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) 1999-2006  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->DrawBuffer->_Status != GL_FRAMEBUFFER_COMPLETE_EXT) {
 136       _mesa_error(ctx, GL_INVALID_FRAMEBUFFER_OPERATION_EXT,
 137                   "glClear(incomplete framebuffer)");
 138       return;
 139    }
 140
 141    if (ctx->RenderMode == GL_RENDER) {
 142       const GLint x = ctx->DrawBuffer->_Xmin;
 143       const GLint y = ctx->DrawBuffer->_Ymin;
 144       const GLint height = ctx->DrawBuffer->_Ymax - ctx->DrawBuffer->_Ymin;
 145       const GLint width  = ctx->DrawBuffer->_Xmax - ctx->DrawBuffer->_Xmin;
 146       GLbitfield bufferMask;
 147
 148       /* don't clear depth buffer if depth writing disabled */
 149       if (!ctx->Depth.Mask)
 150          mask &= ~GL_DEPTH_BUFFER_BIT;
 151
 152       /* Build the bitmask to send to device driver's Clear function.
 153        * Note that the GL_COLOR_BUFFER_BIT flag will expand to 0, 1, 2 or 4
 154        * of the BUFFER_BIT_FRONT/BACK_LEFT/RIGHT flags, or one of the
 155        * BUFFER_BIT_COLORn flags.
 156        */
 157       bufferMask = 0;
 158       if (mask & GL_COLOR_BUFFER_BIT) {
 159          bufferMask |= ctx->DrawBuffer->_ColorDrawBufferMask[0];
 160       }
 161
 162       if ((mask & GL_DEPTH_BUFFER_BIT)
 163           && ctx->DrawBuffer->Visual.haveDepthBuffer) {
 164          bufferMask |= BUFFER_BIT_DEPTH;
 165       }
 166
 167       if ((mask & GL_STENCIL_BUFFER_BIT)
 168           && ctx->DrawBuffer->Visual.haveStencilBuffer) {
 169          bufferMask |= BUFFER_BIT_STENCIL;
 170       }
 171
 172       if ((mask & GL_ACCUM_BUFFER_BIT)
 173           && ctx->DrawBuffer->Visual.haveAccumBuffer) {
 174          bufferMask |= BUFFER_BIT_ACCUM;
 175       }
 176
 177       ASSERT(ctx->Driver.Clear);
 178       ctx->Driver.Clear( ctx, bufferMask, (GLboolean) !ctx->Scissor.Enabled,
 179                          x, y, width, height );
 180    }
 181 }
 182
 183
 184
 185 /**
 186  * Return bitmask of BUFFER_BIT_* flags indicating which color buffers are
 187  * available to the rendering context.
 188  * This depends on the framebuffer we're writing to.  For window system
 189  * framebuffers we look at the framebuffer's visual.  But for user-
 190  * create framebuffers we look at the number of supported color attachments.
 191  */
 192 static GLbitfield
 193 supported_buffer_bitmask(const GLcontext *ctx, GLuint framebufferID)
 194 {
 195    GLbitfield mask = 0x0;
 196
 197    if (framebufferID > 0) {
 198       /* A user-created renderbuffer */
 199       GLuint i;
 200       ASSERT(ctx->Extensions.EXT_framebuffer_object);
 201       for (i = 0; i < ctx->Const.MaxColorAttachments; i++) {
 202          mask |= (BUFFER_BIT_COLOR0 << i);
 203       }
 204    }
 205    else {
 206       /* A window system renderbuffer */
 207       GLint i;
 208       mask = BUFFER_BIT_FRONT_LEFT; /* always have this */
 209       if (ctx->Visual.stereoMode) {
 210          mask |= BUFFER_BIT_FRONT_RIGHT;
 211          if (ctx->Visual.doubleBufferMode) {
 212             mask |= BUFFER_BIT_BACK_LEFT | BUFFER_BIT_BACK_RIGHT;
 213          }
 214       }
 215       else if (ctx->Visual.doubleBufferMode) {
 216          mask |= BUFFER_BIT_BACK_LEFT;
 217       }
 218
 219       for (i = 0; i < ctx->Visual.numAuxBuffers; i++) {
 220          mask |= (BUFFER_BIT_AUX0 << i);
 221       }
 222    }
 223
 224    return mask;
 225 }
 226
 227
 228 /**
 229  * Helper routine used by glDrawBuffer and glDrawBuffersARB.
