src/mesa/main/buffers.c

   1 /*
   2  * Mesa 3-D graphics library
   3  * Version:  7.1
   4  *
   5  * Copyright (C) 1999-2007  Brian Paul   All Rights Reserved.
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a
   8  * copy of this software and associated documentation files (the "Software"),
   9  * to deal in the Software without restriction, including without limitation
  10  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  11  * and/or sell copies of the Software, and to permit persons to whom the
  12  * Software is furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included
  15  * in all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  18  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  20  * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
  21  * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  22  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  23  */
  24
  25
  26 /**
  27  * \file buffers.c
  28  * General framebuffer-related functions, like glClear, glScissor, etc.
  29  */
  30
  31
  32
  33 #include "glheader.h"
  34 #include "buffers.h"
  35 #include "colormac.h"
  36 #include "context.h"
  37 #include "enums.h"
  38 #include "fbobject.h"
  39 #include "state.h"
  40
  41
  42 #define BAD_MASK ~0u
  43
  44
  45 #if _HAVE_FULL_GL
  46 void GLAPIENTRY
  47 _mesa_ClearIndex( GLfloat c )
  48 {
  49    GET_CURRENT_CONTEXT(ctx);
  50    ASSERT_OUTSIDE_BEGIN_END(ctx);
  51
  52    if (ctx->Color.ClearIndex == (GLuint) c)
  53       return;
  54
  55    FLUSH_VERTICES(ctx, _NEW_COLOR);
  56    ctx->Color.ClearIndex = (GLuint) c;
  57
  58    if (!ctx->Visual.rgbMode && ctx->Driver.ClearIndex) {
  59       /* it's OK to call glClearIndex in RGBA mode but it should be a NOP */
  60       (*ctx->Driver.ClearIndex)( ctx, ctx->Color.ClearIndex );
  61    }
  62 }
  63 #endif
  64
  65
  66 /**
  67  * Specify the clear values for the color buffers.
  68  *
  69  * \param red red color component.
  70  * \param green green color component.
  71  * \param blue blue color component.
  72  * \param alpha alpha component.
  73  *
  74  * \sa glClearColor().
  75  *
  76  * Clamps the parameters and updates gl_colorbuffer_attrib::ClearColor.  On a
  77  * change, flushes the vertices and notifies the driver via the
  78  * dd_function_table::ClearColor callback.
  79  */
  80 void GLAPIENTRY
  81 _mesa_ClearColor( GLclampf red, GLclampf green, GLclampf blue, GLclampf alpha )
  82 {
  83    GLfloat tmp[4];
  84    GET_CURRENT_CONTEXT(ctx);
  85    ASSERT_OUTSIDE_BEGIN_END(ctx);
  86
  87    tmp[0] = CLAMP(red,   0.0F, 1.0F);
  88    tmp[1] = CLAMP(green, 0.0F, 1.0F);
  89    tmp[2] = CLAMP(blue,  0.0F, 1.0F);
  90    tmp[3] = CLAMP(alpha, 0.0F, 1.0F);
  91
  92    if (TEST_EQ_4V(tmp, ctx->Color.ClearColor))
  93       return; /* no change */
  94
  95    FLUSH_VERTICES(ctx, _NEW_COLOR);
  96    COPY_4V(ctx->Color.ClearColor, tmp);
  97
  98    if (ctx->Visual.rgbMode && ctx->Driver.ClearColor) {
  99       /* it's OK to call glClearColor in CI mode but it should be a NOP */
 100       (*ctx->Driver.ClearColor)(ctx, ctx->Color.ClearColor);
 101    }
 102 }
 103
 104
 105 /**
 106  * Clear buffers.
 107  *
 108  * \param mask bit-mask indicating the buffers to be cleared.
 109  *
 110  * Flushes the vertices and verifies the parameter. If __GLcontextRec::NewState
 111  * is set then calls _mesa_update_state() to update gl_frame_buffer::_Xmin,
 112  * etc. If the rasterization mode is set to GL_RENDER then requests the driver
 113  * to clear the buffers, via the dd_function_table::Clear callback.
