src/mesa/drivers/dri/i965/brw_clip_util.c

   1 /*
   2  Copyright (C) Intel Corp.  2006.  All Rights Reserved.
   3  Intel funded Tungsten Graphics to
   4  develop this 3D driver.
   5
   6  Permission is hereby granted, free of charge, to any person obtaining
   7  a copy of this software and associated documentation files (the
   8  "Software"), to deal in the Software without restriction, including
   9  without limitation the rights to use, copy, modify, merge, publish,
  10  distribute, sublicense, and/or sell copies of the Software, and to
  11  permit persons to whom the Software is furnished to do so, subject to
  12  the following conditions:
  13
  14  The above copyright notice and this permission notice (including the
  15  next paragraph) shall be included in all copies or substantial
  16  portions of the Software.
  17
  18  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  19  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  20  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
  21  IN NO EVENT SHALL THE COPYRIGHT OWNER(S) AND/OR ITS SUPPLIERS BE
  22  LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  23  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  24  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  25
  26  **********************************************************************/
  27  /*
  28   * Authors:
  29   *   Keith Whitwell <keithw@vmware.com>
  30   */
  31
  32
  33 #include "main/macros.h"
  34 #include "main/enums.h"
  35 #include "program/program.h"
  36
  37 #include "intel_batchbuffer.h"
  38
  39 #include "brw_defines.h"
  40 #include "brw_context.h"
  41 #include "brw_eu.h"
  42 #include "brw_clip.h"
  43
  44
  45
  46
  47 struct brw_reg get_tmp( struct brw_clip_compile *c )
  48 {
  49    struct brw_reg tmp = brw_vec4_grf(c->last_tmp, 0);
  50
  51    if (++c->last_tmp > c->prog_data.total_grf)
  52       c->prog_data.total_grf = c->last_tmp;
  53
  54    return tmp;
  55 }
  56
  57 static void release_tmp( struct brw_clip_compile *c, struct brw_reg tmp )
  58 {
  59    if (tmp.nr == c->last_tmp-1)
  60       c->last_tmp--;
  61 }
  62
  63
  64 static struct brw_reg make_plane_ud(GLuint x, GLuint y, GLuint z, GLuint w)
  65 {
  66    return brw_imm_ud((w<<24) | (z<<16) | (y<<8) | x);
  67 }
  68
  69
  70 void brw_clip_init_planes( struct brw_clip_compile *c )
  71 {
  72    struct brw_codegen *p = &c->func;
  73
  74    if (!c->key.nr_userclip) {
  75       brw_MOV(p, get_element_ud(c->reg.fixed_planes, 0), make_plane_ud( 0,    0, 0xff, 1));
  76       brw_MOV(p, get_element_ud(c->reg.fixed_planes, 1), make_plane_ud( 0,    0,    1, 1));
  77       brw_MOV(p, get_element_ud(c->reg.fixed_planes, 2), make_plane_ud( 0, 0xff,    0, 1));
  78       brw_MOV(p, get_element_ud(c->reg.fixed_planes, 3), make_plane_ud( 0,    1,    0, 1));
  79       brw_MOV(p, get_element_ud(c->reg.fixed_planes, 4), make_plane_ud(0xff,  0,    0, 1));
  80       brw_MOV(p, get_element_ud(c->reg.fixed_planes, 5), make_plane_ud( 1,    0,    0, 1));
  81    }
  82 }
  83
  84
  85
  86 #define W 3
  87
  88 /* Project 'pos' to screen space (or back again), overwrite with results:
  89  */
  90 void brw_clip_project_position(struct brw_clip_compile *c, struct brw_reg pos )
  91 {
  92    struct brw_codegen *p = &c->func;
  93
  94    /* calc rhw
  95     */
  96    brw_math_invert(p, get_element(pos, W), get_element(pos, W));
  97
  98    /* value.xyz *= value.rhw
  99     */
 100    brw_set_default_access_mode(p, BRW_ALIGN_16);
 101    brw_MUL(p, brw_writemask(pos, WRITEMASK_XYZ), pos,
 102            brw_swizzle(pos, BRW_SWIZZLE_WWWW));
 103    brw_set_default_access_mode(p, BRW_ALIGN_1);
 104 }
 105
 106
 107 static void brw_clip_project_vertex( struct brw_clip_compile *c,
 108                                      struct brw_indirect vert_addr )
 109 {
 110    struct brw_codegen *p = &c->func;
 111    struct brw_reg tmp = get_tmp(c);
 112    GLuint hpos_offset = brw_varying_to_offset(&c->vue_map, VARYING_SLOT_POS);
 113    GLuint ndc_offset = brw_varying_to_offset(&c->vue_map,
 114                                              BRW_VARYING_SLOT_NDC);
 115
 116    /* Fixup position.  Extract from the original vertex and re-project
 117     * to screen space:
 118     */
 119    brw_MOV(p, tmp, deref_4f(vert_addr, hpos_offset));
 120    brw_clip_project_position(c, tmp);
 121    brw_MOV(p, deref_4f(vert_addr, ndc_offset), tmp);
 122
 123    release_tmp(c, tmp);
 124 }
 125
 126
 127
 128
 129 /* Interpolate between two vertices and put the result into a0.0.
