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    if (MESA_VERBOSE & VERBOSE_API)
 122       _mesa_debug(ctx, "glClear 0x%x\n", mask);
 123
 124    if (mask & ~(GL_COLOR_BUFFER_BIT |
 125                 GL_DEPTH_BUFFER_BIT |
 126                 GL_STENCIL_BUFFER_BIT |
 127                 GL_ACCUM_BUFFER_BIT)) {
 128       /* invalid bit set */
 129       _mesa_error( ctx, GL_INVALID_VALUE, "glClear(0x%x)", mask);
 130       return;
 131    }
 132
 133    if (ctx->NewState) {
 134       _mesa_update_state( ctx );        /* update _Xmin, etc */
 135    }
 136
 137    if (ctx->DrawBuffer->_Status != GL_FRAMEBUFFER_COMPLETE_EXT) {
 138       _mesa_error(ctx, GL_INVALID_FRAMEBUFFER_OPERATION_EXT,
 139                   "glClear(incomplete framebuffer)");
 140       return;
 141    }
 142
 143    if (ctx->DrawBuffer->Width == 0 || ctx->DrawBuffer->Height == 0)
 144       return;
 145
 146    if (ctx->RenderMode == GL_RENDER) {
 147       GLbitfield bufferMask;
 148
 149       /* don't clear depth buffer if depth writing disabled */
 150       if (!ctx->Depth.Mask)
 151          mask &= ~GL_DEPTH_BUFFER_BIT;
 152
 153       /* Build the bitmask to send to device driver's Clear function.
 154        * Note that the GL_COLOR_BUFFER_BIT flag will expand to 0, 1, 2 or 4
 155        * of the BUFFER_BIT_FRONT/BACK_LEFT/RIGHT flags, or one of the
 156        * BUFFER_BIT_COLORn flags.
 157        */
 158       bufferMask = 0;
 159       if (mask & GL_COLOR_BUFFER_BIT) {
 160          bufferMask |= ctx->DrawBuffer->_ColorDrawBufferMask[0];
 161       }
 162
 163       if ((mask & GL_DEPTH_BUFFER_BIT)
 164           && ctx->DrawBuffer->Visual.haveDepthBuffer) {
 165          bufferMask |= BUFFER_BIT_DEPTH;
 166       }
 167
 168       if ((mask & GL_STENCIL_BUFFER_BIT)
 169           && ctx->DrawBuffer->Visual.haveStencilBuffer) {
 170          bufferMask |= BUFFER_BIT_STENCIL;
 171       }
 172
 173       if ((mask & GL_ACCUM_BUFFER_BIT)
 174           && ctx->DrawBuffer->Visual.haveAccumBuffer) {
 175          bufferMask |= BUFFER_BIT_ACCUM;
 176       }
 177
 178       ASSERT(ctx->Driver.Clear);
 179       ctx->Driver.Clear(ctx, bufferMask);
 180    }
 181 }
 182
 183
 184
 185 /**
 186  * Return bitmask of BUFFER_BIT_* flags indicating which color buffers are
 187  * available to the rendering context (for drawing or reading).
 188  * This depends on the type of framebuffer.  For window system framebuffers
 189  * we look at the framebuffer's visual.  But for user-create framebuffers we
 190  * look at the number of supported color attachments.
