src/mesa/main/buffers.c

   1 /*
   2  * Mesa 3-D graphics library
   3  * Version:  6.5.2
   4  *
   5  * Copyright (C) 1999-2006  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->RenderMode == GL_RENDER) {
 144       const GLint x = ctx->DrawBuffer->_Xmin;
 145       const GLint y = ctx->DrawBuffer->_Ymin;
 146       const GLint height = ctx->DrawBuffer->_Ymax - ctx->DrawBuffer->_Ymin;
 147       const GLint width  = ctx->DrawBuffer->_Xmax - ctx->DrawBuffer->_Xmin;
 148       GLbitfield bufferMask;
 149
 150       /* don't clear depth buffer if depth writing disabled */
 151       if (!ctx->Depth.Mask)
 152          mask &= ~GL_DEPTH_BUFFER_BIT;
 153
 154       /* Build the bitmask to send to device driver's Clear function.
 155        * Note that the GL_COLOR_BUFFER_BIT flag will expand to 0, 1, 2 or 4
 156        * of the BUFFER_BIT_FRONT/BACK_LEFT/RIGHT flags, or one of the
 157        * BUFFER_BIT_COLORn flags.
 158        */
 159       bufferMask = 0;
 160       if (mask & GL_COLOR_BUFFER_BIT) {
 161          bufferMask |= ctx->DrawBuffer->_ColorDrawBufferMask[0];
 162       }
 163
 164       if ((mask & GL_DEPTH_BUFFER_BIT)
 165           && ctx->DrawBuffer->Visual.haveDepthBuffer) {
 166          bufferMask |= BUFFER_BIT_DEPTH;
 167       }
 168
 169       if ((mask & GL_STENCIL_BUFFER_BIT)
 170           && ctx->DrawBuffer->Visual.haveStencilBuffer) {
 171          bufferMask |= BUFFER_BIT_STENCIL;
 172       }
 173
 174       if ((mask & GL_ACCUM_BUFFER_BIT)
 175           && ctx->DrawBuffer->Visual.haveAccumBuffer) {
 176          bufferMask |= BUFFER_BIT_ACCUM;
 177       }
 178
 179       ASSERT(ctx->Driver.Clear);
 180       ctx->Driver.Clear( ctx, bufferMask, (GLboolean) !ctx->Scissor.Enabled,
 181                          x, y, width, height );
 182    }
 183 }
 184
 185
 186
 187 /**
 188  * Return bitmask of BUFFER_BIT_* flags indicating which color buffers are
 189  * available to the rendering context.
 190  * This depends on the framebuffer we're writing to.  For window system
 191  * framebuffers we look at the framebuffer's visual.  But for user-
 192  * create framebuffers we look at the number of supported color attachments.
 193  */
 194 static GLbitfield
 195 supported_buffer_bitmask(const GLcontext *ctx, GLuint framebufferID)
 196 {
 197    GLbitfield mask = 0x0;
 198
 199    if (framebufferID > 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 renderbuffer */
 209       GLint i;
 210       mask = BUFFER_BIT_FRONT_LEFT; /* always have this */
 211       if (ctx->Visual.stereoMode) {
 212          mask |= BUFFER_BIT_FRONT_RIGHT;
 213          if (ctx->Visual.doubleBufferMode) {
 214             mask |= BUFFER_BIT_BACK_LEFT | BUFFER_BIT_BACK_RIGHT;
 215          }
 216       }
 217       else if (ctx->Visual.doubleBufferMode) {
 218          mask |= BUFFER_BIT_BACK_LEFT;
 219       }
 220
 221       for (i = 0; i < ctx->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    GLuint bufferID;
 344    GLbitfield destMask;
 345    GET_CURRENT_CONTEXT(ctx);
 346    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx); /* too complex... */
 347
 348    if (MESA_VERBOSE & VERBOSE_API) {
 349       _mesa_debug(ctx, "glDrawBuffer %s\n", _mesa_lookup_enum_by_nr(buffer));
 350    }
 351
 352    bufferID = ctx->DrawBuffer->Name;
 353
 354    if (buffer == GL_NONE) {
 355       destMask = 0x0;
 356    }
 357    else {
 358       const GLbitfield supportedMask = supported_buffer_bitmask(ctx, bufferID);
 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
 378 /**
 379  * Called by glDrawBuffersARB; specifies the destination color renderbuffers
 380  * for N fragment program color outputs.
