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 BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
  20  * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  21  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  22  */
  23
  24
  25 /*
  26  * Vertex transform feedback support.
  27  *
  28  * Authors:
  29  *   Brian Paul
  30  */
  31
  32
  33 #include "buffers.h"
  34 #include "bufferobj.h"
  35 #include "context.h"
  36 #include "hash.h"
  37 #include "macros.h"
  38 #include "mfeatures.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);
 199 }
 200
 201
 202 /** Default fallback for ctx->Driver.BeginTransformFeedback() */
 203 static void
 204 begin_transform_feedback(struct gl_context *ctx, GLenum mode,
 205                          struct gl_transform_feedback_object *obj)
 206 {
 207    /* nop */
 208 }
 209
 210 /** Default fallback for ctx->Driver.EndTransformFeedback() */
 211 static void
 212 end_transform_feedback(struct gl_context *ctx,
 213                        struct gl_transform_feedback_object *obj)
 214 {
 215    /* nop */
 216 }
 217
 218 /** Default fallback for ctx->Driver.PauseTransformFeedback() */
 219 static void
 220 pause_transform_feedback(struct gl_context *ctx,
 221                          struct gl_transform_feedback_object *obj)
 222 {
 223    /* nop */
 224 }
 225
 226 /** Default fallback for ctx->Driver.ResumeTransformFeedback() */
 227 static void
 228 resume_transform_feedback(struct gl_context *ctx,
 229                           struct gl_transform_feedback_object *obj)
 230 {
 231    /* nop */
 232 }
 233
 234
 235 /**
 236  * Plug in default device driver functions for transform feedback.
 237  * Most drivers will override some/all of these.
 238  */
 239 void
 240 _mesa_init_transform_feedback_functions(struct dd_function_table *driver)
 241 {
 242    driver->NewTransformFeedback = new_transform_feedback;
 243    driver->DeleteTransformFeedback = delete_transform_feedback;
 244    driver->BeginTransformFeedback = begin_transform_feedback;
 245    driver->EndTransformFeedback = end_transform_feedback;
 246    driver->PauseTransformFeedback = pause_transform_feedback;
 247    driver->ResumeTransformFeedback = resume_transform_feedback;
 248 }
 249
 250
 251 /**
 252  * Fill in the correct Size value for each buffer in \c obj.
 253  *
 254  * From the GL 4.3 spec, section 6.1.1 ("Binding Buffer Objects to Indexed
 255  * Targets"):
 256  *
 257  *   BindBufferBase binds the entire buffer, even when the size of the buffer
 258  *   is changed after the binding is established. It is equivalent to calling
 259  *   BindBufferRange with offset zero, while size is determined by the size of
 260  *   the bound buffer at the time the binding is used.
 261  *
 262  *   Regardless of the size specified with BindBufferRange, or indirectly with
 263  *   BindBufferBase, the GL will never read or write beyond the end of a bound
 264  *   buffer. In some cases this constraint may result in visibly different
 265  *   behavior when a buffer overflow would otherwise result, such as described
 266  *   for transform feedback operations in section 13.2.2.
 267  */
 268 static void
 269 compute_transform_feedback_buffer_sizes(
 270       struct gl_transform_feedback_object *obj)
 271 {
 272    unsigned i = 0;
 273    for (i = 0; i < MAX_FEEDBACK_BUFFERS; ++i) {
 274       GLintptr offset = obj->Offset[i];
 275       GLsizeiptr buffer_size
 276          = obj->Buffers[i] == NULL ? 0 : obj->Buffers[i]->Size;
 277       GLsizeiptr available_space
 278          = buffer_size <= offset ? 0 : buffer_size - offset;
 279       GLsizeiptr computed_size;
 280       if (obj->RequestedSize[i] == 0) {
 281          /* No size was specified at the time the buffer was bound, so allow
 282           * writing to all available space in the buffer.
 283           */
 284          computed_size = available_space;
 285       } else {
 286          /* A size was specified at the time the buffer was bound, however
 287           * it's possible that the buffer has shrunk since then.  So only
 288           * allow writing to the minimum of the specified size and the space
 289           * available.
