1 /* 2 * Copyright 2015 Red Hat 3 * 4 * Permission is hereby granted, free of charge, to any person obtaining a 5 * copy of this software and associated documentation files (the "Software"), 6 * to deal in the Software without restriction, including without limitation 7 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 8 * and/or sell copies of the Software, and to permit persons to whom the 9 * Software is furnished to do so, subject to the following conditions: 10 * 11 * The above copyright notice and this permission notice (including the next 12 * paragraph) shall be included in all copies or substantial portions of the 13 * Software. 14 * 15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS 21 * IN THE SOFTWARE. 22 * 23 * Authors: 24 * Rob Clark <robclark (at) freedesktop.org> 25 */ 26 27 #include "nir.h" 28 #include "nir_builder.h" 29 30 #define MAX_COLORS 2 /* VARYING_SLOT_COL0/COL1 */ 31 32 typedef struct { 33 nir_builder b; 34 nir_shader *shader; 35 struct { 36 nir_variable *front; /* COLn */ 37 nir_variable *back; /* BFCn */ 38 } colors[MAX_COLORS]; 39 int colors_count; 40 } lower_2side_state; 41 42 43 /* Lowering pass for fragment shaders to emulated two-sided-color. For 44 * each COLOR input, a corresponding BCOLOR input is created, and bcsel 45 * instruction used to select front or back color based on FACE. 46 */ 47 48 static nir_variable * 49 create_input(nir_shader *shader, unsigned drvloc, gl_varying_slot slot) 50 { 51 nir_variable *var = rzalloc(shader, nir_variable); 52 53 var->data.driver_location = drvloc; 54 var->type = glsl_vec4_type(); 55 var->data.mode = nir_var_shader_in; 56 var->name = ralloc_asprintf(var, "in_%d", drvloc); 57 var->data.index = 0; 58 var->data.location = slot; 59 60 exec_list_push_tail(&shader->inputs, &var->node); 61 62 shader->num_inputs++; /* TODO use type_size() */ 63 64 return var; 65 } 66 67 static nir_ssa_def * 68 load_input(nir_builder *b, nir_variable *in) 69 { 70 nir_intrinsic_instr *load; 71 72 load = nir_intrinsic_instr_create(b->shader, nir_intrinsic_load_input); 73 load->num_components = 4; 74 nir_intrinsic_set_base(load, in->data.driver_location); 75 load->src[0] = nir_src_for_ssa(nir_imm_int(b, 0)); 76 nir_ssa_dest_init(&load->instr, &load->dest, 4, 32, NULL); 77 nir_builder_instr_insert(b, &load->instr); 78 79 return &load->dest.ssa; 80 } 81 82 static int 83 setup_inputs(lower_2side_state *state) 84 { 85 int maxloc = -1; 86 87 /* find color inputs: */ 88 nir_foreach_variable(var, &state->shader->inputs) { 89 int loc = var->data.driver_location; 90 91 /* keep track of last used driver-location.. we'll be 92 * appending BCLr after last existing input: 93 */ 94 maxloc = MAX2(maxloc, loc); 95 96 switch (var->data.location) { 97 case VARYING_SLOT_COL0: 98 case VARYING_SLOT_COL1: 99 assert(state->colors_count < ARRAY_SIZE(state->colors)); 100 state->colors[state->colors_count].front = var; 101 state->colors_count++; 102 break; 103 } 104 } 105 106 /* if we don't have any color inputs, nothing to do: */ 107 if (state->colors_count == 0) 108 return -1; 109 110 /* add required back-face color inputs: */ 111 for (int i = 0; i < state->colors_count; i++) { 112 gl_varying_slot slot; 113 114 if (state->colors[i].front->data.location == VARYING_SLOT_COL0) 115 slot = VARYING_SLOT_BFC0; 116 else 117 slot = VARYING_SLOT_BFC1; 118 119 state->colors[i].back = create_input(state->shader, ++maxloc, slot); 120 } 121 122 return 0; 123 } 124 125 static bool 126 nir_lower_two_sided_color_block(nir_block *block, 127 lower_2side_state *state) 128 { 129 nir_builder *b = &state->b; 130 131 nir_foreach_instr_safe(instr, block) { 132 if (instr->type != nir_instr_type_intrinsic) 133 continue; 134 135 nir_intrinsic_instr *intr = nir_instr_as_intrinsic(instr); 136 137 if (intr->intrinsic != nir_intrinsic_load_input) 138 continue; 139 140 int idx; 141 for (idx = 0; idx < state->colors_count; idx++) { 142 unsigned drvloc = 143 state->colors[idx].front->data.driver_location; 144 if (nir_intrinsic_base(intr) == drvloc) { 145 assert(nir_src_as_const_value(intr->src[0])); 146 break; 147 } 148 } 149 150 if (idx == state->colors_count) 151 continue; 152 153 /* replace load_input(COLn) with 154 * bcsel(load_system_value(FACE), load_input(COLn), load_input(BFCn)) 155 */ 156 b->cursor = nir_before_instr(&intr->instr); 157 nir_ssa_def *face = nir_load_front_face(b); 158 nir_ssa_def *front = load_input(b, state->colors[idx].front); 159 nir_ssa_def *back = load_input(b, state->colors[idx].back); 160 nir_ssa_def *color = nir_bcsel(b, face, front, back); 161 162 assert(intr->dest.is_ssa); 163 nir_ssa_def_rewrite_uses(&intr->dest.ssa, nir_src_for_ssa(color)); 164 } 165 166 return true; 167 } 168 169 static void 170 nir_lower_two_sided_color_impl(nir_function_impl *impl, 171 lower_2side_state *state) 172 { 173 nir_builder *b = &state->b; 174 175 nir_builder_init(b, impl); 176 177 nir_foreach_block(block, impl) { 178 nir_lower_two_sided_color_block(block, state); 179 } 180 181 nir_metadata_preserve(impl, nir_metadata_block_index | 182 nir_metadata_dominance); 183 } 184 185 void 186 nir_lower_two_sided_color(nir_shader *shader) 187 { 188 lower_2side_state state = { 189 .shader = shader, 190 }; 191 192 if (shader->stage != MESA_SHADER_FRAGMENT) 193 return; 194 195 if (setup_inputs(&state) != 0) 196 return; 197 198 nir_foreach_function(function, shader) { 199 if (function->impl) 200 nir_lower_two_sided_color_impl(function->impl, &state); 201 } 202 203 } 204