 130  * Increment a0.0 accordingly.
 131  *
 132  * Beware that dest_ptr can be equal to v0_ptr!
 133  */
 134 void brw_clip_interp_vertex( struct brw_clip_compile *c,
 135                              struct brw_indirect dest_ptr,
 136                              struct brw_indirect v0_ptr, /* from */
 137                              struct brw_indirect v1_ptr, /* to */
 138                              struct brw_reg t0,
 139                              bool force_edgeflag)
 140 {
 141    struct brw_codegen *p = &c->func;
 142    struct brw_reg t_nopersp, v0_ndc_copy;
 143    GLuint slot;
 144
 145    /* Just copy the vertex header:
 146     */
 147    /*
 148     * After CLIP stage, only first 256 bits of the VUE are read
 149     * back on Ironlake, so needn't change it
 150     */
 151    brw_copy_indirect_to_indirect(p, dest_ptr, v0_ptr, 1);
 152
 153
 154    /* First handle the 3D and NDC interpolation, in case we
 155     * need noperspective interpolation. Doing it early has no
 156     * performance impact in any case.
 157     */
 158
 159    /* Take a copy of the v0 NDC coordinates, in case dest == v0. */
 160    if (c->has_noperspective_shading) {
 161       GLuint offset = brw_varying_to_offset(&c->vue_map,
 162                                                  BRW_VARYING_SLOT_NDC);
 163       v0_ndc_copy = get_tmp(c);
 164       brw_MOV(p, v0_ndc_copy, deref_4f(v0_ptr, offset));
 165    }
 166
 167    /* Compute the new 3D position
 168     *
 169     * dest_hpos = v0_hpos * (1 - t0) + v1_hpos * t0
 170     */
 171    {
 172       GLuint delta = brw_varying_to_offset(&c->vue_map, VARYING_SLOT_POS);
 173       struct brw_reg tmp = get_tmp(c);
 174       brw_MUL(p, vec4(brw_null_reg()), deref_4f(v1_ptr, delta), t0);
 175       brw_MAC(p, tmp, negate(deref_4f(v0_ptr, delta)), t0);
 176       brw_ADD(p, deref_4f(dest_ptr, delta), deref_4f(v0_ptr, delta), tmp);
 177       release_tmp(c, tmp);
 178    }
 179
 180    /* Recreate the projected (NDC) coordinate in the new vertex header */
 181    brw_clip_project_vertex(c, dest_ptr);
 182
 183    /* If we have noperspective attributes,
 184     * we need to compute the screen-space t
 185     */
 186    if (c->has_noperspective_shading) {
 187       GLuint delta = brw_varying_to_offset(&c->vue_map,
 188                                                 BRW_VARYING_SLOT_NDC);
 189       struct brw_reg tmp = get_tmp(c);
 190       t_nopersp = get_tmp(c);
 191
 192       /* t_nopersp = vec4(v1.xy, dest.xy) */
 193       brw_MOV(p, t_nopersp, deref_4f(v1_ptr, delta));
 194       brw_MOV(p, tmp, deref_4f(dest_ptr, delta));
 195       brw_set_default_access_mode(p, BRW_ALIGN_16);
 196       brw_MOV(p,
 197               brw_writemask(t_nopersp, WRITEMASK_ZW),
 198               brw_swizzle(tmp, BRW_SWIZZLE_XYXY));
 199
 200       /* t_nopersp = vec4(v1.xy, dest.xy) - v0.xyxy */
 201       brw_ADD(p, t_nopersp, t_nopersp,
 202               negate(brw_swizzle(v0_ndc_copy, BRW_SWIZZLE_XYXY)));
 203
 204       /* Add the absolute values of the X and Y deltas so that if
 205        * the points aren't in the same place on the screen we get
 206        * nonzero values to divide.
