src/mesa/drivers/dri/intel_winsys/intel_buffers.c

   1 /**************************************************************************
   2  *
   3  * Copyright 2003 Tungsten Graphics, Inc., Cedar Park, Texas.
   4  * 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
   8  * "Software"), to deal in the Software without restriction, including
   9  * without limitation the rights to use, copy, modify, merge, publish,
  10  * distribute, sub license, and/or sell copies of the Software, and to
  11  * permit persons to whom the Software is furnished to do so, subject to
  12  * the following conditions:
  13  *
  14  * The above copyright notice and this permission notice (including the
  15  * next paragraph) shall be included in all copies or substantial portions
  16  * of the Software.
  17  *
  18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  19  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  20  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
  21  * IN NO EVENT SHALL TUNGSTEN GRAPHICS AND/OR ITS SUPPLIERS BE LIABLE FOR
  22  * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
  23  * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
  24  * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  25  *
  26  **************************************************************************/
  27
  28 #include "intel_screen.h"
  29 #include "intel_context.h"
  30 #include "intel_blit.h"
  31 #include "intel_buffers.h"
  32 #include "intel_depthstencil.h"
  33 #include "intel_fbo.h"
  34 #include "intel_batchbuffer.h"
  35 #include "intel_reg.h"
  36 #include "context.h"
  37 #include "utils.h"
  38 #include "drirenderbuffer.h"
  39 #include "framebuffer.h"
  40 #include "vblank.h"
  41
  42 #include "pipe/p_context.h"
  43
  44 /* This block can be removed when libdrm >= 2.3.1 is required */
  45
  46 #ifndef DRM_VBLANK_FLIP
  47
  48 #define DRM_VBLANK_FLIP 0x8000000
  49
  50 typedef struct drm_i915_flip {
  51    int pipes;
  52 } drm_i915_flip_t;
  53
  54 #undef DRM_IOCTL_I915_FLIP
  55 #define DRM_IOCTL_I915_FLIP DRM_IOW(DRM_COMMAND_BASE + DRM_I915_FLIP, \
  56                                     drm_i915_flip_t)
  57
  58 #endif
  59
  60
  61 /**
  62  * XXX move this into a new dri/common/cliprects.c file.
  63  */
  64 GLboolean
  65 intel_intersect_cliprects(drm_clip_rect_t * dst,
  66                           const drm_clip_rect_t * a,
  67                           const drm_clip_rect_t * b)
  68 {
  69    GLint bx = b->x1;
  70    GLint by = b->y1;
  71    GLint bw = b->x2 - bx;
  72    GLint bh = b->y2 - by;
  73
  74    if (bx < a->x1)
  75       bw -= a->x1 - bx, bx = a->x1;
  76    if (by < a->y1)
  77       bh -= a->y1 - by, by = a->y1;
  78    if (bx + bw > a->x2)
  79       bw = a->x2 - bx;
  80    if (by + bh > a->y2)
  81       bh = a->y2 - by;
  82    if (bw <= 0)
  83       return GL_FALSE;
  84    if (bh <= 0)
  85       return GL_FALSE;
  86
  87    dst->x1 = bx;
  88    dst->y1 = by;
  89    dst->x2 = bx + bw;
  90    dst->y2 = by + bh;
  91
  92    return GL_TRUE;
  93 }
  94
  95 /**
  96  * Return pointer to current color drawing region, or NULL.
  97  */
  98 struct pipe_region *
  99 intel_drawbuf_region(struct intel_context *intel)
 100 {
 101    struct intel_renderbuffer *irbColor =
 102       intel_renderbuffer(intel->ctx.DrawBuffer->_ColorDrawBuffers[0][0]);
 103    if (irbColor)
 104       return irbColor->region;
 105    else
 106       return NULL;
 107 }
 108
 109 /**
 110  * Return pointer to current color reading region, or NULL.
