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.CurrentProgram[MESA_SHADER_VERTEX] == NULL) {
 391       _mesa_error(ctx, GL_INVALID_OPERATION,
 392                   "glBeginTransformFeedback(no program active)");
 393       return;
 394    }
 395
 396    info =
 397       &ctx->Shader.CurrentProgram[MESA_SHADER_VERTEX]->LinkedTransformFeedback;
 398
 399    if (info->NumOutputs == 0) {
 400       _mesa_error(ctx, GL_INVALID_OPERATION,
 401                   "glBeginTransformFeedback(no varyings to record)");
 402       return;
 403    }
 404
 405    switch (mode) {
 406    case GL_POINTS:
 407       vertices_per_prim = 1;
 408       break;
 409    case GL_LINES:
 410       vertices_per_prim = 2;
 411       break;
 412    case GL_TRIANGLES:
 413       vertices_per_prim = 3;
 414       break;
 415    default:
 416       _mesa_error(ctx, GL_INVALID_ENUM, "glBeginTransformFeedback(mode)");
 417       return;
 418    }
 419
 420    if (obj->Active) {
 421       _mesa_error(ctx, GL_INVALID_OPERATION,
 422                   "glBeginTransformFeedback(already active)");
 423       return;
 424    }
 425
 426    for (i = 0; i < info->NumBuffers; ++i) {
 427       if (obj->BufferNames[i] == 0) {
 428          _mesa_error(ctx, GL_INVALID_OPERATION,
 429                      "glBeginTransformFeedback(binding point %d does not have "
 430                      "a buffer object bound)", i);
 431          return;
 432       }
 433    }
 434
 435    FLUSH_VERTICES(ctx, 0);
 436    ctx->NewDriverState |= ctx->DriverFlags.NewTransformFeedback;
 437
 438    obj->Active = GL_TRUE;
 439    ctx->TransformFeedback.Mode = mode;
 440
 441    compute_transform_feedback_buffer_sizes(obj);
 442
 443    if (_mesa_is_gles3(ctx)) {
 444       /* In GLES3, we are required to track the usage of the transform
 445        * feedback buffer and report INVALID_OPERATION if a draw call tries to
 446        * exceed it.  So compute the maximum number of vertices that we can
 447        * write without overflowing any of the buffers currently being used for
 448        * feedback.
 449        */
 450       unsigned max_vertices
 451          = _mesa_compute_max_transform_feedback_vertices(obj, info);
 452       obj->GlesRemainingPrims = max_vertices / vertices_per_prim;
 453    }
 454
 455    obj->shader_program = ctx->Shader.CurrentProgram[MESA_SHADER_VERTEX];
 456
 457    assert(ctx->Driver.BeginTransformFeedback);
 458    ctx->Driver.BeginTransformFeedback(ctx, mode, obj);
 459 }
 460
 461
 462 void GLAPIENTRY
 463 _mesa_EndTransformFeedback(void)
 464 {
 465    struct gl_transform_feedback_object *obj;
 466    GET_CURRENT_CONTEXT(ctx);
 467
 468    obj = ctx->TransformFeedback.CurrentObject;
 469
 470    if (!obj->Active) {
 471       _mesa_error(ctx, GL_INVALID_OPERATION,
 472                   "glEndTransformFeedback(not active)");
 473       return;
 474    }
 475
 476    FLUSH_VERTICES(ctx, 0);
 477    ctx->NewDriverState |= ctx->DriverFlags.NewTransformFeedback;
 478
 479    ctx->TransformFeedback.CurrentObject->Active = GL_FALSE;
 480    ctx->TransformFeedback.CurrentObject->Paused = GL_FALSE;
 481    ctx->TransformFeedback.CurrentObject->EndedAnytime = GL_TRUE;
 482
 483    assert(ctx->Driver.EndTransformFeedback);
 484    ctx->Driver.EndTransformFeedback(ctx, obj);
 485 }
 486
 487
 488 /**
 489  * Helper used by BindBufferRange() and BindBufferBase().