 290           */
 291          computed_size = MIN2(available_space, obj->RequestedSize[i]);
 292       }
 293
 294       /* Legal sizes must be multiples of four, so round down if necessary. */
 295       obj->Size[i] = computed_size & ~0x3;
 296    }
 297 }
 298
 299
 300 /**
 301  * Compute the maximum number of vertices that can be written to the currently
 302  * enabled transform feedback buffers without overflowing any of them.
 303  */
 304 unsigned
 305 _mesa_compute_max_transform_feedback_vertices(
 306       const struct gl_transform_feedback_object *obj,
 307       const struct gl_transform_feedback_info *info)
 308 {
 309    unsigned max_index = 0xffffffff;
 310    unsigned i;
 311
 312    for (i = 0; i < info->NumBuffers; ++i) {
 313       unsigned stride = info->BufferStride[i];
 314       unsigned max_for_this_buffer;
 315
 316       /* Skip any inactive buffers, which have a stride of 0. */
 317       if (stride == 0)
 318          continue;
 319
 320       max_for_this_buffer = obj->Size[i] / (4 * stride);
 321       max_index = MIN2(max_index, max_for_this_buffer);
 322    }
 323
 324    return max_index;
 325 }
 326
 327
 328 /**
 329  ** Begin API functions
 330  **/
 331
 332
 333 void GLAPIENTRY
 334 _mesa_BeginTransformFeedback(GLenum mode)
 335 {
 336    struct gl_transform_feedback_object *obj;
 337    struct gl_transform_feedback_info *info;
 338    GLuint i;
 339    unsigned vertices_per_prim;
 340    GET_CURRENT_CONTEXT(ctx);
 341
 342    obj = ctx->TransformFeedback.CurrentObject;
 343
 344    if (ctx->Shader.CurrentVertexProgram == NULL) {
 345       _mesa_error(ctx, GL_INVALID_OPERATION,
 346                   "glBeginTransformFeedback(no program active)");
 347       return;
 348    }
 349
 350    info = &ctx->Shader.CurrentVertexProgram->LinkedTransformFeedback;
 351
 352    if (info->NumOutputs == 0) {
 353       _mesa_error(ctx, GL_INVALID_OPERATION,
 354                   "glBeginTransformFeedback(no varyings to record)");
 355       return;
 356    }
 357
 358    switch (mode) {
 359    case GL_POINTS:
 360       vertices_per_prim = 1;
 361       break;
 362    case GL_LINES:
 363       vertices_per_prim = 2;
 364       break;
 365    case GL_TRIANGLES:
 366       vertices_per_prim = 3;
 367       break;
 368    default:
 369       _mesa_error(ctx, GL_INVALID_ENUM, "glBeginTransformFeedback(mode)");
 370       return;
 371    }
 372
 373    if (obj->Active) {
 374       _mesa_error(ctx, GL_INVALID_OPERATION,
 375                   "glBeginTransformFeedback(already active)");
 376       return;
 377    }
 378
 379    for (i = 0; i < info->NumBuffers; ++i) {
 380       if (obj->BufferNames[i] == 0) {
 381          _mesa_error(ctx, GL_INVALID_OPERATION,
 382                      "glBeginTransformFeedback(binding point %d does not have "
 383                      "a buffer object bound)", i);
 384          return;
 385       }
 386    }
 387
 388    FLUSH_VERTICES(ctx, _NEW_TRANSFORM_FEEDBACK);
 389    obj->Active = GL_TRUE;
 390    ctx->TransformFeedback.Mode = mode;
 391
 392    compute_transform_feedback_buffer_sizes(obj);
 393
 394    if (_mesa_is_gles3(ctx)) {
 395       /* In GLES3, we are required to track the usage of the transform
 396        * feedback buffer and report INVALID_OPERATION if a draw call tries to
 397        * exceed it.  So compute the maximum number of vertices that we can
 398        * write without overflowing any of the buffers currently being used for
 399        * feedback.