 191  * \param fb  the framebuffer to draw to, or read from
 192  * \return  bitmask of BUFFER_BIT_* flags
 193  */
 194 static GLbitfield
 195 supported_buffer_bitmask(const GLcontext *ctx, const struct gl_framebuffer *fb)
 196 {
 197    GLbitfield mask = 0x0;
 198
 199    if (fb->Name > 0) {
 200       /* A user-created renderbuffer */
 201       GLuint i;
 202       ASSERT(ctx->Extensions.EXT_framebuffer_object);
 203       for (i = 0; i < ctx->Const.MaxColorAttachments; i++) {
 204          mask |= (BUFFER_BIT_COLOR0 << i);
 205       }
 206    }
 207    else {
 208       /* A window system framebuffer */
 209       GLint i;
 210       mask = BUFFER_BIT_FRONT_LEFT; /* always have this */
 211       if (fb->Visual.stereoMode) {
 212          mask |= BUFFER_BIT_FRONT_RIGHT;
 213          if (fb->Visual.doubleBufferMode) {
 214             mask |= BUFFER_BIT_BACK_LEFT | BUFFER_BIT_BACK_RIGHT;
 215          }
 216       }
 217       else if (fb->Visual.doubleBufferMode) {
 218          mask |= BUFFER_BIT_BACK_LEFT;
 219       }
 220
 221       for (i = 0; i < fb->Visual.numAuxBuffers; i++) {
 222          mask |= (BUFFER_BIT_AUX0 << i);
 223       }
 224    }
 225
 226    return mask;
 227 }
 228
 229
 230 /**
 231  * Helper routine used by glDrawBuffer and glDrawBuffersARB.
 232  * Given a GLenum naming one or more color buffers (such as
 233  * GL_FRONT_AND_BACK), return the corresponding bitmask of BUFFER_BIT_* flags.
 234  */
 235 static GLbitfield
 236 draw_buffer_enum_to_bitmask(GLenum buffer)
 237 {
 238    switch (buffer) {
 239       case GL_NONE:
 240          return 0;
 241       case GL_FRONT:
 242          return BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_FRONT_RIGHT;
 243       case GL_BACK:
 244          return BUFFER_BIT_BACK_LEFT | BUFFER_BIT_BACK_RIGHT;
 245       case GL_RIGHT:
 246          return BUFFER_BIT_FRONT_RIGHT | BUFFER_BIT_BACK_RIGHT;
 247       case GL_FRONT_RIGHT:
 248          return BUFFER_BIT_FRONT_RIGHT;
 249       case GL_BACK_RIGHT:
 250          return BUFFER_BIT_BACK_RIGHT;
 251       case GL_BACK_LEFT:
 252          return BUFFER_BIT_BACK_LEFT;
 253       case GL_FRONT_AND_BACK:
 254          return BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT
 255               | BUFFER_BIT_FRONT_RIGHT | BUFFER_BIT_BACK_RIGHT;
 256       case GL_LEFT:
 257          return BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT;
 258       case GL_FRONT_LEFT:
 259          return BUFFER_BIT_FRONT_LEFT;
 260       case GL_AUX0:
 261          return BUFFER_BIT_AUX0;
 262       case GL_AUX1:
 263          return BUFFER_BIT_AUX1;
 264       case GL_AUX2:
 265          return BUFFER_BIT_AUX2;
 266       case GL_AUX3:
 267          return BUFFER_BIT_AUX3;
 268       case GL_COLOR_ATTACHMENT0_EXT:
 269          return BUFFER_BIT_COLOR0;
 270       case GL_COLOR_ATTACHMENT1_EXT:
 271          return BUFFER_BIT_COLOR1;
 272       case GL_COLOR_ATTACHMENT2_EXT:
 273          return BUFFER_BIT_COLOR2;
 274       case GL_COLOR_ATTACHMENT3_EXT:
 275          return BUFFER_BIT_COLOR3;
 276       default:
 277          /* error */
 278          return BAD_MASK;
 279    }
 280 }
 281
 282
 283 /**
 284  * Helper routine used by glReadBuffer.
 285  * Given a GLenum naming a color buffer, return the index of the corresponding
 286  * renderbuffer (a BUFFER_* value).
 287  * return -1 for an invalid buffer.