 114  */
 115 void GLAPIENTRY
 116 _mesa_Clear( GLbitfield mask )
 117 {
 118    GET_CURRENT_CONTEXT(ctx);
 119    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx);
 120
 121    FLUSH_CURRENT(ctx, 0);
 122
 123    if (MESA_VERBOSE & VERBOSE_API)
 124       _mesa_debug(ctx, "glClear 0x%x\n", mask);
 125
 126    if (mask & ~(GL_COLOR_BUFFER_BIT |
 127                 GL_DEPTH_BUFFER_BIT |
 128                 GL_STENCIL_BUFFER_BIT |
 129                 GL_ACCUM_BUFFER_BIT)) {
 130       /* invalid bit set */
 131       _mesa_error( ctx, GL_INVALID_VALUE, "glClear(0x%x)", mask);
 132       return;
 133    }
 134
 135    if (ctx->NewState) {
 136       _mesa_update_state( ctx );        /* update _Xmin, etc */
 137    }
 138
 139    if (ctx->DrawBuffer->_Status != GL_FRAMEBUFFER_COMPLETE_EXT) {
 140       _mesa_error(ctx, GL_INVALID_FRAMEBUFFER_OPERATION_EXT,
 141                   "glClear(incomplete framebuffer)");
 142       return;
 143    }
 144
 145    if (ctx->DrawBuffer->Width == 0 || ctx->DrawBuffer->Height == 0)
 146       return;
 147
 148    if (ctx->RenderMode == GL_RENDER) {
 149       GLbitfield bufferMask;
 150
 151       /* don't clear depth buffer if depth writing disabled */
 152       if (!ctx->Depth.Mask)
 153          mask &= ~GL_DEPTH_BUFFER_BIT;
 154
 155       /* Build the bitmask to send to device driver's Clear function.
 156        * Note that the GL_COLOR_BUFFER_BIT flag will expand to 0, 1, 2 or 4
 157        * of the BUFFER_BIT_FRONT/BACK_LEFT/RIGHT flags, or one of the
 158        * BUFFER_BIT_COLORn flags.
 159        */
 160       bufferMask = 0;
 161       if (mask & GL_COLOR_BUFFER_BIT) {
 162          bufferMask |= ctx->DrawBuffer->_ColorDrawBufferMask[0];
 163       }
 164
 165       if ((mask & GL_DEPTH_BUFFER_BIT)
 166           && ctx->DrawBuffer->Visual.haveDepthBuffer) {
 167          bufferMask |= BUFFER_BIT_DEPTH;
 168       }
 169
 170       if ((mask & GL_STENCIL_BUFFER_BIT)
 171           && ctx->DrawBuffer->Visual.haveStencilBuffer) {
 172          bufferMask |= BUFFER_BIT_STENCIL;
 173       }
 174
 175       if ((mask & GL_ACCUM_BUFFER_BIT)
 176           && ctx->DrawBuffer->Visual.haveAccumBuffer) {
 177          bufferMask |= BUFFER_BIT_ACCUM;
 178       }
 179
 180       ASSERT(ctx->Driver.Clear);
 181       ctx->Driver.Clear(ctx, bufferMask);
 182    }
 183 }
 184
 185
 186
 187 /**
 188  * Return bitmask of BUFFER_BIT_* flags indicating which color buffers are
 189  * available to the rendering context (for drawing or reading).
 190  * This depends on the type of framebuffer.  For window system framebuffers
 191  * we look at the framebuffer's visual.  But for user-create framebuffers we
 192  * look at the number of supported color attachments.
