src/mesa/main/buffers.c

   1 /**
   2  * \file buffers.c
   3  * Frame buffer management.
   4  */
   5
   6 /*
   7  * Mesa 3-D graphics library
   8  * Version:  6.5
   9  *
  10  * Copyright (C) 1999-2005  Brian Paul   All Rights Reserved.
  11  *
  12  * Permission is hereby granted, free of charge, to any person obtaining a
  13  * copy of this software and associated documentation files (the "Software"),
  14  * to deal in the Software without restriction, including without limitation
  15  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  16  * and/or sell copies of the Software, and to permit persons to whom the
  17  * Software is furnished to do so, subject to the following conditions:
  18  *
  19  * The above copyright notice and this permission notice shall be included
  20  * in all copies or substantial portions of the Software.
  21  *
  22  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  23  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  24  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  25  * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
  26  * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  27  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  28  */
  29
  30
  31 #include "glheader.h"
  32 #include "buffers.h"
  33 #include "colormac.h"
  34 #include "context.h"
  35 #include "enums.h"
  36 #include "fbobject.h"
  37 #include "state.h"
  38
  39
  40 #define BAD_MASK ~0u
  41
  42
  43 #if _HAVE_FULL_GL
  44 void GLAPIENTRY
  45 _mesa_ClearIndex( GLfloat c )
  46 {
  47    GET_CURRENT_CONTEXT(ctx);
  48    ASSERT_OUTSIDE_BEGIN_END(ctx);
  49
  50    if (ctx->Color.ClearIndex == (GLuint) c)
  51       return;
  52
  53    FLUSH_VERTICES(ctx, _NEW_COLOR);
  54    ctx->Color.ClearIndex = (GLuint) c;
  55
  56    if (!ctx->Visual.rgbMode && ctx->Driver.ClearIndex) {
  57       /* it's OK to call glClearIndex in RGBA mode but it should be a NOP */
  58       (*ctx->Driver.ClearIndex)( ctx, ctx->Color.ClearIndex );
  59    }
  60 }
  61 #endif
  62
  63
  64 /**
  65  * Specify the clear values for the color buffers.
  66  *
  67  * \param red red color component.
  68  * \param green green color component.
  69  * \param blue blue color component.
  70  * \param alpha alpha component.
  71  *
  72  * \sa glClearColor().
  73  *
  74  * Clamps the parameters and updates gl_colorbuffer_attrib::ClearColor.  On a
  75  * change, flushes the vertices and notifies the driver via the
  76  * dd_function_table::ClearColor callback.
  77  */
  78 void GLAPIENTRY
  79 _mesa_ClearColor( GLclampf red, GLclampf green, GLclampf blue, GLclampf alpha )
  80 {
  81    GLfloat tmp[4];
  82    GET_CURRENT_CONTEXT(ctx);
  83    ASSERT_OUTSIDE_BEGIN_END(ctx);
  84
  85    tmp[0] = CLAMP(red,   0.0F, 1.0F);
  86    tmp[1] = CLAMP(green, 0.0F, 1.0F);
  87    tmp[2] = CLAMP(blue,  0.0F, 1.0F);
  88    tmp[3] = CLAMP(alpha, 0.0F, 1.0F);
  89
  90    if (TEST_EQ_4V(tmp, ctx->Color.ClearColor))
  91       return; /* no change */
  92
  93    FLUSH_VERTICES(ctx, _NEW_COLOR);
  94    COPY_4V(ctx->Color.ClearColor, tmp);
  95
  96    if (ctx->Visual.rgbMode && ctx->Driver.ClearColor) {
  97       /* it's OK to call glClearColor in CI mode but it should be a NOP */
  98       (*ctx->Driver.ClearColor)(ctx, ctx->Color.ClearColor);
  99    }
 100 }
 101
 102
 103 /**
 104  * Clear buffers.
 105  *
 106  * \param mask bit-mask indicating the buffers to be cleared.
 107  *
 108  * Flushes the vertices and verifies the parameter. If __GLcontextRec::NewState
 109  * is set then calls _mesa_update_state() to update gl_frame_buffer::_Xmin,
 110  * etc. If the rasterization mode is set to GL_RENDER then requests the driver
 111  * to clear the buffers, via the dd_function_table::Clear callback.
