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  * Transform feedback support.
  28  *
  29  * Authors:
  30  *   Brian Paul
  31  */
  32
  33
  34 #include "buffers.h"
  35 #include "context.h"
  36 #include "hash.h"
  37 #include "macros.h"
  38 #include "mtypes.h"
  39 #include "transformfeedback.h"
  40 #include "shaderapi.h"
  41 #include "shaderobj.h"
  42 #include "main/dispatch.h"
  43
  44 #include "program/prog_parameter.h"
  45
  46 struct using_program_tuple
  47 {
  48    struct gl_shader_program *shProg;
  49    bool found;
  50 };
  51
  52 static void
  53 active_xfb_object_references_program(GLuint key, void *data, void *user_data)
  54 {
  55    struct using_program_tuple *callback_data = user_data;
  56    struct gl_transform_feedback_object *obj = data;
  57    if (obj->Active && obj->shader_program == callback_data->shProg)
  58       callback_data->found = true;
  59 }
  60
  61 /**
  62  * Return true if any active transform feedback object is using a program.
  63  */
  64 bool
  65 _mesa_transform_feedback_is_using_program(struct gl_context *ctx,
  66                                           struct gl_shader_program *shProg)
  67 {
  68    struct using_program_tuple callback_data;
  69    callback_data.shProg = shProg;
  70    callback_data.found = false;
  71
  72    _mesa_HashWalk(ctx->TransformFeedback.Objects,
  73                   active_xfb_object_references_program, &callback_data);
  74
  75    /* Also check DefaultObject, as it's not in the Objects hash table. */
  76    active_xfb_object_references_program(0, ctx->TransformFeedback.DefaultObject,
  77                                         &callback_data);
  78
  79    return callback_data.found;
  80 }
  81
  82 /**
  83  * Do reference counting of transform feedback buffers.
  84  */
  85 static void
  86 reference_transform_feedback_object(struct gl_transform_feedback_object **ptr,
  87                                     struct gl_transform_feedback_object *obj)
  88 {
  89    if (*ptr == obj)
  90       return;
  91
  92    if (*ptr) {
  93       /* Unreference the old object */
  94       struct gl_transform_feedback_object *oldObj = *ptr;
  95
  96       assert(oldObj->RefCount > 0);
  97       oldObj->RefCount--;
  98
  99       if (oldObj->RefCount == 0) {
 100          GET_CURRENT_CONTEXT(ctx);
 101          if (ctx)
 102             ctx->Driver.DeleteTransformFeedback(ctx, oldObj);
 103       }
 104
 105       *ptr = NULL;
 106    }
 107    assert(!*ptr);
 108
 109    if (obj) {
 110       /* reference new object */
 111       if (obj->RefCount == 0) {
 112          _mesa_problem(NULL, "referencing deleted transform feedback object");
 113          *ptr = NULL;
 114       }
 115       else {
 116          obj->RefCount++;
 117          obj->EverBound = GL_TRUE;
 118          *ptr = obj;
 119       }
 120    }
 121 }
 122
 123
 124 /**
 125  * Check that all the buffer objects currently bound for transform
 126  * feedback actually exist.  Raise a GL_INVALID_OPERATION error if
 127  * any buffers are missing.
 128  * \return GL_TRUE for success, GL_FALSE if error
 129  */
 130 GLboolean
 131 _mesa_validate_transform_feedback_buffers(struct gl_context *ctx)
 132 {
 133    /* XXX to do */
 134    return GL_TRUE;
 135 }
 136
 137
 138
 139 /**
 140  * Per-context init for transform feedback.
 141  */
 142 void
 143 _mesa_init_transform_feedback(struct gl_context *ctx)
 144 {
 145    /* core mesa expects this, even a dummy one, to be available */
 146    assert(ctx->Driver.NewTransformFeedback);
 147
 148    ctx->TransformFeedback.DefaultObject =
 149       ctx->Driver.NewTransformFeedback(ctx, 0);
 150
 151    assert(ctx->TransformFeedback.DefaultObject->RefCount == 1);
 152
 153    reference_transform_feedback_object(&ctx->TransformFeedback.CurrentObject,
 154                                        ctx->TransformFeedback.DefaultObject);
 155
 156    assert(ctx->TransformFeedback.DefaultObject->RefCount == 2);
 157
 158    ctx->TransformFeedback.Objects = _mesa_NewHashTable();
 159
 160    _mesa_reference_buffer_object(ctx,
 161                                  &ctx->TransformFeedback.CurrentBuffer,
 162                                  ctx->Shared->NullBufferObj);
 163 }
 164
 165
 166
 167 /**
 168  * Callback for _mesa_HashDeleteAll().
