src/mesa/main/transformfeedback.c

   1 /*
   2  * Mesa 3-D graphics library
   3  *
   4  * Copyright (C) 2010  VMware, Inc.  All Rights Reserved.
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a
   7  * copy of this software and associated documentation files (the "Software"),
   8  * to deal in the Software without restriction, including without limitation
   9  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  10  * and/or sell copies of the Software, and to permit persons to whom the
  11  * Software is furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included
  14  * in all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  17  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  20  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  21  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  22  * OTHER DEALINGS IN THE SOFTWARE.
  23  */
  24
  25
  26 /*
  27  * Vertex transform feedback support.
  28  *
  29  * Authors:
  30  *   Brian Paul
  31  */
  32
  33
  34 #include "buffers.h"
  35 #include "bufferobj.h"
  36 #include "context.h"
  37 #include "hash.h"
  38 #include "macros.h"
  39 #include "mtypes.h"
  40 #include "transformfeedback.h"
  41 #include "shaderapi.h"
  42 #include "shaderobj.h"
  43 #include "main/dispatch.h"
  44
  45 #include "program/prog_parameter.h"
  46
  47 struct using_program_tuple
  48 {
  49    struct gl_shader_program *shProg;
  50    bool found;
  51 };
  52
  53 static void
  54 active_xfb_object_references_program(GLuint key, void *data, void *user_data)
  55 {
  56    struct using_program_tuple *callback_data = user_data;
  57    struct gl_transform_feedback_object *obj = data;
  58    if (obj->Active && obj->shader_program == callback_data->shProg)
  59       callback_data->found = true;
  60 }
  61
  62 /**
  63  * Return true if any active transform feedback object is using a program.
  64  */
  65 bool
  66 _mesa_transform_feedback_is_using_program(struct gl_context *ctx,
  67                                           struct gl_shader_program *shProg)
  68 {
  69    struct using_program_tuple callback_data;
  70    callback_data.shProg = shProg;
  71    callback_data.found = false;
  72
  73    _mesa_HashWalk(ctx->TransformFeedback.Objects,
  74                   active_xfb_object_references_program, &callback_data);
  75
  76    /* Also check DefaultObject, as it's not in the Objects hash table. */
  77    active_xfb_object_references_program(0, ctx->TransformFeedback.DefaultObject,
  78                                         &callback_data);
  79
  80    return callback_data.found;
  81 }
  82
  83 /**
  84  * Do reference counting of transform feedback buffers.
  85  */
  86 static void
  87 reference_transform_feedback_object(struct gl_transform_feedback_object **ptr,
  88                                     struct gl_transform_feedback_object *obj)
  89 {
  90    if (*ptr == obj)
  91       return;
  92
  93    if (*ptr) {
  94       /* Unreference the old object */
  95       struct gl_transform_feedback_object *oldObj = *ptr;
  96
  97       ASSERT(oldObj->RefCount > 0);
  98       oldObj->RefCount--;
  99
 100       if (oldObj->RefCount == 0) {
 101          GET_CURRENT_CONTEXT(ctx);
 102          if (ctx)
 103             ctx->Driver.DeleteTransformFeedback(ctx, oldObj);
 104       }
 105
 106       *ptr = NULL;
 107    }
 108    ASSERT(!*ptr);
 109
 110    if (obj) {
 111       /* reference new object */
 112       if (obj->RefCount == 0) {
 113          _mesa_problem(NULL, "referencing deleted transform feedback object");
 114          *ptr = NULL;
 115       }
 116       else {
 117          obj->RefCount++;
 118          obj->EverBound = GL_TRUE;
 119          *ptr = obj;
 120       }
 121    }
 122 }
 123
 124
 125 /**
 126  * Check that all the buffer objects currently bound for transform
 127  * feedback actually exist.  Raise a GL_INVALID_OPERATION error if
 128  * any buffers are missing.
 129  * \return GL_TRUE for success, GL_FALSE if error
 130  */
 131 GLboolean
 132 _mesa_validate_transform_feedback_buffers(struct gl_context *ctx)
 133 {
 134    /* XXX to do */
 135    return GL_TRUE;
 136 }
 137
 138
 139
 140 /**
 141  * Per-context init for transform feedback.