 207        *
 208        * After that, we have vert1 - vert0 in t_nopersp.x and
 209        * vertnew - vert0 in t_nopersp.y
 210        *
 211        * t_nopersp = vec2(|v1.x  -v0.x| + |v1.y  -v0.y|,
 212        *                  |dest.x-v0.x| + |dest.y-v0.y|)
 213        */
 214       brw_ADD(p,
 215               brw_writemask(t_nopersp, WRITEMASK_XY),
 216               brw_abs(brw_swizzle(t_nopersp, BRW_SWIZZLE_XZXZ)),
 217               brw_abs(brw_swizzle(t_nopersp, BRW_SWIZZLE_YWYW)));
 218       brw_set_default_access_mode(p, BRW_ALIGN_1);
 219
 220       /* If the points are in the same place, just substitute a
 221        * value to avoid divide-by-zero
 222        */
 223       brw_CMP(p, vec1(brw_null_reg()), BRW_CONDITIONAL_EQ,
 224               vec1(t_nopersp),
 225               brw_imm_f(0));
 226       brw_IF(p, BRW_EXECUTE_1);
 227       brw_MOV(p, t_nopersp, brw_imm_vf4(brw_float_to_vf(1.0),
 228                                         brw_float_to_vf(0.0),
 229                                         brw_float_to_vf(0.0),
 230                                         brw_float_to_vf(0.0)));
 231       brw_ENDIF(p);
 232
 233       /* Now compute t_nopersp = t_nopersp.y/t_nopersp.x and broadcast it. */
 234       brw_math_invert(p, get_element(t_nopersp, 0), get_element(t_nopersp, 0));
 235       brw_MUL(p, vec1(t_nopersp), vec1(t_nopersp),
 236             vec1(suboffset(t_nopersp, 1)));
 237       brw_set_default_access_mode(p, BRW_ALIGN_16);
 238       brw_MOV(p, t_nopersp, brw_swizzle(t_nopersp, BRW_SWIZZLE_XXXX));
 239       brw_set_default_access_mode(p, BRW_ALIGN_1);
 240
 241       release_tmp(c, tmp);
 242       release_tmp(c, v0_ndc_copy);
 243    }
 244
 245    /* Now we can iterate over each attribute
 246     * (could be done in pairs?)
 247     */
 248    for (slot = 0; slot < c->vue_map.num_slots; slot++) {
 249       int varying = c->vue_map.slot_to_varying[slot];
 250       GLuint delta = brw_vue_slot_to_offset(slot);
 251
 252       /* HPOS, NDC already handled above */
 253       if (varying == VARYING_SLOT_POS || varying == BRW_VARYING_SLOT_NDC)
 254          continue;
 255
 256
 257       if (varying == VARYING_SLOT_EDGE) {
 258          if (force_edgeflag)
 259             brw_MOV(p, deref_4f(dest_ptr, delta), brw_imm_f(1));
 260          else
 261             brw_MOV(p, deref_4f(dest_ptr, delta), deref_4f(v0_ptr, delta));
 262       } else if (varying == VARYING_SLOT_PSIZ) {
 263          /* PSIZ doesn't need interpolation because it isn't used by the
 264           * fragment shader.