 169  */
 170 static void
 171 delete_cb(GLuint key, void *data, void *userData)
 172 {
 173    struct gl_context *ctx = (struct gl_context *) userData;
 174    struct gl_transform_feedback_object *obj =
 175       (struct gl_transform_feedback_object *) data;
 176
 177    ctx->Driver.DeleteTransformFeedback(ctx, obj);
 178 }
 179
 180
 181 /**
 182  * Per-context free/clean-up for transform feedback.
 183  */
 184 void
 185 _mesa_free_transform_feedback(struct gl_context *ctx)
 186 {
 187    /* core mesa expects this, even a dummy one, to be available */
 188    assert(ctx->Driver.NewTransformFeedback);
 189
 190    _mesa_reference_buffer_object(ctx,
 191                                  &ctx->TransformFeedback.CurrentBuffer,
 192                                  NULL);
 193
 194    /* Delete all feedback objects */
 195    _mesa_HashDeleteAll(ctx->TransformFeedback.Objects, delete_cb, ctx);
 196    _mesa_DeleteHashTable(ctx->TransformFeedback.Objects);
 197
 198    /* Delete the default feedback object */
 199    assert(ctx->Driver.DeleteTransformFeedback);
 200    ctx->Driver.DeleteTransformFeedback(ctx,
 201                                        ctx->TransformFeedback.DefaultObject);
 202
 203    ctx->TransformFeedback.CurrentObject = NULL;
 204 }
 205
 206
 207 /** Initialize the fields of a gl_transform_feedback_object. */
 208 void
 209 _mesa_init_transform_feedback_object(struct gl_transform_feedback_object *obj,
 210                                      GLuint name)
 211 {
 212    if (!obj)
 213       return;
 214
 215    obj->Name = name;
 216    obj->RefCount = 1;
 217    obj->EverBound = GL_FALSE;
 218 }
 219
 220
 221 /** Default fallback for ctx->Driver.NewTransformFeedback() */
 222 static struct gl_transform_feedback_object *
 223 new_transform_feedback(struct gl_context *ctx, GLuint name)
 224 {
 225    struct gl_transform_feedback_object *obj;
 226    obj = CALLOC_STRUCT(gl_transform_feedback_object);
 227    _mesa_init_transform_feedback_object(obj, name);
 228    return obj;
 229 }
 230
 231 /** Default fallback for ctx->Driver.DeleteTransformFeedback() */
 232 static void
 233 delete_transform_feedback(struct gl_context *ctx,
 234                           struct gl_transform_feedback_object *obj)
 235 {
 236    GLuint i;
 237
 238    for (i = 0; i < ARRAY_SIZE(obj->Buffers); i++) {
 239       _mesa_reference_buffer_object(ctx, &obj->Buffers[i], NULL);
 240    }
 241
 242    free(obj->Label);
 243    free(obj);
 244 }
 245
 246
 247 /** Default fallback for ctx->Driver.BeginTransformFeedback() */
 248 static void
 249 begin_transform_feedback(struct gl_context *ctx, GLenum mode,
 250                          struct gl_transform_feedback_object *obj)
 251 {
 252    /* nop */
 253 }
 254
 255 /** Default fallback for ctx->Driver.EndTransformFeedback() */
 256 static void
 257 end_transform_feedback(struct gl_context *ctx,
 258                        struct gl_transform_feedback_object *obj)
 259 {
 260    /* nop */
 261 }
 262
 263 /** Default fallback for ctx->Driver.PauseTransformFeedback() */
 264 static void
 265 pause_transform_feedback(struct gl_context *ctx,
 266                          struct gl_transform_feedback_object *obj)
 267 {
 268    /* nop */
 269 }
 270
 271 /** Default fallback for ctx->Driver.ResumeTransformFeedback() */
 272 static void
 273 resume_transform_feedback(struct gl_context *ctx,
 274                           struct gl_transform_feedback_object *obj)
 275 {
 276    /* nop */
 277 }
 278
 279
 280 /**
 281  * Plug in default device driver functions for transform feedback.
 282  * Most drivers will override some/all of these.
 283  */
 284 void
 285 _mesa_init_transform_feedback_functions(struct dd_function_table *driver)
 286 {
 287    driver->NewTransformFeedback = new_transform_feedback;
 288    driver->DeleteTransformFeedback = delete_transform_feedback;
 289    driver->BeginTransformFeedback = begin_transform_feedback;
 290    driver->EndTransformFeedback = end_transform_feedback;
 291    driver->PauseTransformFeedback = pause_transform_feedback;
 292    driver->ResumeTransformFeedback = resume_transform_feedback;
 293 }
 294
 295
 296 /**
 297  * Fill in the correct Size value for each buffer in \c obj.
 298  *
 299  * From the GL 4.3 spec, section 6.1.1 ("Binding Buffer Objects to Indexed
 300  * Targets"):
 301  *
 302  *   BindBufferBase binds the entire buffer, even when the size of the buffer
 303  *   is changed after the binding is established. It is equivalent to calling
 304  *   BindBufferRange with offset zero, while size is determined by the size of
 305  *   the bound buffer at the time the binding is used.