 381  * \sa _mesa_DrawBuffer
 382  * \param n  number of outputs
 383  * \param buffers  array [n] of renderbuffer names.  Unlike glDrawBuffer, the
 384  *                 names cannot specify more than one buffer.  For example,
 385  *                 GL_FRONT_AND_BACK is illegal.
 386  */
 387 void GLAPIENTRY
 388 _mesa_DrawBuffersARB(GLsizei n, const GLenum *buffers)
 389 {
 390    GLint output;
 391    GLuint bufferID;
 392    GLbitfield usedBufferMask, supportedMask;
 393    GLbitfield destMask[MAX_DRAW_BUFFERS];
 394    GET_CURRENT_CONTEXT(ctx);
 395    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx);
 396
 397    if (!ctx->Extensions.ARB_draw_buffers) {
 398       _mesa_error(ctx, GL_INVALID_OPERATION, "glDrawBuffersARB");
 399       return;
 400    }
 401    if (n < 1 || n > (GLsizei) ctx->Const.MaxDrawBuffers) {
 402       _mesa_error(ctx, GL_INVALID_VALUE, "glDrawBuffersARB(n)");
 403       return;
 404    }
 405
 406    bufferID = ctx->DrawBuffer->Name;
 407
 408    supportedMask = supported_buffer_bitmask(ctx, bufferID);
 409    usedBufferMask = 0x0;
 410
 411    /* complicated error checking... */
 412    for (output = 0; output < n; output++) {
 413       if (buffers[output] == GL_NONE) {
 414          destMask[output] = 0x0;
 415       }
 416       else {
 417          destMask[output] = draw_buffer_enum_to_bitmask(buffers[output]);
 418          if (destMask[output] == BAD_MASK
 419              || _mesa_bitcount(destMask[output]) > 1) {
 420             _mesa_error(ctx, GL_INVALID_ENUM, "glDrawBuffersARB(buffer)");
 421             return;
 422          }
 423          destMask[output] &= supportedMask;
 424          if (destMask[output] == 0) {
 425             _mesa_error(ctx, GL_INVALID_OPERATION,
 426                         "glDrawBuffersARB(unsupported buffer)");
 427             return;
 428          }
 429          if (destMask[output] & usedBufferMask) {
 430             /* can't specify a dest buffer more than once! */
 431             _mesa_error(ctx, GL_INVALID_OPERATION,
 432                         "glDrawBuffersARB(duplicated buffer)");
 433             return;
 434          }
 435
 436          /* update bitmask */
 437          usedBufferMask |= destMask[output];
 438       }
 439    }
 440
 441    /* OK, if we get here, there were no errors so set the new state */
 442    _mesa_drawbuffers(ctx, n, buffers, destMask);
 443 }
 444
 445
 446 /**
 447  * Set color output state.  Traditionally, there was only one color
 448  * output, but fragment programs can now have several distinct color
 449  * outputs (see GL_ARB_draw_buffers).  This function sets the state
 450  * for one such color output.
 451  * \param ctx  current context
 452  * \param output  which fragment program output
 453  * \param buffer  buffer to write to (like GL_LEFT)
 454  * \param destMask  BUFFER_* bitmask
 455  *                  (like BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT).