 288  */
 289 static GLint
 290 read_buffer_enum_to_index(GLenum buffer)
 291 {
 292    switch (buffer) {
 293       case GL_FRONT:
 294          return BUFFER_FRONT_LEFT;
 295       case GL_BACK:
 296          return BUFFER_BACK_LEFT;
 297       case GL_RIGHT:
 298          return BUFFER_FRONT_RIGHT;
 299       case GL_FRONT_RIGHT:
 300          return BUFFER_FRONT_RIGHT;
 301       case GL_BACK_RIGHT:
 302          return BUFFER_BACK_RIGHT;
 303       case GL_BACK_LEFT:
 304          return BUFFER_BACK_LEFT;
 305       case GL_LEFT:
 306          return BUFFER_FRONT_LEFT;
 307       case GL_FRONT_LEFT:
 308          return BUFFER_FRONT_LEFT;
 309       case GL_AUX0:
 310          return BUFFER_AUX0;
 311       case GL_AUX1:
 312          return BUFFER_AUX1;
 313       case GL_AUX2:
 314          return BUFFER_AUX2;
 315       case GL_AUX3:
 316          return BUFFER_AUX3;
 317       case GL_COLOR_ATTACHMENT0_EXT:
 318          return BUFFER_COLOR0;
 319       case GL_COLOR_ATTACHMENT1_EXT:
 320          return BUFFER_COLOR1;
 321       case GL_COLOR_ATTACHMENT2_EXT:
 322          return BUFFER_COLOR2;
 323       case GL_COLOR_ATTACHMENT3_EXT:
 324          return BUFFER_COLOR3;
 325       default:
 326          /* error */
 327          return -1;
 328    }
 329 }
 330
 331
 332 /**
 333  * Called by glDrawBuffer().
 334  * Specify which renderbuffer(s) to draw into for the first color output.
 335  * <buffer> can name zero, one, two or four renderbuffers!
 336  * \sa _mesa_DrawBuffersARB
 337  *
 338  * \param buffer  buffer token such as GL_LEFT or GL_FRONT_AND_BACK, etc.
 339  */
 340 void GLAPIENTRY
 341 _mesa_DrawBuffer(GLenum buffer)
 342 {
 343    GLbitfield destMask;
 344    GET_CURRENT_CONTEXT(ctx);
 345    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx); /* too complex... */
 346
 347    if (MESA_VERBOSE & VERBOSE_API) {
 348       _mesa_debug(ctx, "glDrawBuffer %s\n", _mesa_lookup_enum_by_nr(buffer));
 349    }
 350
 351    if (buffer == GL_NONE) {
 352       destMask = 0x0;
 353    }
 354    else {
 355       const GLbitfield supportedMask
 356          = supported_buffer_bitmask(ctx, ctx->DrawBuffer);
 357       destMask = draw_buffer_enum_to_bitmask(buffer);
 358       if (destMask == BAD_MASK) {
 359          /* totally bogus buffer */
 360          _mesa_error(ctx, GL_INVALID_ENUM, "glDrawBuffer(buffer)");
 361          return;
 362       }
 363       destMask &= supportedMask;
 364       if (destMask == 0x0) {
 365          /* none of the named color buffers exist! */
 366          _mesa_error(ctx, GL_INVALID_OPERATION, "glDrawBuffer(buffer)");
 367          return;
 368       }
 369    }
 370
 371    /* if we get here, there's no error so set new state */
 372    _mesa_drawbuffers(ctx, 1, &buffer, &destMask);
 373
 374    /*
 375     * Call device driver function.
 376     */
 377    if (ctx->Driver.DrawBuffers)
 378       ctx->Driver.DrawBuffers(ctx, 1, &buffer);
 379    else if (ctx->Driver.DrawBuffer)
 380       ctx->Driver.DrawBuffer(ctx, buffer);
 381 }
 382
 383
 384 /**
 385  * Called by glDrawBuffersARB; specifies the destination color renderbuffers
 386  * for N fragment program color outputs.
 387  * \sa _mesa_DrawBuffer
 388  * \param n  number of outputs
 389  * \param buffers  array [n] of renderbuffer names.  Unlike glDrawBuffer, the
 390  *                 names cannot specify more than one buffer.  For example,
 391  *                 GL_FRONT_AND_BACK is illegal.