 265           */
 266       } else if (varying < VARYING_SLOT_MAX) {
 267          /* This is a true vertex result (and not a special value for the VUE
 268           * header), so interpolate:
 269           *
 270           *        New = attr0 + t*attr1 - t*attr0
 271           *
 272           * Unless the attribute is flat shaded -- in which case just copy
 273           * from one of the sources (doesn't matter which; already copied from pv)
 274           */
 275          GLuint interp = c->key.interpolation_mode.mode[slot];
 276
 277          if (interp != INTERP_MODE_FLAT) {
 278             struct brw_reg tmp = get_tmp(c);
 279             struct brw_reg t =
 280                interp == INTERP_MODE_NOPERSPECTIVE ? t_nopersp : t0;
 281
 282             brw_MUL(p,
 283                   vec4(brw_null_reg()),
 284                   deref_4f(v1_ptr, delta),
 285                   t);
 286
 287             brw_MAC(p,
 288                   tmp,
 289                   negate(deref_4f(v0_ptr, delta)),
 290                   t);
 291
 292             brw_ADD(p,
 293                   deref_4f(dest_ptr, delta),
 294                   deref_4f(v0_ptr, delta),
 295                   tmp);
 296
 297             release_tmp(c, tmp);
 298          }
 299          else {
 300             brw_MOV(p,
 301                   deref_4f(dest_ptr, delta),
 302                   deref_4f(v0_ptr, delta));
 303          }
 304       }
 305    }
 306
 307    if (c->vue_map.num_slots % 2) {
 308       GLuint delta = brw_vue_slot_to_offset(c->vue_map.num_slots);
 309
 310       brw_MOV(p, deref_4f(dest_ptr, delta), brw_imm_f(0));
 311    }
 312
 313    if (c->has_noperspective_shading)
 314       release_tmp(c, t_nopersp);
 315 }
 316
 317 void brw_clip_emit_vue(struct brw_clip_compile *c,
 318                        struct brw_indirect vert,
 319                        enum brw_urb_write_flags flags,
 320                        GLuint header)
 321 {
 322    struct brw_codegen *p = &c->func;
 323    bool allocate = flags & BRW_URB_WRITE_ALLOCATE;
 324
 325    brw_clip_ff_sync(c);
 326
 327    /* Any URB entry that is allocated must subsequently be used or discarded,
 328     * so it doesn't make sense to mark EOT and ALLOCATE at the same time.
 329     */
 330    assert(!(allocate && (flags & BRW_URB_WRITE_EOT)));
 331
 332    /* Copy the vertex from vertn into m1..mN+1:
 333     */
 334    brw_copy_from_indirect(p, brw_message_reg(1), vert, c->nr_regs);
 335
 336    /* Overwrite PrimType and PrimStart in the message header, for
 337     * each vertex in turn:
 338     */
 339    brw_MOV(p, get_element_ud(c->reg.R0, 2), brw_imm_ud(header));
 340
 341
 342    /* Send each vertex as a separate write to the urb.  This
 343     * is different to the concept in brw_sf_emit.c, where
 344     * subsequent writes are used to build up a single urb
 345     * entry.  Each of these writes instantiates a separate
 346     * urb entry - (I think... what about 'allocate'?)
 347     */
 348    brw_urb_WRITE(p,
 349                  allocate ? c->reg.R0 : retype(brw_null_reg(), BRW_REGISTER_TYPE_UD),
 350                  0,
 351                  c->reg.R0,
 352                  flags,
 353                  c->nr_regs + 1, /* msg length */
 354                  allocate ? 1 : 0, /* response_length */
 355                  0,             /* urb offset */
 356                  BRW_URB_SWIZZLE_NONE);
 357 }
 358
 359
 360
 361 void brw_clip_kill_thread(struct brw_clip_compile *c)
 362 {
 363    struct brw_codegen *p = &c->func;
 364
 365    brw_clip_ff_sync(c);
 366    /* Send an empty message to kill the thread and release any
 367     * allocated urb entry:
 368     */
 369    brw_urb_WRITE(p,
 370                  retype(brw_null_reg(), BRW_REGISTER_TYPE_UD),
 371                  0,
 372                  c->reg.R0,
 373                  BRW_URB_WRITE_UNUSED | BRW_URB_WRITE_EOT_COMPLETE,
 374                  1,             /* msg len */
 375                  0,             /* response len */
 376                  0,
 377                  BRW_URB_SWIZZLE_NONE);
 378 }
 379
 380
 381
 382
 383 struct brw_reg brw_clip_plane0_address( struct brw_clip_compile *c )
 384 {
 385    return brw_address(c->reg.fixed_planes);
 386 }
 387
 388
 389 struct brw_reg brw_clip_plane_stride( struct brw_clip_compile *c )
 390 {
 391    if (c->key.nr_userclip) {
 392       return brw_imm_uw(16);
 393    }
 394    else {
 395       return brw_imm_uw(4);
 396    }
 397 }
 398
 399
 400 /* Distribute flatshaded attributes from provoking vertex prior to
 401  * clipping.