 142  */
 143 void
 144 _mesa_init_transform_feedback(struct gl_context *ctx)
 145 {
 146    /* core mesa expects this, even a dummy one, to be available */
 147    ASSERT(ctx->Driver.NewTransformFeedback);
 148
 149    ctx->TransformFeedback.DefaultObject =
 150       ctx->Driver.NewTransformFeedback(ctx, 0);
 151
 152    assert(ctx->TransformFeedback.DefaultObject->RefCount == 1);
 153
 154    reference_transform_feedback_object(&ctx->TransformFeedback.CurrentObject,
 155                                        ctx->TransformFeedback.DefaultObject);
 156
 157    assert(ctx->TransformFeedback.DefaultObject->RefCount == 2);
 158
 159    ctx->TransformFeedback.Objects = _mesa_NewHashTable();
 160
 161    _mesa_reference_buffer_object(ctx,
 162                                  &ctx->TransformFeedback.CurrentBuffer,
 163                                  ctx->Shared->NullBufferObj);
 164 }
 165
 166
 167
 168 /**
 169  * Callback for _mesa_HashDeleteAll().
 170  */
 171 static void
 172 delete_cb(GLuint key, void *data, void *userData)
 173 {
 174    struct gl_context *ctx = (struct gl_context *) userData;
 175    struct gl_transform_feedback_object *obj =
 176       (struct gl_transform_feedback_object *) data;
 177
 178    ctx->Driver.DeleteTransformFeedback(ctx, obj);
 179 }
 180
 181
 182 /**
 183  * Per-context free/clean-up for transform feedback.
 184  */
 185 void
 186 _mesa_free_transform_feedback(struct gl_context *ctx)
 187 {
 188    /* core mesa expects this, even a dummy one, to be available */
 189    ASSERT(ctx->Driver.NewTransformFeedback);
 190
 191    _mesa_reference_buffer_object(ctx,
 192                                  &ctx->TransformFeedback.CurrentBuffer,
 193                                  NULL);
 194
 195    /* Delete all feedback objects */
 196    _mesa_HashDeleteAll(ctx->TransformFeedback.Objects, delete_cb, ctx);
 197    _mesa_DeleteHashTable(ctx->TransformFeedback.Objects);
 198
 199    /* Delete the default feedback object */
 200    assert(ctx->Driver.DeleteTransformFeedback);
 201    ctx->Driver.DeleteTransformFeedback(ctx,
 202                                        ctx->TransformFeedback.DefaultObject);
 203
 204    ctx->TransformFeedback.CurrentObject = NULL;
 205 }
 206
 207
 208 /** Initialize the fields of a gl_transform_feedback_object. */
 209 void
 210 _mesa_init_transform_feedback_object(struct gl_transform_feedback_object *obj,
 211                                      GLuint name)
 212 {
 213    if (!obj)
 214       return;
 215
 216    obj->Name = name;
 217    obj->RefCount = 1;
 218    obj->EverBound = GL_FALSE;
 219 }
 220
 221
 222 /** Default fallback for ctx->Driver.NewTransformFeedback() */
 223 static struct gl_transform_feedback_object *
 224 new_transform_feedback(struct gl_context *ctx, GLuint name)
 225 {
 226    struct gl_transform_feedback_object *obj;
 227    obj = CALLOC_STRUCT(gl_transform_feedback_object);
 228    _mesa_init_transform_feedback_object(obj, name);
 229    return obj;
 230 }
 231
 232 /** Default fallback for ctx->Driver.DeleteTransformFeedback() */
 233 static void
 234 delete_transform_feedback(struct gl_context *ctx,
 235                           struct gl_transform_feedback_object *obj)
 236 {
 237    GLuint i;
 238
 239    for (i = 0; i < Elements(obj->Buffers); i++) {
 240       _mesa_reference_buffer_object(ctx, &obj->Buffers[i], NULL);
 241    }
 242
 243    free(obj->Label);
 244    free(obj);
 245 }
 246
 247
 248 /** Default fallback for ctx->Driver.BeginTransformFeedback() */
 249 static void
 250 begin_transform_feedback(struct gl_context *ctx, GLenum mode,
 251                          struct gl_transform_feedback_object *obj)
 252 {
 253    /* nop */
 254 }
 255
 256 /** Default fallback for ctx->Driver.EndTransformFeedback() */
 257 static void
 258 end_transform_feedback(struct gl_context *ctx,
 259                        struct gl_transform_feedback_object *obj)
 260 {
 261    /* nop */
 262 }
 263
 264 /** Default fallback for ctx->Driver.PauseTransformFeedback() */
 265 static void
 266 pause_transform_feedback(struct gl_context *ctx,
 267                          struct gl_transform_feedback_object *obj)
 268 {
 269    /* nop */
 270 }
 271
 272 /** Default fallback for ctx->Driver.ResumeTransformFeedback() */
 273 static void
 274 resume_transform_feedback(struct gl_context *ctx,
 275                           struct gl_transform_feedback_object *obj)
 276 {
 277    /* nop */
 278 }
 279
 280
 281 /**
 282  * Plug in default device driver functions for transform feedback.
 283  * Most drivers will override some/all of these.