 111  */
 112 struct pipe_region *
 113 intel_readbuf_region(struct intel_context *intel)
 114 {
 115    struct intel_renderbuffer *irb
 116       = intel_renderbuffer(intel->ctx.ReadBuffer->_ColorReadBuffer);
 117    if (irb)
 118       return irb->region;
 119    else
 120       return NULL;
 121 }
 122
 123
 124
 125 /**
 126  * Update the following fields for rendering:
 127  *   intel->numClipRects
 128  *   intel->pClipRects
 129  */
 130 static void
 131 intelSetRenderbufferClipRects(struct intel_context *intel)
 132 {
 133    /* zero-sized buffers might be legal? */
 134    assert(intel->ctx.DrawBuffer->Width > 0);
 135    assert(intel->ctx.DrawBuffer->Height > 0);
 136    intel->fboRect.x1 = 0;
 137    intel->fboRect.y1 = 0;
 138    intel->fboRect.x2 = intel->ctx.DrawBuffer->Width;
 139    intel->fboRect.y2 = intel->ctx.DrawBuffer->Height;
 140    intel->numClipRects = 1;
 141    intel->pClipRects = &intel->fboRect;
 142 }
 143
 144
 145 /**
 146  * This will be called whenever the currently bound window is moved/resized.
 147  * XXX: actually, it seems to NOT be called when the window is only moved (BP).
 148  */
 149 void
 150 intelWindowMoved(struct intel_context *intel)
 151 {
 152    GLcontext *ctx = &intel->ctx;
 153    __DRIdrawablePrivate *dPriv = intel->driDrawable;
 154    struct intel_framebuffer *intel_fb = dPriv->driverPrivate;
 155
 156    if (!intel->ctx.DrawBuffer) {
 157       /* when would this happen? -BP */
 158       assert(0);
 159       intel->numClipRects = 0;
 160    }
 161
 162    /* Update Mesa's notion of window size */
 163    driUpdateFramebufferSize(ctx, dPriv);
 164    intel_fb->Base.Initialized = GL_TRUE; /* XXX remove someday */
 165
 166    {
 167       drmI830Sarea *sarea = intel->sarea;
 168       drm_clip_rect_t drw_rect = { .x1 = dPriv->x, .x2 = dPriv->x + dPriv->w,
 169                                    .y1 = dPriv->y, .y2 = dPriv->y + dPriv->h };
 170       drm_clip_rect_t pipeA_rect = { .x1 = sarea->pipeA_x, .y1 = sarea->pipeA_y,
 171                                      .x2 = sarea->pipeA_x + sarea->pipeA_w,
 172                                      .y2 = sarea->pipeA_y + sarea->pipeA_h };
 173       drm_clip_rect_t pipeB_rect = { .x1 = sarea->pipeB_x, .y1 = sarea->pipeB_y,
 174                                      .x2 = sarea->pipeB_x + sarea->pipeB_w,
 175                                      .y2 = sarea->pipeB_y + sarea->pipeB_h };
 176       GLint areaA = driIntersectArea( drw_rect, pipeA_rect );
 177       GLint areaB = driIntersectArea( drw_rect, pipeB_rect );
 178       GLuint flags = intel_fb->vblank_flags;
 179       GLboolean pf_active;
 180       GLint pf_pipes;
 181
 182       /* Update page flipping info
 183        */
 184       pf_pipes = 0;
 185
 186       if (areaA > 0)
 187          pf_pipes |= 1;
 188
 189       if (areaB > 0)
 190          pf_pipes |= 2;
 191
 192       intel_fb->pf_current_page = (intel->sarea->pf_current_page >>
 193                                    (intel_fb->pf_pipes & 0x2)) & 0x3;
 194
 195       intel_fb->pf_num_pages = 2 /*intel->intelScreen->third.handle ? 3 : 2*/;
 196
 197       pf_active = pf_pipes && (pf_pipes & intel->sarea->pf_active) == pf_pipes;
 198
 199       if (INTEL_DEBUG & DEBUG_LOCK)
 200          if (pf_active != intel_fb->pf_active)
 201             _mesa_printf("%s - Page flipping %sactive\n", __progname,
 202                          pf_active ? "" : "in");
 203
 204       if (pf_active) {
 205          /* Sync pages between pipes if we're flipping on both at the same time */
 206          if (pf_pipes == 0x3 && pf_pipes != intel_fb->pf_pipes &&
 207              (intel->sarea->pf_current_page & 0x3) !=
 208              (((intel->sarea->pf_current_page) >> 2) & 0x3)) {
 209             drm_i915_flip_t flip;
 210
 211             if (intel_fb->pf_current_page ==
 212                 (intel->sarea->pf_current_page & 0x3)) {
 213                /* XXX: This is ugly, but emitting two flips 'in a row' can cause
 214                 * lockups for unknown reasons.
