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