src/glsl/nir/nir_lower_samplers.cpp

   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 "../program.h"
  28 #include "program/hash_table.h"
  29 #include "ir_uniform.h"
  30
  31 extern "C" {
  32 #include "main/compiler.h"
  33 #include "main/mtypes.h"
  34 #include "program/prog_parameter.h"
  35 #include "program/program.h"
  36 }
  37
  38 static unsigned
  39 get_deref_name_offset(nir_deref_var *deref_var,
  40                       gl_shader_program *shader_program, char **name,
  41                       void *mem_ctx)
  42 {
  43    nir_deref *deref = &deref_var->deref;
  44    nir_deref_array *deref_array;
  45    nir_deref_struct *deref_struct;
  46
  47    *name = ralloc_strdup(mem_ctx, deref_var->var->name);
  48
  49    while (deref->child != NULL) {
  50       deref = deref->child;
  51       switch (deref->deref_type) {
  52          case nir_deref_type_array:
  53             deref_array = nir_deref_as_array(deref);
  54             if (deref_array->has_indirect) {
  55                /* GLSL 1.10 and 1.20 allowed variable sampler array indices,
  56                 * while GLSL 1.30 requires that the array indices be
  57                 * constant integer expressions.  We don't expect any driver
  58                 * to actually work with a really variable array index, so
  59                 * all that would work would be an unrolled loop counter that
  60                 * ends up being constant.
  61                 */
  62                ralloc_strcat(&shader_program->InfoLog,
  63                            "warning: Variable sampler array index unsupported.\n"
  64                            "This feature of the language was removed in GLSL 1.20 "
  65                            "and is unlikely to be supported for 1.10 in Mesa.\n");
  66             }
  67             if (deref->child == NULL) {
  68                return deref_array->base_offset;
  69             }
  70             ralloc_asprintf_append(name, "[%u]", deref_array->base_offset);
  71             break;
  72
  73          case nir_deref_type_struct:
  74             deref_struct = nir_deref_as_struct(deref);
  75             ralloc_asprintf_append(name, ".%s", deref_struct->elem);
  76             break;
  77
  78          default:
  79             assert(0);
  80             break;
  81       }
  82    }
  83
  84    return 0;
  85 }
  86
  87 static unsigned
  88 get_sampler_index(nir_deref_var *sampler,
  89                   struct gl_shader_program *shader_program,
  90                   const struct gl_program *prog)
  91 {
  92    void *mem_ctx = ralloc_context(NULL);
  93    char *name;
  94    unsigned offset = get_deref_name_offset(sampler, shader_program, &name,
  95                                            mem_ctx);
  96
  97    GLuint shader = _mesa_program_enum_to_shader_stage(prog->Target);
  98
  99    unsigned location;
 100    if (!shader_program->UniformHash->get(location, name)) {
 101       linker_error(shader_program,
 102                    "failed to find sampler named %s.\n", name);
 103       return 0;
 104    }
 105
 106    if (!shader_program->UniformStorage[location].sampler[shader].active) {
 107       assert(0 && "cannot return a sampler");
 108       linker_error(shader_program,
 109                    "cannot return a sampler named %s, because it is not "
 110                    "used in this shader stage. This is a driver bug.\n",
 111                    name);
 112       return 0;
 113    }
 114
 115    ralloc_free(mem_ctx);
 116
 117    return shader_program->UniformStorage[location].sampler[shader].index +
 118           offset;
 119 }
 120
 121 static void
 122 lower_sampler(nir_tex_instr *instr, struct gl_shader_program *shader_program,
 123               const struct gl_program *prog)
 124 {
 125    if (instr->sampler) {
 126       instr->sampler_index = get_sampler_index(instr->sampler, shader_program,
 127                                              prog);
 128       instr->sampler = NULL;
 129    }
 130 }
 131
 132 typedef struct {
 133    struct gl_shader_program *shader_program;
 134    struct gl_program *prog;
 135 } lower_state;
 136
 137 static bool
 138 lower_block_cb(nir_block *block, void *_state)
 139 {
 140    lower_state *state = (lower_state *) _state;
 141
 142    nir_foreach_instr(block, instr) {
 143       if (instr->type == nir_instr_type_texture) {
 144          nir_tex_instr *tex_instr = nir_instr_as_texture(instr);
 145          lower_sampler(tex_instr, state->shader_program, state->prog);
 146       }
 147    }
 148
 149    return true;
 150 }
 151
 152 static void
 153 lower_impl(nir_function_impl *impl, struct gl_shader_program *shader_program,
 154            struct gl_program *prog)
 155 {
 156    lower_state state;
 157    state.shader_program = shader_program;
 158    state.prog = prog;
 159    nir_foreach_block(impl, lower_block_cb, &state);
 160 }
 161
 162 extern "C" void
 163 nir_lower_samplers(nir_shader *shader, struct gl_shader_program *shader_program,
 164                    struct gl_program *prog)
 165 {
 166    nir_foreach_overload(shader, overload) {
 167       if (overload->impl)
 168          lower_impl(overload->impl, shader_program, prog);
 169    }
 170 }