 400        */
 401       unsigned max_vertices
 402          = _mesa_compute_max_transform_feedback_vertices(obj, info);
 403       obj->GlesRemainingPrims = max_vertices / vertices_per_prim;
 404    }
 405
 406    assert(ctx->Driver.BeginTransformFeedback);
 407    ctx->Driver.BeginTransformFeedback(ctx, mode, obj);
 408 }
 409
 410
 411 void GLAPIENTRY
 412 _mesa_EndTransformFeedback(void)
 413 {
 414    struct gl_transform_feedback_object *obj;
 415    GET_CURRENT_CONTEXT(ctx);
 416
 417    obj = ctx->TransformFeedback.CurrentObject;
 418
 419    if (!obj->Active) {
 420       _mesa_error(ctx, GL_INVALID_OPERATION,
 421                   "glEndTransformFeedback(not active)");
 422       return;
 423    }
 424
 425    FLUSH_VERTICES(ctx, _NEW_TRANSFORM_FEEDBACK);
 426    ctx->TransformFeedback.CurrentObject->Active = GL_FALSE;
 427    ctx->TransformFeedback.CurrentObject->Paused = GL_FALSE;
 428    ctx->TransformFeedback.CurrentObject->EndedAnytime = GL_TRUE;
 429
 430    assert(ctx->Driver.EndTransformFeedback);
 431    ctx->Driver.EndTransformFeedback(ctx, obj);
 432 }
 433
 434
 435 /**
 436  * Helper used by BindBufferRange() and BindBufferBase().
 437  */
 438 static void
 439 bind_buffer_range(struct gl_context *ctx, GLuint index,
 440                   struct gl_buffer_object *bufObj,
 441                   GLintptr offset, GLsizeiptr size)
 442 {
 443    struct gl_transform_feedback_object *obj =
 444       ctx->TransformFeedback.CurrentObject;
 445
 446    /* Note: no need to FLUSH_VERTICES or flag _NEW_TRANSFORM_FEEDBACK, because
 447     * transform feedback buffers can't be changed while transform feedback is
 448     * active.
 449     */
 450
 451    /* The general binding point */
 452    _mesa_reference_buffer_object(ctx,
 453                                  &ctx->TransformFeedback.CurrentBuffer,
 454                                  bufObj);
 455
 456    /* The per-attribute binding point */
 457    _mesa_reference_buffer_object(ctx,
 458                                  &obj->Buffers[index],
 459                                  bufObj);
 460
 461    obj->BufferNames[index] = bufObj->Name;
 462
 463    obj->Offset[index] = offset;
 464    obj->RequestedSize[index] = size;
 465 }
 466
 467
 468 /**
 469  * Specify a buffer object to receive vertex shader results.  Plus,
 470  * specify the starting offset to place the results, and max size.
 471  * Called from the glBindBufferRange() function.
 472  */
 473 void
 474 _mesa_bind_buffer_range_transform_feedback(struct gl_context *ctx,
 475                                            GLuint index,
 476                                            struct gl_buffer_object *bufObj,
 477                                            GLintptr offset,
 478                                            GLsizeiptr size)
 479 {
 480    struct gl_transform_feedback_object *obj;
 481
 482    obj = ctx->TransformFeedback.CurrentObject;
 483
 484    if (obj->Active) {
 485       _mesa_error(ctx, GL_INVALID_OPERATION,
 486                   "glBindBufferRange(transform feedback active)");
 487       return;
 488    }
 489
 490    if (index >= ctx->Const.MaxTransformFeedbackBuffers) {
 491       _mesa_error(ctx, GL_INVALID_VALUE, "glBindBufferRange(index=%d)", index);
 492       return;
 493    }
 494
 495    if (size & 0x3) {
 496       /* must a multiple of four */
 497       _mesa_error(ctx, GL_INVALID_VALUE, "glBindBufferRange(size=%d)", (int) size);
 498       return;
 499    }
 500
 501    if (offset & 0x3) {
 502       /* must be multiple of four */
 503       _mesa_error(ctx, GL_INVALID_VALUE,
 504                   "glBindBufferRange(offset=%d)", (int) offset);
 505       return;
 506    }
 507
 508    bind_buffer_range(ctx, index, bufObj, offset, size);
 509 }
 510
 511
 512 /**
 513  * Specify a buffer object to receive vertex shader results.