 215                 */
 216                intel->sarea->pf_current_page =
 217                   intel->sarea->pf_current_page & 0x3;
 218                intel->sarea->pf_current_page |=
 219                   ((intel_fb->pf_current_page + intel_fb->pf_num_pages - 1) %
 220                    intel_fb->pf_num_pages) << 2;
 221
 222                flip.pipes = 0x2;
 223             } else {
 224                intel->sarea->pf_current_page =
 225                   intel->sarea->pf_current_page & (0x3 << 2);
 226                intel->sarea->pf_current_page |=
 227                   (intel_fb->pf_current_page + intel_fb->pf_num_pages - 1) %
 228                   intel_fb->pf_num_pages;
 229
 230                flip.pipes = 0x1;
 231             }
 232
 233             drmCommandWrite(intel->driFd, DRM_I915_FLIP, &flip, sizeof(flip));
 234          }
 235
 236          intel_fb->pf_pipes = pf_pipes;
 237       }
 238
 239       intel_fb->pf_active = pf_active;
 240       intel_flip_renderbuffers(intel_fb);
 241       intel_draw_buffer(&intel->ctx, intel->ctx.DrawBuffer);
 242
 243       /* Update vblank info
 244        */
 245       if (areaB > areaA || (areaA == areaB && areaB > 0)) {
 246          flags = intel_fb->vblank_flags | VBLANK_FLAG_SECONDARY;
 247       } else {
 248          flags = intel_fb->vblank_flags & ~VBLANK_FLAG_SECONDARY;
 249       }
 250
 251       if (flags != intel_fb->vblank_flags && intel_fb->vblank_flags &&
 252           !(intel_fb->vblank_flags & VBLANK_FLAG_NO_IRQ)) {
 253          drmVBlank vbl;
 254          int i;
 255
 256          vbl.request.type = DRM_VBLANK_ABSOLUTE;
 257
 258          if ( intel_fb->vblank_flags & VBLANK_FLAG_SECONDARY ) {
 259             vbl.request.type |= DRM_VBLANK_SECONDARY;
 260          }
 261
 262          for (i = 0; i < intel_fb->pf_num_pages; i++) {
 263             if (!intel_fb->color_rb[i] ||
 264                 (intel_fb->vbl_waited - intel_fb->color_rb[i]->vbl_pending) <=
 265                 (1<<23))
 266                continue;
 267
 268             vbl.request.sequence = intel_fb->color_rb[i]->vbl_pending;
 269             drmWaitVBlank(intel->driFd, &vbl);
 270          }
 271
 272          intel_fb->vblank_flags = flags;
 273          driGetCurrentVBlank(dPriv, intel_fb->vblank_flags, &intel_fb->vbl_seq);
 274          intel_fb->vbl_waited = intel_fb->vbl_seq;
 275
 276          for (i = 0; i < intel_fb->pf_num_pages; i++) {
 277             if (intel_fb->color_rb[i])
 278                intel_fb->color_rb[i]->vbl_pending = intel_fb->vbl_waited;
 279          }
 280       }
 281    }
 282
 283    /* This will be picked up by looking at the dirty state flags:
 284     */
 285
 286    /* Update hardware scissor */
 287 //   ctx->Driver.Scissor(ctx, ctx->Scissor.X, ctx->Scissor.Y,
 288 //                       ctx->Scissor.Width, ctx->Scissor.Height);
 289
 290    /* Re-calculate viewport related state */
 291 //   ctx->Driver.DepthRange( ctx, ctx->Viewport.Near, ctx->Viewport.Far );
 292 }
 293
 294
 295
 296
 297
 298 /* Emit wait for pending flips */
 299 void
 300 intel_wait_flips(struct intel_context *intel, GLuint batch_flags)
 301 {
 302    struct intel_framebuffer *intel_fb =
 303       (struct intel_framebuffer *) intel->ctx.DrawBuffer;
 304    struct intel_renderbuffer *intel_rb =
 305       intel_get_renderbuffer(&intel_fb->Base,
 306                              intel_fb->Base._ColorDrawBufferMask[0] ==
 307                              BUFFER_BIT_FRONT_LEFT ? BUFFER_FRONT_LEFT :
 308                              BUFFER_BACK_LEFT);
 309
 310    if (intel_fb->Base.Name == 0 && intel_rb->pf_pending == intel_fb->pf_seq) {
 311       GLint pf_pipes = intel_fb->pf_pipes;
 312       BATCH_LOCALS;
 313
