src/compiler/nir/nir_lower_samplers.c

   1 /*
   2  * Copyright (C) 2005-2007  Brian Paul   All Rights Reserved.
   3  * Copyright (C) 2008  VMware, Inc.   All Rights Reserved.
   4  * Copyright © 2014 Intel Corporation
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a
   7  * copy of this software and associated documentation files (the "Software"),
   8  * to deal in the Software without restriction, including without limitation
   9  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  10  * and/or sell copies of the Software, and to permit persons to whom the
  11  * Software is furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice (including the next
  14  * paragraph) shall be included in all copies or substantial portions of the
  15  * Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  20  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  22  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  23  * DEALINGS IN THE SOFTWARE.
  24  */
  25
  26 #include "nir.h"
  27 #include "nir_builder.h"
  28 #include "program/hash_table.h"
  29 #include "compiler/glsl/ir_uniform.h"
  30
  31 #include "main/compiler.h"
  32 #include "main/mtypes.h"
  33 #include "program/prog_parameter.h"
  34 #include "program/program.h"
  35
  36 /* Calculate the sampler index based on array indicies and also
  37  * calculate the base uniform location for struct members.
  38  */
  39 static void
  40 calc_sampler_offsets(nir_deref *tail, nir_tex_instr *instr,
  41                      unsigned *array_elements, nir_ssa_def **indirect,
  42                      nir_builder *b, unsigned *location)
  43 {
  44    if (tail->child == NULL)
  45       return;
  46
  47    switch (tail->child->deref_type) {
  48    case nir_deref_type_array: {
  49       nir_deref_array *deref_array = nir_deref_as_array(tail->child);
  50
  51       assert(deref_array->deref_array_type != nir_deref_array_type_wildcard);
  52
  53       calc_sampler_offsets(tail->child, instr, array_elements,
  54                            indirect, b, location);
  55       instr->texture_index += deref_array->base_offset * *array_elements;
  56
  57       if (deref_array->deref_array_type == nir_deref_array_type_indirect) {
  58          nir_ssa_def *mul =
  59             nir_imul(b, nir_imm_int(b, *array_elements),
  60                      nir_ssa_for_src(b, deref_array->indirect, 1));
  61
  62          nir_instr_rewrite_src(&instr->instr, &deref_array->indirect,
  63                                NIR_SRC_INIT);
  64
  65          if (*indirect) {
  66             *indirect = nir_iadd(b, *indirect, mul);
  67          } else {
  68             *indirect = mul;
  69          }
  70       }
  71
  72       *array_elements *= glsl_get_length(tail->type);
  73        break;
  74    }
  75
  76    case nir_deref_type_struct: {
  77       nir_deref_struct *deref_struct = nir_deref_as_struct(tail->child);
  78       *location += glsl_get_record_location_offset(tail->type, deref_struct->index);
  79       calc_sampler_offsets(tail->child, instr, array_elements,
  80                            indirect, b, location);
  81       break;
  82    }
  83
  84    default:
  85       unreachable("Invalid deref type");
  86       break;
  87    }
  88 }
  89
  90 static void
  91 lower_sampler(nir_tex_instr *instr, const struct gl_shader_program *shader_program,
  92               gl_shader_stage stage, nir_builder *b)
  93 {
  94    if (instr->texture == NULL)
  95       return;
  96
  97    /* In GLSL, we only fill out the texture field.  The sampler is inferred */
  98    assert(instr->sampler == NULL);
  99
 100    instr->texture_index = 0;
 101    unsigned location = instr->texture->var->data.location;
 102    unsigned array_elements = 1;
 103    nir_ssa_def *indirect = NULL;
 104
 105    b->cursor = nir_before_instr(&instr->instr);
 106    calc_sampler_offsets(&instr->texture->deref, instr, &array_elements,
 107                         &indirect, b, &location);
 108
 109    if (indirect) {
 110       assert(array_elements >= 1);
 111       indirect = nir_umin(b, indirect, nir_imm_int(b, array_elements - 1));
 112
 113       /* First, we have to resize the array of texture sources */
 114       nir_tex_src *new_srcs = rzalloc_array(instr, nir_tex_src,
 115                                             instr->num_srcs + 2);
 116
 117       for (unsigned i = 0; i < instr->num_srcs; i++) {
 118          new_srcs[i].src_type = instr->src[i].src_type;
 119          nir_instr_move_src(&instr->instr, &new_srcs[i].src,
 120                             &instr->src[i].src);
 121       }
 122
 123       ralloc_free(instr->src);
 124       instr->src = new_srcs;
 125
 126       /* Now we can go ahead and move the source over to being a
 127        * first-class texture source.
 128        */
 129       instr->src[instr->num_srcs].src_type = nir_tex_src_texture_offset;
 130       instr->num_srcs++;
 131       nir_instr_rewrite_src(&instr->instr,
 132                             &instr->src[instr->num_srcs - 1].src,
 133                             nir_src_for_ssa(indirect));
 134
 135       instr->src[instr->num_srcs].src_type = nir_tex_src_sampler_offset;
 136       instr->num_srcs++;
 137       nir_instr_rewrite_src(&instr->instr,
 138                             &instr->src[instr->num_srcs - 1].src,
 139                             nir_src_for_ssa(indirect));
 140
 141       instr->texture_array_size = array_elements;
 142    }
 143
 144    if (location > shader_program->NumUniformStorage - 1 ||
 145        !shader_program->UniformStorage[location].opaque[stage].active) {
 146       assert(!"cannot return a sampler");
 147       return;
 148    }
 149
 150    instr->texture_index +=
 151       shader_program->UniformStorage[location].opaque[stage].index;
 152
 153    instr->sampler_index = instr->texture_index;
 154
 155    instr->texture = NULL;
 156 }
 157
 158 static void
 159 lower_impl(nir_function_impl *impl, const struct gl_shader_program *shader_program,
 160            gl_shader_stage stage)
 161 {
 162    nir_builder b;
 163    nir_builder_init(&b, impl);
 164
 165    nir_foreach_block(block, impl) {
 166       nir_foreach_instr(instr, block) {
 167          if (instr->type == nir_instr_type_tex)
 168             lower_sampler(nir_instr_as_tex(instr), shader_program, stage, &b);
 169       }
 170    }
 171 }
 172
 173 void
 174 nir_lower_samplers(nir_shader *shader,
 175                    const struct gl_shader_program *shader_program)
 176 {
 177    nir_foreach_function(function, shader) {
 178       if (function->impl)
 179          lower_impl(function->impl, shader_program, shader->stage);
 180    }
 181 }