 193  * \param fb  the framebuffer to draw to, or read from
 194  * \return  bitmask of BUFFER_BIT_* flags
 195  */
 196 static GLbitfield
 197 supported_buffer_bitmask(const GLcontext *ctx, const struct gl_framebuffer *fb)
 198 {
 199    GLbitfield mask = 0x0;
 200
 201    if (fb->Name > 0) {
 202       /* A user-created renderbuffer */
 203       GLuint i;
 204       ASSERT(ctx->Extensions.EXT_framebuffer_object);
 205       for (i = 0; i < ctx->Const.MaxColorAttachments; i++) {
 206          mask |= (BUFFER_BIT_COLOR0 << i);
 207       }
 208    }
 209    else {
 210       /* A window system framebuffer */
 211       GLint i;
 212       mask = BUFFER_BIT_FRONT_LEFT; /* always have this */
 213       if (fb->Visual.stereoMode) {
 214          mask |= BUFFER_BIT_FRONT_RIGHT;
 215          if (fb->Visual.doubleBufferMode) {
 216             mask |= BUFFER_BIT_BACK_LEFT | BUFFER_BIT_BACK_RIGHT;
 217          }
 218       }
 219       else if (fb->Visual.doubleBufferMode) {
 220          mask |= BUFFER_BIT_BACK_LEFT;
 221       }
 222
 223       for (i = 0; i < fb->Visual.numAuxBuffers; i++) {
 224          mask |= (BUFFER_BIT_AUX0 << i);
 225       }
 226    }
 227
 228    return mask;
 229 }
 230
 231
 232 /**
 233  * Helper routine used by glDrawBuffer and glDrawBuffersARB.
 234  * Given a GLenum naming one or more color buffers (such as
 235  * GL_FRONT_AND_BACK), return the corresponding bitmask of BUFFER_BIT_* flags.
 236  */
 237 static GLbitfield
 238 draw_buffer_enum_to_bitmask(GLenum buffer)
 239 {
 240    switch (buffer) {
 241       case GL_NONE:
 242          return 0;
 243       case GL_FRONT:
 244          return BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_FRONT_RIGHT;
 245       case GL_BACK:
 246          return BUFFER_BIT_BACK_LEFT | BUFFER_BIT_BACK_RIGHT;
 247       case GL_RIGHT:
 248          return BUFFER_BIT_FRONT_RIGHT | BUFFER_BIT_BACK_RIGHT;
 249       case GL_FRONT_RIGHT:
 250          return BUFFER_BIT_FRONT_RIGHT;
 251       case GL_BACK_RIGHT:
 252          return BUFFER_BIT_BACK_RIGHT;
 253       case GL_BACK_LEFT:
 254          return BUFFER_BIT_BACK_LEFT;
 255       case GL_FRONT_AND_BACK:
 256          return BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT
 257               | BUFFER_BIT_FRONT_RIGHT | BUFFER_BIT_BACK_RIGHT;
 258       case GL_LEFT:
 259          return BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT;
 260       case GL_FRONT_LEFT:
 261          return BUFFER_BIT_FRONT_LEFT;
 262       case GL_AUX0:
 263          return BUFFER_BIT_AUX0;
 264       case GL_AUX1:
 265          return BUFFER_BIT_AUX1;
 266       case GL_AUX2:
 267          return BUFFER_BIT_AUX2;
 268       case GL_AUX3:
 269          return BUFFER_BIT_AUX3;
 270       case GL_COLOR_ATTACHMENT0_EXT:
 271          return BUFFER_BIT_COLOR0;
 272       case GL_COLOR_ATTACHMENT1_EXT:
 273          return BUFFER_BIT_COLOR1;
 274       case GL_COLOR_ATTACHMENT2_EXT:
 275          return BUFFER_BIT_COLOR2;
 276       case GL_COLOR_ATTACHMENT3_EXT:
 277          return BUFFER_BIT_COLOR3;
 278       default:
 279          /* error */
 280          return BAD_MASK;
 281    }
 282 }
 283
 284
 285 /**
 286  * Helper routine used by glReadBuffer.
 287  * Given a GLenum naming a color buffer, return the index of the corresponding
 288  * renderbuffer (a BUFFER_* value).
 289  * return -1 for an invalid buffer.