 314       /* Wait for pending flips to take effect */
 315       BEGIN_BATCH(2, batch_flags);
 316       OUT_BATCH(pf_pipes & 0x1 ? (MI_WAIT_FOR_EVENT | MI_WAIT_FOR_PLANE_A_FLIP)
 317                 : 0);
 318       OUT_BATCH(pf_pipes & 0x2 ? (MI_WAIT_FOR_EVENT | MI_WAIT_FOR_PLANE_B_FLIP)
 319                 : 0);
 320       ADVANCE_BATCH();
 321
 322       intel_rb->pf_pending--;
 323    }
 324 }
 325
 326 #if 0
 327 /* Flip the front & back buffers
 328  */
 329 static GLboolean
 330 intelPageFlip(const __DRIdrawablePrivate * dPriv)
 331 {
 332    struct intel_context *intel;
 333    int ret;
 334    struct intel_framebuffer *intel_fb = dPriv->driverPrivate;
 335
 336    if (INTEL_DEBUG & DEBUG_IOCTL)
 337       fprintf(stderr, "%s\n", __FUNCTION__);
 338
 339    assert(dPriv);
 340    assert(dPriv->driContextPriv);
 341    assert(dPriv->driContextPriv->driverPrivate);
 342
 343    intel = (struct intel_context *) dPriv->driContextPriv->driverPrivate;
 344
 345    if (intel->intelScreen->drmMinor < 9)
 346       return GL_FALSE;
 347
 348    intelFlush(&intel->ctx);
 349
 350    ret = 0;
 351
 352    LOCK_HARDWARE(intel);
 353
 354    if (dPriv->numClipRects && intel_fb->pf_active) {
 355       drm_i915_flip_t flip;
 356
 357       flip.pipes = intel_fb->pf_pipes;
 358
 359       ret = drmCommandWrite(intel->driFd, DRM_I915_FLIP, &flip, sizeof(flip));
 360    }
 361
 362    UNLOCK_HARDWARE(intel);
 363
 364    if (ret || !intel_fb->pf_active)
 365       return GL_FALSE;
 366
 367    if (!dPriv->numClipRects) {
 368       usleep(10000);    /* throttle invisible client 10ms */
 369    }
 370
 371    intel_fb->pf_current_page = (intel->sarea->pf_current_page >>
 372                                 (intel_fb->pf_pipes & 0x2)) & 0x3;
 373
 374    if (dPriv->numClipRects != 0) {
 375       intel_get_renderbuffer(&intel_fb->Base, BUFFER_FRONT_LEFT)->pf_pending =
 376       intel_get_renderbuffer(&intel_fb->Base, BUFFER_BACK_LEFT)->pf_pending =
 377          ++intel_fb->pf_seq;
 378    }
 379
 380    intel_flip_renderbuffers(intel_fb);
 381    intel_draw_buffer(&intel->ctx, &intel_fb->Base);
 382
 383    if (INTEL_DEBUG & DEBUG_IOCTL)
 384       fprintf(stderr, "%s: success\n", __FUNCTION__);
 385
 386    return GL_TRUE;
 387 }
 388 #endif
 389
 390
 391 static GLboolean
 392 intelScheduleSwap(const __DRIdrawablePrivate * dPriv, GLboolean *missed_target)
 393 {
 394    struct intel_framebuffer *intel_fb = dPriv->driverPrivate;
 395    unsigned int interval = driGetVBlankInterval(dPriv, intel_fb->vblank_flags);
 396    struct intel_context *intel =
 397       intelScreenContext(dPriv->driScreenPriv->private);
 398    const intelScreenPrivate *intelScreen = intel->intelScreen;
 399    unsigned int target;
 400    drm_i915_vblank_swap_t swap;
 401    GLboolean ret;
 402
 403    if (!intel_fb->vblank_flags ||
 404        (intel_fb->vblank_flags & VBLANK_FLAG_NO_IRQ) ||
 405        intelScreen->drmMinor < (intel_fb->pf_active ? 9 : 6))
 406       return GL_FALSE;
 407
 408    swap.seqtype = DRM_VBLANK_ABSOLUTE;
 409
 410    if (intel_fb->vblank_flags & VBLANK_FLAG_SYNC) {
 411       swap.seqtype |= DRM_VBLANK_NEXTONMISS;
 412    } else if (interval == 0) {
 413       return GL_FALSE;
 414    }
 415
 416    swap.drawable = dPriv->hHWDrawable;
 417    target = swap.sequence = intel_fb->vbl_seq + interval;
 418
 419    if ( intel_fb->vblank_flags & VBLANK_FLAG_SECONDARY ) {
 420       swap.seqtype |= DRM_VBLANK_SECONDARY;
 421    }
 422
 423    LOCK_HARDWARE(intel);
 424
 425    intel_batchbuffer_flush(intel->batch);
 426
 427    if ( intel_fb->pf_active ) {
 428       swap.seqtype |= DRM_VBLANK_FLIP;
 429
 430       intel_fb->pf_current_page = (((intel->sarea->pf_current_page >>