 284  */
 285 void
 286 _mesa_init_transform_feedback_functions(struct dd_function_table *driver)
 287 {
 288    driver->NewTransformFeedback = new_transform_feedback;
 289    driver->DeleteTransformFeedback = delete_transform_feedback;
 290    driver->BeginTransformFeedback = begin_transform_feedback;
 291    driver->EndTransformFeedback = end_transform_feedback;
 292    driver->PauseTransformFeedback = pause_transform_feedback;
 293    driver->ResumeTransformFeedback = resume_transform_feedback;
 294 }
 295
 296
 297 /**
 298  * Fill in the correct Size value for each buffer in \c obj.
 299  *
 300  * From the GL 4.3 spec, section 6.1.1 ("Binding Buffer Objects to Indexed
 301  * Targets"):
 302  *
 303  *   BindBufferBase binds the entire buffer, even when the size of the buffer
 304  *   is changed after the binding is established. It is equivalent to calling
 305  *   BindBufferRange with offset zero, while size is determined by the size of
 306  *   the bound buffer at the time the binding is used.
 307  *
 308  *   Regardless of the size specified with BindBufferRange, or indirectly with
 309  *   BindBufferBase, the GL will never read or write beyond the end of a bound
 310  *   buffer. In some cases this constraint may result in visibly different
 311  *   behavior when a buffer overflow would otherwise result, such as described
 312  *   for transform feedback operations in section 13.2.2.
 313  */
 314 static void
 315 compute_transform_feedback_buffer_sizes(
 316       struct gl_transform_feedback_object *obj)
 317 {
 318    unsigned i = 0;
 319    for (i = 0; i < MAX_FEEDBACK_BUFFERS; ++i) {
 320       GLintptr offset = obj->Offset[i];
 321       GLsizeiptr buffer_size
 322          = obj->Buffers[i] == NULL ? 0 : obj->Buffers[i]->Size;
 323       GLsizeiptr available_space
 324          = buffer_size <= offset ? 0 : buffer_size - offset;
 325       GLsizeiptr computed_size;
 326       if (obj->RequestedSize[i] == 0) {
 327          /* No size was specified at the time the buffer was bound, so allow
 328           * writing to all available space in the buffer.
 329           */
 330          computed_size = available_space;
 331       } else {
 332          /* A size was specified at the time the buffer was bound, however
 333           * it's possible that the buffer has shrunk since then.  So only
 334           * allow writing to the minimum of the specified size and the space
 335           * available.
 336           */
 337          computed_size = MIN2(available_space, obj->RequestedSize[i]);
 338       }
 339
 340       /* Legal sizes must be multiples of four, so round down if necessary. */
 341       obj->Size[i] = computed_size & ~0x3;
 342    }
 343 }
 344
 345
 346 /**
 347  * Compute the maximum number of vertices that can be written to the currently
 348  * enabled transform feedback buffers without overflowing any of them.
 349  */
 350 unsigned
 351 _mesa_compute_max_transform_feedback_vertices(
 352       const struct gl_transform_feedback_object *obj,
 353       const struct gl_transform_feedback_info *info)
 354 {
 355    unsigned max_index = 0xffffffff;
 356    unsigned i;
 357
 358    for (i = 0; i < info->NumBuffers; ++i) {
 359       unsigned stride = info->BufferStride[i];
 360       unsigned max_for_this_buffer;
 361
 362       /* Skip any inactive buffers, which have a stride of 0. */
 363       if (stride == 0)
 364          continue;
 365
 366       max_for_this_buffer = obj->Size[i] / (4 * stride);
 367       max_index = MIN2(max_index, max_for_this_buffer);
 368    }
 369
 370    return max_index;
 371 }
 372
 373
 374 /**
 375  ** Begin API functions
 376  **/
 377
 378
 379 void GLAPIENTRY
 380 _mesa_BeginTransformFeedback(GLenum mode)
 381 {
 382    struct gl_transform_feedback_object *obj;
 383    struct gl_transform_feedback_info *info;
 384    GLuint i;
 385    unsigned vertices_per_prim;
 386    GET_CURRENT_CONTEXT(ctx);
 387
 388    obj = ctx->TransformFeedback.CurrentObject;
 389
 390    if (ctx->Shader.CurrentVertexProgram == NULL) {
 391       _mesa_error(ctx, GL_INVALID_OPERATION,
 392                   "glBeginTransformFeedback(no program active)");
 393       return;
 394    }
 395
 396    info = &ctx->Shader.CurrentVertexProgram->LinkedTransformFeedback;
 397