 456  */
 457 static void
 458 set_color_output(GLcontext *ctx, GLuint output, GLenum buffer,
 459                  GLbitfield destMask)
 460 {
 461    struct gl_framebuffer *fb = ctx->DrawBuffer;
 462
 463    ASSERT(output < ctx->Const.MaxDrawBuffers);
 464
 465    /* Set per-FBO state */
 466    fb->ColorDrawBuffer[output] = buffer;
 467    fb->_ColorDrawBufferMask[output] = destMask;
 468    /* not really needed, will be set later */
 469    fb->_NumColorDrawBuffers[output] = 0;
 470
 471    /* Set traditional state var */
 472    ctx->Color.DrawBuffer[output] = buffer;
 473 }
 474
 475
 476 /**
 477  * Helper routine used by _mesa_DrawBuffer, _mesa_DrawBuffersARB and
 478  * _mesa_PopAttrib to set drawbuffer state.
 479  * All error checking will have been done prior to calling this function
 480  * so nothing should go wrong at this point.
 481  * \param ctx  current context
 482  * \param n    number of color outputs to set
 483  * \param buffers  array[n] of colorbuffer names, like GL_LEFT.
 484  * \param destMask  array[n] of BUFFER_* bitmasks which correspond to the
 485  *                  colorbuffer names.  (i.e. GL_FRONT_AND_BACK =>
 486  *                  BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT).
 487  */
 488 void
 489 _mesa_drawbuffers(GLcontext *ctx, GLuint n, const GLenum *buffers,
 490                   const GLbitfield *destMask)
 491 {
 492    GLbitfield mask[MAX_DRAW_BUFFERS];
 493    GLuint output;
 494
 495    if (!destMask) {
 496       /* compute destMask values now */
 497       const GLuint bufferID = ctx->DrawBuffer->Name;
 498       const GLbitfield supportedMask = supported_buffer_bitmask(ctx, bufferID);
 499       for (output = 0; output < n; output++) {
 500          mask[output] = draw_buffer_enum_to_bitmask(buffers[output]);
 501          ASSERT(mask[output] != BAD_MASK);
 502          mask[output] &= supportedMask;
 503       }
 504       destMask = mask;
 505    }
 506
 507    for (output = 0; output < n; output++) {
 508       set_color_output(ctx, output, buffers[output], destMask[output]);
 509    }
 510
 511    /* set remaining color outputs to NONE */
 512    for (output = n; output < ctx->Const.MaxDrawBuffers; output++) {
 513       set_color_output(ctx, output, GL_NONE, 0x0);
 514    }
 515
 516    ctx->NewState |= _NEW_COLOR;
 517
 518    /*
 519     * Call device driver function.
 520     */
 521    if (ctx->Driver.DrawBuffers)
 522       ctx->Driver.DrawBuffers(ctx, n, buffers);
 523    else if (ctx->Driver.DrawBuffer)
 524       ctx->Driver.DrawBuffer(ctx, buffers[0]);
 525 }
 526
 527
 528
 529 /**
 530  * Called by glReadBuffer to set the source renderbuffer for reading pixels.
 531  * \param mode color buffer such as GL_FRONT, GL_BACK, etc.
 532  */
 533 void GLAPIENTRY
 534 _mesa_ReadBuffer(GLenum buffer)
 535 {
 536    struct gl_framebuffer *fb;
 537    GLbitfield supportedMask;
 538    GLint srcBuffer;
 539    GLuint bufferID;
 540    GET_CURRENT_CONTEXT(ctx);
 541    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx);
 542
 543    fb = ctx->ReadBuffer;
 544    bufferID = fb->Name;
 545
 546    if (MESA_VERBOSE & VERBOSE_API)
 547       _mesa_debug(ctx, "glReadBuffer %s\n", _mesa_lookup_enum_by_nr(buffer));
 548
 549    if (bufferID > 0 && buffer == GL_NONE) {
 550       /* This is legal for user-created framebuffer objects */
 551       srcBuffer = -1;
 552    }
 553    else {
 554       /* general case / window-system framebuffer */
 555       srcBuffer = read_buffer_enum_to_index(buffer);
 556       if (srcBuffer == -1) {
 557          _mesa_error(ctx, GL_INVALID_ENUM, "glReadBuffer(buffer=0x%x)", buffer);
 558          return;
 559       }
 560       supportedMask = supported_buffer_bitmask(ctx, bufferID);
 561       if (((1 << srcBuffer) & supportedMask) == 0) {
 562          _mesa_error(ctx, GL_INVALID_OPERATION, "glReadBuffer(buffer=0x%x)", buffer);
 563          return;
 564       }
 565    }
 566
 567    if (bufferID == 0) {
 568       ctx->Pixel.ReadBuffer = buffer;
 569    }
 570    fb->ColorReadBuffer = buffer;
 571    fb->_ColorReadBufferIndex = srcBuffer;
 572
 573    ctx->NewState |= _NEW_PIXEL;
 574
 575    /*
 576     * Call device driver function.