 514  * As above, but start at offset = 0.
 515  * Called from the glBindBufferBase() function.
 516  */
 517 void
 518 _mesa_bind_buffer_base_transform_feedback(struct gl_context *ctx,
 519                                           GLuint index,
 520                                           struct gl_buffer_object *bufObj)
 521 {
 522    struct gl_transform_feedback_object *obj;
 523
 524    obj = ctx->TransformFeedback.CurrentObject;
 525
 526    if (obj->Active) {
 527       _mesa_error(ctx, GL_INVALID_OPERATION,
 528                   "glBindBufferBase(transform feedback active)");
 529       return;
 530    }
 531
 532    if (index >= ctx->Const.MaxTransformFeedbackBuffers) {
 533       _mesa_error(ctx, GL_INVALID_VALUE, "glBindBufferBase(index=%d)", index);
 534       return;
 535    }
 536
 537    bind_buffer_range(ctx, index, bufObj, 0, 0);
 538 }
 539
 540
 541 /**
 542  * Specify a buffer object to receive vertex shader results, plus the
 543  * offset in the buffer to start placing results.
 544  * This function is part of GL_EXT_transform_feedback, but not GL3.
 545  */
 546 void GLAPIENTRY
 547 _mesa_BindBufferOffsetEXT(GLenum target, GLuint index, GLuint buffer,
 548                           GLintptr offset)
 549 {
 550    struct gl_transform_feedback_object *obj;
 551    struct gl_buffer_object *bufObj;
 552    GET_CURRENT_CONTEXT(ctx);
 553
 554    if (target != GL_TRANSFORM_FEEDBACK_BUFFER) {
 555       _mesa_error(ctx, GL_INVALID_ENUM, "glBindBufferOffsetEXT(target)");
 556       return;
 557    }
 558
 559    obj = ctx->TransformFeedback.CurrentObject;
 560
 561    if (obj->Active) {
 562       _mesa_error(ctx, GL_INVALID_OPERATION,
 563                   "glBindBufferOffsetEXT(transform feedback active)");
 564       return;
 565    }
 566
 567    if (index >= ctx->Const.MaxTransformFeedbackBuffers) {
 568       _mesa_error(ctx, GL_INVALID_VALUE,
 569                   "glBindBufferOffsetEXT(index=%d)", index);
 570       return;
 571    }
 572
 573    if (offset & 0x3) {
 574       /* must be multiple of four */
 575       _mesa_error(ctx, GL_INVALID_VALUE,
 576                   "glBindBufferOffsetEXT(offset=%d)", (int) offset);
 577       return;
 578    }
 579
 580    if (buffer == 0) {
 581       bufObj = ctx->Shared->NullBufferObj;
 582    } else {
 583       bufObj = _mesa_lookup_bufferobj(ctx, buffer);
 584    }
 585
 586    if (!bufObj) {
 587       _mesa_error(ctx, GL_INVALID_OPERATION,
 588                   "glBindBufferOffsetEXT(invalid buffer=%u)", buffer);
 589       return;
 590    }
 591
 592    bind_buffer_range(ctx, index, bufObj, offset, 0);
 593 }
 594
 595
 596 /**
 597  * This function specifies the vertex shader outputs to be written
 598  * to the feedback buffer(s), and in what order.