 398    if (info->NumOutputs == 0) {
 399       _mesa_error(ctx, GL_INVALID_OPERATION,
 400                   "glBeginTransformFeedback(no varyings to record)");
 401       return;
 402    }
 403
 404    switch (mode) {
 405    case GL_POINTS:
 406       vertices_per_prim = 1;
 407       break;
 408    case GL_LINES:
 409       vertices_per_prim = 2;
 410       break;
 411    case GL_TRIANGLES:
 412       vertices_per_prim = 3;
 413       break;
 414    default:
 415       _mesa_error(ctx, GL_INVALID_ENUM, "glBeginTransformFeedback(mode)");
 416       return;
 417    }
 418
 419    if (obj->Active) {
 420       _mesa_error(ctx, GL_INVALID_OPERATION,
 421                   "glBeginTransformFeedback(already active)");
 422       return;
 423    }
 424
 425    for (i = 0; i < info->NumBuffers; ++i) {
 426       if (obj->BufferNames[i] == 0) {
 427          _mesa_error(ctx, GL_INVALID_OPERATION,
 428                      "glBeginTransformFeedback(binding point %d does not have "
 429                      "a buffer object bound)", i);
 430          return;
 431       }
 432    }
 433
 434    FLUSH_VERTICES(ctx, 0);
 435    ctx->NewDriverState |= ctx->DriverFlags.NewTransformFeedback;
 436
 437    obj->Active = GL_TRUE;
 438    ctx->TransformFeedback.Mode = mode;
 439
 440    compute_transform_feedback_buffer_sizes(obj);
 441
 442    if (_mesa_is_gles3(ctx)) {
 443       /* In GLES3, we are required to track the usage of the transform
 444        * feedback buffer and report INVALID_OPERATION if a draw call tries to
 445        * exceed it.  So compute the maximum number of vertices that we can
 446        * write without overflowing any of the buffers currently being used for
 447        * feedback.
 448        */
 449       unsigned max_vertices
 450          = _mesa_compute_max_transform_feedback_vertices(obj, info);
 451       obj->GlesRemainingPrims = max_vertices / vertices_per_prim;
 452    }
 453
 454    obj->shader_program = ctx->Shader.CurrentVertexProgram;
 455
 456    assert(ctx->Driver.BeginTransformFeedback);
 457    ctx->Driver.BeginTransformFeedback(ctx, mode, obj);
 458 }
 459
 460
 461 void GLAPIENTRY
 462 _mesa_EndTransformFeedback(void)
 463 {
 464    struct gl_transform_feedback_object *obj;
 465    GET_CURRENT_CONTEXT(ctx);
 466
 467    obj = ctx->TransformFeedback.CurrentObject;
 468
 469    if (!obj->Active) {
 470       _mesa_error(ctx, GL_INVALID_OPERATION,
 471                   "glEndTransformFeedback(not active)");
 472       return;
 473    }
 474
 475    FLUSH_VERTICES(ctx, 0);
 476    ctx->NewDriverState |= ctx->DriverFlags.NewTransformFeedback;
 477
 478    ctx->TransformFeedback.CurrentObject->Active = GL_FALSE;
 479    ctx->TransformFeedback.CurrentObject->Paused = GL_FALSE;
 480    ctx->TransformFeedback.CurrentObject->EndedAnytime = GL_TRUE;
 481
 482    assert(ctx->Driver.EndTransformFeedback);
 483    ctx->Driver.EndTransformFeedback(ctx, obj);
 484 }
 485
 486
 487 /**
 488  * Helper used by BindBufferRange() and BindBufferBase().
 489  */
 490 static void
 491 bind_buffer_range(struct gl_context *ctx, GLuint index,
 492                   struct gl_buffer_object *bufObj,
 493                   GLintptr offset, GLsizeiptr size)
 494 {
 495    struct gl_transform_feedback_object *obj =
 496       ctx->TransformFeedback.CurrentObject;
 497
 498    /* Note: no need to FLUSH_VERTICES or flag NewTransformFeedback, because
 499     * transform feedback buffers can't be changed while transform feedback is
 500     * active.
 501     */
 502
 503    /* The general binding point */
 504    _mesa_reference_buffer_object(ctx,
 505                                  &ctx->TransformFeedback.CurrentBuffer,
 506                                  bufObj);
 507
 508    /* The per-attribute binding point */
 509    _mesa_reference_buffer_object(ctx,
 510                                  &obj->Buffers[index],
 511                                  bufObj);
 512
 513    obj->BufferNames[index] = bufObj->Name;
 514
 515    obj->Offset[index] = offset;
 516    obj->RequestedSize[index] = size;
 517 }
 518
 519
 520 /**
 521  * Specify a buffer object to receive vertex shader results.  Plus,
 522  * specify the starting offset to place the results, and max size.
 523  * Called from the glBindBufferRange() function.