 290  */
 291 static GLint
 292 read_buffer_enum_to_index(GLenum buffer)
 293 {
 294    switch (buffer) {
 295       case GL_FRONT:
 296          return BUFFER_FRONT_LEFT;
 297       case GL_BACK:
 298          return BUFFER_BACK_LEFT;
 299       case GL_RIGHT:
 300          return BUFFER_FRONT_RIGHT;
 301       case GL_FRONT_RIGHT:
 302          return BUFFER_FRONT_RIGHT;
 303       case GL_BACK_RIGHT:
 304          return BUFFER_BACK_RIGHT;
 305       case GL_BACK_LEFT:
 306          return BUFFER_BACK_LEFT;
 307       case GL_LEFT:
 308          return BUFFER_FRONT_LEFT;
 309       case GL_FRONT_LEFT:
 310          return BUFFER_FRONT_LEFT;
 311       case GL_AUX0:
 312          return BUFFER_AUX0;
 313       case GL_AUX1:
 314          return BUFFER_AUX1;
 315       case GL_AUX2:
 316          return BUFFER_AUX2;
 317       case GL_AUX3:
 318          return BUFFER_AUX3;
 319       case GL_COLOR_ATTACHMENT0_EXT:
 320          return BUFFER_COLOR0;
 321       case GL_COLOR_ATTACHMENT1_EXT:
 322          return BUFFER_COLOR1;
 323       case GL_COLOR_ATTACHMENT2_EXT:
 324          return BUFFER_COLOR2;
 325       case GL_COLOR_ATTACHMENT3_EXT:
 326          return BUFFER_COLOR3;
 327       default:
 328          /* error */
 329          return -1;
 330    }
 331 }
 332
 333
 334 /**
 335  * Called by glDrawBuffer().
 336  * Specify which renderbuffer(s) to draw into for the first color output.
 337  * <buffer> can name zero, one, two or four renderbuffers!
 338  * \sa _mesa_DrawBuffersARB
 339  *
 340  * \param buffer  buffer token such as GL_LEFT or GL_FRONT_AND_BACK, etc.
 341  */
 342 void GLAPIENTRY
 343 _mesa_DrawBuffer(GLenum buffer)
 344 {
 345    GLbitfield destMask;
 346    GET_CURRENT_CONTEXT(ctx);
 347    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx); /* too complex... */
 348
 349    if (MESA_VERBOSE & VERBOSE_API) {
 350       _mesa_debug(ctx, "glDrawBuffer %s\n", _mesa_lookup_enum_by_nr(buffer));
 351    }
 352
 353    if (buffer == GL_NONE) {
 354       destMask = 0x0;
 355    }
 356    else {
 357       const GLbitfield supportedMask
 358          = supported_buffer_bitmask(ctx, ctx->DrawBuffer);
 359       destMask = draw_buffer_enum_to_bitmask(buffer);
 360       if (destMask == BAD_MASK) {
 361          /* totally bogus buffer */
 362          _mesa_error(ctx, GL_INVALID_ENUM, "glDrawBuffer(buffer)");
 363          return;
 364       }
 365       destMask &= supportedMask;
 366       if (destMask == 0x0) {
 367          /* none of the named color buffers exist! */
 368          _mesa_error(ctx, GL_INVALID_OPERATION, "glDrawBuffer(buffer)");
 369          return;
 370       }
 371    }
 372
 373    /* if we get here, there's no error so set new state */
 374    _mesa_drawbuffers(ctx, 1, &buffer, &destMask);
 375
 376    /*
 377     * Call device driver function.
 378     */
 379    if (ctx->Driver.DrawBuffers)
 380       ctx->Driver.DrawBuffers(ctx, 1, &buffer);
 381    else if (ctx->Driver.DrawBuffer)
 382       ctx->Driver.DrawBuffer(ctx, buffer);
 383 }
 384
 385
 386 /**
 387  * Called by glDrawBuffersARB; specifies the destination color renderbuffers
 388  * for N fragment program color outputs.
 389  * \sa _mesa_DrawBuffer
 390  * \param n  number of outputs
 391  * \param buffers  array [n] of renderbuffer names.  Unlike glDrawBuffer, the
 392  *                 names cannot specify more than one buffer.  For example,
 393  *                 GL_FRONT_AND_BACK is illegal.