 599  */
 600 void GLAPIENTRY
 601 _mesa_TransformFeedbackVaryings(GLuint program, GLsizei count,
 602                                 const GLchar * const *varyings,
 603                                 GLenum bufferMode)
 604 {
 605    struct gl_shader_program *shProg;
 606    GLint i;
 607    GET_CURRENT_CONTEXT(ctx);
 608
 609    switch (bufferMode) {
 610    case GL_INTERLEAVED_ATTRIBS:
 611       break;
 612    case GL_SEPARATE_ATTRIBS:
 613       break;
 614    default:
 615       _mesa_error(ctx, GL_INVALID_ENUM,
 616                   "glTransformFeedbackVaryings(bufferMode)");
 617       return;
 618    }
 619
 620    if (count < 0 ||
 621        (bufferMode == GL_SEPARATE_ATTRIBS &&
 622         (GLuint) count > ctx->Const.MaxTransformFeedbackBuffers)) {
 623       _mesa_error(ctx, GL_INVALID_VALUE,
 624                   "glTransformFeedbackVaryings(count=%d)", count);
 625       return;
 626    }
 627
 628    shProg = _mesa_lookup_shader_program(ctx, program);
 629    if (!shProg) {
 630       _mesa_error(ctx, GL_INVALID_VALUE,
 631                   "glTransformFeedbackVaryings(program=%u)", program);
 632       return;
 633    }
 634
 635    if (ctx->Extensions.ARB_transform_feedback3) {
 636       if (bufferMode == GL_INTERLEAVED_ATTRIBS) {
 637          unsigned buffers = 1;
 638
 639          for (i = 0; i < count; i++) {
 640             if (strcmp(varyings[i], "gl_NextBuffer") == 0)
 641                buffers++;
 642          }
 643
 644          if (buffers > ctx->Const.MaxTransformFeedbackBuffers) {
 645             _mesa_error(ctx, GL_INVALID_OPERATION,
 646                         "glTransformFeedbackVaryings(too many gl_NextBuffer "
 647                         "occurences)");
 648             return;
 649          }
 650       } else {
 651          for (i = 0; i < count; i++) {
 652             if (strcmp(varyings[i], "gl_NextBuffer") == 0 ||
 653                 strcmp(varyings[i], "gl_SkipComponents1") == 0 ||
 654                 strcmp(varyings[i], "gl_SkipComponents2") == 0 ||
 655                 strcmp(varyings[i], "gl_SkipComponents3") == 0 ||
 656                 strcmp(varyings[i], "gl_SkipComponents4") == 0) {
 657                _mesa_error(ctx, GL_INVALID_OPERATION,
 658                            "glTransformFeedbackVaryings(SEPARATE_ATTRIBS,"
 659                            "varying=%s)",
 660                            varyings[i]);
 661                return;
 662             }
 663          }
 664       }
 665    }
 666
 667    /* free existing varyings, if any */
 668    for (i = 0; i < (GLint) shProg->TransformFeedback.NumVarying; i++) {
 669       free(shProg->TransformFeedback.VaryingNames[i]);
 670    }
 671    free(shProg->TransformFeedback.VaryingNames);
 672
 673    /* allocate new memory for varying names */
 674    shProg->TransformFeedback.VaryingNames =
 675       malloc(count * sizeof(GLchar *));
 676
 677    if (!shProg->TransformFeedback.VaryingNames) {
 678       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glTransformFeedbackVaryings()");
 679       return;
 680    }
 681
 682    /* Save the new names and the count */
 683    for (i = 0; i < count; i++) {
 684       shProg->TransformFeedback.VaryingNames[i] = _mesa_strdup(varyings[i]);
 685    }
 686    shProg->TransformFeedback.NumVarying = count;
 687
 688    shProg->TransformFeedback.BufferMode = bufferMode;
 689
 690    /* No need to set _NEW_TRANSFORM_FEEDBACK (or invoke FLUSH_VERTICES) since
 691     * the varyings won't be used until shader link time.
 692     */
 693 }
 694
 695
 696 /**
 697  * Get info about the vertex shader's outputs which are to be written
 698  * to the feedback buffer(s).