 490  */
 491 static void
 492 bind_buffer_range(struct gl_context *ctx, GLuint index,
 493                   struct gl_buffer_object *bufObj,
 494                   GLintptr offset, GLsizeiptr size)
 495 {
 496    struct gl_transform_feedback_object *obj =
 497       ctx->TransformFeedback.CurrentObject;
 498
 499    /* Note: no need to FLUSH_VERTICES or flag NewTransformFeedback, because
 500     * transform feedback buffers can't be changed while transform feedback is
 501     * active.
 502     */
 503
 504    /* The general binding point */
 505    _mesa_reference_buffer_object(ctx,
 506                                  &ctx->TransformFeedback.CurrentBuffer,
 507                                  bufObj);
 508
 509    /* The per-attribute binding point */
 510    _mesa_reference_buffer_object(ctx,
 511                                  &obj->Buffers[index],
 512                                  bufObj);
 513
 514    obj->BufferNames[index] = bufObj->Name;
 515
 516    obj->Offset[index] = offset;
 517    obj->RequestedSize[index] = size;
 518 }
 519
 520
 521 /**
 522  * Specify a buffer object to receive vertex shader results.  Plus,
 523  * specify the starting offset to place the results, and max size.
 524  * Called from the glBindBufferRange() function.
 525  */
 526 void
 527 _mesa_bind_buffer_range_transform_feedback(struct gl_context *ctx,
 528                                            GLuint index,
 529                                            struct gl_buffer_object *bufObj,
 530                                            GLintptr offset,
 531                                            GLsizeiptr size)
 532 {
 533    struct gl_transform_feedback_object *obj;
 534
 535    obj = ctx->TransformFeedback.CurrentObject;
 536
 537    if (obj->Active) {
 538       _mesa_error(ctx, GL_INVALID_OPERATION,
 539                   "glBindBufferRange(transform feedback active)");
 540       return;
 541    }
 542
 543    if (index >= ctx->Const.MaxTransformFeedbackBuffers) {
 544       _mesa_error(ctx, GL_INVALID_VALUE, "glBindBufferRange(index=%d)", index);
 545       return;
 546    }
 547
 548    if (size & 0x3) {
 549       /* must a multiple of four */
 550       _mesa_error(ctx, GL_INVALID_VALUE, "glBindBufferRange(size=%d)", (int) size);
 551       return;
 552    }
 553
 554    if (offset & 0x3) {
 555       /* must be multiple of four */
 556       _mesa_error(ctx, GL_INVALID_VALUE,
 557                   "glBindBufferRange(offset=%d)", (int) offset);
 558       return;
 559    }
 560
 561    bind_buffer_range(ctx, index, bufObj, offset, size);
 562 }
 563
 564
 565 /**
 566  * Specify a buffer object to receive vertex shader results.
 567  * As above, but start at offset = 0.
 568  * Called from the glBindBufferBase() function.
 569  */
 570 void
 571 _mesa_bind_buffer_base_transform_feedback(struct gl_context *ctx,
 572                                           GLuint index,
 573                                           struct gl_buffer_object *bufObj)
 574 {
 575    struct gl_transform_feedback_object *obj;
 576
 577    obj = ctx->TransformFeedback.CurrentObject;
 578
 579    if (obj->Active) {
 580       _mesa_error(ctx, GL_INVALID_OPERATION,
 581                   "glBindBufferBase(transform feedback active)");
 582       return;
 583    }
 584
 585    if (index >= ctx->Const.MaxTransformFeedbackBuffers) {
 586       _mesa_error(ctx, GL_INVALID_VALUE, "glBindBufferBase(index=%d)", index);
 587       return;
 588    }
 589
 590    bind_buffer_range(ctx, index, bufObj, 0, 0);
 591 }
 592
 593
 594 /**
 595  * Specify a buffer object to receive vertex shader results, plus the
 596  * offset in the buffer to start placing results.
 597  * This function is part of GL_EXT_transform_feedback, but not GL3.