 392  */
 393 void GLAPIENTRY
 394 _mesa_DrawBuffersARB(GLsizei n, const GLenum *buffers)
 395 {
 396    GLint output;
 397    GLbitfield usedBufferMask, supportedMask;
 398    GLbitfield destMask[MAX_DRAW_BUFFERS];
 399    GET_CURRENT_CONTEXT(ctx);
 400    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx);
 401
 402    if (!ctx->Extensions.ARB_draw_buffers) {
 403       _mesa_error(ctx, GL_INVALID_OPERATION, "glDrawBuffersARB");
 404       return;
 405    }
 406    if (n < 1 || n > (GLsizei) ctx->Const.MaxDrawBuffers) {
 407       _mesa_error(ctx, GL_INVALID_VALUE, "glDrawBuffersARB(n)");
 408       return;
 409    }
 410
 411    supportedMask = supported_buffer_bitmask(ctx, ctx->DrawBuffer);
 412    usedBufferMask = 0x0;
 413
 414    /* complicated error checking... */
 415    for (output = 0; output < n; output++) {
 416       if (buffers[output] == GL_NONE) {
 417          destMask[output] = 0x0;
 418       }
 419       else {
 420          destMask[output] = draw_buffer_enum_to_bitmask(buffers[output]);
 421          if (destMask[output] == BAD_MASK
 422              || _mesa_bitcount(destMask[output]) > 1) {
 423             _mesa_error(ctx, GL_INVALID_ENUM, "glDrawBuffersARB(buffer)");
 424             return;
 425          }
 426          destMask[output] &= supportedMask;
 427          if (destMask[output] == 0) {
 428             _mesa_error(ctx, GL_INVALID_OPERATION,
 429                         "glDrawBuffersARB(unsupported buffer)");
 430             return;
 431          }
 432          if (destMask[output] & usedBufferMask) {
 433             /* can't specify a dest buffer more than once! */
 434             _mesa_error(ctx, GL_INVALID_OPERATION,
 435                         "glDrawBuffersARB(duplicated buffer)");
 436             return;
 437          }
 438
 439          /* update bitmask */
 440          usedBufferMask |= destMask[output];
 441       }
 442    }
 443
 444    /* OK, if we get here, there were no errors so set the new state */
 445    _mesa_drawbuffers(ctx, n, buffers, destMask);
 446
 447    /*
 448     * Call device driver function.
 449     */
 450    if (ctx->Driver.DrawBuffers)
 451       ctx->Driver.DrawBuffers(ctx, n, buffers);
 452    else if (ctx->Driver.DrawBuffer)
 453       ctx->Driver.DrawBuffer(ctx, buffers[0]);
 454 }
 455
 456
 457 /**
 458  * Set color output state.  Traditionally, there was only one color
 459  * output, but fragment programs can now have several distinct color
 460  * outputs (see GL_ARB_draw_buffers).  This function sets the state
 461  * for one such color output.
 462  * \param ctx  current context
 463  * \param output  which fragment program output
 464  * \param buffer  buffer to write to (like GL_LEFT)
 465  * \param destMask  BUFFER_* bitmask
 466  *                  (like BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT).
 467  */
 468 static void
 469 set_color_output(GLcontext *ctx, GLuint output, GLenum buffer,
 470                  GLbitfield destMask)
 471 {
 472    struct gl_framebuffer *fb = ctx->DrawBuffer;
 473
 474    ASSERT(output < ctx->Const.MaxDrawBuffers);
 475
 476    /* Set per-FBO state */
 477    fb->ColorDrawBuffer[output] = buffer;
 478    fb->_ColorDrawBufferMask[output] = destMask;
 479    /* not really needed, will be set later */
 480    fb->_NumColorDrawBuffers[output] = 0;
 481
 482    if (fb->Name == 0) {
 483       /* Only set the per-context DrawBuffer state if we're currently
 484        * drawing to a window system framebuffer.