 306  *
 307  *   Regardless of the size specified with BindBufferRange, or indirectly with
 308  *   BindBufferBase, the GL will never read or write beyond the end of a bound
 309  *   buffer. In some cases this constraint may result in visibly different
 310  *   behavior when a buffer overflow would otherwise result, such as described
 311  *   for transform feedback operations in section 13.2.2.
 312  */
 313 static void
 314 compute_transform_feedback_buffer_sizes(
 315       struct gl_transform_feedback_object *obj)
 316 {
 317    unsigned i = 0;
 318    for (i = 0; i < MAX_FEEDBACK_BUFFERS; ++i) {
 319       GLintptr offset = obj->Offset[i];
 320       GLsizeiptr buffer_size
 321          = obj->Buffers[i] == NULL ? 0 : obj->Buffers[i]->Size;
 322       GLsizeiptr available_space
 323          = buffer_size <= offset ? 0 : buffer_size - offset;
 324       GLsizeiptr computed_size;
 325       if (obj->RequestedSize[i] == 0) {
 326          /* No size was specified at the time the buffer was bound, so allow
 327           * writing to all available space in the buffer.
 328           */
 329          computed_size = available_space;
 330       } else {
 331          /* A size was specified at the time the buffer was bound, however
 332           * it's possible that the buffer has shrunk since then.  So only
 333           * allow writing to the minimum of the specified size and the space
 334           * available.
 335           */
 336          computed_size = MIN2(available_space, obj->RequestedSize[i]);
 337       }
 338
 339       /* Legal sizes must be multiples of four, so round down if necessary. */
 340       obj->Size[i] = computed_size & ~0x3;
 341    }
 342 }
 343
 344
 345 /**
 346  * Compute the maximum number of vertices that can be written to the currently
 347  * enabled transform feedback buffers without overflowing any of them.
 348  */
 349 unsigned
 350 _mesa_compute_max_transform_feedback_vertices(
 351       const struct gl_transform_feedback_object *obj,
 352       const struct gl_transform_feedback_info *info)
 353 {
 354    unsigned max_index = 0xffffffff;
 355    unsigned i;
 356
 357    for (i = 0; i < info->NumBuffers; ++i) {
 358       unsigned stride = info->BufferStride[i];
 359       unsigned max_for_this_buffer;
 360
 361       /* Skip any inactive buffers, which have a stride of 0. */
 362       if (stride == 0)
 363          continue;
 364
 365       max_for_this_buffer = obj->Size[i] / (4 * stride);
 366       max_index = MIN2(max_index, max_for_this_buffer);
 367    }
 368
 369    return max_index;
 370 }
 371
 372
 373 /**
 374  ** Begin API functions
 375  **/
 376
 377
 378 /**
 379  * Figure out which stage of the pipeline is the source of transform feedback
 380  * data given the current context state, and return its gl_shader_program.
 381  *
 382  * If no active program can generate transform feedback data (i.e. no vertex
 383  * shader is active), returns NULL.
 384  */
 385 static struct gl_shader_program *
 386 get_xfb_source(struct gl_context *ctx)
 387 {
 388    int i;
 389    for (i = MESA_SHADER_GEOMETRY; i >= MESA_SHADER_VERTEX; i--) {
 390       if (ctx->_Shader->CurrentProgram[i] != NULL)
 391          return ctx->_Shader->CurrentProgram[i];
 392    }
 393    return NULL;
 394 }
 395
 396
 397 void GLAPIENTRY
 398 _mesa_BeginTransformFeedback(GLenum mode)
 399 {
 400    struct gl_transform_feedback_object *obj;
 401    struct gl_transform_feedback_info *info = NULL;
 402    struct gl_shader_program *source;
 403    GLuint i;
 404    unsigned vertices_per_prim;
 405    GET_CURRENT_CONTEXT(ctx);
 406
 407    obj = ctx->TransformFeedback.CurrentObject;
 408
 409    /* Figure out what pipeline stage is the source of data for transform
 410     * feedback.