 112  */
 113 void GLAPIENTRY
 114 _mesa_Clear( GLbitfield mask )
 115 {
 116    GET_CURRENT_CONTEXT(ctx);
 117    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx);
 118
 119    if (MESA_VERBOSE & VERBOSE_API)
 120       _mesa_debug(ctx, "glClear 0x%x\n", mask);
 121
 122    if (mask & ~(GL_COLOR_BUFFER_BIT |
 123                 GL_DEPTH_BUFFER_BIT |
 124                 GL_STENCIL_BUFFER_BIT |
 125                 GL_ACCUM_BUFFER_BIT)) {
 126       /* invalid bit set */
 127       _mesa_error( ctx, GL_INVALID_VALUE, "glClear(0x%x)", mask);
 128       return;
 129    }
 130
 131    if (ctx->NewState) {
 132       _mesa_update_state( ctx );        /* update _Xmin, etc */
 133    }
 134
 135    if (ctx->RenderMode == GL_RENDER) {
 136       const GLint x = ctx->DrawBuffer->_Xmin;
 137       const GLint y = ctx->DrawBuffer->_Ymin;
 138       const GLint height = ctx->DrawBuffer->_Ymax - ctx->DrawBuffer->_Ymin;
 139       const GLint width  = ctx->DrawBuffer->_Xmax - ctx->DrawBuffer->_Xmin;
 140       GLbitfield bufferMask;
 141
 142       /* don't clear depth buffer if depth writing disabled */
 143       if (!ctx->Depth.Mask)
 144          mask &= ~GL_DEPTH_BUFFER_BIT;
 145
 146       /* Build the bitmask to send to device driver's Clear function.
 147        * Note that the GL_COLOR_BUFFER_BIT flag will expand to 0, 1, 2 or 4
 148        * of the BUFFER_BIT_FRONT/BACK_LEFT/RIGHT flags, or one of the
 149        * BUFFER_BIT_COLORn flags.
 150        */
 151       bufferMask = 0;
 152       if (mask & GL_COLOR_BUFFER_BIT) {
 153          bufferMask |= ctx->DrawBuffer->_ColorDrawBufferMask[0];
 154       }
 155
 156       if ((mask & GL_DEPTH_BUFFER_BIT)
 157           && ctx->DrawBuffer->Visual.haveDepthBuffer) {
 158          bufferMask |= BUFFER_BIT_DEPTH;
 159       }
 160
 161       if ((mask & GL_STENCIL_BUFFER_BIT)
 162           && ctx->DrawBuffer->Visual.haveStencilBuffer) {
 163          bufferMask |= BUFFER_BIT_STENCIL;
 164       }
 165
 166       if ((mask & GL_ACCUM_BUFFER_BIT)
 167           && ctx->DrawBuffer->Visual.haveAccumBuffer) {
 168          bufferMask |= BUFFER_BIT_ACCUM;
 169       }
 170
 171       ASSERT(ctx->Driver.Clear);
 172       ctx->Driver.Clear( ctx, bufferMask, (GLboolean) !ctx->Scissor.Enabled,
 173                          x, y, width, height );
 174    }
 175 }
 176
 177
 178
 179 /**
 180  * Return bitmask of BUFFER_BIT_* flags indicating which color buffers are
 181  * available to the rendering context.
 182  * This depends on the framebuffer we're writing to.  For window system
 183  * framebuffers we look at the framebuffer's visual.  But for user-
 184  * create framebuffers we look at the number of supported color attachments.
 185  */
 186 static GLbitfield
 187 supported_buffer_bitmask(const GLcontext *ctx, GLuint framebufferID)
 188 {
 189    GLbitfield mask = 0x0;
 190    GLint i;
 191
 192    if (framebufferID > 0) {
 193       /* A user-created renderbuffer */
 194       ASSERT(ctx->Extensions.EXT_framebuffer_object);
 195       for (i = 0; i < ctx->Const.MaxColorAttachments; i++) {
 196          mask |= (BUFFER_BIT_COLOR0 << i);
 197       }
 198    }
 199    else {
 200       /* A window system renderbuffer */
 201       mask = BUFFER_BIT_FRONT_LEFT; /* always have this */
 202       if (ctx->Visual.stereoMode) {
 203          mask |= BUFFER_BIT_FRONT_RIGHT;
 204          if (ctx->Visual.doubleBufferMode) {
 205             mask |= BUFFER_BIT_BACK_LEFT | BUFFER_BIT_BACK_RIGHT;
 206          }
 207       }
 208       else if (ctx->Visual.doubleBufferMode) {
 209          mask |= BUFFER_BIT_BACK_LEFT;
 210       }
 211
 212       for (i = 0; i < ctx->Visual.numAuxBuffers; i++) {
 213          mask |= (BUFFER_BIT_AUX0 << i);
 214       }
 215    }
 216
 217    return mask;
 218 }
 219
 220
 221 /**
 222  * Helper routine used by glDrawBuffer and glDrawBuffersARB.