 485        */
 486       ctx->Color.DrawBuffer[output] = buffer;
 487    }
 488 }
 489
 490
 491 /**
 492  * Helper routine used by _mesa_DrawBuffer, _mesa_DrawBuffersARB and
 493  * other places (window fbo fixup) to set fbo (and the old ctx) fields.
 494  * All error checking will have been done prior to calling this function
 495  * so nothing should go wrong at this point.
 496  * \param ctx  current context
 497  * \param n    number of color outputs to set
 498  * \param buffers  array[n] of colorbuffer names, like GL_LEFT.
 499  * \param destMask  array[n] of BUFFER_* bitmasks which correspond to the
 500  *                  colorbuffer names.  (i.e. GL_FRONT_AND_BACK =>
 501  *                  BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT).
 502  */
 503 void
 504 _mesa_drawbuffers(GLcontext *ctx, GLuint n, const GLenum *buffers,
 505                   const GLbitfield *destMask)
 506 {
 507    GLbitfield mask[MAX_DRAW_BUFFERS];
 508    GLuint output;
 509
 510    if (!destMask) {
 511       /* compute destMask values now */
 512       const GLbitfield supportedMask
 513          = supported_buffer_bitmask(ctx, ctx->DrawBuffer);
 514       for (output = 0; output < n; output++) {
 515          mask[output] = draw_buffer_enum_to_bitmask(buffers[output]);
 516          ASSERT(mask[output] != BAD_MASK);
 517          mask[output] &= supportedMask;
 518       }
 519       destMask = mask;
 520    }
 521
 522    for (output = 0; output < n; output++) {
 523       set_color_output(ctx, output, buffers[output], destMask[output]);
 524    }
 525
 526    /* set remaining color outputs to NONE */
 527    for (output = n; output < ctx->Const.MaxDrawBuffers; output++) {
 528       set_color_output(ctx, output, GL_NONE, 0x0);
 529    }
 530
 531    ctx->NewState |= _NEW_COLOR;
 532 }
 533
 534
 535 GLboolean
 536 _mesa_readbuffer_update_fields(GLcontext *ctx, GLenum buffer)
 537 {
 538    struct gl_framebuffer *fb;
 539    GLbitfield supportedMask;
 540    GLint srcBuffer;
 541
 542    fb = ctx->ReadBuffer;
 543
 544    if (MESA_VERBOSE & VERBOSE_API)
 545       _mesa_debug(ctx, "glReadBuffer %s\n", _mesa_lookup_enum_by_nr(buffer));
 546
 547    if (fb->Name > 0 && buffer == GL_NONE) {
 548       /* This is legal for user-created framebuffer objects */
 549       srcBuffer = -1;
 550    }
 551    else {
 552       /* general case / window-system framebuffer */
 553       srcBuffer = read_buffer_enum_to_index(buffer);
 554       if (srcBuffer == -1) {
 555          _mesa_error(ctx, GL_INVALID_ENUM, "glReadBuffer(buffer=0x%x)", buffer);
 556          return GL_FALSE;
 557       }
 558       supportedMask = supported_buffer_bitmask(ctx, fb);
 559       if (((1 << srcBuffer) & supportedMask) == 0) {
 560          _mesa_error(ctx, GL_INVALID_OPERATION, "glReadBuffer(buffer=0x%x)", buffer);
 561          return GL_FALSE;
 562       }
 563    }
 564
 565    if (fb->Name == 0) {
 566       ctx->Pixel.ReadBuffer = buffer;
 567    }
 568    fb->ColorReadBuffer = buffer;
 569    fb->_ColorReadBufferIndex = srcBuffer;
 570
 571    return GL_TRUE;
 572 }
 573
 574
 575
 576 /**
 577  * Called by glReadBuffer to set the source renderbuffer for reading pixels.
 578  * \param mode color buffer such as GL_FRONT, GL_BACK, etc.