 411     */
 412    source = get_xfb_source(ctx);
 413    if (source == NULL) {
 414       _mesa_error(ctx, GL_INVALID_OPERATION,
 415                   "glBeginTransformFeedback(no program active)");
 416       return;
 417    }
 418
 419    info = &source->LinkedTransformFeedback;
 420
 421    if (info->NumOutputs == 0) {
 422       _mesa_error(ctx, GL_INVALID_OPERATION,
 423                   "glBeginTransformFeedback(no varyings to record)");
 424       return;
 425    }
 426
 427    switch (mode) {
 428    case GL_POINTS:
 429       vertices_per_prim = 1;
 430       break;
 431    case GL_LINES:
 432       vertices_per_prim = 2;
 433       break;
 434    case GL_TRIANGLES:
 435       vertices_per_prim = 3;
 436       break;
 437    default:
 438       _mesa_error(ctx, GL_INVALID_ENUM, "glBeginTransformFeedback(mode)");
 439       return;
 440    }
 441
 442    if (obj->Active) {
 443       _mesa_error(ctx, GL_INVALID_OPERATION,
 444                   "glBeginTransformFeedback(already active)");
 445       return;
 446    }
 447
 448    for (i = 0; i < info->NumBuffers; ++i) {
 449       if (obj->BufferNames[i] == 0) {
 450          _mesa_error(ctx, GL_INVALID_OPERATION,
 451                      "glBeginTransformFeedback(binding point %d does not have "
 452                      "a buffer object bound)", i);
 453          return;
 454       }
 455    }
 456
 457    FLUSH_VERTICES(ctx, 0);
 458    ctx->NewDriverState |= ctx->DriverFlags.NewTransformFeedback;
 459
 460    obj->Active = GL_TRUE;
 461    ctx->TransformFeedback.Mode = mode;
 462
 463    compute_transform_feedback_buffer_sizes(obj);
 464
 465    if (_mesa_is_gles3(ctx)) {
 466       /* In GLES3, we are required to track the usage of the transform
 467        * feedback buffer and report INVALID_OPERATION if a draw call tries to
 468        * exceed it.  So compute the maximum number of vertices that we can
 469        * write without overflowing any of the buffers currently being used for
 470        * feedback.
 471        */
 472       unsigned max_vertices
 473          = _mesa_compute_max_transform_feedback_vertices(obj, info);
 474       obj->GlesRemainingPrims = max_vertices / vertices_per_prim;
 475    }
 476
 477    if (obj->shader_program != source) {
 478       ctx->NewDriverState |= ctx->DriverFlags.NewTransformFeedbackProg;
 479       obj->shader_program = source;
 480    }
 481
 482    assert(ctx->Driver.BeginTransformFeedback);
 483    ctx->Driver.BeginTransformFeedback(ctx, mode, obj);
 484 }
 485
 486
 487 void GLAPIENTRY
 488 _mesa_EndTransformFeedback(void)
 489 {
 490    struct gl_transform_feedback_object *obj;
 491    GET_CURRENT_CONTEXT(ctx);
 492
 493    obj = ctx->TransformFeedback.CurrentObject;
 494
 495    if (!obj->Active) {
 496       _mesa_error(ctx, GL_INVALID_OPERATION,
 497                   "glEndTransformFeedback(not active)");
 498       return;
 499    }
 500
 501    FLUSH_VERTICES(ctx, 0);
 502    ctx->NewDriverState |= ctx->DriverFlags.NewTransformFeedback;
 503
 504    ctx->TransformFeedback.CurrentObject->Active = GL_FALSE;
 505    ctx->TransformFeedback.CurrentObject->Paused = GL_FALSE;
 506    ctx->TransformFeedback.CurrentObject->EndedAnytime = GL_TRUE;
 507
 508    assert(ctx->Driver.EndTransformFeedback);
 509    ctx->Driver.EndTransformFeedback(ctx, obj);
 510 }
 511
 512
 513 /**
 514  * Helper used by BindBufferRange() and BindBufferBase().
 515  */
 516 static void
 517 bind_buffer_range(struct gl_context *ctx, GLuint index,
 518                   struct gl_buffer_object *bufObj,
 519                   GLintptr offset, GLsizeiptr size)
 520 {
 521    struct gl_transform_feedback_object *obj =
 522       ctx->TransformFeedback.CurrentObject;
 523
 524    /* Note: no need to FLUSH_VERTICES or flag NewTransformFeedback, because
 525     * transform feedback buffers can't be changed while transform feedback is
 526     * active.
 527     */
 528
 529    /* The general binding point */
 530    _mesa_reference_buffer_object(ctx,
 531                                  &ctx->TransformFeedback.CurrentBuffer,
 532                                  bufObj);
 533
 534    /* The per-attribute binding point */
 535    _mesa_set_transform_feedback_binding(ctx, obj, index, bufObj, offset, size);
 536 }
 537
 538
 539 /**
 540  * Specify a buffer object to receive transform feedback results.  Plus,
 541  * specify the starting offset to place the results, and max size.
 542  * Called from the glBindBufferRange() function.