 524  */
 525 void
 526 _mesa_bind_buffer_range_transform_feedback(struct gl_context *ctx,
 527                                            GLuint index,
 528                                            struct gl_buffer_object *bufObj,
 529                                            GLintptr offset,
 530                                            GLsizeiptr size)
 531 {
 532    struct gl_transform_feedback_object *obj;
 533
 534    obj = ctx->TransformFeedback.CurrentObject;
 535
 536    if (obj->Active) {
 537       _mesa_error(ctx, GL_INVALID_OPERATION,
 538                   "glBindBufferRange(transform feedback active)");
 539       return;
 540    }
 541
 542    if (index >= ctx->Const.MaxTransformFeedbackBuffers) {
 543       _mesa_error(ctx, GL_INVALID_VALUE, "glBindBufferRange(index=%d)", index);
 544       return;
 545    }
 546
 547    if (size & 0x3) {
 548       /* must a multiple of four */
 549       _mesa_error(ctx, GL_INVALID_VALUE, "glBindBufferRange(size=%d)", (int) size);
 550       return;
 551    }
 552
 553    if (offset & 0x3) {
 554       /* must be multiple of four */
 555       _mesa_error(ctx, GL_INVALID_VALUE,
 556                   "glBindBufferRange(offset=%d)", (int) offset);
 557       return;
 558    }
 559
 560    bind_buffer_range(ctx, index, bufObj, offset, size);
 561 }
 562
 563
 564 /**
 565  * Specify a buffer object to receive vertex shader results.
 566  * As above, but start at offset = 0.
 567  * Called from the glBindBufferBase() function.
 568  */
 569 void
 570 _mesa_bind_buffer_base_transform_feedback(struct gl_context *ctx,
 571                                           GLuint index,
 572                                           struct gl_buffer_object *bufObj)
 573 {
 574    struct gl_transform_feedback_object *obj;
 575
 576    obj = ctx->TransformFeedback.CurrentObject;
 577
 578    if (obj->Active) {
 579       _mesa_error(ctx, GL_INVALID_OPERATION,
 580                   "glBindBufferBase(transform feedback active)");
 581       return;
 582    }
 583
 584    if (index >= ctx->Const.MaxTransformFeedbackBuffers) {
 585       _mesa_error(ctx, GL_INVALID_VALUE, "glBindBufferBase(index=%d)", index);
 586       return;
 587    }
 588
 589    bind_buffer_range(ctx, index, bufObj, 0, 0);
 590 }
 591
 592
 593 /**
 594  * Specify a buffer object to receive vertex shader results, plus the
 595  * offset in the buffer to start placing results.
 596  * This function is part of GL_EXT_transform_feedback, but not GL3.
 597  */
 598 void GLAPIENTRY
 599 _mesa_BindBufferOffsetEXT(GLenum target, GLuint index, GLuint buffer,
 600                           GLintptr offset)
 601 {
 602    struct gl_transform_feedback_object *obj;
 603    struct gl_buffer_object *bufObj;
 604    GET_CURRENT_CONTEXT(ctx);
 605
 606    if (target != GL_TRANSFORM_FEEDBACK_BUFFER) {
 607       _mesa_error(ctx, GL_INVALID_ENUM, "glBindBufferOffsetEXT(target)");
 608       return;
 609    }
 610
 611    obj = ctx->TransformFeedback.CurrentObject;
 612
 613    if (obj->Active) {
 614       _mesa_error(ctx, GL_INVALID_OPERATION,
 615                   "glBindBufferOffsetEXT(transform feedback active)");
 616       return;
 617    }
 618
 619    if (index >= ctx->Const.MaxTransformFeedbackBuffers) {
 620       _mesa_error(ctx, GL_INVALID_VALUE,
 621                   "glBindBufferOffsetEXT(index=%d)", index);
 622       return;
 623    }
 624
 625    if (offset & 0x3) {
 626       /* must be multiple of four */
 627       _mesa_error(ctx, GL_INVALID_VALUE,
 628                   "glBindBufferOffsetEXT(offset=%d)", (int) offset);
 629       return;
 630    }
 631
 632    if (buffer == 0) {
 633       bufObj = ctx->Shared->NullBufferObj;
 634    } else {
 635       bufObj = _mesa_lookup_bufferobj(ctx, buffer);
 636    }
 637
 638    if (!bufObj) {
 639       _mesa_error(ctx, GL_INVALID_OPERATION,
 640                   "glBindBufferOffsetEXT(invalid buffer=%u)", buffer);
 641       return;
 642    }
 643
 644    bind_buffer_range(ctx, index, bufObj, offset, 0);
 645 }
 646
 647
 648 /**
 649  * This function specifies the vertex shader outputs to be written
 650  * to the feedback buffer(s), and in what order.