 598  */
 599 void GLAPIENTRY
 600 _mesa_BindBufferOffsetEXT(GLenum target, GLuint index, GLuint buffer,
 601                           GLintptr offset)
 602 {
 603    struct gl_transform_feedback_object *obj;
 604    struct gl_buffer_object *bufObj;
 605    GET_CURRENT_CONTEXT(ctx);
 606
 607    if (target != GL_TRANSFORM_FEEDBACK_BUFFER) {
 608       _mesa_error(ctx, GL_INVALID_ENUM, "glBindBufferOffsetEXT(target)");
 609       return;
 610    }
 611
 612    obj = ctx->TransformFeedback.CurrentObject;
 613
 614    if (obj->Active) {
 615       _mesa_error(ctx, GL_INVALID_OPERATION,
 616                   "glBindBufferOffsetEXT(transform feedback active)");
 617       return;
 618    }
 619
 620    if (index >= ctx->Const.MaxTransformFeedbackBuffers) {
 621       _mesa_error(ctx, GL_INVALID_VALUE,
 622                   "glBindBufferOffsetEXT(index=%d)", index);
 623       return;
 624    }
 625
 626    if (offset & 0x3) {
 627       /* must be multiple of four */
 628       _mesa_error(ctx, GL_INVALID_VALUE,
 629                   "glBindBufferOffsetEXT(offset=%d)", (int) offset);
 630       return;
 631    }
 632
 633    if (buffer == 0) {
 634       bufObj = ctx->Shared->NullBufferObj;
 635    } else {
 636       bufObj = _mesa_lookup_bufferobj(ctx, buffer);
 637    }
 638
 639    if (!bufObj) {
 640       _mesa_error(ctx, GL_INVALID_OPERATION,
 641                   "glBindBufferOffsetEXT(invalid buffer=%u)", buffer);
 642       return;
 643    }
 644
 645    bind_buffer_range(ctx, index, bufObj, offset, 0);
 646 }
 647
 648
 649 /**
 650  * This function specifies the vertex shader outputs to be written
 651  * to the feedback buffer(s), and in what order.
 652  */
 653 void GLAPIENTRY
 654 _mesa_TransformFeedbackVaryings(GLuint program, GLsizei count,
 655                                 const GLchar * const *varyings,
 656                                 GLenum bufferMode)
 657 {
 658    struct gl_shader_program *shProg;
 659    GLint i;
 660    GET_CURRENT_CONTEXT(ctx);
 661
 662    /* From the ARB_transform_feedback2 specification:
 663     * "The error INVALID_OPERATION is generated by TransformFeedbackVaryings
 664     *  if the current transform feedback object is active, even if paused."
 665     */
 666    if (ctx->TransformFeedback.CurrentObject->Active) {
 667       _mesa_error(ctx, GL_INVALID_OPERATION,
 668                "glTransformFeedbackVaryings(current object is active)");
 669       return;
 670    }
 671
 672    switch (bufferMode) {
 673    case GL_INTERLEAVED_ATTRIBS:
 674       break;
 675    case GL_SEPARATE_ATTRIBS:
 676       break;
 677    default:
 678       _mesa_error(ctx, GL_INVALID_ENUM,
 679                   "glTransformFeedbackVaryings(bufferMode)");
 680       return;
 681    }
 682
 683    if (count < 0 ||
 684        (bufferMode == GL_SEPARATE_ATTRIBS &&
 685         (GLuint) count > ctx->Const.MaxTransformFeedbackBuffers)) {
 686       _mesa_error(ctx, GL_INVALID_VALUE,
 687                   "glTransformFeedbackVaryings(count=%d)", count);
 688       return;
 689    }
 690
 691    shProg = _mesa_lookup_shader_program(ctx, program);
 692    if (!shProg) {
 693       _mesa_error(ctx, GL_INVALID_VALUE,
 694                   "glTransformFeedbackVaryings(program=%u)", program);
 695       return;
 696    }
 697
 698    if (ctx->Extensions.ARB_transform_feedback3) {
 699       if (bufferMode == GL_INTERLEAVED_ATTRIBS) {
 700          unsigned buffers = 1;
 701
 702          for (i = 0; i < count; i++) {
 703             if (strcmp(varyings[i], "gl_NextBuffer") == 0)
 704                buffers++;
 705          }
 706
 707          if (buffers > ctx->Const.MaxTransformFeedbackBuffers) {
 708             _mesa_error(ctx, GL_INVALID_OPERATION,
 709                         "glTransformFeedbackVaryings(too many gl_NextBuffer "
 710                         "occurences)");
