroma_range(b, nir_channel(b, raw_channels, 2),
                              bpcs[2], conversion->ycbcr_range),
                 nir_imm_float(b, 1.0f));
  
     if (conversion->ycbcr_model == VK_SAMPLER_YCBCR_MODEL_CONVERSION_YCBCR_IDENTITY)
        return expanded_channels;
  
     const nir_const_value_3_4 *conversion_matrix =
        ycbcr_model_to_rgb_matrix(conversion->ycbcr_model);
  
     nir_ssa_def *converted_channels[] = {
        nir_fdot4(b, expanded_channels, nir_build_imm(b, 4, 32, conversion_matrix->v[0])),
        nir_fdot4(b, expanded_channels, nir_build_imm(b, 4, 32, conversion_matrix->v[1])),
        nir_fdot4(b, expanded_channels, nir_build_imm(b, 4, 32, conversion_matrix->v[2]))
     };
  
     return nir_vec4(b,
                     converted_channels[0], converted_channels[1],
                     converted_channels[2], nir_imm_float(b, 1.0f));
  }
  
  /* TODO: we should probably replace this with a push constant/uniform. */
  static nir_ssa_def *
  get_texture_size(struct ycbcr_state *state, nir_deref_instr *texture)
  {
     if (state->image_size)
        return state->image_size;
  
     nir_builder *b = state->builder;
     const struct glsl_type *type = texture->type;
     nir_tex_instr *tex = nir_tex_instr_create(b->shader, 1);
  
     tex->op = nir_texop_txs;
     tex->sampler_dim = glsl_get_sampler_dim(type);
     tex->is_array = glsl_sampler_type_is_array(type);
     tex->is_shadow = glsl_sampler_type_is_shadow(type);
     tex->dest_type = nir_type_int;
  
     tex->src[0].src_type = nir_tex_src_texture_deref;
     tex->src[0].src = nir_src_for_ssa(&texture->dest.ssa);
  
     nir_ssa_dest_init(&tex->instr, &tex->dest,
                       nir_tex_instr_dest_size(tex), 32, NULL);
     nir_builder_instr_insert(b, &tex->instr);
  
     state->image_size = nir_i2f32(b, &tex->dest.ssa);
  
     return state->image_size;
  }
  
  static nir_ssa_def *
  implicit_downsampled_coord(nir_builder *b,
                             nir_ssa_def *value,
                             nir_ssa_def *max_value,
                             int div_scale)
  {
     return nir_fadd(b,
                     value,
                     nir_fdiv(b,
                              nir_imm_float(b, 1.0f),
                              nir_fmul(b,
                                       nir_imm_float(b, div_scale),
                                       max_value)));
  }
  
  static nir_ssa_def *
  implicit_downsampled_coords(struct ycbcr_state *state,
                              nir_ssa_def *old_coords,
                              const struct anv_format_plane *plane_format)
  {
     nir_builder *b = state->builder;
     struct anv_ycbcr_conversion *conversion = state->conversion;
     nir_ssa_def *image_size = get_texture_size(state, state->tex_deref);
     nir_ssa_def *comp[4] = { NULL, };
     int c;
  
     for (c = 0; c < ARRAY_SIZE(conversion->chroma_offsets); c++) {
        if (plane_format->denominator_scales[c] > 1 &&
            conversion->chroma_offsets[c] == VK_CHROMA_LOCATION_COSITED_EVEN) {
           comp[c] = implicit_downsampled_coord(b,
                                                nir_channel(b, old_coords, c),
                                                nir_channel(b, image_size, c),
                                                plane_format->denominator_scales[c]);
        } else {
           comp[c] = nir_channel(b, old_coords, c);
        }
     }
  
     /* Leave other coordinates untouched */
     for (; c < old_coords->num_components; c++)
        comp[c] = nir_channel(b, old_coords, c);
  
     return nir_vec(b, comp, old_coords->num_components);
  }
  
  static nir_ssa_def *
  create_plane_tex_instr_implicit(struct ycbcr_state *state,
                                  uint32_t plane)
  {
     nir_builder *b = state->builder;
     struct anv_ycbcr_conversion *conversion = state->conversion;
     const struct anv_format_plane *plane_format =
        &conversion->format->planes[plane];
     nir_tex_instr *old_tex = state->origin_tex;
     nir_tex_instr *tex = nir_tex_instr_create(b->shader, old_tex->num_srcs + 1);
  
     for (uint32_t i = 0; i < old_tex->num_srcs; i++) {
        tex->src[i].src_type = old_tex->src[i].src_type;
  