 431                                      (intel_fb->pf_pipes & 0x2)) & 0x3) + 1) %
 432                                   intel_fb->pf_num_pages;
 433    }
 434
 435    if (!drmCommandWriteRead(intel->driFd, DRM_I915_VBLANK_SWAP, &swap,
 436                             sizeof(swap))) {
 437       intel_fb->vbl_seq = swap.sequence;
 438       swap.sequence -= target;
 439       *missed_target = swap.sequence > 0 && swap.sequence <= (1 << 23);
 440
 441       intel_get_renderbuffer(&intel_fb->Base, BUFFER_BACK_LEFT)->vbl_pending =
 442          intel_get_renderbuffer(&intel_fb->Base,
 443                                 BUFFER_FRONT_LEFT)->vbl_pending =
 444          intel_fb->vbl_seq;
 445
 446       if (swap.seqtype & DRM_VBLANK_FLIP) {
 447          intel_flip_renderbuffers(intel_fb);
 448          intel_draw_buffer(&intel->ctx, intel->ctx.DrawBuffer);
 449       }
 450
 451       ret = GL_TRUE;
 452    } else {
 453       if (swap.seqtype & DRM_VBLANK_FLIP) {
 454          intel_fb->pf_current_page = ((intel->sarea->pf_current_page >>
 455                                         (intel_fb->pf_pipes & 0x2)) & 0x3) %
 456                                      intel_fb->pf_num_pages;
 457       }
 458
 459       ret = GL_FALSE;
 460    }
 461
 462    UNLOCK_HARDWARE(intel);
 463
 464    return ret;
 465 }
 466
 467 void
 468 intelSwapBuffers(__DRIdrawablePrivate * dPriv)
 469 {
 470    if (dPriv->driContextPriv && dPriv->driContextPriv->driverPrivate) {
 471       GET_CURRENT_CONTEXT(ctx);
 472       struct intel_context *intel;
 473
 474       if (ctx == NULL)
 475          return;
 476
 477       intel = intel_context(ctx);
 478
 479       if (ctx->Visual.doubleBufferMode) {
 480          GLboolean missed_target;
 481          struct intel_framebuffer *intel_fb = dPriv->driverPrivate;
 482          int64_t ust;
 483
 484          _mesa_notifySwapBuffers(ctx);  /* flush pending rendering comands */
 485
 486          if (!intelScheduleSwap(dPriv, &missed_target)) {
 487             driWaitForVBlank(dPriv, &intel_fb->vbl_seq, intel_fb->vblank_flags,
 488                              &missed_target);
 489
 490             intelCopyBuffer(dPriv, NULL);
 491          }
 492
 493          intel_fb->swap_count++;
 494          (*dri_interface->getUST) (&ust);
 495          if (missed_target) {
 496             intel_fb->swap_missed_count++;
 497             intel_fb->swap_missed_ust = ust - intel_fb->swap_ust;
 498          }
 499
 500          intel_fb->swap_ust = ust;
 501       }
 502    }
 503    else {
 504       /* XXX this shouldn't be an error but we can't handle it for now */
 505       fprintf(stderr, "%s: drawable has no context!\n", __FUNCTION__);
 506    }
 507 }
 508
 509 void
 510 intelCopySubBuffer(__DRIdrawablePrivate * dPriv, int x, int y, int w, int h)
 511 {
 512    if (dPriv->driContextPriv && dPriv->driContextPriv->driverPrivate) {
 513       struct intel_context *intel =
 514          (struct intel_context *) dPriv->driContextPriv->driverPrivate;
 515       GLcontext *ctx = &intel->ctx;
 516
 517       if (ctx->Visual.doubleBufferMode) {
 518          drm_clip_rect_t rect;
 519          /* fixup cliprect (driDrawable may have changed?) later */
 520          rect.x1 = x;
 521          rect.y1 = y;
 522          rect.x2 = w;
 523          rect.y2 = h;
 524          _mesa_notifySwapBuffers(ctx);  /* flush pending rendering comands */
 525          intelCopyBuffer(dPriv, &rect);
 526       }
 527    }
 528    else {
 529       /* XXX this shouldn't be an error but we can't handle it for now */
 530       fprintf(stderr, "%s: drawable has no context!\n", __FUNCTION__);
 531    }
 532 }
 533
 534
 535 /**
 536  * Update the hardware state for drawing into a window or framebuffer object.