 577     */
 578    if (ctx->Driver.ReadBuffer)
 579       (*ctx->Driver.ReadBuffer)(ctx, buffer);
 580 }
 581
 582
 583 #if _HAVE_FULL_GL
 584
 585 /**
 586  * XXX THIS IS OBSOLETE - drivers should take care of detecting window
 587  * size changes and act accordingly, likely calling _mesa_resize_framebuffer().
 588  *
 589  * GL_MESA_resize_buffers extension.
 590  *
 591  * When this function is called, we'll ask the window system how large
 592  * the current window is.  If it's a new size, we'll call the driver's
 593  * ResizeBuffers function.  The driver will then resize its color buffers
 594  * as needed, and maybe call the swrast's routine for reallocating
 595  * swrast-managed depth/stencil/accum/etc buffers.
 596  * \note This function should only be called through the GL API, not
 597  * from device drivers (as was done in the past).
 598  */
 599
 600 void _mesa_resizebuffers( GLcontext *ctx )
 601 {
 602    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH( ctx );
 603
 604    if (MESA_VERBOSE & VERBOSE_API)
 605       _mesa_debug(ctx, "glResizeBuffersMESA\n");
 606
 607    if (!ctx->Driver.GetBufferSize) {
 608       return;
 609    }
 610
 611    if (ctx->WinSysDrawBuffer) {
 612       GLuint newWidth, newHeight;
 613       GLframebuffer *buffer = ctx->WinSysDrawBuffer;
 614
 615       assert(buffer->Name == 0);
 616
 617       /* ask device driver for size of output buffer */
 618       ctx->Driver.GetBufferSize( buffer, &newWidth, &newHeight );
 619
 620       /* see if size of device driver's color buffer (window) has changed */
 621       if (buffer->Width != newWidth || buffer->Height != newHeight) {
 622          if (ctx->Driver.ResizeBuffers)
 623             ctx->Driver.ResizeBuffers(ctx, buffer, newWidth, newHeight );
 624       }
 625    }
 626
 627    if (ctx->WinSysReadBuffer
 628        && ctx->WinSysReadBuffer != ctx->WinSysDrawBuffer) {
 629       GLuint newWidth, newHeight;
 630       GLframebuffer *buffer = ctx->WinSysReadBuffer;
 631
 632       assert(buffer->Name == 0);
 633
 634       /* ask device driver for size of read buffer */
 635       ctx->Driver.GetBufferSize( buffer, &newWidth, &newHeight );
 636
 637       /* see if size of device driver's color buffer (window) has changed */
 638       if (buffer->Width != newWidth || buffer->Height != newHeight) {
 639          if (ctx->Driver.ResizeBuffers)
 640             ctx->Driver.ResizeBuffers(ctx, buffer, newWidth, newHeight );
 641       }
 642    }
 643
 644    ctx->NewState |= _NEW_BUFFERS;  /* to update scissor / window bounds */
 645 }
 646
 647
 648 /*
 649  * XXX THIS IS OBSOLETE
 650  */
 651 void GLAPIENTRY
 652 _mesa_ResizeBuffersMESA( void )
 653 {
 654    GET_CURRENT_CONTEXT(ctx);
 655
 656    _mesa_resizebuffers( ctx );
 657 }
 658
 659
 660 /*
 661  * XXX move somewhere else someday?