 711             return;
 712          }
 713       } else {
 714          for (i = 0; i < count; i++) {
 715             if (strcmp(varyings[i], "gl_NextBuffer") == 0 ||
 716                 strcmp(varyings[i], "gl_SkipComponents1") == 0 ||
 717                 strcmp(varyings[i], "gl_SkipComponents2") == 0 ||
 718                 strcmp(varyings[i], "gl_SkipComponents3") == 0 ||
 719                 strcmp(varyings[i], "gl_SkipComponents4") == 0) {
 720                _mesa_error(ctx, GL_INVALID_OPERATION,
 721                            "glTransformFeedbackVaryings(SEPARATE_ATTRIBS,"
 722                            "varying=%s)",
 723                            varyings[i]);
 724                return;
 725             }
 726          }
 727       }
 728    }
 729
 730    /* free existing varyings, if any */
 731    for (i = 0; i < (GLint) shProg->TransformFeedback.NumVarying; i++) {
 732       free(shProg->TransformFeedback.VaryingNames[i]);
 733    }
 734    free(shProg->TransformFeedback.VaryingNames);
 735
 736    /* allocate new memory for varying names */
 737    shProg->TransformFeedback.VaryingNames =
 738       malloc(count * sizeof(GLchar *));
 739
 740    if (!shProg->TransformFeedback.VaryingNames) {
 741       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glTransformFeedbackVaryings()");
 742       return;
 743    }
 744
 745    /* Save the new names and the count */
 746    for (i = 0; i < count; i++) {
 747       shProg->TransformFeedback.VaryingNames[i] = _mesa_strdup(varyings[i]);
 748    }
 749    shProg->TransformFeedback.NumVarying = count;
 750
 751    shProg->TransformFeedback.BufferMode = bufferMode;
 752
 753    /* No need to invoke FLUSH_VERTICES or flag NewTransformFeedback since
 754     * the varyings won't be used until shader link time.
 755     */
 756 }
 757
 758
 759 /**
 760  * Get info about the vertex shader's outputs which are to be written
 761  * to the feedback buffer(s).
 762  */
 763 void GLAPIENTRY
 764 _mesa_GetTransformFeedbackVarying(GLuint program, GLuint index,
 765                                   GLsizei bufSize, GLsizei *length,
 766                                   GLsizei *size, GLenum *type, GLchar *name)
 767 {
 768    const struct gl_shader_program *shProg;
 769    const struct gl_transform_feedback_info *linked_xfb_info;
 770    GET_CURRENT_CONTEXT(ctx);
 771
 772    shProg = _mesa_lookup_shader_program(ctx, program);
 773    if (!shProg) {
 774       _mesa_error(ctx, GL_INVALID_VALUE,
 775                   "glGetTransformFeedbackVarying(program=%u)", program);
 776       return;
 777    }
 778
 779    linked_xfb_info = &shProg->LinkedTransformFeedback;
 780    if (index >= (GLuint) linked_xfb_info->NumVarying) {
 781       _mesa_error(ctx, GL_INVALID_VALUE,
 782                   "glGetTransformFeedbackVarying(index=%u)", index);
 783       return;
 784    }
 785
 786    /* return the varying's name and length */
 787    _mesa_copy_string(name, bufSize, length,
 788                      linked_xfb_info->Varyings[index].Name);
 789
 790    /* return the datatype and value's size (in datatype units) */
 791    if (type)
 792       *type = linked_xfb_info->Varyings[index].Type;
 793    if (size)
 794       *size = linked_xfb_info->Varyings[index].Size;
 795 }
 796
 797
 798
 799 struct gl_transform_feedback_object *
 800 _mesa_lookup_transform_feedback_object(struct gl_context *ctx, GLuint name)
 801 {
 802    if (name == 0) {
 803       return ctx->TransformFeedback.DefaultObject;
 804    }
 805    else
 806       return (struct gl_transform_feedback_object *)
 807          _mesa_HashLookup(ctx->TransformFeedback.Objects, name);
 808 }
 809
 810
 811 /**
 812  * Create new transform feedback objects.   Transform feedback objects
 813  * encapsulate the state related to transform feedback to allow quickly
 814  * switching state (and drawing the results, below).
