1/* 2 * Copyright 2013 VMware, Inc. 3 * All Rights Reserved. 4 * 5 * Permission is hereby granted, free of charge, to any person obtaining a 6 * copy of this software and associated documentation files (the 7 * "Software"), to deal in the Software without restriction, including 8 * without limitation the rights to use, copy, modify, merge, publish, 9 * distribute, sub license, and/or sell copies of the Software, and to 10 * permit persons to whom the Software is furnished to do so, subject to 11 * the following conditions: 12 * 13 * The above copyright notice and this permission notice (including the 14 * next paragraph) shall be included in all copies or substantial portions 15 * of the Software. 16 * 17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS 18 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 19 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. 20 * IN NO EVENT SHALL THE AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR 21 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, 22 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE 23 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. 24 */ 25 26 27/** 28 * This utility transforms fragment shaders to facilitate two-sided lighting. 29 * 30 * Basically, if the FS has any color inputs (TGSI_SEMANTIC_COLOR) we'll: 31 * 1. create corresponding back-color inputs (TGSI_SEMANTIC_BCOLOR) 32 * 2. use the FACE register to choose between front/back colors and put the 33 * selected color in new temp regs. 34 * 3. replace reads of the original color inputs with the new temp regs. 35 * 36 * Then, the driver just needs to link the VS front/back output colors to 37 * the FS front/back input colors. 38 */ 39 40#include "util/u_debug.h" 41#include "util/u_math.h" 42#include "tgsi_info.h" 43#include "tgsi_two_side.h" 44#include "tgsi_transform.h" 45 46 47#define INVALID_INDEX 9999 48 49 50struct two_side_transform_context 51{ 52 struct tgsi_transform_context base; 53 uint num_temps; 54 uint num_inputs; 55 uint face_input; /**< index of the FACE input */ 56 uint front_color_input[2]; /**< INPUT regs */ 57 uint front_color_interp[2];/**< TGSI_INTERPOLATE_x */ 58 uint back_color_input[2]; /**< INPUT regs */ 59 uint new_colors[2]; /**< TEMP regs */ 60}; 61 62 63static inline struct two_side_transform_context * 64two_side_transform_context(struct tgsi_transform_context *ctx) 65{ 66 return (struct two_side_transform_context *) ctx; 67} 68 69 70static void 71xform_decl(struct tgsi_transform_context *ctx, 72 struct tgsi_full_declaration *decl) 73{ 74 struct two_side_transform_context *ts = two_side_transform_context(ctx); 75 unsigned range_end = decl->Range.Last + 1; 76 77 if (decl->Declaration.File == TGSI_FILE_INPUT) { 78 if (decl->Semantic.Name == TGSI_SEMANTIC_COLOR) { 79 /* found a front color */ 80 assert(decl->Semantic.Index < 2); 81 ts->front_color_input[decl->Semantic.Index] = decl->Range.First; 82 ts->front_color_interp[decl->Semantic.Index] = decl->Interp.Interpolate; 83 } 84 else if (decl->Semantic.Name == TGSI_SEMANTIC_FACE) { 85 ts->face_input = decl->Range.First; 86 } 87 ts->num_inputs = MAX2(ts->num_inputs, range_end); 88 } 89 else if (decl->Declaration.File == TGSI_FILE_TEMPORARY) { 90 ts->num_temps = MAX2(ts->num_temps, range_end); 91 } 92 93 ctx->emit_declaration(ctx, decl); 94} 95 96 97static void 98emit_prolog(struct tgsi_transform_context *ctx) 99{ 100 struct two_side_transform_context *ts = two_side_transform_context(ctx); 101 struct tgsi_full_declaration decl; 102 struct tgsi_full_instruction inst; 103 uint num_colors = 0; 104 uint i; 105 106 /* Declare 0, 1 or 2 new BCOLOR inputs */ 107 for (i = 0; i < 2; i++) { 108 if (ts->front_color_input[i] != INVALID_INDEX) { 109 decl = tgsi_default_full_declaration(); 110 decl.Declaration.File = TGSI_FILE_INPUT; 111 decl.Declaration.Interpolate = 1; 112 decl.Declaration.Semantic = 1; 113 decl.Semantic.Name = TGSI_SEMANTIC_BCOLOR; 114 decl.Semantic.Index = i; 115 decl.Range.First = decl.Range.Last = ts->num_inputs++; 116 decl.Interp.Interpolate = ts->front_color_interp[i]; 117 ctx->emit_declaration(ctx, &decl); 118 ts->back_color_input[i] = decl.Range.First; 119 num_colors++; 120 } 121 } 122 123 if (num_colors > 0) { 124 /* Declare 1 or 2 temp registers */ 125 decl = tgsi_default_full_declaration(); 126 decl.Declaration.File = TGSI_FILE_TEMPORARY; 127 decl.Range.First = ts->num_temps; 128 decl.Range.Last = ts->num_temps + num_colors - 1; 129 ctx->emit_declaration(ctx, &decl); 130 ts->new_colors[0] = ts->num_temps; 131 ts->new_colors[1] = ts->num_temps + 1; 132 133 if (ts->face_input == INVALID_INDEX) { 134 /* declare FACE INPUT register */ 135 decl = tgsi_default_full_declaration(); 136 decl.Declaration.File = TGSI_FILE_INPUT; 137 decl.Declaration.Semantic = 1; 138 decl.Semantic.Name = TGSI_SEMANTIC_FACE; 139 decl.Semantic.Index = 0; 140 decl.Range.First = decl.Range.Last = ts->num_inputs++; 141 ctx->emit_declaration(ctx, &decl); 142 ts->face_input = decl.Range.First; 143 } 144 145 /* CMP temp[c0], face, bcolor[c0], fcolor[c0] 146 * temp[c0] = face < 0.0 ? bcolor[c0] : fcolor[c0] 147 */ 148 for (i = 0; i < 2; i++) { 149 if (ts->front_color_input[i] != INVALID_INDEX) { 150 inst = tgsi_default_full_instruction(); 151 inst.Instruction.Opcode = TGSI_OPCODE_CMP; 152 inst.Instruction.NumDstRegs = 1; 153 inst.Dst[0].Register.File = TGSI_FILE_TEMPORARY; 154 inst.Dst[0].Register.Index = ts->new_colors[i]; 155 inst.Instruction.NumSrcRegs = 3; 156 inst.Src[0].Register.File = TGSI_FILE_INPUT; 157 inst.Src[0].Register.Index = ts->face_input; 158 inst.Src[1].Register.File = TGSI_FILE_INPUT; 159 inst.Src[1].Register.Index = ts->back_color_input[i]; 160 inst.Src[2].Register.File = TGSI_FILE_INPUT; 161 inst.Src[2].Register.Index = ts->front_color_input[i]; 162 163 ctx->emit_instruction(ctx, &inst); 164 } 165 } 166 } 167} 168 169 170static void 171xform_inst(struct tgsi_transform_context *ctx, 172 struct tgsi_full_instruction *inst) 173{ 174 struct two_side_transform_context *ts = two_side_transform_context(ctx); 175 const struct tgsi_opcode_info *info = 176 tgsi_get_opcode_info(inst->Instruction.Opcode); 177 uint i, j; 178 179 /* Look for src regs which reference the input color and replace 180 * them with the temp color. 181 */ 182 for (i = 0; i < info->num_src; i++) { 183 if (inst->Src[i].Register.File == TGSI_FILE_INPUT) { 184 for (j = 0; j < 2; j++) { 185 if (inst->Src[i].Register.Index == (int)ts->front_color_input[j]) { 186 /* replace color input with temp reg */ 187 inst->Src[i].Register.File = TGSI_FILE_TEMPORARY; 188 inst->Src[i].Register.Index = ts->new_colors[j]; 189 break; 190 } 191 } 192 } 193 } 194 195 ctx->emit_instruction(ctx, inst); 196} 197 198 199struct tgsi_token * 200tgsi_add_two_side(const struct tgsi_token *tokens_in) 201{ 202 struct two_side_transform_context transform; 203 const uint num_new_tokens = 100; /* should be enough */ 204 const uint new_len = tgsi_num_tokens(tokens_in) + num_new_tokens; 205 206 /* setup transformation context */ 207 memset(&transform, 0, sizeof(transform)); 208 transform.base.transform_declaration = xform_decl; 209 transform.base.transform_instruction = xform_inst; 210 transform.base.prolog = emit_prolog; 211 transform.face_input = INVALID_INDEX; 212 transform.front_color_input[0] = INVALID_INDEX; 213 transform.front_color_input[1] = INVALID_INDEX; 214 transform.front_color_interp[0] = TGSI_INTERPOLATE_COLOR; 215 transform.front_color_interp[1] = TGSI_INTERPOLATE_COLOR; 216 transform.back_color_input[0] = INVALID_INDEX; 217 transform.back_color_input[1] = INVALID_INDEX; 218 219 return tgsi_transform_shader(tokens_in, new_len, &transform.base); 220} 221