1 /* 2 * Copyright 2011 Intel Corporation 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 24 /** 25 * @file brw_vue_map.c 26 * 27 * This file computes the "VUE map" for a (non-fragment) shader stage, which 28 * describes the layout of its output varyings. The VUE map is used to match 29 * outputs from one stage with the inputs of the next. 30 * 31 * Largely, varyings can be placed however we like - producers/consumers simply 32 * have to agree on the layout. However, there is also a "VUE Header" that 33 * prescribes a fixed-layout for items that interact with fixed function 34 * hardware, such as the clipper and rasterizer. 35 * 36 * Authors: 37 * Paul Berry <stereotype441 (at) gmail.com> 38 * Chris Forbes <chrisf (at) ijw.co.nz> 39 * Eric Anholt <eric (at) anholt.net> 40 */ 41 42 43 #include "brw_context.h" 44 45 static inline void 46 assign_vue_slot(struct brw_vue_map *vue_map, int varying, int slot) 47 { 48 /* Make sure this varying hasn't been assigned a slot already */ 49 assert (vue_map->varying_to_slot[varying] == -1); 50 51 vue_map->varying_to_slot[varying] = slot; 52 vue_map->slot_to_varying[slot] = varying; 53 } 54 55 /** 56 * Compute the VUE map for a shader stage. 57 */ 58 void 59 brw_compute_vue_map(const struct gen_device_info *devinfo, 60 struct brw_vue_map *vue_map, 61 GLbitfield64 slots_valid, 62 bool separate) 63 { 64 /* Keep using the packed/contiguous layout on old hardware - we only need 65 * the SSO layout when using geometry/tessellation shaders or 32 FS input 66 * varyings, which only exist on Gen >= 6. It's also a bit more efficient. 67 */ 68 if (devinfo->gen < 6) 69 separate = false; 70 71 if (separate) { 72 /* In SSO mode, we don't know whether the adjacent stage will 73 * read/write gl_ClipDistance, which has a fixed slot location. 74 * We have to assume the worst and reserve a slot for it, or else 75 * the rest of our varyings will be off by a slot. 76 * 77 * Note that we don't have to worry about COL/BFC, as those built-in 78 * variables only exist in legacy GL, which only supports VS and FS. 79 */ 80 slots_valid |= BITFIELD64_BIT(VARYING_SLOT_CLIP_DIST0); 81 slots_valid |= BITFIELD64_BIT(VARYING_SLOT_CLIP_DIST1); 82 } 83 84 vue_map->slots_valid = slots_valid; 85 vue_map->separate = separate; 86 87 /* gl_Layer and gl_ViewportIndex don't get their own varying slots -- they 88 * are stored in the first VUE slot (VARYING_SLOT_PSIZ). 89 */ 90 slots_valid &= ~(VARYING_BIT_LAYER | VARYING_BIT_VIEWPORT); 91 92 /* Make sure that the values we store in vue_map->varying_to_slot and 93 * vue_map->slot_to_varying won't overflow the signed chars that are used 94 * to store them. Note that since vue_map->slot_to_varying sometimes holds 95 * values equal to BRW_VARYING_SLOT_COUNT, we need to ensure that 96 * BRW_VARYING_SLOT_COUNT is <= 127, not 128. 97 */ 98 STATIC_ASSERT(BRW_VARYING_SLOT_COUNT <= 127); 99 100 for (int i = 0; i < BRW_VARYING_SLOT_COUNT; ++i) { 101 vue_map->varying_to_slot[i] = -1; 102 vue_map->slot_to_varying[i] = BRW_VARYING_SLOT_PAD; 103 } 104 105 int slot = 0; 106 107 /* VUE header: format depends on chip generation and whether clipping is 108 * enabled. 109 * 110 * See the Sandybridge PRM, Volume 2 Part 1, section 1.5.1 (page 30), 111 * "Vertex URB Entry (VUE) Formats" which describes the VUE header layout. 112 */ 113 if (devinfo->gen < 6) { 114 /* There are 8 dwords in VUE header pre-Ironlake: 115 * dword 0-3 is indices, point width, clip flags. 