 579  */
 580 void GLAPIENTRY
 581 _mesa_ReadBuffer(GLenum buffer)
 582 {
 583    GET_CURRENT_CONTEXT(ctx);
 584    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx);
 585
 586    if (MESA_VERBOSE & VERBOSE_API)
 587       _mesa_debug(ctx, "glReadBuffer %s\n", _mesa_lookup_enum_by_nr(buffer));
 588
 589    if (!_mesa_readbuffer_update_fields(ctx, buffer))
 590       return;
 591
 592    ctx->NewState |= _NEW_PIXEL;
 593
 594    /*
 595     * Call device driver function.
 596     */
 597    if (ctx->Driver.ReadBuffer)
 598       (*ctx->Driver.ReadBuffer)(ctx, buffer);
 599 }
 600
 601
 602 #if _HAVE_FULL_GL
 603
 604 /**
 605  * XXX THIS IS OBSOLETE - drivers should take care of detecting window
 606  * size changes and act accordingly, likely calling _mesa_resize_framebuffer().
 607  *
 608  * GL_MESA_resize_buffers extension.
 609  *
 610  * When this function is called, we'll ask the window system how large
 611  * the current window is.  If it's a new size, we'll call the driver's
 612  * ResizeBuffers function.  The driver will then resize its color buffers
 613  * as needed, and maybe call the swrast's routine for reallocating
 614  * swrast-managed depth/stencil/accum/etc buffers.
 615  * \note This function should only be called through the GL API, not
 616  * from device drivers (as was done in the past).
 617  */
 618
 619 void _mesa_resizebuffers( GLcontext *ctx )
 620 {
 621    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH( ctx );
 622
 623    if (MESA_VERBOSE & VERBOSE_API)
 624       _mesa_debug(ctx, "glResizeBuffersMESA\n");
 625
 626    if (!ctx->Driver.GetBufferSize) {
 627       return;
 628    }
 629
 630    if (ctx->WinSysDrawBuffer) {
 631       GLuint newWidth, newHeight;
 632       GLframebuffer *buffer = ctx->WinSysDrawBuffer;
 633
 634       assert(buffer->Name == 0);
 635
 636       /* ask device driver for size of output buffer */
 637       ctx->Driver.GetBufferSize( buffer, &newWidth, &newHeight );
 638
 639       /* see if size of device driver's color buffer (window) has changed */
 640       if (buffer->Width != newWidth || buffer->Height != newHeight) {
 641          if (ctx->Driver.ResizeBuffers)
 642             ctx->Driver.ResizeBuffers(ctx, buffer, newWidth, newHeight );
 643       }
 644    }
 645
 646    if (ctx->WinSysReadBuffer
 647        && ctx->WinSysReadBuffer != ctx->WinSysDrawBuffer) {
 648       GLuint newWidth, newHeight;
 649       GLframebuffer *buffer = ctx->WinSysReadBuffer;
 650
 651       assert(buffer->Name == 0);
 652
 653       /* ask device driver for size of read buffer */
 654       ctx->Driver.GetBufferSize( buffer, &newWidth, &newHeight );
 655
 656       /* see if size of device driver's color buffer (window) has changed */
 657       if (buffer->Width != newWidth || buffer->Height != newHeight) {
 658          if (ctx->Driver.ResizeBuffers)
 659             ctx->Driver.ResizeBuffers(ctx, buffer, newWidth, newHeight );
 660       }
 661    }
 662
 663    ctx->NewState |= _NEW_BUFFERS;  /* to update scissor / window bounds */
 664 }
 665
 666
 667 /*
 668  * XXX THIS IS OBSOLETE
 669  */
 670 void GLAPIENTRY
 671 _mesa_ResizeBuffersMESA( void )
 672 {
 673    GET_CURRENT_CONTEXT(ctx);
 674
 675    if (ctx->Extensions.MESA_resize_buffers)
 676       _mesa_resizebuffers( ctx );
 677 }
 678
 679
 680 /*
 681  * XXX move somewhere else someday?