 402  */
 403 void brw_clip_copy_flatshaded_attributes( struct brw_clip_compile *c,
 404                            GLuint to, GLuint from )
 405 {
 406    struct brw_codegen *p = &c->func;
 407
 408    for (int i = 0; i < c->vue_map.num_slots; i++) {
 409       if (c->key.interpolation_mode.mode[i] == INTERP_MODE_FLAT) {
 410          brw_MOV(p,
 411                  byte_offset(c->reg.vertex[to], brw_vue_slot_to_offset(i)),
 412                  byte_offset(c->reg.vertex[from], brw_vue_slot_to_offset(i)));
 413       }
 414    }
 415 }
 416
 417
 418
 419 void brw_clip_init_clipmask( struct brw_clip_compile *c )
 420 {
 421    struct brw_codegen *p = &c->func;
 422    struct brw_reg incoming = get_element_ud(c->reg.R0, 2);
 423
 424    /* Shift so that lowest outcode bit is rightmost:
 425     */
 426    brw_SHR(p, c->reg.planemask, incoming, brw_imm_ud(26));
 427
 428    if (c->key.nr_userclip) {
 429       struct brw_reg tmp = retype(vec1(get_tmp(c)), BRW_REGISTER_TYPE_UD);
 430
 431       /* Rearrange userclip outcodes so that they come directly after
 432        * the fixed plane bits.
 433        */
 434       if (p->devinfo->gen == 5 || p->devinfo->is_g4x)
 435          brw_AND(p, tmp, incoming, brw_imm_ud(0xff<<14));
 436       else
 437          brw_AND(p, tmp, incoming, brw_imm_ud(0x3f<<14));
 438
 439       brw_SHR(p, tmp, tmp, brw_imm_ud(8));
 440       brw_OR(p, c->reg.planemask, c->reg.planemask, tmp);
 441
 442       release_tmp(c, tmp);
 443    }
 444 }
 445
 446 void brw_clip_ff_sync(struct brw_clip_compile *c)
 447 {
 448     struct brw_codegen *p = &c->func;
 449
 450     if (p->devinfo->gen == 5) {
 451         brw_AND(p, brw_null_reg(), c->reg.ff_sync, brw_imm_ud(0x1));
 452         brw_inst_set_cond_modifier(p->devinfo, brw_last_inst, BRW_CONDITIONAL_Z);
 453         brw_IF(p, BRW_EXECUTE_1);
 454         {
 455             brw_OR(p, c->reg.ff_sync, c->reg.ff_sync, brw_imm_ud(0x1));
 456             brw_ff_sync(p,
 457                         c->reg.R0,
 458                         0,
 459                         c->reg.R0,
 460                         1, /* allocate */
 461                         1, /* response length */
 462                         0 /* eot */);
 463         }
 464         brw_ENDIF(p);
 465         brw_set_default_predicate_control(p, BRW_PREDICATE_NONE);
 466     }
 467 }
 468
 469 void brw_clip_init_ff_sync(struct brw_clip_compile *c)
 470 {
 471     struct brw_codegen *p = &c->func;
 472
 473     if (p->devinfo->gen == 5) {
 474         brw_MOV(p, c->reg.ff_sync, brw_imm_ud(0));
 475     }
 476 }