 651  */
 652 void GLAPIENTRY
 653 _mesa_TransformFeedbackVaryings(GLuint program, GLsizei count,
 654                                 const GLchar * const *varyings,
 655                                 GLenum bufferMode)
 656 {
 657    struct gl_shader_program *shProg;
 658    GLint i;
 659    GET_CURRENT_CONTEXT(ctx);
 660
 661    /* From the ARB_transform_feedback2 specification:
 662     * "The error INVALID_OPERATION is generated by TransformFeedbackVaryings
 663     *  if the current transform feedback object is active, even if paused."
 664     */
 665    if (ctx->TransformFeedback.CurrentObject->Active) {
 666       _mesa_error(ctx, GL_INVALID_OPERATION,
 667                "glTransformFeedbackVaryings(current object is active)");
 668       return;
 669    }
 670
 671    switch (bufferMode) {
 672    case GL_INTERLEAVED_ATTRIBS:
 673       break;
 674    case GL_SEPARATE_ATTRIBS:
 675       break;
 676    default:
 677       _mesa_error(ctx, GL_INVALID_ENUM,
 678                   "glTransformFeedbackVaryings(bufferMode)");
 679       return;
 680    }
 681
 682    if (count < 0 ||
 683        (bufferMode == GL_SEPARATE_ATTRIBS &&
 684         (GLuint) count > ctx->Const.MaxTransformFeedbackBuffers)) {
 685       _mesa_error(ctx, GL_INVALID_VALUE,
 686                   "glTransformFeedbackVaryings(count=%d)", count);
 687       return;
 688    }
 689
 690    shProg = _mesa_lookup_shader_program(ctx, program);
 691    if (!shProg) {
 692       _mesa_error(ctx, GL_INVALID_VALUE,
 693                   "glTransformFeedbackVaryings(program=%u)", program);
 694       return;
 695    }
 696
 697    if (ctx->Extensions.ARB_transform_feedback3) {
 698       if (bufferMode == GL_INTERLEAVED_ATTRIBS) {
 699          unsigned buffers = 1;
 700
 701          for (i = 0; i < count; i++) {
 702             if (strcmp(varyings[i], "gl_NextBuffer") == 0)
 703                buffers++;
 704          }
 705
 706          if (buffers > ctx->Const.MaxTransformFeedbackBuffers) {
 707             _mesa_error(ctx, GL_INVALID_OPERATION,
 708                         "glTransformFeedbackVaryings(too many gl_NextBuffer "
 709                         "occurences)");
 710             return;
 711          }
 712       } else {
 713          for (i = 0; i < count; i++) {
 714             if (strcmp(varyings[i], "gl_NextBuffer") == 0 ||
 715                 strcmp(varyings[i], "gl_SkipComponents1") == 0 ||
 716                 strcmp(varyings[i], "gl_SkipComponents2") == 0 ||
 717                 strcmp(varyings[i], "gl_SkipComponents3") == 0 ||
 718                 strcmp(varyings[i], "gl_SkipComponents4") == 0) {
 719                _mesa_error(ctx, GL_INVALID_OPERATION,
 720                            "glTransformFeedbackVaryings(SEPARATE_ATTRIBS,"
 721                            "varying=%s)",
 722                            varyings[i]);
 723                return;
 724             }
 725          }
 726       }
 727    }
 728
 729    /* free existing varyings, if any */
 730    for (i = 0; i < (GLint) shProg->TransformFeedback.NumVarying; i++) {
 731       free(shProg->TransformFeedback.VaryingNames[i]);
 732    }
 733    free(shProg->TransformFeedback.VaryingNames);
 734
 735    /* allocate new memory for varying names */
 736    shProg->TransformFeedback.VaryingNames =
 737       malloc(count * sizeof(GLchar *));
 738
 739    if (!shProg->TransformFeedback.VaryingNames) {
 740       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glTransformFeedbackVaryings()");
 741       return;
 742    }
 743
 744    /* Save the new names and the count */
 745    for (i = 0; i < count; i++) {
 746       shProg->TransformFeedback.VaryingNames[i] = _mesa_strdup(varyings[i]);
 747    }
 748    shProg->TransformFeedback.NumVarying = count;
 749
 750    shProg->TransformFeedback.BufferMode = bufferMode;
 751
 752    /* No need to invoke FLUSH_VERTICES or flag NewTransformFeedback since
 753     * the varyings won't be used until shader link time.
 754     */
 755 }
 756
 757
 758 /**
 759  * Get info about the vertex shader's outputs which are to be written
 760  * to the feedback buffer(s).