 815  * Part of GL_ARB_transform_feedback2.
 816  */
 817 void GLAPIENTRY
 818 _mesa_GenTransformFeedbacks(GLsizei n, GLuint *names)
 819 {
 820    GLuint first;
 821    GET_CURRENT_CONTEXT(ctx);
 822
 823    if (n < 0) {
 824       _mesa_error(ctx, GL_INVALID_VALUE, "glGenTransformFeedbacks(n < 0)");
 825       return;
 826    }
 827
 828    if (!names)
 829       return;
 830
 831    /* we don't need contiguous IDs, but this might be faster */
 832    first = _mesa_HashFindFreeKeyBlock(ctx->TransformFeedback.Objects, n);
 833    if (first) {
 834       GLsizei i;
 835       for (i = 0; i < n; i++) {
 836          struct gl_transform_feedback_object *obj
 837             = ctx->Driver.NewTransformFeedback(ctx, first + i);
 838          if (!obj) {
 839             _mesa_error(ctx, GL_OUT_OF_MEMORY, "glGenTransformFeedbacks");
 840             return;
 841          }
 842          names[i] = first + i;
 843          _mesa_HashInsert(ctx->TransformFeedback.Objects, first + i, obj);
 844       }
 845    }
 846    else {
 847       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glGenTransformFeedbacks");
 848    }
 849 }
 850
 851
 852 /**
 853  * Is the given ID a transform feedback object?
 854  * Part of GL_ARB_transform_feedback2.
 855  */
 856 GLboolean GLAPIENTRY
 857 _mesa_IsTransformFeedback(GLuint name)
 858 {
 859    struct gl_transform_feedback_object *obj;
 860    GET_CURRENT_CONTEXT(ctx);
 861
 862    ASSERT_OUTSIDE_BEGIN_END_WITH_RETVAL(ctx, GL_FALSE);
 863
 864    if (name == 0)
 865       return GL_FALSE;
 866
 867    obj = _mesa_lookup_transform_feedback_object(ctx, name);
 868    if (obj == NULL)
 869       return GL_FALSE;
 870
 871    return obj->EverBound;
 872 }
 873
 874
 875 /**
 876  * Bind the given transform feedback object.
 877  * Part of GL_ARB_transform_feedback2.
 878  */
 879 void GLAPIENTRY
 880 _mesa_BindTransformFeedback(GLenum target, GLuint name)
 881 {
 882    struct gl_transform_feedback_object *obj;
 883    GET_CURRENT_CONTEXT(ctx);
 884
 885    if (target != GL_TRANSFORM_FEEDBACK) {
 886       _mesa_error(ctx, GL_INVALID_ENUM, "glBindTransformFeedback(target)");
 887       return;
 888    }
 889
 890    if (_mesa_is_xfb_active_and_unpaused(ctx)) {
 891       _mesa_error(ctx, GL_INVALID_OPERATION,
 892               "glBindTransformFeedback(transform is active, or not paused)");
 893       return;
 894    }
 895
 896    obj = _mesa_lookup_transform_feedback_object(ctx, name);
 897    if (!obj) {
 898       _mesa_error(ctx, GL_INVALID_OPERATION,
 899                   "glBindTransformFeedback(name=%u)", name);
 900       return;
 901    }
 902
 903    reference_transform_feedback_object(&ctx->TransformFeedback.CurrentObject,
 904                                        obj);
 905 }
 906
 907
 908 /**
 909  * Delete the given transform feedback objects.
