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 50 struct 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 63 static inline struct two_side_transform_context * 64 two_side_transform_context(struct tgsi_transform_context *ctx) 65 { 66 return (struct two_side_transform_context *) ctx; 67 } 68 69 70 static void 71 xform_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 76 if (decl->Declaration.File == TGSI_FILE_INPUT) { 77 if (decl->Semantic.Name == TGSI_SEMANTIC_COLOR) { 78 /* found a front color */ 79 assert(decl->Semantic.Index < 2); 80 ts->front_color_input[decl->Semantic.Index] = decl->Range.First; 81 ts->front_color_interp[decl->Semantic.Index] = decl->Interp.Interpolate; 82 } 83 else if (decl->Semantic.Name == TGSI_SEMANTIC_FACE) { 84 ts->face_input = decl->Range.First; 85 } 86 ts->num_inputs = MAX2(ts->num_inputs, decl->Range.Last + 1); 87 } 88 else if (decl->Declaration.File == TGSI_FILE_TEMPORARY) { 89 ts->num_temps = MAX2(ts->num_temps, decl->Range.Last + 1); 90 } 91 92 ctx->emit_declaration(ctx, decl); 93 } 94 95 96 static void 97 emit_prolog(struct tgsi_transform_context *ctx) 98 { 99 struct two_side_transform_context *ts = two_side_transform_context(ctx); 100 struct tgsi_full_declaration decl; 101 struct tgsi_full_instruction inst; 102 uint num_colors = 0; 103 uint i; 104 105 /* Declare 0, 1 or 2 new BCOLOR inputs */ 106 for (i = 0; i < 2; i++) { 107 if (ts->front_color_input[i] != INVALID_INDEX) { 108 decl = tgsi_default_full_declaration(); 109 decl.Declaration.File = TGSI_FILE_INPUT; 110 decl.Declaration.Interpolate = 1; 111 decl.Declaration.Semantic = 1; 112 decl.Semantic.Name = TGSI_SEMANTIC_BCOLOR; 113 decl.Semantic.Index = i; 114 decl.Range.First = decl.Range.Last = ts->num_inputs++; 115 decl.Interp.Interpolate = ts->front_color_interp[i]; 116 ctx->emit_declaration(ctx, &decl); 117 ts->back_color_input[i] = decl.Range.First; 118 num_colors++; 119 } 120 } 121 122 if (num_colors > 0) { 123 /* Declare 1 or 2 temp registers */ 124 decl = tgsi_default_full_declaration(); 125 decl.Declaration.File = TGSI_FILE_TEMPORARY; 126 decl.Range.First = ts->num_temps; 127 decl.Range.Last = ts->num_temps + num_colors - 1; 128 ctx->emit_declaration(ctx, &decl); 129 ts->new_colors[0] = ts->num_temps; 130 ts->new_colors[1] = ts->num_temps + 1; 131 132 if (ts->face_input == INVALID_INDEX) { 133 /* declare FACE INPUT register */ 134 decl = tgsi_default_full_declaration(); 135 decl.Declaration.File = TGSI_FILE_INPUT; 136 decl.Declaration.Semantic = 1; 137 decl.Semantic.Name = TGSI_SEMANTIC_FACE; 138 decl.Semantic.Index = 0; 139 decl.Range.First = decl.Range.Last = ts->num_inputs++; 140 ctx->emit_declaration(ctx, &decl); 141 ts->face_input = decl.Range.First; 142 } 143 144 /* CMP temp[c0], face, bcolor[c0], fcolor[c0] 145 * temp[c0] = face < 0.0 ? bcolor[c0] : fcolor[c0] 146 */ 147 for (i = 0; i < 2; i++) { 148 if (ts->front_color_input[i] != INVALID_INDEX) { 149 inst = tgsi_default_full_instruction(); 150 inst.Instruction.Opcode = TGSI_OPCODE_CMP; 151 inst.Instruction.NumDstRegs = 1; 152 inst.Dst[0].Register.File = TGSI_FILE_TEMPORARY; 153 inst.Dst[0].Register.Index = ts->new_colors[i]; 154 inst.Instruction.NumSrcRegs = 3; 155 inst.Src[0].Register.File = TGSI_FILE_INPUT; 156 inst.Src[0].Register.Index = ts->face_input; 157 inst.Src[1].Register.File = TGSI_FILE_INPUT; 158 inst.Src[1].Register.Index = ts->back_color_input[i]; 159 inst.Src[2].Register.File = TGSI_FILE_INPUT; 160 inst.Src[2].Register.Index = ts->front_color_input[i]; 161 162 ctx->emit_instruction(ctx, &inst); 163 } 164 } 165 } 166 } 167 168 169 static void 170 xform_inst(struct tgsi_transform_context *ctx, 171 struct tgsi_full_instruction *inst) 172 { 173 struct two_side_transform_context *ts = two_side_transform_context(ctx); 174 const struct tgsi_opcode_info *info = 175 tgsi_get_opcode_info(inst->Instruction.Opcode); 176 uint i, j; 177 178 /* Look for src regs which reference the input color and replace 179 * them with the temp color. 180 */ 181 for (i = 0; i < info->num_src; i++) { 182 if (inst->Src[i].Register.File == TGSI_FILE_INPUT) { 183 for (j = 0; j < 2; j++) { 184 if (inst->Src[i].Register.Index == ts->front_color_input[j]) { 185 /* replace color input with temp reg */ 186 inst->Src[i].Register.File = TGSI_FILE_TEMPORARY; 187 inst->Src[i].Register.Index = ts->new_colors[j]; 188 break; 189 } 190 } 191 } 192 } 193 194 ctx->emit_instruction(ctx, inst); 195 } 196 197 198 struct tgsi_token * 199 tgsi_add_two_side(const struct tgsi_token *tokens_in) 200 { 201 struct two_side_transform_context transform; 202 const uint num_new_tokens = 100; /* should be enough */ 203 const uint new_len = tgsi_num_tokens(tokens_in) + num_new_tokens; 204 struct tgsi_token *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 /* allocate new tokens buffer */ 220 new_tokens = tgsi_alloc_tokens(new_len); 221 if (!new_tokens) 222 return NULL; 223 224 /* transform the shader */ 225 tgsi_transform_shader(tokens_in, new_tokens, new_len, &transform.base); 226 227 return new_tokens; 228 } 229