 223  * Given a GLenum naming one or more color buffers (such as
 224  * GL_FRONT_AND_BACK), return the corresponding bitmask of BUFFER_BIT_* flags.
 225  */
 226 static GLbitfield
 227 draw_buffer_enum_to_bitmask(GLenum buffer)
 228 {
 229    switch (buffer) {
 230       case GL_NONE:
 231          return 0;
 232       case GL_FRONT:
 233          return BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_FRONT_RIGHT;
 234       case GL_BACK:
 235          return BUFFER_BIT_BACK_LEFT | BUFFER_BIT_BACK_RIGHT;
 236       case GL_RIGHT:
 237          return BUFFER_BIT_FRONT_RIGHT | BUFFER_BIT_BACK_RIGHT;
 238       case GL_FRONT_RIGHT:
 239          return BUFFER_BIT_FRONT_RIGHT;
 240       case GL_BACK_RIGHT:
 241          return BUFFER_BIT_BACK_RIGHT;
 242       case GL_BACK_LEFT:
 243          return BUFFER_BIT_BACK_LEFT;
 244       case GL_FRONT_AND_BACK:
 245          return BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT
 246               | BUFFER_BIT_FRONT_RIGHT | BUFFER_BIT_BACK_RIGHT;
 247       case GL_LEFT:
 248          return BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT;
 249       case GL_FRONT_LEFT:
 250          return BUFFER_BIT_FRONT_LEFT;
 251       case GL_AUX0:
 252          return BUFFER_BIT_AUX0;
 253       case GL_AUX1:
 254          return BUFFER_BIT_AUX1;
 255       case GL_AUX2:
 256          return BUFFER_BIT_AUX2;
 257       case GL_AUX3:
 258          return BUFFER_BIT_AUX3;
 259       case GL_COLOR_ATTACHMENT0_EXT:
 260          return BUFFER_BIT_COLOR0;
 261       case GL_COLOR_ATTACHMENT1_EXT:
 262          return BUFFER_BIT_COLOR1;
 263       case GL_COLOR_ATTACHMENT2_EXT:
 264          return BUFFER_BIT_COLOR2;
 265       case GL_COLOR_ATTACHMENT3_EXT:
 266          return BUFFER_BIT_COLOR3;
 267       default:
 268          /* error */
 269          return BAD_MASK;
 270    }
 271 }
 272
 273
 274 /**
 275  * Helper routine used by glReadBuffer.
 276  * Given a GLenum naming a color buffer, return the index of the corresponding
 277  * renderbuffer (a BUFFER_* value).
 278  * return -1 for an invalid buffer.
 279  */
 280 static GLint
 281 read_buffer_enum_to_index(GLenum buffer)
 282 {
 283    switch (buffer) {
 284       case GL_FRONT:
 285          return BUFFER_FRONT_LEFT;
 286       case GL_BACK:
 287          return BUFFER_BACK_LEFT;
 288       case GL_RIGHT:
 289          return BUFFER_FRONT_RIGHT;
 290       case GL_FRONT_RIGHT:
 291          return BUFFER_FRONT_RIGHT;
 292       case GL_BACK_RIGHT:
 293          return BUFFER_BACK_RIGHT;
 294       case GL_BACK_LEFT:
 295          return BUFFER_BACK_LEFT;
 296       case GL_LEFT:
 297          return BUFFER_FRONT_LEFT;
 298       case GL_FRONT_LEFT:
 299          return BUFFER_FRONT_LEFT;
 300       case GL_AUX0:
 301          return BUFFER_AUX0;
 302       case GL_AUX1:
 303          return BUFFER_AUX1;
 304       case GL_AUX2:
 305          return BUFFER_AUX2;
 306       case GL_AUX3:
 307          return BUFFER_AUX3;
 308       case GL_COLOR_ATTACHMENT0_EXT:
 309          return BUFFER_COLOR0;
 310       case GL_COLOR_ATTACHMENT1_EXT:
 311          return BUFFER_COLOR1;
 312       case GL_COLOR_ATTACHMENT2_EXT:
 313          return BUFFER_COLOR2;
 314       case GL_COLOR_ATTACHMENT3_EXT:
 315          return BUFFER_COLOR3;
 316       default:
 317          /* error */
 318          return -1;
 319    }
 320 }
 321
 322
 323 /**
 324  * Called by glDrawBuffer().