 543  */
 544 void
 545 _mesa_bind_buffer_range_transform_feedback(struct gl_context *ctx,
 546                                            GLuint index,
 547                                            struct gl_buffer_object *bufObj,
 548                                            GLintptr offset,
 549                                            GLsizeiptr size)
 550 {
 551    struct gl_transform_feedback_object *obj;
 552
 553    obj = ctx->TransformFeedback.CurrentObject;
 554
 555    if (obj->Active) {
 556       _mesa_error(ctx, GL_INVALID_OPERATION,
 557                   "glBindBufferRange(transform feedback active)");
 558       return;
 559    }
 560
 561    if (index >= ctx->Const.MaxTransformFeedbackBuffers) {
 562       _mesa_error(ctx, GL_INVALID_VALUE, "glBindBufferRange(index=%d)", index);
 563       return;
 564    }
 565
 566    if (size & 0x3) {
 567       /* must a multiple of four */
 568       _mesa_error(ctx, GL_INVALID_VALUE, "glBindBufferRange(size=%d)", (int) size);
 569       return;
 570    }
 571
 572    if (offset & 0x3) {
 573       /* must be multiple of four */
 574       _mesa_error(ctx, GL_INVALID_VALUE,
 575                   "glBindBufferRange(offset=%d)", (int) offset);
 576       return;
 577    }
 578
 579    bind_buffer_range(ctx, index, bufObj, offset, size);
 580 }
 581
 582
 583 /**
 584  * Specify a buffer object to receive transform feedback results.
 585  * As above, but start at offset = 0.
 586  * Called from the glBindBufferBase() function.
 587  */
 588 void
 589 _mesa_bind_buffer_base_transform_feedback(struct gl_context *ctx,
 590                                           GLuint index,
 591                                           struct gl_buffer_object *bufObj)
 592 {
 593    struct gl_transform_feedback_object *obj;
 594
 595    obj = ctx->TransformFeedback.CurrentObject;
 596
 597    if (obj->Active) {
 598       _mesa_error(ctx, GL_INVALID_OPERATION,
 599                   "glBindBufferBase(transform feedback active)");
 600       return;
 601    }
 602
 603    if (index >= ctx->Const.MaxTransformFeedbackBuffers) {
 604       _mesa_error(ctx, GL_INVALID_VALUE, "glBindBufferBase(index=%d)", index);
 605       return;
 606    }
 607
 608    bind_buffer_range(ctx, index, bufObj, 0, 0);
 609 }
 610
 611
 612 /**
 613  * Specify a buffer object to receive transform feedback results, plus the
 614  * offset in the buffer to start placing results.
 615  * This function is part of GL_EXT_transform_feedback, but not GL3.
 616  */
 617 void GLAPIENTRY
 618 _mesa_BindBufferOffsetEXT(GLenum target, GLuint index, GLuint buffer,
 619                           GLintptr offset)
 620 {
 621    struct gl_transform_feedback_object *obj;
 622    struct gl_buffer_object *bufObj;
 623    GET_CURRENT_CONTEXT(ctx);
 624
 625    if (target != GL_TRANSFORM_FEEDBACK_BUFFER) {
 626       _mesa_error(ctx, GL_INVALID_ENUM, "glBindBufferOffsetEXT(target)");
 627       return;
 628    }
 629
 630    obj = ctx->TransformFeedback.CurrentObject;
 631
 632    if (obj->Active) {
 633       _mesa_error(ctx, GL_INVALID_OPERATION,
 634                   "glBindBufferOffsetEXT(transform feedback active)");
 635       return;
 636    }
 637
 638    if (index >= ctx->Const.MaxTransformFeedbackBuffers) {
 639       _mesa_error(ctx, GL_INVALID_VALUE,
 640                   "glBindBufferOffsetEXT(index=%d)", index);
 641       return;
 642    }
 643
 644    if (offset & 0x3) {
 645       /* must be multiple of four */
 646       _mesa_error(ctx, GL_INVALID_VALUE,
 647                   "glBindBufferOffsetEXT(offset=%d)", (int) offset);
 648       return;
 649    }
 650
 651    if (buffer == 0) {
 652       bufObj = ctx->Shared->NullBufferObj;
 653    } else {
 654       bufObj = _mesa_lookup_bufferobj(ctx, buffer);
 655    }
 656
 657    if (!bufObj) {
 658       _mesa_error(ctx, GL_INVALID_OPERATION,
 659                   "glBindBufferOffsetEXT(invalid buffer=%u)", buffer);
 660       return;
 661    }
 662
 663    bind_buffer_range(ctx, index, bufObj, offset, 0);
 664 }
 665
 666
 667 /**
 668  * This function specifies the transform feedback outputs to be written
 669  * to the feedback buffer(s), and in what order.
 670  */
 671 void GLAPIENTRY
 672 _mesa_TransformFeedbackVaryings(GLuint program, GLsizei count,
 673                                 const GLchar * const *varyings,
 674                                 GLenum bufferMode)
 675 {
 676    struct gl_shader_program *shProg;
 677    GLint i;
 678    GET_CURRENT_CONTEXT(ctx);
 679
 680    /* From the ARB_transform_feedback2 specification:
 681     * "The error INVALID_OPERATION is generated by TransformFeedbackVaryings
 682     *  if the current transform feedback object is active, even if paused."