        switch (old_tex->src[i].src_type) {
        case nir_tex_src_coord:
           if (plane_format->has_chroma && conversion->chroma_reconstruction) {
              assert(old_tex->src[i].src.is_ssa);
              tex->src[i].src =
                 nir_src_for_ssa(implicit_downsampled_coords(state,
                                                             old_tex->src[i].src.ssa,
                                                             plane_format));
              break;
           }
           /* fall through */
        default:
           nir_src_copy(&tex->src[i].src, &old_tex->src[i].src, tex);
           break;
        }
     }
     tex->src[tex->num_srcs - 1].src = nir_src_for_ssa(nir_imm_int(b, plane));
     tex->src[tex->num_srcs - 1].src_type = nir_tex_src_plane;
  
     tex->sampler_dim = old_tex->sampler_dim;
     tex->dest_type = old_tex->dest_type;
  
     tex->op = old_tex->op;
     tex->coord_components = old_tex->coord_components;
     tex->is_new_style_shadow = old_tex->is_new_style_shadow;
     tex->component = old_tex->component;
  
     tex->texture_index = old_tex->texture_index;
     tex->texture_array_size = old_tex->texture_array_size;
     tex->sampler_index = old_tex->sampler_index;
     tex->is_array = old_tex->is_array;
  
     nir_ssa_dest_init(&tex->instr, &tex->dest,
                       old_tex->dest.ssa.num_components,
                       nir_dest_bit_size(old_tex->dest), NULL);
     nir_builder_instr_insert(b, &tex->instr);
  
     return &tex->dest.ssa;
  }
  
  static unsigned
  channel_to_component(enum isl_channel_select channel)
  {
     switch (channel) {
     case ISL_CHANNEL_SELECT_RED:
        return 0;
     case ISL_CHANNEL_SELECT_GREEN:
        return 1;
     case ISL_CHANNEL_SELECT_BLUE:
        return 2;
     case ISL_CHANNEL_SELECT_ALPHA:
        return 3;
     default:
        unreachable("invalid channel");
        return 0;
     }
  }
  
  static enum isl_channel_select
  swizzle_channel(struct isl_swizzle swizzle, unsigned channel)
  {
     switch (channel) {
     case 0:
        return swizzle.r;
     case 1:
        return swizzle.g;
     case 2:
        return swizzle.b;
     case 3:
        return swizzle.a;
     default:
        unreachable("invalid channel");
        return 0;
     }
  }
  
  static bool
  try_lower_tex_ycbcr(const struct anv_pipeline_layout *layout,
                      nir_builder *builder,
                      nir_tex_instr *tex)
  {
     int deref_src_idx = nir_tex_instr_src_index(tex, nir_tex_src_texture_deref);
     assert(deref_src_idx >= 0);
     nir_deref_instr *deref = nir_src_as_deref(tex->src[deref_src_idx].src);
  
     nir_variable *var = nir_deref_instr_get_variable(deref);
     const struct anv_descriptor_set_layout *set_layout =
        layout->set[var->data.descriptor_set].layout;
     const struct anv_descriptor_set_binding_layout *binding =
        &set_layout->binding[var->data.binding];
  
     /* For the following instructions, we don't apply any change and let the
      * instruction apply to the first plane.
      */
     if (tex->op == nir_texop_txs ||
         tex->op == nir_texop_query_levels ||
         tex->op == nir_texop_lod)
        return false;
  
     if (binding->immutable_samplers == NULL)
        return false;
  
     assert(tex->texture_index == 0);
     unsigned array_index = 0;
     if (deref->deref_type != nir_deref_type_var) {
        assert(deref->deref_type == nir_deref_type_array);
        if (!nir_src_is_const(deref->arr.index))
           return false;
        array_index = nir_src_as_uint(deref->arr.index);
        array_index = MIN2(array_index, binding->array_size - 1);
     }
     const struct anv_sampler *sampler = binding->immutable_samplers[array_index];
  
     if (sampler->conversion == NULL)
        return false;
  
     struct ycbcr_state state = {
        .builder = builder,
        .origin_tex = tex,
        .tex_deref = deref,
        .conversion = sampler->conversion,
     };
  
     builder->cursor = nir_before_instr(&tex->instr);
  
     const struct anv_format *format = state.conversion->format;
     const struct isl_format_layout *y_isl_layout = NULL;
     for (uint32_t p = 0; p < format->n_planes; p++) {
        if (!format->planes[p].has_chroma)
           y_isl_layout = isl_format_get_layout(format->planes[p].isl_format);
     }
     assert(y_isl_layout != NULL);
     uint8_t y_bpc = y_isl_layout->channels_array[0].bits;
  