 394  */
 395 void GLAPIENTRY
 396 _mesa_DrawBuffersARB(GLsizei n, const GLenum *buffers)
 397 {
 398    GLint output;
 399    GLbitfield usedBufferMask, supportedMask;
 400    GLbitfield destMask[MAX_DRAW_BUFFERS];
 401    GET_CURRENT_CONTEXT(ctx);
 402    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx);
 403
 404    if (!ctx->Extensions.ARB_draw_buffers) {
 405       _mesa_error(ctx, GL_INVALID_OPERATION, "glDrawBuffersARB");
 406       return;
 407    }
 408    if (n < 1 || n > (GLsizei) ctx->Const.MaxDrawBuffers) {
 409       _mesa_error(ctx, GL_INVALID_VALUE, "glDrawBuffersARB(n)");
 410       return;
 411    }
 412
 413    supportedMask = supported_buffer_bitmask(ctx, ctx->DrawBuffer);
 414    usedBufferMask = 0x0;
 415
 416    /* complicated error checking... */
 417    for (output = 0; output < n; output++) {
 418       if (buffers[output] == GL_NONE) {
 419          destMask[output] = 0x0;
 420       }
 421       else {
 422          destMask[output] = draw_buffer_enum_to_bitmask(buffers[output]);
 423          if (destMask[output] == BAD_MASK
 424              || _mesa_bitcount(destMask[output]) > 1) {
 425             _mesa_error(ctx, GL_INVALID_ENUM, "glDrawBuffersARB(buffer)");
 426             return;
 427          }
 428          destMask[output] &= supportedMask;
 429          if (destMask[output] == 0) {
 430             _mesa_error(ctx, GL_INVALID_OPERATION,
 431                         "glDrawBuffersARB(unsupported buffer)");
 432             return;
 433          }
 434          if (destMask[output] & usedBufferMask) {
 435             /* can't specify a dest buffer more than once! */
 436             _mesa_error(ctx, GL_INVALID_OPERATION,
 437                         "glDrawBuffersARB(duplicated buffer)");
 438             return;
 439          }
 440
 441          /* update bitmask */
 442          usedBufferMask |= destMask[output];
 443       }
 444    }
 445
 446    /* OK, if we get here, there were no errors so set the new state */
 447    _mesa_drawbuffers(ctx, n, buffers, destMask);
 448
 449    /*
 450     * Call device driver function.
 451     */
 452    if (ctx->Driver.DrawBuffers)
 453       ctx->Driver.DrawBuffers(ctx, n, buffers);
 454    else if (ctx->Driver.DrawBuffer)
 455       ctx->Driver.DrawBuffer(ctx, buffers[0]);
 456 }
 457
 458
 459 /**
 460  * Set color output state.  Traditionally, there was only one color
 461  * output, but fragment programs can now have several distinct color
 462  * outputs (see GL_ARB_draw_buffers).  This function sets the state
 463  * for one such color output.
 464  * \param ctx  current context
 465  * \param output  which fragment program output
 466  * \param buffer  buffer to write to (like GL_LEFT)
 467  * \param destMask  BUFFER_* bitmask
 468  *                  (like BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT).
 469  */
 470 static void
 471 set_color_output(GLcontext *ctx, GLuint output, GLenum buffer,
 472                  GLbitfield destMask)
 473 {
 474    struct gl_framebuffer *fb = ctx->DrawBuffer;
 475
 476    ASSERT(output < ctx->Const.MaxDrawBuffers);
 477
 478    /* Set per-FBO state */
 479    fb->ColorDrawBuffer[output] = buffer;
 480    fb->_ColorDrawBufferMask[output] = destMask;
 481    /* not really needed, will be set later */
 482    fb->_NumColorDrawBuffers[output] = 0;
 483
 484    if (fb->Name == 0)
 485    /* Set traditional state var */
 486       ctx->Color.DrawBuffer[output] = buffer;
 487 }
 488
 489
 490 /**
 491  * Helper routine used by _mesa_DrawBuffer, _mesa_DrawBuffersARB and
 492  * other places (window fbo fixup) to set fbo (and the old ctx) fields.
 493  * All error checking will have been done prior to calling this function
 494  * so nothing should go wrong at this point.
 495  * \param ctx  current context
 496  * \param n    number of color outputs to set
 497  * \param buffers  array[n] of colorbuffer names, like GL_LEFT.
 498  * \param destMask  array[n] of BUFFER_* bitmasks which correspond to the
 499  *                  colorbuffer names.  (i.e. GL_FRONT_AND_BACK =>
 500  *                  BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT).