 683     */
 684    if (ctx->TransformFeedback.CurrentObject->Active) {
 685       _mesa_error(ctx, GL_INVALID_OPERATION,
 686                "glTransformFeedbackVaryings(current object is active)");
 687       return;
 688    }
 689
 690    switch (bufferMode) {
 691    case GL_INTERLEAVED_ATTRIBS:
 692       break;
 693    case GL_SEPARATE_ATTRIBS:
 694       break;
 695    default:
 696       _mesa_error(ctx, GL_INVALID_ENUM,
 697                   "glTransformFeedbackVaryings(bufferMode)");
 698       return;
 699    }
 700
 701    if (count < 0 ||
 702        (bufferMode == GL_SEPARATE_ATTRIBS &&
 703         (GLuint) count > ctx->Const.MaxTransformFeedbackBuffers)) {
 704       _mesa_error(ctx, GL_INVALID_VALUE,
 705                   "glTransformFeedbackVaryings(count=%d)", count);
 706       return;
 707    }
 708
 709    shProg = _mesa_lookup_shader_program(ctx, program);
 710    if (!shProg) {
 711       _mesa_error(ctx, GL_INVALID_VALUE,
 712                   "glTransformFeedbackVaryings(program=%u)", program);
 713       return;
 714    }
 715
 716    if (ctx->Extensions.ARB_transform_feedback3) {
 717       if (bufferMode == GL_INTERLEAVED_ATTRIBS) {
 718          unsigned buffers = 1;
 719
 720          for (i = 0; i < count; i++) {
 721             if (strcmp(varyings[i], "gl_NextBuffer") == 0)
 722                buffers++;
 723          }
 724
 725          if (buffers > ctx->Const.MaxTransformFeedbackBuffers) {
 726             _mesa_error(ctx, GL_INVALID_OPERATION,
 727                         "glTransformFeedbackVaryings(too many gl_NextBuffer "
 728                         "occurences)");
 729             return;
 730          }
 731       } else {
 732          for (i = 0; i < count; i++) {
 733             if (strcmp(varyings[i], "gl_NextBuffer") == 0 ||
 734                 strcmp(varyings[i], "gl_SkipComponents1") == 0 ||
 735                 strcmp(varyings[i], "gl_SkipComponents2") == 0 ||
 736                 strcmp(varyings[i], "gl_SkipComponents3") == 0 ||
 737                 strcmp(varyings[i], "gl_SkipComponents4") == 0) {
 738                _mesa_error(ctx, GL_INVALID_OPERATION,
 739                            "glTransformFeedbackVaryings(SEPARATE_ATTRIBS,"
 740                            "varying=%s)",
 741                            varyings[i]);
 742                return;
 743             }
 744          }
 745       }
 746    }
 747
 748    /* free existing varyings, if any */
 749    for (i = 0; i < (GLint) shProg->TransformFeedback.NumVarying; i++) {
 750       free(shProg->TransformFeedback.VaryingNames[i]);
 751    }
 752    free(shProg->TransformFeedback.VaryingNames);
 753
 754    /* allocate new memory for varying names */
 755    shProg->TransformFeedback.VaryingNames =
 756       malloc(count * sizeof(GLchar *));
 757
 758    if (!shProg->TransformFeedback.VaryingNames) {
 759       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glTransformFeedbackVaryings()");
 760       return;
 761    }
 762
 763    /* Save the new names and the count */
 764    for (i = 0; i < count; i++) {
 765       shProg->TransformFeedback.VaryingNames[i] = strdup(varyings[i]);
 766    }
 767    shProg->TransformFeedback.NumVarying = count;
 768
 769    shProg->TransformFeedback.BufferMode = bufferMode;
 770
 771    /* No need to invoke FLUSH_VERTICES or flag NewTransformFeedback since
 772     * the varyings won't be used until shader link time.
 773     */
 774 }
 775
 776
 777 /**
 778  * Get info about the transform feedback outputs which are to be written
 779  * to the feedback buffer(s).