 325  * Specify which renderbuffer(s) to draw into for the first color output.
 326  * <buffer> can name zero, one, two or four renderbuffers!
 327  * \sa _mesa_DrawBuffersARB
 328  *
 329  * \param buffer  buffer token such as GL_LEFT or GL_FRONT_AND_BACK, etc.
 330  */
 331 void GLAPIENTRY
 332 _mesa_DrawBuffer(GLenum buffer)
 333 {
 334    GLuint bufferID;
 335    GLbitfield destMask;
 336    GET_CURRENT_CONTEXT(ctx);
 337    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx); /* too complex... */
 338
 339    if (MESA_VERBOSE & VERBOSE_API) {
 340       _mesa_debug(ctx, "glDrawBuffer %s\n", _mesa_lookup_enum_by_nr(buffer));
 341    }
 342
 343    bufferID = ctx->DrawBuffer->Name;
 344
 345    if (buffer == GL_NONE) {
 346       destMask = 0x0;
 347    }
 348    else {
 349       const GLbitfield supportedMask = supported_buffer_bitmask(ctx, bufferID);
 350       destMask = draw_buffer_enum_to_bitmask(buffer);
 351       if (destMask == BAD_MASK) {
 352          /* totally bogus buffer */
 353          _mesa_error(ctx, GL_INVALID_ENUM, "glDrawBuffer(buffer)");
 354          return;
 355       }
 356       destMask &= supportedMask;
 357       if (destMask == 0x0) {
 358          /* none of the named color buffers exist! */
 359          _mesa_error(ctx, GL_INVALID_OPERATION, "glDrawBuffer(buffer)");
 360          return;
 361       }
 362    }
 363
 364    /* if we get here, there's no error so set new state */
 365    _mesa_drawbuffers(ctx, 1, &buffer, &destMask);
 366 }
 367
 368
 369 /**
 370  * Called by glDrawBuffersARB; specifies the destination color renderbuffers
 371  * for N fragment program color outputs.
 372  * \sa _mesa_DrawBuffer
 373  * \param n  number of outputs
 374  * \param buffers  array [n] of renderbuffer names.  Unlike glDrawBuffer, the
 375  *                 names cannot specify more than one buffer.  For example,
 376  *                 GL_FRONT_AND_BACK is illegal.
 377  */
 378 void GLAPIENTRY
 379 _mesa_DrawBuffersARB(GLsizei n, const GLenum *buffers)
 380 {
 381    GLint output;
 382    GLuint bufferID;
 383    GLbitfield usedBufferMask, supportedMask;
 384    GLbitfield destMask[MAX_DRAW_BUFFERS];
 385    GET_CURRENT_CONTEXT(ctx);
 386    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx);
 387
 388    if (!ctx->Extensions.ARB_draw_buffers) {
 389       _mesa_error(ctx, GL_INVALID_OPERATION, "glDrawBuffersARB");
 390       return;
 391    }
 392    if (n < 1 || n > (GLsizei) ctx->Const.MaxDrawBuffers) {
 393       _mesa_error(ctx, GL_INVALID_VALUE, "glDrawBuffersARB(n)");
 394       return;
 395    }
 396
 397    bufferID = ctx->DrawBuffer->Name;
 398
 399    supportedMask = supported_buffer_bitmask(ctx, bufferID);
 400    usedBufferMask = 0x0;
 401
 402    /* complicated error checking... */
 403    for (output = 0; output < n; output++) {
 404       if (buffers[output] == GL_NONE) {
 405          destMask[output] = 0x0;
 406       }
 407       else {
 408          destMask[output] = draw_buffer_enum_to_bitmask(buffers[output]);
 409          if (destMask[output] == BAD_MASK
 410              || _mesa_bitcount(destMask[output]) > 1) {
 411             _mesa_error(ctx, GL_INVALID_ENUM, "glDrawBuffersARB(buffer)");
 412             return;
 413          }
 414          destMask[output] &= supportedMask;
 415          if (destMask[output] == 0) {
 416             _mesa_error(ctx, GL_INVALID_OPERATION,
 417                         "glDrawBuffersARB(unsupported buffer)");
 418             return;
 419          }
 420          if (destMask[output] & usedBufferMask) {
 421             /* can't specify a dest buffer more than once! */
 422             _mesa_error(ctx, GL_INVALID_OPERATION,
 423                         "glDrawBuffersARB(duplicated buffer)");
 424             return;
 425          }
 426
 427          /* update bitmask */
 428          usedBufferMask |= destMask[output];
 429       }
 430    }
 431
 432    /* OK, if we get here, there were no errors so set the new state */
 433    _mesa_drawbuffers(ctx, n, buffers, destMask);
 434 }
 435
 436
 437 /**
 438  * Set color output state.  Traditionally, there was only one color
 439  * output, but fragment programs can now have several distinct color
 440  * outputs (see GL_ARB_draw_buffers).  This function sets the state
 441  * for one such color output.