 699  */
 700 void GLAPIENTRY
 701 _mesa_GetTransformFeedbackVarying(GLuint program, GLuint index,
 702                                   GLsizei bufSize, GLsizei *length,
 703                                   GLsizei *size, GLenum *type, GLchar *name)
 704 {
 705    const struct gl_shader_program *shProg;
 706    const struct gl_transform_feedback_info *linked_xfb_info;
 707    GET_CURRENT_CONTEXT(ctx);
 708
 709    shProg = _mesa_lookup_shader_program(ctx, program);
 710    if (!shProg) {
 711       _mesa_error(ctx, GL_INVALID_VALUE,
 712                   "glGetTransformFeedbackVarying(program=%u)", program);
 713       return;
 714    }
 715
 716    linked_xfb_info = &shProg->LinkedTransformFeedback;
 717    if (index >= (GLuint) linked_xfb_info->NumVarying) {
 718       _mesa_error(ctx, GL_INVALID_VALUE,
 719                   "glGetTransformFeedbackVarying(index=%u)", index);
 720       return;
 721    }
 722
 723    /* return the varying's name and length */
 724    _mesa_copy_string(name, bufSize, length,
 725                      linked_xfb_info->Varyings[index].Name);
 726
 727    /* return the datatype and value's size (in datatype units) */
 728    if (type)
 729       *type = linked_xfb_info->Varyings[index].Type;
 730    if (size)
 731       *size = linked_xfb_info->Varyings[index].Size;
 732 }
 733
 734
 735
 736 struct gl_transform_feedback_object *
 737 _mesa_lookup_transform_feedback_object(struct gl_context *ctx, GLuint name)
 738 {
 739    if (name == 0) {
 740       return ctx->TransformFeedback.DefaultObject;
 741    }
 742    else
 743       return (struct gl_transform_feedback_object *)
 744          _mesa_HashLookup(ctx->TransformFeedback.Objects, name);
 745 }
 746
 747
 748 /**
 749  * Create new transform feedback objects.   Transform feedback objects
 750  * encapsulate the state related to transform feedback to allow quickly
 751  * switching state (and drawing the results, below).
 752  * Part of GL_ARB_transform_feedback2.
 753  */
 754 void GLAPIENTRY
 755 _mesa_GenTransformFeedbacks(GLsizei n, GLuint *names)
 756 {
 757    GLuint first;
 758    GET_CURRENT_CONTEXT(ctx);
 759
 760    if (n < 0) {
 761       _mesa_error(ctx, GL_INVALID_VALUE, "glGenTransformFeedbacks(n < 0)");
 762       return;
 763    }
 764
 765    if (!names)
 766       return;
 767
 768    /* we don't need contiguous IDs, but this might be faster */
 769    first = _mesa_HashFindFreeKeyBlock(ctx->TransformFeedback.Objects, n);
 770    if (first) {
 771       GLsizei i;
 772       for (i = 0; i < n; i++) {
 773          struct gl_transform_feedback_object *obj
 774             = ctx->Driver.NewTransformFeedback(ctx, first + i);
 775          if (!obj) {
 776             _mesa_error(ctx, GL_OUT_OF_MEMORY, "glGenTransformFeedbacks");
 777             return;
 778          }
 779          names[i] = first + i;
 780          _mesa_HashInsert(ctx->TransformFeedback.Objects, first + i, obj);
 781       }
 782    }
 783    else {
 784       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glGenTransformFeedbacks");
 785    }
 786 }
 787
 788
 789 /**
 790  * Is the given ID a transform feedback object?
 791  * Part of GL_ARB_transform_feedback2.
 792  */
 793 GLboolean GLAPIENTRY
 794 _mesa_IsTransformFeedback(GLuint name)
 795 {
 796    struct gl_transform_feedback_object *obj;
 797    GET_CURRENT_CONTEXT(ctx);
 798
 799    ASSERT_OUTSIDE_BEGIN_END_WITH_RETVAL(ctx, GL_FALSE);
 800
 801    if (name == 0)
 802       return GL_FALSE;
 803
 804    obj = _mesa_lookup_transform_feedback_object(ctx, name);
 805    if (obj == NULL)
 806       return GL_FALSE;
 807
 808    return obj->EverBound;
 809 }
 810
 811
 812 /**
 813  * Bind the given transform feedback object.
 814  * Part of GL_ARB_transform_feedback2.