 761  */
 762 void GLAPIENTRY
 763 _mesa_GetTransformFeedbackVarying(GLuint program, GLuint index,
 764                                   GLsizei bufSize, GLsizei *length,
 765                                   GLsizei *size, GLenum *type, GLchar *name)
 766 {
 767    const struct gl_shader_program *shProg;
 768    const struct gl_transform_feedback_info *linked_xfb_info;
 769    GET_CURRENT_CONTEXT(ctx);
 770
 771    shProg = _mesa_lookup_shader_program(ctx, program);
 772    if (!shProg) {
 773       _mesa_error(ctx, GL_INVALID_VALUE,
 774                   "glGetTransformFeedbackVarying(program=%u)", program);
 775       return;
 776    }
 777
 778    linked_xfb_info = &shProg->LinkedTransformFeedback;
 779    if (index >= (GLuint) linked_xfb_info->NumVarying) {
 780       _mesa_error(ctx, GL_INVALID_VALUE,
 781                   "glGetTransformFeedbackVarying(index=%u)", index);
 782       return;
 783    }
 784
 785    /* return the varying's name and length */
 786    _mesa_copy_string(name, bufSize, length,
 787                      linked_xfb_info->Varyings[index].Name);
 788
 789    /* return the datatype and value's size (in datatype units) */
 790    if (type)
 791       *type = linked_xfb_info->Varyings[index].Type;
 792    if (size)
 793       *size = linked_xfb_info->Varyings[index].Size;
 794 }
 795
 796
 797
 798 struct gl_transform_feedback_object *
 799 _mesa_lookup_transform_feedback_object(struct gl_context *ctx, GLuint name)
 800 {
 801    if (name == 0) {
 802       return ctx->TransformFeedback.DefaultObject;
 803    }
 804    else
 805       return (struct gl_transform_feedback_object *)
 806          _mesa_HashLookup(ctx->TransformFeedback.Objects, name);
 807 }
 808
 809
 810 /**
 811  * Create new transform feedback objects.   Transform feedback objects
 812  * encapsulate the state related to transform feedback to allow quickly
 813  * switching state (and drawing the results, below).
 814  * Part of GL_ARB_transform_feedback2.
 815  */
 816 void GLAPIENTRY
 817 _mesa_GenTransformFeedbacks(GLsizei n, GLuint *names)
 818 {
 819    GLuint first;
 820    GET_CURRENT_CONTEXT(ctx);
 821
 822    if (n < 0) {
 823       _mesa_error(ctx, GL_INVALID_VALUE, "glGenTransformFeedbacks(n < 0)");
 824       return;
 825    }
 826
 827    if (!names)
 828       return;
 829
 830    /* we don't need contiguous IDs, but this might be faster */
 831    first = _mesa_HashFindFreeKeyBlock(ctx->TransformFeedback.Objects, n);
 832    if (first) {
 833       GLsizei i;
 834       for (i = 0; i < n; i++) {
 835          struct gl_transform_feedback_object *obj
 836             = ctx->Driver.NewTransformFeedback(ctx, first + i);
 837          if (!obj) {
 838             _mesa_error(ctx, GL_OUT_OF_MEMORY, "glGenTransformFeedbacks");
 839             return;
 840          }
 841          names[i] = first + i;
 842          _mesa_HashInsert(ctx->TransformFeedback.Objects, first + i, obj);
 843       }
 844    }
 845    else {
 846       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glGenTransformFeedbacks");
 847    }
 848 }
 849
 850
 851 /**
 852  * Is the given ID a transform feedback object?
 853  * Part of GL_ARB_transform_feedback2.
 854  */
 855 GLboolean GLAPIENTRY
 856 _mesa_IsTransformFeedback(GLuint name)
 857 {
 858    struct gl_transform_feedback_object *obj;
 859    GET_CURRENT_CONTEXT(ctx);
 860
 861    ASSERT_OUTSIDE_BEGIN_END_WITH_RETVAL(ctx, GL_FALSE);
 862
 863    if (name == 0)
 864       return GL_FALSE;
 865
 866    obj = _mesa_lookup_transform_feedback_object(ctx, name);
 867    if (obj == NULL)
 868       return GL_FALSE;
 869
 870    return obj->EverBound;
 871 }
 872
 873
 874 /**
 875  * Bind the given transform feedback object.
 876  * Part of GL_ARB_transform_feedback2.