 442  * \param ctx  current context
 443  * \param output  which fragment program output
 444  * \param buffer  buffer to write to (like GL_LEFT)
 445  * \param destMask  BUFFER_* bitmask
 446  *                  (like BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT).
 447  */
 448 static void
 449 set_color_output(GLcontext *ctx, GLuint output, GLenum buffer,
 450                  GLbitfield destMask)
 451 {
 452    struct gl_framebuffer *fb = ctx->DrawBuffer;
 453
 454    ASSERT(output < ctx->Const.MaxDrawBuffers);
 455
 456    fb->ColorDrawBuffer[output] = buffer;
 457    fb->_ColorDrawBufferMask[output] = destMask;
 458
 459    if (fb->Name == 0) {
 460       /* Set traditional state var */
 461       ctx->Color.DrawBuffer[output] = buffer;
 462    }
 463
 464    /* not really needed, will be set later */
 465    fb->_NumColorDrawBuffers[output] = 0;
 466 }
 467
 468
 469 /**
 470  * Helper routine used by _mesa_DrawBuffer, _mesa_DrawBuffersARB and
 471  * _mesa_PopAttrib to set drawbuffer state.
 472  * All error checking will have been done prior to calling this function
 473  * so nothing should go wrong at this point.
 474  * \param ctx  current context
 475  * \param n    number of color outputs to set
 476  * \param buffers  array[n] of colorbuffer names, like GL_LEFT.
 477  * \param destMask  array[n] of BUFFER_* bitmasks which correspond to the
 478  *                  colorbuffer names.  (i.e. GL_FRONT_AND_BACK =>
 479  *                  BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT).
 480  */
 481 void
 482 _mesa_drawbuffers(GLcontext *ctx, GLsizei n, const GLenum *buffers,
 483                   const GLbitfield *destMask)
 484 {
 485    GLbitfield mask[MAX_DRAW_BUFFERS];
 486    GLint output;
 487
 488    if (!destMask) {
 489       /* compute destMask values now */
 490       const GLuint bufferID = ctx->DrawBuffer->Name;
 491       const GLbitfield supportedMask = supported_buffer_bitmask(ctx, bufferID);
 492       for (output = 0; output < n; output++) {
 493          mask[output] = draw_buffer_enum_to_bitmask(buffers[output]);
 494          ASSERT(mask[output] != BAD_MASK);
 495          mask[output] &= supportedMask;
 496       }
 497       destMask = mask;
 498    }
 499
 500    for (output = 0; output < n; output++) {
 501       set_color_output(ctx, output, buffers[output], destMask[output]);
 502    }
 503
 504    /* set remaining color outputs to NONE */
 505    for (output = n; output < ctx->Const.MaxDrawBuffers; output++) {
 506       set_color_output(ctx, output, GL_NONE, 0x0);
 507    }
 508
 509    ctx->NewState |= _NEW_COLOR;
 510
 511    /*
 512     * Call device driver function.
 513     */
 514    if (ctx->Driver.DrawBuffers)
 515       ctx->Driver.DrawBuffers(ctx, n, buffers);
 516    else if (ctx->Driver.DrawBuffer)
 517       ctx->Driver.DrawBuffer(ctx, buffers[0]);
 518 }
 519
 520
 521
 522 /**
 523  * Called by glReadBuffer to set the source renderbuffer for reading pixels.