     /* |ycbcr_comp| holds components in the order : Cr-Y-Cb */
     nir_ssa_def *zero = nir_imm_float(builder, 0.0f);
     nir_ssa_def *one = nir_imm_float(builder, 1.0f);
     /* Use extra 2 channels for following swizzle */
     nir_ssa_def *ycbcr_comp[5] = { zero, zero, zero, one, zero };
  
     uint8_t ycbcr_bpcs[5];
     memset(ycbcr_bpcs, y_bpc, sizeof(ycbcr_bpcs));
  
     /* Go through all the planes and gather the samples into a |ycbcr_comp|
      * while applying a swizzle required by the spec:
      *
      *    R, G, B should respectively map to Cr, Y, Cb
      */
     for (uint32_t p = 0; p < format->n_planes; p++) {
        const struct anv_format_plane *plane_format = &format->planes[p];
        nir_ssa_def *plane_sample = create_plane_tex_instr_implicit(&state, p);
  
        for (uint32_t pc = 0; pc < 4; pc++) {
           enum isl_channel_select ycbcr_swizzle =
              swizzle_channel(plane_format->ycbcr_swizzle, pc);
           if (ycbcr_swizzle == ISL_CHANNEL_SELECT_ZERO)
              continue;
  
           unsigned ycbcr_component = channel_to_component(ycbcr_swizzle);
           ycbcr_comp[ycbcr_component] = nir_channel(builder, plane_sample, pc);
  
           /* Also compute the number of bits for each component. */
           const struct isl_format_layout *isl_layout =
              isl_format_get_layout(plane_format->isl_format);
           ycbcr_bpcs[ycbcr_component] = isl_layout->channels_array[pc].bits;
        }
     }
  
     /* Now remaps components to the order specified by the conversion. */
     nir_ssa_def *swizzled_comp[4] = { NULL, };
     uint32_t swizzled_bpcs[4] = { 0, };
  
     for (uint32_t i = 0; i < ARRAY_SIZE(state.conversion->mapping); i++) {
        /* Maps to components in |ycbcr_comp| */
        static const uint32_t swizzle_mapping[] = {
           [VK_COMPONENT_SWIZZLE_ZERO] = 4,
           [VK_COMPONENT_SWIZZLE_ONE]  = 3,
           [VK_COMPONENT_SWIZZLE_R]    = 0,
           [VK_COMPONENT_SWIZZLE_G]    = 1,
           [VK_COMPONENT_SWIZZLE_B]    = 2,
           [VK_COMPONENT_SWIZZLE_A]    = 3,
        };
        const VkComponentSwizzle m = state.conversion->mapping[i];
  
        if (m == VK_COMPONENT_SWIZZLE_IDENTITY) {
           swizzled_comp[i] = ycbcr_comp[i];
           swizzled_bpcs[i] = ycbcr_bpcs[i];
        } else {
           swizzled_comp[i] = ycbcr_comp[swizzle_mapping[m]];
           swizzled_bpcs[i] = ycbcr_bpcs[swizzle_mapping[m]];
        }
     }
  
     nir_ssa_def *result = nir_vec(builder, swizzled_comp, 4);
     if (state.conversion->ycbcr_model != VK_SAMPLER_YCBCR_MODEL_CONVERSION_RGB_IDENTITY)
        result = convert_ycbcr(&state, result, swizzled_bpcs);
  
     nir_ssa_def_rewrite_uses(&tex->dest.ssa, nir_src_for_ssa(result));
     nir_instr_remove(&tex->instr);
  
     return true;
  }
  
  bool
  anv_nir_lower_ycbcr_textures(nir_shader *shader,
                               const struct anv_pipeline_layout *layout)
  {
     bool progress = false;
  
     nir_foreach_function(function, shader) {
        if (!function->impl)
           continue;
  
        bool function_progress = false;
        nir_builder builder;
        nir_builder_init(&builder, function->impl);
  
        nir_foreach_block(block, function->impl) {
           nir_foreach_instr_safe(instr, block) {
              if (instr->type != nir_instr_type_tex)
                 continue;
  
              nir_tex_instr *tex = nir_instr_as_tex(instr);
              function_progress |= try_lower_tex_ycbcr(layout, &builder, tex);
           }
        }
  
        if (function_progress) {
           nir_metadata_preserve(function->impl,
                                 nir_metadata_block_index |
                                 nir_metadata_dominance);
        }
  
        progress |= function_progress;
     }
  
     return progress;
  }
  