 815  */
 816 void GLAPIENTRY
 817 _mesa_BindTransformFeedback(GLenum target, GLuint name)
 818 {
 819    struct gl_transform_feedback_object *obj;
 820    GET_CURRENT_CONTEXT(ctx);
 821
 822    if (target != GL_TRANSFORM_FEEDBACK) {
 823       _mesa_error(ctx, GL_INVALID_ENUM, "glBindTransformFeedback(target)");
 824       return;
 825    }
 826
 827    if (_mesa_is_xfb_active_and_unpaused(ctx)) {
 828       _mesa_error(ctx, GL_INVALID_OPERATION,
 829               "glBindTransformFeedback(transform is active, or not paused)");
 830       return;
 831    }
 832
 833    obj = _mesa_lookup_transform_feedback_object(ctx, name);
 834    if (!obj) {
 835       _mesa_error(ctx, GL_INVALID_OPERATION,
 836                   "glBindTransformFeedback(name=%u)", name);
 837       return;
 838    }
 839
 840    reference_transform_feedback_object(&ctx->TransformFeedback.CurrentObject,
 841                                        obj);
 842 }
 843
 844
 845 /**
 846  * Delete the given transform feedback objects.
 847  * Part of GL_ARB_transform_feedback2.
 848  */
 849 void GLAPIENTRY
 850 _mesa_DeleteTransformFeedbacks(GLsizei n, const GLuint *names)
 851 {
 852    GLint i;
 853    GET_CURRENT_CONTEXT(ctx);
 854
 855    if (n < 0) {
 856       _mesa_error(ctx, GL_INVALID_VALUE, "glDeleteTransformFeedbacks(n < 0)");
 857       return;
 858    }
 859
 860    if (!names)
 861       return;
 862
 863    for (i = 0; i < n; i++) {
 864       if (names[i] > 0) {
 865          struct gl_transform_feedback_object *obj
 866             = _mesa_lookup_transform_feedback_object(ctx, names[i]);
 867          if (obj) {
 868             if (obj->Active) {
 869                _mesa_error(ctx, GL_INVALID_OPERATION,
 870                            "glDeleteTransformFeedbacks(object %u is active)",
 871                            names[i]);
 872                return;
 873             }
 874             _mesa_HashRemove(ctx->TransformFeedback.Objects, names[i]);
 875             /* unref, but object may not be deleted until later */
 876             reference_transform_feedback_object(&obj, NULL);
 877          }
 878       }
 879    }
 880 }
 881
 882
 883 /**
 884  * Pause transform feedback.
 885  * Part of GL_ARB_transform_feedback2.
 886  */
 887 void GLAPIENTRY
 888 _mesa_PauseTransformFeedback(void)
 889 {
 890    struct gl_transform_feedback_object *obj;
 891    GET_CURRENT_CONTEXT(ctx);
 892
 893    obj = ctx->TransformFeedback.CurrentObject;
 894
 895    if (!_mesa_is_xfb_active_and_unpaused(ctx)) {
 896       _mesa_error(ctx, GL_INVALID_OPERATION,
 897            "glPauseTransformFeedback(feedback not active or already paused)");
 898       return;
 899    }
 900
 901    FLUSH_VERTICES(ctx, _NEW_TRANSFORM_FEEDBACK);
 902    obj->Paused = GL_TRUE;
 903
 904    assert(ctx->Driver.PauseTransformFeedback);
 905    ctx->Driver.PauseTransformFeedback(ctx, obj);
 906 }
 907
 908
 909 /**
 910  * Resume transform feedback.
 911  * Part of GL_ARB_transform_feedback2.
 912  */
 913 void GLAPIENTRY
 914 _mesa_ResumeTransformFeedback(void)
 915 {
 916    struct gl_transform_feedback_object *obj;
 917    GET_CURRENT_CONTEXT(ctx);
 918
 919    obj = ctx->TransformFeedback.CurrentObject;
 920
 921    if (!obj->Active || !obj->Paused) {
 922       _mesa_error(ctx, GL_INVALID_OPERATION,
 923                "glResumeTransformFeedback(feedback not active or not paused)");
 924       return;
 925    }
 926
 927    FLUSH_VERTICES(ctx, _NEW_TRANSFORM_FEEDBACK);
 928    obj->Paused = GL_FALSE;
 929
 930    assert(ctx->Driver.ResumeTransformFeedback);
 931    ctx->Driver.ResumeTransformFeedback(ctx, obj);
 932 }