 524  * \param mode color buffer such as GL_FRONT, GL_BACK, etc.
 525  */
 526 void GLAPIENTRY
 527 _mesa_ReadBuffer(GLenum buffer)
 528 {
 529    struct gl_framebuffer *fb;
 530    GLbitfield supportedMask;
 531    GLint srcBuffer;
 532    GLuint bufferID;
 533    GET_CURRENT_CONTEXT(ctx);
 534    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx);
 535
 536    fb = ctx->ReadBuffer;
 537    bufferID = fb->Name;
 538
 539    if (MESA_VERBOSE & VERBOSE_API)
 540       _mesa_debug(ctx, "glReadBuffer %s\n", _mesa_lookup_enum_by_nr(buffer));
 541
 542    if (bufferID > 0 && buffer == GL_NONE) {
 543       /* This is legal for user-created framebuffer objects */
 544       srcBuffer = -1;
 545    }
 546    else {
 547       /* general case / window-system framebuffer */
 548       srcBuffer = read_buffer_enum_to_index(buffer);
 549       if (srcBuffer == -1) {
 550          _mesa_error(ctx, GL_INVALID_ENUM, "glReadBuffer(buffer)");
 551          return;
 552       }
 553       supportedMask = supported_buffer_bitmask(ctx, bufferID);
 554       if (((1 << srcBuffer) & supportedMask) == 0) {
 555          _mesa_error(ctx, GL_INVALID_OPERATION, "glReadBuffer(buffer)");
 556          return;
 557       }
 558    }
 559
 560    if (bufferID == 0) {
 561       ctx->Pixel.ReadBuffer = buffer;
 562    }
 563    fb->ColorReadBuffer = buffer;
 564    fb->_ColorReadBufferIndex = srcBuffer;
 565
 566    ctx->NewState |= _NEW_PIXEL;
 567
 568    /*
 569     * Call device driver function.
 570     */
 571    if (ctx->Driver.ReadBuffer)
 572       (*ctx->Driver.ReadBuffer)(ctx, buffer);
 573 }
 574
 575
 576 #if _HAVE_FULL_GL
 577
 578 /**
 579  * GL_MESA_resize_buffers extension.
 580  *
 581  * When this function is called, we'll ask the window system how large
 582  * the current window is.  If it's a new size, we'll call the driver's
 583  * ResizeBuffers function.  The driver will then resize its color buffers
 584  * as needed, and maybe call the swrast's routine for reallocating
 585  * swrast-managed depth/stencil/accum/etc buffers.
 586  * \note This function should only be called through the GL API, not
 587  * from device drivers (as was done in the past).
 588  */
 589 void GLAPIENTRY
 590 _mesa_ResizeBuffersMESA( void )
 591 {
 592    GET_CURRENT_CONTEXT(ctx);
 593
 594    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH( ctx );
 595
 596    if (MESA_VERBOSE & VERBOSE_API)
 597       _mesa_debug(ctx, "glResizeBuffersMESA\n");
 598
 599    if (ctx->WinSysDrawBuffer) {
 600       GLuint newWidth, newHeight;
 601       GLframebuffer *buffer = ctx->WinSysDrawBuffer;
 602
 603       assert(buffer->Name == 0);
 604
 605       /* ask device driver for size of output buffer */
 606       ctx->Driver.GetBufferSize( buffer, &newWidth, &newHeight );
 607
 608       /* see if size of device driver's color buffer (window) has changed */
 609       if (buffer->Width != newWidth || buffer->Height != newHeight) {
 610          if (ctx->Driver.ResizeBuffers)
 611             ctx->Driver.ResizeBuffers(ctx, buffer, newWidth, newHeight );
 612       }
 613    }
 614
 615    if (ctx->WinSysReadBuffer
 616        && ctx->WinSysReadBuffer != ctx->WinSysDrawBuffer) {
 617       GLuint newWidth, newHeight;
 618       GLframebuffer *buffer = ctx->WinSysReadBuffer;
 619
 620       assert(buffer->Name == 0);
 621
 622       /* ask device driver for size of read buffer */
 623       ctx->Driver.GetBufferSize( buffer, &newWidth, &newHeight );
 624
 625       /* see if size of device driver's color buffer (window) has changed */
 626       if (buffer->Width != newWidth || buffer->Height != newHeight) {
 627          if (ctx->Driver.ResizeBuffers)
 628             ctx->Driver.ResizeBuffers(ctx, buffer, newWidth, newHeight );
 629       }
 630    }
 631
 632    ctx->NewState |= _NEW_BUFFERS;  /* to update scissor / window bounds */
 633 }
 634
 635
 636 /*
 637  * XXX move somewhere else someday?