 501  */
 502 void
 503 _mesa_drawbuffers(GLcontext *ctx, GLuint n, const GLenum *buffers,
 504                   const GLbitfield *destMask)
 505 {
 506    GLbitfield mask[MAX_DRAW_BUFFERS];
 507    GLuint output;
 508
 509    if (!destMask) {
 510       /* compute destMask values now */
 511       const GLbitfield supportedMask
 512          = supported_buffer_bitmask(ctx, ctx->DrawBuffer);
 513       for (output = 0; output < n; output++) {
 514          mask[output] = draw_buffer_enum_to_bitmask(buffers[output]);
 515          ASSERT(mask[output] != BAD_MASK);
 516          mask[output] &= supportedMask;
 517       }
 518       destMask = mask;
 519    }
 520
 521    for (output = 0; output < n; output++) {
 522       set_color_output(ctx, output, buffers[output], destMask[output]);
 523    }
 524
 525    /* set remaining color outputs to NONE */
 526    for (output = n; output < ctx->Const.MaxDrawBuffers; output++) {
 527       set_color_output(ctx, output, GL_NONE, 0x0);
 528    }
 529
 530    ctx->NewState |= _NEW_BUFFERS;
 531 }
 532
 533
 534 GLboolean
 535 _mesa_readbuffer_update_fields(GLcontext *ctx, GLenum buffer)
 536 {
 537    struct gl_framebuffer *fb;
 538    GLbitfield supportedMask;
 539    GLint srcBuffer;
 540
 541    fb = ctx->ReadBuffer;
 542
 543    if (MESA_VERBOSE & VERBOSE_API)
 544       _mesa_debug(ctx, "glReadBuffer %s\n", _mesa_lookup_enum_by_nr(buffer));
 545
 546    if (fb->Name > 0 && buffer == GL_NONE) {
 547       /* This is legal for user-created framebuffer objects */
 548       srcBuffer = -1;
 549    }
 550    else {
 551       /* general case / window-system framebuffer */
 552       srcBuffer = read_buffer_enum_to_index(buffer);
 553       if (srcBuffer == -1) {
 554          _mesa_error(ctx, GL_INVALID_ENUM, "glReadBuffer(buffer=0x%x)", buffer);
 555          return GL_FALSE;
 556       }
 557       supportedMask = supported_buffer_bitmask(ctx, fb);
 558       if (((1 << srcBuffer) & supportedMask) == 0) {
 559          _mesa_error(ctx, GL_INVALID_OPERATION, "glReadBuffer(buffer=0x%x)", buffer);
 560          return GL_FALSE;
 561       }
 562    }
 563
 564    if (fb->Name == 0) {
 565       ctx->Pixel.ReadBuffer = buffer;
 566    }
 567    fb->ColorReadBuffer = buffer;
 568    fb->_ColorReadBufferIndex = srcBuffer;
 569
 570    return GL_TRUE;
 571 }
 572
 573
 574
 575 /**
 576  * Called by glReadBuffer to set the source renderbuffer for reading pixels.
 577  * \param mode color buffer such as GL_FRONT, GL_BACK, etc.
 578  */
 579 void GLAPIENTRY
 580 _mesa_ReadBuffer(GLenum buffer)
 581 {
 582    GET_CURRENT_CONTEXT(ctx);
 583    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx);
 584
 585    if (MESA_VERBOSE & VERBOSE_API)
 586       _mesa_debug(ctx, "glReadBuffer %s\n", _mesa_lookup_enum_by_nr(buffer));
 587
 588    if (!_mesa_readbuffer_update_fields(ctx, buffer))
 589       return;
 590
 591    ctx->NewState |= _NEW_BUFFERS;
 592
 593    /*
 594     * Call device driver function.
 595     */
 596    if (ctx->Driver.ReadBuffer)
 597       (*ctx->Driver.ReadBuffer)(ctx, buffer);
 598 }
 599
 600
 601 #if _HAVE_FULL_GL
 602
 603 /**
 604  * XXX THIS IS OBSOLETE - drivers should take care of detecting window
 605  * size changes and act accordingly, likely calling _mesa_resize_framebuffer().
 606  *
 607  * GL_MESA_resize_buffers extension.
 608  *
 609  * When this function is called, we'll ask the window system how large
 610  * the current window is.  If it's a new size, we'll call the driver's
 611  * ResizeBuffers function.  The driver will then resize its color buffers
 612  * as needed, and maybe call the swrast's routine for reallocating
 613  * swrast-managed depth/stencil/accum/etc buffers.