 877  */
 878 void GLAPIENTRY
 879 _mesa_BindTransformFeedback(GLenum target, GLuint name)
 880 {
 881    struct gl_transform_feedback_object *obj;
 882    GET_CURRENT_CONTEXT(ctx);
 883
 884    if (target != GL_TRANSFORM_FEEDBACK) {
 885       _mesa_error(ctx, GL_INVALID_ENUM, "glBindTransformFeedback(target)");
 886       return;
 887    }
 888
 889    if (_mesa_is_xfb_active_and_unpaused(ctx)) {
 890       _mesa_error(ctx, GL_INVALID_OPERATION,
 891               "glBindTransformFeedback(transform is active, or not paused)");
 892       return;
 893    }
 894
 895    obj = _mesa_lookup_transform_feedback_object(ctx, name);
 896    if (!obj) {
 897       _mesa_error(ctx, GL_INVALID_OPERATION,
 898                   "glBindTransformFeedback(name=%u)", name);
 899       return;
 900    }
 901
 902    reference_transform_feedback_object(&ctx->TransformFeedback.CurrentObject,
 903                                        obj);
 904 }
 905
 906
 907 /**
 908  * Delete the given transform feedback objects.
 909  * Part of GL_ARB_transform_feedback2.
 910  */
 911 void GLAPIENTRY
 912 _mesa_DeleteTransformFeedbacks(GLsizei n, const GLuint *names)
 913 {
 914    GLint i;
 915    GET_CURRENT_CONTEXT(ctx);
 916
 917    if (n < 0) {
 918       _mesa_error(ctx, GL_INVALID_VALUE, "glDeleteTransformFeedbacks(n < 0)");
 919       return;
 920    }
 921
 922    if (!names)
 923       return;
 924
 925    for (i = 0; i < n; i++) {
 926       if (names[i] > 0) {
 927          struct gl_transform_feedback_object *obj
 928             = _mesa_lookup_transform_feedback_object(ctx, names[i]);
 929          if (obj) {
 930             if (obj->Active) {
 931                _mesa_error(ctx, GL_INVALID_OPERATION,
 932                            "glDeleteTransformFeedbacks(object %u is active)",
 933                            names[i]);
 934                return;
 935             }
 936             _mesa_HashRemove(ctx->TransformFeedback.Objects, names[i]);
 937             /* unref, but object may not be deleted until later */
 938             reference_transform_feedback_object(&obj, NULL);
 939          }
 940       }
 941    }
 942 }
 943
 944
 945 /**
 946  * Pause transform feedback.
 947  * Part of GL_ARB_transform_feedback2.
 948  */
 949 void GLAPIENTRY
 950 _mesa_PauseTransformFeedback(void)
 951 {
 952    struct gl_transform_feedback_object *obj;
 953    GET_CURRENT_CONTEXT(ctx);
 954
 955    obj = ctx->TransformFeedback.CurrentObject;
 956
 957    if (!_mesa_is_xfb_active_and_unpaused(ctx)) {
 958       _mesa_error(ctx, GL_INVALID_OPERATION,
 959            "glPauseTransformFeedback(feedback not active or already paused)");
 960       return;
 961    }
 962
 963    FLUSH_VERTICES(ctx, 0);
 964    ctx->NewDriverState |= ctx->DriverFlags.NewTransformFeedback;
 965
 966    obj->Paused = GL_TRUE;
 967
 968    assert(ctx->Driver.PauseTransformFeedback);
 969    ctx->Driver.PauseTransformFeedback(ctx, obj);
 970 }
 971
 972
 973 /**
 974  * Resume transform feedback.
 975  * Part of GL_ARB_transform_feedback2.
 976  */
 977 void GLAPIENTRY
 978 _mesa_ResumeTransformFeedback(void)
 979 {
 980    struct gl_transform_feedback_object *obj;
 981    GET_CURRENT_CONTEXT(ctx);
 982
 983    obj = ctx->TransformFeedback.CurrentObject;
 984
 985    if (!obj->Active || !obj->Paused) {
 986       _mesa_error(ctx, GL_INVALID_OPERATION,
 987                "glResumeTransformFeedback(feedback not active or not paused)");
 988       return;
 989    }
 990
 991    /* From the ARB_transform_feedback2 specification:
 992     * "The error INVALID_OPERATION is generated by ResumeTransformFeedback if
 993     *  the program object being used by the current transform feedback object
 994     *  is not active."
 995     */
 996    if (obj->shader_program != ctx->Shader.CurrentVertexProgram) {
 997       _mesa_error(ctx, GL_INVALID_OPERATION,
 998                   "glResumeTransformFeedback(wrong vertex program bound)");
 999       return;
1000    }
1001
1002    FLUSH_VERTICES(ctx, 0);
1003    ctx->NewDriverState |= ctx->DriverFlags.NewTransformFeedback;
1004
1005    obj->Paused = GL_FALSE;
1006
1007    assert(ctx->Driver.ResumeTransformFeedback);
1008    ctx->Driver.ResumeTransformFeedback(ctx, obj);
1009 }