 780  */
 781 void GLAPIENTRY
 782 _mesa_GetTransformFeedbackVarying(GLuint program, GLuint index,
 783                                   GLsizei bufSize, GLsizei *length,
 784                                   GLsizei *size, GLenum *type, GLchar *name)
 785 {
 786    const struct gl_shader_program *shProg;
 787    const struct gl_transform_feedback_info *linked_xfb_info;
 788    GET_CURRENT_CONTEXT(ctx);
 789
 790    shProg = _mesa_lookup_shader_program(ctx, program);
 791    if (!shProg) {
 792       _mesa_error(ctx, GL_INVALID_VALUE,
 793                   "glGetTransformFeedbackVarying(program=%u)", program);
 794       return;
 795    }
 796
 797    linked_xfb_info = &shProg->LinkedTransformFeedback;
 798    if (index >= (GLuint) linked_xfb_info->NumVarying) {
 799       _mesa_error(ctx, GL_INVALID_VALUE,
 800                   "glGetTransformFeedbackVarying(index=%u)", index);
 801       return;
 802    }
 803
 804    /* return the varying's name and length */
 805    _mesa_copy_string(name, bufSize, length,
 806                      linked_xfb_info->Varyings[index].Name);
 807
 808    /* return the datatype and value's size (in datatype units) */
 809    if (type)
 810       *type = linked_xfb_info->Varyings[index].Type;
 811    if (size)
 812       *size = linked_xfb_info->Varyings[index].Size;
 813 }
 814
 815
 816
 817 struct gl_transform_feedback_object *
 818 _mesa_lookup_transform_feedback_object(struct gl_context *ctx, GLuint name)
 819 {
 820    if (name == 0) {
 821       return ctx->TransformFeedback.DefaultObject;
 822    }
 823    else
 824       return (struct gl_transform_feedback_object *)
 825          _mesa_HashLookup(ctx->TransformFeedback.Objects, name);
 826 }
 827
 828 static void
 829 create_transform_feedbacks(struct gl_context *ctx, GLsizei n, GLuint *ids,
 830                            bool dsa)
 831 {
 832    GLuint first;
 833    const char* func;
 834
 835    if (dsa)
 836       func = "glCreateTransformFeedbacks";
 837    else
 838       func = "glGenTransformFeedbacks";
 839
 840    if (n < 0) {
 841       _mesa_error(ctx, GL_INVALID_VALUE, "%s(n < 0)", func);
 842       return;
 843    }
 844
 845    if (!ids)
 846       return;
 847
 848    /* we don't need contiguous IDs, but this might be faster */
 849    first = _mesa_HashFindFreeKeyBlock(ctx->TransformFeedback.Objects, n);
 850    if (first) {
 851       GLsizei i;
 852       for (i = 0; i < n; i++) {
 853          struct gl_transform_feedback_object *obj
 854             = ctx->Driver.NewTransformFeedback(ctx, first + i);
 855          if (!obj) {
 856             _mesa_error(ctx, GL_OUT_OF_MEMORY, "%s", func);
 857             return;
 858          }
 859          ids[i] = first + i;
 860          _mesa_HashInsert(ctx->TransformFeedback.Objects, first + i, obj);
 861          if (dsa) {
 862             /* this is normally done at bind time in the non-dsa case */
 863             obj->EverBound = GL_TRUE;
 864          }
 865       }
 866    }
 867    else {
 868       _mesa_error(ctx, GL_OUT_OF_MEMORY, "%s", func);
 869    }
 870 }
 871
 872 /**
 873  * Create new transform feedback objects.   Transform feedback objects
 874  * encapsulate the state related to transform feedback to allow quickly
 875  * switching state (and drawing the results, below).
 876  * Part of GL_ARB_transform_feedback2.
 877  */
 878 void GLAPIENTRY
 879 _mesa_GenTransformFeedbacks(GLsizei n, GLuint *names)
 880 {
 881    GET_CURRENT_CONTEXT(ctx);
 882
 883    /* GenTransformFeedbacks should just reserve the object names that a
 884     * subsequent call to BindTransformFeedback should actively create. For
 885     * the sake of simplicity, we reserve the names and create the objects
 886     * straight away.
 887     */
 888
 889    create_transform_feedbacks(ctx, n, names, false);
 890 }
 891
 892 /**
 893  * Create new transform feedback objects.   Transform feedback objects
 894  * encapsulate the state related to transform feedback to allow quickly
 895  * switching state (and drawing the results, below).
 896  * Part of GL_ARB_direct_state_access.
 897  */
 898 void GLAPIENTRY
 899 _mesa_CreateTransformFeedbacks(GLsizei n, GLuint *names)
 900 {
 901    GET_CURRENT_CONTEXT(ctx);
 902
 903    create_transform_feedbacks(ctx, n, names, true);
 904 }
 905
 906
 907 /**
 908  * Is the given ID a transform feedback object?
 909  * Part of GL_ARB_transform_feedback2.
 910  */
 911 GLboolean GLAPIENTRY
 912 _mesa_IsTransformFeedback(GLuint name)
 913 {
 914    struct gl_transform_feedback_object *obj;
 915    GET_CURRENT_CONTEXT(ctx);
 916
 917    ASSERT_OUTSIDE_BEGIN_END_WITH_RETVAL(ctx, GL_FALSE);
 918
 919    if (name == 0)
 920       return GL_FALSE;
 921
 922    obj = _mesa_lookup_transform_feedback_object(ctx, name);
 923    if (obj == NULL)
 924       return GL_FALSE;
 925
 926    return obj->EverBound;
 927 }
 928
 929
 930 /**
 931  * Bind the given transform feedback object.
 932  * Part of GL_ARB_transform_feedback2.