 682  */
 683 void GLAPIENTRY
 684 _mesa_SampleCoverageARB(GLclampf value, GLboolean invert)
 685 {
 686    GET_CURRENT_CONTEXT(ctx);
 687
 688    if (!ctx->Extensions.ARB_multisample) {
 689       _mesa_error(ctx, GL_INVALID_OPERATION, "glSampleCoverageARB");
 690       return;
 691    }
 692
 693    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH( ctx );
 694    ctx->Multisample.SampleCoverageValue = (GLfloat) CLAMP(value, 0.0, 1.0);
 695    ctx->Multisample.SampleCoverageInvert = invert;
 696    ctx->NewState |= _NEW_MULTISAMPLE;
 697 }
 698
 699 #endif /* _HAVE_FULL_GL */
 700
 701
 702
 703 /**
 704  * Define the scissor box.
 705  *
 706  * \param x, y coordinates of the scissor box lower-left corner.
 707  * \param width width of the scissor box.
 708  * \param height height of the scissor box.
 709  *
 710  * \sa glScissor().
 711  *
 712  * Verifies the parameters and updates __GLcontextRec::Scissor. On a
 713  * change flushes the vertices and notifies the driver via
 714  * the dd_function_table::Scissor callback.
 715  */
 716 void
 717 _mesa_set_scissor(GLcontext *ctx,
 718                   GLint x, GLint y, GLsizei width, GLsizei height)
 719 {
 720    if (x == ctx->Scissor.X &&
 721        y == ctx->Scissor.Y &&
 722        width == ctx->Scissor.Width &&
 723        height == ctx->Scissor.Height)
 724       return;
 725
 726    FLUSH_VERTICES(ctx, _NEW_SCISSOR);
 727    ctx->Scissor.X = x;
 728    ctx->Scissor.Y = y;
 729    ctx->Scissor.Width = width;
 730    ctx->Scissor.Height = height;
 731
 732    if (ctx->Driver.Scissor)
 733       ctx->Driver.Scissor( ctx, x, y, width, height );
 734 }
 735
 736
 737 void GLAPIENTRY
 738 _mesa_Scissor( GLint x, GLint y, GLsizei width, GLsizei height )
 739 {
 740    GET_CURRENT_CONTEXT(ctx);
 741    ASSERT_OUTSIDE_BEGIN_END(ctx);
 742
 743    if (width < 0 || height < 0) {
 744       _mesa_error( ctx, GL_INVALID_VALUE, "glScissor" );
 745       return;
 746    }
 747
 748    if (MESA_VERBOSE & VERBOSE_API)
 749       _mesa_debug(ctx, "glScissor %d %d %d %d\n", x, y, width, height);
 750
 751    _mesa_set_scissor(ctx, x, y, width, height);
 752 }
 753
 754
 755
 756 /**********************************************************************/
 757 /** \name Initialization */
 758 /*@{*/
 759
 760 /**
 761  * Initialize the context's scissor state.
 762  * \param ctx  the GL context.
 763  */
 764 void
 765 _mesa_init_scissor(GLcontext *ctx)
 766 {
 767    /* Scissor group */
 768    ctx->Scissor.Enabled = GL_FALSE;
 769    ctx->Scissor.X = 0;
 770    ctx->Scissor.Y = 0;
 771    ctx->Scissor.Width = 0;
 772    ctx->Scissor.Height = 0;
 773 }
 774
 775
 776 /**
 777  * Initialize the context's multisample state.
 778  * \param ctx  the GL context.
 779  */
 780 void
 781 _mesa_init_multisample(GLcontext *ctx)
 782 {
 783    ctx->Multisample.Enabled = GL_FALSE;
 784    ctx->Multisample.SampleAlphaToCoverage = GL_FALSE;
 785    ctx->Multisample.SampleAlphaToOne = GL_FALSE;
 786    ctx->Multisample.SampleCoverage = GL_FALSE;
 787    ctx->Multisample.SampleCoverageValue = 1.0;
 788    ctx->Multisample.SampleCoverageInvert = GL_FALSE;
 789 }
 790
 791 /*@}*/