 638  */
 639 void GLAPIENTRY
 640 _mesa_SampleCoverageARB(GLclampf value, GLboolean invert)
 641 {
 642    GET_CURRENT_CONTEXT(ctx);
 643
 644    if (!ctx->Extensions.ARB_multisample) {
 645       _mesa_error(ctx, GL_INVALID_OPERATION, "glSampleCoverageARB");
 646       return;
 647    }
 648
 649    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH( ctx );
 650    ctx->Multisample.SampleCoverageValue = (GLfloat) CLAMP(value, 0.0, 1.0);
 651    ctx->Multisample.SampleCoverageInvert = invert;
 652    ctx->NewState |= _NEW_MULTISAMPLE;
 653 }
 654
 655 #endif /* _HAVE_FULL_GL */
 656
 657
 658
 659 /**
 660  * Define the scissor box.
 661  *
 662  * \param x, y coordinates of the scissor box lower-left corner.
 663  * \param width width of the scissor box.
 664  * \param height height of the scissor box.
 665  *
 666  * \sa glScissor().
 667  *
 668  * Verifies the parameters and updates __GLcontextRec::Scissor. On a
 669  * change flushes the vertices and notifies the driver via
 670  * the dd_function_table::Scissor callback.
 671  */
 672 void GLAPIENTRY
 673 _mesa_Scissor( GLint x, GLint y, GLsizei width, GLsizei height )
 674 {
 675    GET_CURRENT_CONTEXT(ctx);
 676    ASSERT_OUTSIDE_BEGIN_END(ctx);
 677
 678    if (width < 0 || height < 0) {
 679       _mesa_error( ctx, GL_INVALID_VALUE, "glScissor" );
 680       return;
 681    }
 682
 683    if (MESA_VERBOSE & VERBOSE_API)
 684       _mesa_debug(ctx, "glScissor %d %d %d %d\n", x, y, width, height);
 685
 686    if (x == ctx->Scissor.X &&
 687        y == ctx->Scissor.Y &&
 688        width == ctx->Scissor.Width &&
 689        height == ctx->Scissor.Height)
 690       return;
 691
 692    FLUSH_VERTICES(ctx, _NEW_SCISSOR);
 693    ctx->Scissor.X = x;
 694    ctx->Scissor.Y = y;
 695    ctx->Scissor.Width = width;
 696    ctx->Scissor.Height = height;
 697
 698    if (ctx->Driver.Scissor)
 699       ctx->Driver.Scissor( ctx, x, y, width, height );
 700 }
 701
 702
 703
 704 /**********************************************************************/
 705 /** \name Initialization */
 706 /*@{*/
 707
 708 /**
 709  * Initialize the context's scissor state.
 710  * \param ctx  the GL context.
 711  */
 712 void
 713 _mesa_init_scissor(GLcontext *ctx)
 714 {
 715    /* Scissor group */
 716    ctx->Scissor.Enabled = GL_FALSE;
 717    ctx->Scissor.X = 0;
 718    ctx->Scissor.Y = 0;
 719    ctx->Scissor.Width = 0;
 720    ctx->Scissor.Height = 0;
 721 }
 722
 723
 724 /**
 725  * Initialize the context's multisample state.
 726  * \param ctx  the GL context.
 727  */
 728 void
 729 _mesa_init_multisample(GLcontext *ctx)
 730 {
 731    ctx->Multisample.Enabled = GL_FALSE;
 732    ctx->Multisample.SampleAlphaToCoverage = GL_FALSE;
 733    ctx->Multisample.SampleAlphaToOne = GL_FALSE;
 734    ctx->Multisample.SampleCoverage = GL_FALSE;
 735    ctx->Multisample.SampleCoverageValue = 1.0;
 736    ctx->Multisample.SampleCoverageInvert = GL_FALSE;
 737 }
 738
 739 /*@}*/