 537  *
 538  * Called by glDrawBuffer, glBindFramebufferEXT, MakeCurrent, and other
 539  * places within the driver.
 540  *
 541  * Basically, this needs to be called any time the current framebuffer
 542  * changes, the renderbuffers change, or we need to draw into different
 543  * color buffers.
 544  */
 545 void
 546 intel_draw_buffer(GLcontext * ctx, struct gl_framebuffer *fb)
 547 {
 548    struct intel_context *intel = intel_context(ctx);
 549    struct pipe_region *colorRegion, *depthRegion = NULL;
 550    struct intel_renderbuffer *irbDepth = NULL, *irbStencil = NULL;
 551
 552    if (!fb) {
 553       /* this can happen during the initial context initialization */
 554       return;
 555    }
 556
 557    /* Do this here, not core Mesa, since this function is called from
 558     * many places within the driver.
 559     */
 560    if (ctx->NewState & (_NEW_BUFFERS | _NEW_COLOR | _NEW_PIXEL)) {
 561       /* this updates the DrawBuffer->_NumColorDrawBuffers fields, etc */
 562       _mesa_update_framebuffer(ctx);
 563       /* this updates the DrawBuffer's Width/Height if it's a FBO */
 564       _mesa_update_draw_buffer_bounds(ctx);
 565    }
 566
 567    if (fb->_Status != GL_FRAMEBUFFER_COMPLETE_EXT) {
 568       /* this may occur when we're called by glBindFrameBuffer() during
 569        * the process of someone setting up renderbuffers, etc.
 570        */
 571       /*_mesa_debug(ctx, "DrawBuffer: incomplete user FBO\n");*/
 572       return;
 573    }
 574
 575    if (fb->Name)
 576       intel_validate_paired_depth_stencil(ctx, fb);
 577
 578    /*
 579     * How many color buffers are we drawing into?
 580     */
 581    if (fb->_NumColorDrawBuffers[0] != 1) {
 582       /* writing to 0 or 2 or 4 color buffers */
 583       /*_mesa_debug(ctx, "Software rendering\n");*/
 584       FALLBACK(intel, INTEL_FALLBACK_DRAW_BUFFER, GL_TRUE);
 585    }
 586    else {
 587       /* draw to exactly one color buffer */
 588       /*_mesa_debug(ctx, "Hardware rendering\n");*/
 589       FALLBACK(intel, INTEL_FALLBACK_DRAW_BUFFER, GL_FALSE);
 590    }
 591
 592    /*
 593     * Get the intel_renderbuffer for the colorbuffer we're drawing into.
 594     * And set up cliprects.
 595     */
 596    {
 597       struct intel_renderbuffer *irb;
 598       intelSetRenderbufferClipRects(intel);
 599       irb = intel_renderbuffer(fb->_ColorDrawBuffers[0][0]);
 600       colorRegion = (irb && irb->region) ? irb->region : NULL;
 601    }
 602
 603    /* Update culling direction which changes depending on the
 604     * orientation of the buffer:
 605     */
 606    if (ctx->Driver.FrontFace)
 607       ctx->Driver.FrontFace(ctx, ctx->Polygon.FrontFace);
 608    else
 609       ctx->NewState |= _NEW_POLYGON;
 610
 611    if (!colorRegion) {
 612       FALLBACK(intel, INTEL_FALLBACK_DRAW_BUFFER, GL_TRUE);
 613    }
 614    else {
 615       FALLBACK(intel, INTEL_FALLBACK_DRAW_BUFFER, GL_FALSE);
 616    }
 617
 618    /***
 619     *** Get depth buffer region and check if we need a software fallback.