116 * dword 4-7 is ndc position 117 * dword 8-11 is the first vertex data. 118 * 119 * On Ironlake the VUE header is nominally 20 dwords, but the hardware 120 * will accept the same header layout as Gen4 [and should be a bit faster] 121 */ 122 assign_vue_slot(vue_map, VARYING_SLOT_PSIZ, slot++); 123 assign_vue_slot(vue_map, BRW_VARYING_SLOT_NDC, slot++); 124 assign_vue_slot(vue_map, VARYING_SLOT_POS, slot++); 125 } else { 126 /* There are 8 or 16 DWs (D0-D15) in VUE header on Sandybridge: 127 * dword 0-3 of the header is indices, point width, clip flags. 128 * dword 4-7 is the 4D space position 129 * dword 8-15 of the vertex header is the user clip distance if 130 * enabled. 131 * dword 8-11 or 16-19 is the first vertex element data we fill. 132 */ 133 assign_vue_slot(vue_map, VARYING_SLOT_PSIZ, slot++); 134 assign_vue_slot(vue_map, VARYING_SLOT_POS, slot++); 135 if (slots_valid & BITFIELD64_BIT(VARYING_SLOT_CLIP_DIST0)) 136 assign_vue_slot(vue_map, VARYING_SLOT_CLIP_DIST0, slot++); 137 if (slots_valid & BITFIELD64_BIT(VARYING_SLOT_CLIP_DIST1)) 138 assign_vue_slot(vue_map, VARYING_SLOT_CLIP_DIST1, slot++); 139 140 /* front and back colors need to be consecutive so that we can use 141 * ATTRIBUTE_SWIZZLE_INPUTATTR_FACING to swizzle them when doing 142 * two-sided color. 143 */ 144 if (slots_valid & BITFIELD64_BIT(VARYING_SLOT_COL0)) 145 assign_vue_slot(vue_map, VARYING_SLOT_COL0, slot++); 146 if (slots_valid & BITFIELD64_BIT(VARYING_SLOT_BFC0)) 147 assign_vue_slot(vue_map, VARYING_SLOT_BFC0, slot++); 148 if (slots_valid & BITFIELD64_BIT(VARYING_SLOT_COL1)) 149 assign_vue_slot(vue_map, VARYING_SLOT_COL1, slot++); 150 if (slots_valid & BITFIELD64_BIT(VARYING_SLOT_BFC1)) 151 assign_vue_slot(vue_map, VARYING_SLOT_BFC1, slot++); 152 } 153 154 /* The hardware doesn't care about the rest of the vertex outputs, so we 155 * can assign them however we like. For normal programs, we simply assign 156 * them contiguously. 157 * 158 * For separate shader pipelines, we first assign built-in varyings 159 * contiguous slots. This works because ARB_separate_shader_objects 160 * requires that all shaders have matching built-in varying interface 161 * blocks. Next, we assign generic varyings based on their location 162 * (either explicit or linker assigned). This guarantees a fixed layout. 163 * 164 * We generally don't need to assign a slot for VARYING_SLOT_CLIP_VERTEX, 165 * since it's encoded as the clip distances by emit_clip_distances(). 166 * However, it may be output by transform feedback, and we'd rather not 167 * recompute state when TF changes, so we just always include it. 168 */ 169 GLbitfield64 builtins = slots_valid & BITFIELD64_MASK(VARYING_SLOT_VAR0); 170 while (builtins != 0) { 171 const int varying = ffsll(builtins) - 1; 172 if (vue_map->varying_to_slot[varying] == -1) { 173 assign_vue_slot(vue_map, varying, slot++); 174 } 175 builtins &= ~BITFIELD64_BIT(varying); 176 } 177 178 const int first_generic_slot = slot; 179 GLbitfield64 generics = slots_valid & ~BITFIELD64_MASK(VARYING_SLOT_VAR0); 180 while (generics != 0) { 181 const int varying = ffsll(generics) - 1; 182 if (separate) { 183 slot = first_generic_slot + varying - VARYING_SLOT_VAR0; 184 } 185 assign_vue_slot(vue_map, varying, slot++); 186 generics &= ~BITFIELD64_BIT(varying); 187 } 188 189 vue_map->num_slots = slot; 190 vue_map->num_per_vertex_slots = 0; 191 vue_map->num_per_patch_slots = 0; 192 } 193 194 /** 195 * Compute the VUE map for tessellation control shader outputs and 196 * tessellation evaluation shader inputs. 