 910  * Part of GL_ARB_transform_feedback2.
 911  */
 912 void GLAPIENTRY
 913 _mesa_DeleteTransformFeedbacks(GLsizei n, const GLuint *names)
 914 {
 915    GLint i;
 916    GET_CURRENT_CONTEXT(ctx);
 917
 918    if (n < 0) {
 919       _mesa_error(ctx, GL_INVALID_VALUE, "glDeleteTransformFeedbacks(n < 0)");
 920       return;
 921    }
 922
 923    if (!names)
 924       return;
 925
 926    for (i = 0; i < n; i++) {
 927       if (names[i] > 0) {
 928          struct gl_transform_feedback_object *obj
 929             = _mesa_lookup_transform_feedback_object(ctx, names[i]);
 930          if (obj) {
 931             if (obj->Active) {
 932                _mesa_error(ctx, GL_INVALID_OPERATION,
 933                            "glDeleteTransformFeedbacks(object %u is active)",
 934                            names[i]);
 935                return;
 936             }
 937             _mesa_HashRemove(ctx->TransformFeedback.Objects, names[i]);
 938             /* unref, but object may not be deleted until later */
 939             reference_transform_feedback_object(&obj, NULL);
 940          }
 941       }
 942    }
 943 }
 944
 945
 946 /**
 947  * Pause transform feedback.
 948  * Part of GL_ARB_transform_feedback2.
 949  */
 950 void GLAPIENTRY
 951 _mesa_PauseTransformFeedback(void)
 952 {
 953    struct gl_transform_feedback_object *obj;
 954    GET_CURRENT_CONTEXT(ctx);
 955
 956    obj = ctx->TransformFeedback.CurrentObject;
 957
 958    if (!_mesa_is_xfb_active_and_unpaused(ctx)) {
 959       _mesa_error(ctx, GL_INVALID_OPERATION,
 960            "glPauseTransformFeedback(feedback not active or already paused)");
 961       return;
 962    }
 963
 964    FLUSH_VERTICES(ctx, 0);
 965    ctx->NewDriverState |= ctx->DriverFlags.NewTransformFeedback;
 966
 967    obj->Paused = GL_TRUE;
 968
 969    assert(ctx->Driver.PauseTransformFeedback);
 970    ctx->Driver.PauseTransformFeedback(ctx, obj);
 971 }
 972
 973
 974 /**
 975  * Resume transform feedback.
 976  * Part of GL_ARB_transform_feedback2.
 977  */
 978 void GLAPIENTRY
 979 _mesa_ResumeTransformFeedback(void)
 980 {
 981    struct gl_transform_feedback_object *obj;
 982    GET_CURRENT_CONTEXT(ctx);
 983
 984    obj = ctx->TransformFeedback.CurrentObject;
 985
 986    if (!obj->Active || !obj->Paused) {
 987       _mesa_error(ctx, GL_INVALID_OPERATION,
 988                "glResumeTransformFeedback(feedback not active or not paused)");
 989       return;
 990    }
 991
 992    /* From the ARB_transform_feedback2 specification:
 993     * "The error INVALID_OPERATION is generated by ResumeTransformFeedback if
 994     *  the program object being used by the current transform feedback object
 995     *  is not active."
 996     */
 997    if (obj->shader_program != ctx->Shader.CurrentProgram[MESA_SHADER_VERTEX]) {
 998       _mesa_error(ctx, GL_INVALID_OPERATION,
 999                   "glResumeTransformFeedback(wrong vertex program bound)");
1000       return;
1001    }
1002
1003    FLUSH_VERTICES(ctx, 0);
1004    ctx->NewDriverState |= ctx->DriverFlags.NewTransformFeedback;
1005
1006    obj->Paused = GL_FALSE;
1007
1008    assert(ctx->Driver.ResumeTransformFeedback);
1009    ctx->Driver.ResumeTransformFeedback(ctx, obj);
1010 }