 933  */
 934 void GLAPIENTRY
 935 _mesa_BindTransformFeedback(GLenum target, GLuint name)
 936 {
 937    struct gl_transform_feedback_object *obj;
 938    GET_CURRENT_CONTEXT(ctx);
 939
 940    if (target != GL_TRANSFORM_FEEDBACK) {
 941       _mesa_error(ctx, GL_INVALID_ENUM, "glBindTransformFeedback(target)");
 942       return;
 943    }
 944
 945    if (_mesa_is_xfb_active_and_unpaused(ctx)) {
 946       _mesa_error(ctx, GL_INVALID_OPERATION,
 947               "glBindTransformFeedback(transform is active, or not paused)");
 948       return;
 949    }
 950
 951    obj = _mesa_lookup_transform_feedback_object(ctx, name);
 952    if (!obj) {
 953       _mesa_error(ctx, GL_INVALID_OPERATION,
 954                   "glBindTransformFeedback(name=%u)", name);
 955       return;
 956    }
 957
 958    reference_transform_feedback_object(&ctx->TransformFeedback.CurrentObject,
 959                                        obj);
 960 }
 961
 962
 963 /**
 964  * Delete the given transform feedback objects.
 965  * Part of GL_ARB_transform_feedback2.
 966  */
 967 void GLAPIENTRY
 968 _mesa_DeleteTransformFeedbacks(GLsizei n, const GLuint *names)
 969 {
 970    GLint i;
 971    GET_CURRENT_CONTEXT(ctx);
 972
 973    if (n < 0) {
 974       _mesa_error(ctx, GL_INVALID_VALUE, "glDeleteTransformFeedbacks(n < 0)");
 975       return;
 976    }
 977
 978    if (!names)
 979       return;
 980
 981    for (i = 0; i < n; i++) {
 982       if (names[i] > 0) {
 983          struct gl_transform_feedback_object *obj
 984             = _mesa_lookup_transform_feedback_object(ctx, names[i]);
 985          if (obj) {
 986             if (obj->Active) {
 987                _mesa_error(ctx, GL_INVALID_OPERATION,
 988                            "glDeleteTransformFeedbacks(object %u is active)",
 989                            names[i]);
 990                return;
 991             }
 992             _mesa_HashRemove(ctx->TransformFeedback.Objects, names[i]);
 993             /* unref, but object may not be deleted until later */
 994             reference_transform_feedback_object(&obj, NULL);
 995          }
 996       }
 997    }
 998 }
 999
1000
1001 /**
1002  * Pause transform feedback.
1003  * Part of GL_ARB_transform_feedback2.
1004  */
1005 void GLAPIENTRY
1006 _mesa_PauseTransformFeedback(void)
1007 {
1008    struct gl_transform_feedback_object *obj;
1009    GET_CURRENT_CONTEXT(ctx);
1010
1011    obj = ctx->TransformFeedback.CurrentObject;
1012
1013    if (!_mesa_is_xfb_active_and_unpaused(ctx)) {
1014       _mesa_error(ctx, GL_INVALID_OPERATION,
1015            "glPauseTransformFeedback(feedback not active or already paused)");
1016       return;
1017    }
1018
1019    FLUSH_VERTICES(ctx, 0);
1020    ctx->NewDriverState |= ctx->DriverFlags.NewTransformFeedback;
1021
1022    obj->Paused = GL_TRUE;
1023
1024    assert(ctx->Driver.PauseTransformFeedback);
1025    ctx->Driver.PauseTransformFeedback(ctx, obj);
1026 }
1027
1028
1029 /**
1030  * Resume transform feedback.
1031  * Part of GL_ARB_transform_feedback2.
1032  */
1033 void GLAPIENTRY
1034 _mesa_ResumeTransformFeedback(void)
1035 {
1036    struct gl_transform_feedback_object *obj;
1037    GET_CURRENT_CONTEXT(ctx);
1038
1039    obj = ctx->TransformFeedback.CurrentObject;
1040
1041    if (!obj->Active || !obj->Paused) {
1042       _mesa_error(ctx, GL_INVALID_OPERATION,
1043                "glResumeTransformFeedback(feedback not active or not paused)");
1044       return;
1045    }
1046
1047    /* From the ARB_transform_feedback2 specification:
1048     * "The error INVALID_OPERATION is generated by ResumeTransformFeedback if
1049     *  the program object being used by the current transform feedback object
1050     *  is not active."
1051     */
1052    if (obj->shader_program != get_xfb_source(ctx)) {
1053       _mesa_error(ctx, GL_INVALID_OPERATION,
1054                   "glResumeTransformFeedback(wrong program bound)");
1055       return;
1056    }
1057
1058    FLUSH_VERTICES(ctx, 0);
1059    ctx->NewDriverState |= ctx->DriverFlags.NewTransformFeedback;
1060
1061    obj->Paused = GL_FALSE;
1062
1063    assert(ctx->Driver.ResumeTransformFeedback);
1064    ctx->Driver.ResumeTransformFeedback(ctx, obj);
1065 }