197 */ 198 void 199 brw_compute_tess_vue_map(struct brw_vue_map *vue_map, 200 GLbitfield64 vertex_slots, 201 GLbitfield patch_slots) 202 { 203 /* I don't think anything actually uses this... */ 204 vue_map->slots_valid = vertex_slots; 205 206 /* separate isn't really meaningful, but make sure it's initialized */ 207 vue_map->separate = false; 208 209 vertex_slots &= ~(VARYING_BIT_TESS_LEVEL_OUTER | 210 VARYING_BIT_TESS_LEVEL_INNER); 211 212 /* Make sure that the values we store in vue_map->varying_to_slot and 213 * vue_map->slot_to_varying won't overflow the signed chars that are used 214 * to store them. Note that since vue_map->slot_to_varying sometimes holds 215 * values equal to VARYING_SLOT_TESS_MAX , we need to ensure that 216 * VARYING_SLOT_TESS_MAX is <= 127, not 128. 217 */ 218 STATIC_ASSERT(VARYING_SLOT_TESS_MAX <= 127); 219 220 for (int i = 0; i < VARYING_SLOT_TESS_MAX ; ++i) { 221 vue_map->varying_to_slot[i] = -1; 222 vue_map->slot_to_varying[i] = BRW_VARYING_SLOT_PAD; 223 } 224 225 int slot = 0; 226 227 /* The first 8 DWords are reserved for the "Patch Header". 228 * 229 * VARYING_SLOT_TESS_LEVEL_OUTER / INNER live here, but the exact layout 230 * depends on the domain type. They might not be in slots 0 and 1 as 231 * described here, but pretending they're separate allows us to uniquely 232 * identify them by distinct slot locations. 233 */ 234 assign_vue_slot(vue_map, VARYING_SLOT_TESS_LEVEL_INNER, slot++); 235 assign_vue_slot(vue_map, VARYING_SLOT_TESS_LEVEL_OUTER, slot++); 236 237 /* first assign per-patch varyings */ 238 while (patch_slots != 0) { 239 const int varying = ffsll(patch_slots) - 1; 240 if (vue_map->varying_to_slot[varying + VARYING_SLOT_PATCH0] == -1) { 241 assign_vue_slot(vue_map, varying + VARYING_SLOT_PATCH0, slot++); 242 } 243 patch_slots &= ~BITFIELD64_BIT(varying); 244 } 245 246 /* apparently, including the patch header... */ 247 vue_map->num_per_patch_slots = slot; 248 249 /* then assign per-vertex varyings for each vertex in our patch */ 250 while (vertex_slots != 0) { 251 const int varying = ffsll(vertex_slots) - 1; 252 if (vue_map->varying_to_slot[varying] == -1) { 253 assign_vue_slot(vue_map, varying, slot++); 254 } 255 vertex_slots &= ~BITFIELD64_BIT(varying); 256 } 257 258 vue_map->num_per_vertex_slots = slot - vue_map->num_per_patch_slots; 259 vue_map->num_slots = slot; 260 } 261 262 static const char * 263 varying_name(brw_varying_slot slot) 264 { 265 assume(slot < BRW_VARYING_SLOT_COUNT); 266 267 if (slot < VARYING_SLOT_MAX) 268 return gl_varying_slot_name(slot); 269 270 static const char *brw_names[] = { 271 [BRW_VARYING_SLOT_NDC - VARYING_SLOT_MAX] = "BRW_VARYING_SLOT_NDC", 272 [BRW_VARYING_SLOT_PAD - VARYING_SLOT_MAX] = "BRW_VARYING_SLOT_PAD", 273 [BRW_VARYING_SLOT_PNTC - VARYING_SLOT_MAX] = "BRW_VARYING_SLOT_PNTC", 274 }; 275 276 return brw_names[slot - VARYING_SLOT_MAX]; 277 } 278 279 void 280 brw_print_vue_map(FILE *fp, const struct brw_vue_map *vue_map) 281 { 282 if (vue_map->num_per_vertex_slots > 0 || vue_map->num_per_patch_slots > 0) { 283 fprintf(fp, "PUE map (%d slots, %d/patch, %d/vertex, %s)\n", 284 vue_map->num_slots, 285 vue_map->num_per_patch_slots, 286 vue_map->num_per_vertex_slots, 287 vue_map->separate ? "SSO" : "non-SSO"); 288 for (int i = 0; i < vue_map->num_slots; i++) { 289 if (vue_map->slot_to_varying[i] >= VARYING_SLOT_PATCH0) { 290 fprintf(fp, " [%d] VARYING_SLOT_PATCH%d\n", i, 291 vue_map->slot_to_varying[i] - VARYING_SLOT_PATCH0); 292 } else { 293 fprintf(fp, " [%d] %s\n", i, 294 varying_name(vue_map->slot_to_varying[i])); 295 } 296 } 297 } else { 298 fprintf(fp, "VUE map (%d slots, %s)\n", 299 vue_map->num_slots, vue_map->separate ? "SSO" : "non-SSO"); 300 for (int i = 0; i < vue_map->num_slots; i++) { 301 fprintf(fp, " [%d] %s\n", i, 302 varying_name(vue_map->slot_to_varying[i])); 303 } 304 } 305 fprintf(fp, "\n"); 306 } 307
