src/intel/vulkan/anv_nir_lower_ycbcr_textures.c - third_party/mesa - Git at Google

 /*
  * 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(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,
                              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;
 }
	/*
	* 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(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,
	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;
	}