 620     *** Note that the depth buffer is usually a DEPTH_STENCIL buffer.
 621     ***/
 622    if (fb->_DepthBuffer && fb->_DepthBuffer->Wrapped) {
 623       irbDepth = intel_renderbuffer(fb->_DepthBuffer->Wrapped);
 624       if (irbDepth && irbDepth->region) {
 625          FALLBACK(intel, INTEL_FALLBACK_DEPTH_BUFFER, GL_FALSE);
 626          depthRegion = irbDepth->region;
 627       }
 628       else {
 629          FALLBACK(intel, INTEL_FALLBACK_DEPTH_BUFFER, GL_TRUE);
 630          depthRegion = NULL;
 631       }
 632    }
 633    else {
 634       /* not using depth buffer */
 635       FALLBACK(intel, INTEL_FALLBACK_DEPTH_BUFFER, GL_FALSE);
 636       depthRegion = NULL;
 637    }
 638
 639    /***
 640     *** Stencil buffer
 641     *** This can only be hardware accelerated if we're using a
 642     *** combined DEPTH_STENCIL buffer (for now anyway).
 643     ***/
 644    if (fb->_StencilBuffer && fb->_StencilBuffer->Wrapped) {
 645       irbStencil = intel_renderbuffer(fb->_StencilBuffer->Wrapped);
 646       if (irbStencil && irbStencil->region) {
 647          ASSERT(irbStencil->Base._ActualFormat == GL_DEPTH24_STENCIL8_EXT);
 648          FALLBACK(intel, INTEL_FALLBACK_STENCIL_BUFFER, GL_FALSE);
 649          /* need to re-compute stencil hw state */
 650 //         ctx->Driver.Enable(ctx, GL_STENCIL_TEST, ctx->Stencil.Enabled);
 651          if (!depthRegion)
 652             depthRegion = irbStencil->region;
 653       }
 654       else {
 655          FALLBACK(intel, INTEL_FALLBACK_STENCIL_BUFFER, GL_TRUE);
 656       }
 657    }
 658    else {
 659       /* XXX FBO: instead of FALSE, pass ctx->Stencil.Enabled ??? */
 660       FALLBACK(intel, INTEL_FALLBACK_STENCIL_BUFFER, GL_FALSE);
 661       /* need to re-compute stencil hw state */
 662 //      ctx->Driver.Enable(ctx, GL_STENCIL_TEST, ctx->Stencil.Enabled);
 663    }
 664
 665
 666    /**
 667     ** Release old regions, reference new regions
 668     **/
 669
 670    //  intel->vtbl.set_draw_region(intel, colorRegion, depthRegion);
 671
 672    /* update viewport since it depends on window size */
 673 //   ctx->Driver.Viewport(ctx, ctx->Viewport.X, ctx->Viewport.Y,
 674 //                        ctx->Viewport.Width, ctx->Viewport.Height);
 675
 676    /* Update hardware scissor */
 677 //   ctx->Driver.Scissor(ctx, ctx->Scissor.X, ctx->Scissor.Y,
 678 //                       ctx->Scissor.Width, ctx->Scissor.Height);
 679 }
 680
 681
 682 static void
 683 intelDrawBuffer(GLcontext * ctx, GLenum mode)
 684 {
 685    intel_draw_buffer(ctx, ctx->DrawBuffer);
 686 }
 687
 688
 689 static void
 690 intelReadBuffer(GLcontext * ctx, GLenum mode)
 691 {
 692    if (ctx->ReadBuffer == ctx->DrawBuffer) {
 693       /* This will update FBO completeness status.
 694        * A framebuffer will be incomplete if the GL_READ_BUFFER setting
 695        * refers to a missing renderbuffer.  Calling glReadBuffer can set
 696        * that straight and can make the drawing buffer complete.
 697        */
 698       intel_draw_buffer(ctx, ctx->DrawBuffer);
 699    }
 700    /* Generally, functions which read pixels (glReadPixels, glCopyPixels, etc)
 701     * reference ctx->ReadBuffer and do appropriate state checks.
 702     */
 703 }
 704
 705
 706 void
 707 intelInitBufferFuncs(struct dd_function_table *functions)
 708 {
 709    functions->DrawBuffer = intelDrawBuffer;
 710    functions->ReadBuffer = intelReadBuffer;
 711 }