 614  * \note This function should only be called through the GL API, not
 615  * from device drivers (as was done in the past).
 616  */
 617
 618 void _mesa_resizebuffers( GLcontext *ctx )
 619 {
 620    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH( ctx );
 621
 622    if (MESA_VERBOSE & VERBOSE_API)
 623       _mesa_debug(ctx, "glResizeBuffersMESA\n");
 624
 625    if (!ctx->Driver.GetBufferSize) {
 626       return;
 627    }
 628
 629    if (ctx->WinSysDrawBuffer) {
 630       GLuint newWidth, newHeight;
 631       GLframebuffer *buffer = ctx->WinSysDrawBuffer;
 632
 633       assert(buffer->Name == 0);
 634
 635       /* ask device driver for size of output buffer */
 636       ctx->Driver.GetBufferSize( buffer, &newWidth, &newHeight );
 637
 638       /* see if size of device driver's color buffer (window) has changed */
 639       if (buffer->Width != newWidth || buffer->Height != newHeight) {
 640          if (ctx->Driver.ResizeBuffers)
 641             ctx->Driver.ResizeBuffers(ctx, buffer, newWidth, newHeight );
 642       }
 643    }
 644
 645    if (ctx->WinSysReadBuffer
 646        && ctx->WinSysReadBuffer != ctx->WinSysDrawBuffer) {
 647       GLuint newWidth, newHeight;
 648       GLframebuffer *buffer = ctx->WinSysReadBuffer;
 649
 650       assert(buffer->Name == 0);
 651
 652       /* ask device driver for size of read buffer */
 653       ctx->Driver.GetBufferSize( buffer, &newWidth, &newHeight );
 654
 655       /* see if size of device driver's color buffer (window) has changed */
 656       if (buffer->Width != newWidth || buffer->Height != newHeight) {
 657          if (ctx->Driver.ResizeBuffers)
 658             ctx->Driver.ResizeBuffers(ctx, buffer, newWidth, newHeight );
 659       }
 660    }
 661
 662    ctx->NewState |= _NEW_BUFFERS;  /* to update scissor / window bounds */
 663 }
 664
 665
 666 /*
 667  * XXX THIS IS OBSOLETE
 668  */
 669 void GLAPIENTRY
 670 _mesa_ResizeBuffersMESA( void )
 671 {
 672    GET_CURRENT_CONTEXT(ctx);
 673
 674    if (ctx->Extensions.MESA_resize_buffers)
 675       _mesa_resizebuffers( ctx );
 676 }
 677
 678
 679 /*
 680  * XXX move somewhere else someday?
 681  */
 682 void GLAPIENTRY
 683 _mesa_SampleCoverageARB(GLclampf value, GLboolean invert)
 684 {
 685    GET_CURRENT_CONTEXT(ctx);
 686
 687    if (!ctx->Extensions.ARB_multisample) {
 688       _mesa_error(ctx, GL_INVALID_OPERATION, "glSampleCoverageARB");
 689       return;
 690    }
 691
 692    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH( ctx );
 693    ctx->Multisample.SampleCoverageValue = (GLfloat) CLAMP(value, 0.0, 1.0);
 694    ctx->Multisample.SampleCoverageInvert = invert;
 695    ctx->NewState |= _NEW_MULTISAMPLE;
 696 }
 697
 698 #endif /* _HAVE_FULL_GL */
 699
 700
 701
 702 /**
 703  * Initialize the context's multisample state.
 704  * \param ctx  the GL context.
 705  */
 706 void
 707 _mesa_init_multisample(GLcontext *ctx)
 708 {
 709    ctx->Multisample.Enabled = GL_FALSE;
 710    ctx->Multisample.SampleAlphaToCoverage = GL_FALSE;
 711    ctx->Multisample.SampleAlphaToOne = GL_FALSE;
 712    ctx->Multisample.SampleCoverage = GL_FALSE;
 713    ctx->Multisample.SampleCoverageValue = 1.0;
 714    ctx->Multisample.SampleCoverageInvert = GL_FALSE;
 715 }