 662  */
 663 void GLAPIENTRY
 664 _mesa_SampleCoverageARB(GLclampf value, GLboolean invert)
 665 {
 666    GET_CURRENT_CONTEXT(ctx);
 667
 668    if (!ctx->Extensions.ARB_multisample) {
 669       _mesa_error(ctx, GL_INVALID_OPERATION, "glSampleCoverageARB");
 670       return;
 671    }
 672
 673    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH( ctx );
 674    ctx->Multisample.SampleCoverageValue = (GLfloat) CLAMP(value, 0.0, 1.0);
 675    ctx->Multisample.SampleCoverageInvert = invert;
 676    ctx->NewState |= _NEW_MULTISAMPLE;
 677 }
 678
 679 #endif /* _HAVE_FULL_GL */
 680
 681
 682
 683 /**
 684  * Define the scissor box.
 685  *
 686  * \param x, y coordinates of the scissor box lower-left corner.
 687  * \param width width of the scissor box.
 688  * \param height height of the scissor box.
 689  *
 690  * \sa glScissor().
 691  *
 692  * Verifies the parameters and updates __GLcontextRec::Scissor. On a
 693  * change flushes the vertices and notifies the driver via
 694  * the dd_function_table::Scissor callback.
 695  */
 696 void
 697 _mesa_set_scissor(GLcontext *ctx,
 698                   GLint x, GLint y, GLsizei width, GLsizei height)
 699 {
 700    if (x == ctx->Scissor.X &&
 701        y == ctx->Scissor.Y &&
 702        width == ctx->Scissor.Width &&
 703        height == ctx->Scissor.Height)
 704       return;
 705
 706    FLUSH_VERTICES(ctx, _NEW_SCISSOR);
 707    ctx->Scissor.X = x;
 708    ctx->Scissor.Y = y;
 709    ctx->Scissor.Width = width;
 710    ctx->Scissor.Height = height;
 711
 712    if (ctx->Driver.Scissor)
 713       ctx->Driver.Scissor( ctx, x, y, width, height );
 714 }
 715
 716
 717 void GLAPIENTRY
 718 _mesa_Scissor( GLint x, GLint y, GLsizei width, GLsizei height )
 719 {
 720    GET_CURRENT_CONTEXT(ctx);
 721    ASSERT_OUTSIDE_BEGIN_END(ctx);
 722
 723    if (width < 0 || height < 0) {
 724       _mesa_error( ctx, GL_INVALID_VALUE, "glScissor" );
 725       return;
 726    }
 727
 728    if (MESA_VERBOSE & VERBOSE_API)
 729       _mesa_debug(ctx, "glScissor %d %d %d %d\n", x, y, width, height);
 730
 731    _mesa_set_scissor(ctx, x, y, width, height);
 732 }
 733
 734
 735
 736 /**********************************************************************/
 737 /** \name Initialization */
 738 /*@{*/
 739
 740 /**
 741  * Initialize the context's scissor state.
 742  * \param ctx  the GL context.
 743  */
 744 void
 745 _mesa_init_scissor(GLcontext *ctx)
 746 {
 747    /* Scissor group */
 748    ctx->Scissor.Enabled = GL_FALSE;
 749    ctx->Scissor.X = 0;
 750    ctx->Scissor.Y = 0;
 751    ctx->Scissor.Width = 0;
 752    ctx->Scissor.Height = 0;
 753 }
 754
 755
 756 /**
 757  * Initialize the context's multisample state.
 758  * \param ctx  the GL context.
 759  */
 760 void
 761 _mesa_init_multisample(GLcontext *ctx)
 762 {
 763    ctx->Multisample.Enabled = GL_FALSE;
 764    ctx->Multisample.SampleAlphaToCoverage = GL_FALSE;
 765    ctx->Multisample.SampleAlphaToOne = GL_FALSE;
 766    ctx->Multisample.SampleCoverage = GL_FALSE;
 767    ctx->Multisample.SampleCoverageValue = 1.0;
 768    ctx->Multisample.SampleCoverageInvert = GL_FALSE;
 769 }
 770
 771 /*@}*/