 230  * Given a GLenum naming one or more color buffers (such as
 231  * GL_FRONT_AND_BACK), return the corresponding bitmask of BUFFER_BIT_* flags.
 232  */
 233 static GLbitfield
 234 draw_buffer_enum_to_bitmask(GLenum buffer)
 235 {
 236    switch (buffer) {
 237       case GL_NONE:
 238          return 0;
 239       case GL_FRONT:
 240          return BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_FRONT_RIGHT;
 241       case GL_BACK:
 242          return BUFFER_BIT_BACK_LEFT | BUFFER_BIT_BACK_RIGHT;
 243       case GL_RIGHT:
 244          return BUFFER_BIT_FRONT_RIGHT | BUFFER_BIT_BACK_RIGHT;
 245       case GL_FRONT_RIGHT:
 246          return BUFFER_BIT_FRONT_RIGHT;
 247       case GL_BACK_RIGHT:
 248          return BUFFER_BIT_BACK_RIGHT;
 249       case GL_BACK_LEFT:
 250          return BUFFER_BIT_BACK_LEFT;
 251       case GL_FRONT_AND_BACK:
 252          return BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT
 253               | BUFFER_BIT_FRONT_RIGHT | BUFFER_BIT_BACK_RIGHT;
 254       case GL_LEFT:
 255          return BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT;
 256       case GL_FRONT_LEFT:
 257          return BUFFER_BIT_FRONT_LEFT;
 258       case GL_AUX0:
 259          return BUFFER_BIT_AUX0;
 260       case GL_AUX1:
 261          return BUFFER_BIT_AUX1;
 262       case GL_AUX2:
 263          return BUFFER_BIT_AUX2;
 264       case GL_AUX3:
 265          return BUFFER_BIT_AUX3;
 266       case GL_COLOR_ATTACHMENT0_EXT:
 267          return BUFFER_BIT_COLOR0;
 268       case GL_COLOR_ATTACHMENT1_EXT:
 269          return BUFFER_BIT_COLOR1;
 270       case GL_COLOR_ATTACHMENT2_EXT:
 271          return BUFFER_BIT_COLOR2;
 272       case GL_COLOR_ATTACHMENT3_EXT:
 273          return BUFFER_BIT_COLOR3;
 274       default:
 275          /* error */
 276          return BAD_MASK;
 277    }
 278 }
 279
 280
 281 /**
 282  * Helper routine used by glReadBuffer.
 283  * Given a GLenum naming a color buffer, return the index of the corresponding
 284  * renderbuffer (a BUFFER_* value).
 285  * return -1 for an invalid buffer.
 286  */
 287 static GLint
 288 read_buffer_enum_to_index(GLenum buffer)
 289 {
 290    switch (buffer) {
 291       case GL_FRONT:
 292          return BUFFER_FRONT_LEFT;
 293       case GL_BACK:
 294          return BUFFER_BACK_LEFT;
 295       case GL_RIGHT:
 296          return BUFFER_FRONT_RIGHT;
 297       case GL_FRONT_RIGHT:
 298          return BUFFER_FRONT_RIGHT;
 299       case GL_BACK_RIGHT:
 300          return BUFFER_BACK_RIGHT;
 301       case GL_BACK_LEFT:
 302          return BUFFER_BACK_LEFT;
 303       case GL_LEFT:
 304          return BUFFER_FRONT_LEFT;
 305       case GL_FRONT_LEFT:
 306          return BUFFER_FRONT_LEFT;
 307       case GL_AUX0:
 308          return BUFFER_AUX0;
 309       case GL_AUX1:
 310          return BUFFER_AUX1;
 311       case GL_AUX2:
 312          return BUFFER_AUX2;
 313       case GL_AUX3:
 314          return BUFFER_AUX3;
 315       case GL_COLOR_ATTACHMENT0_EXT:
 316          return BUFFER_COLOR0;
 317       case GL_COLOR_ATTACHMENT1_EXT:
 318          return BUFFER_COLOR1;
 319       case GL_COLOR_ATTACHMENT2_EXT:
 320          return BUFFER_COLOR2;
 321       case GL_COLOR_ATTACHMENT3_EXT:
 322          return BUFFER_COLOR3;
 323       default:
 324          /* error */
 325          return -1;
 326    }
 327 }
 328
 329
 330 /**
 331  * Called by glDrawBuffer().
 332  * Specify which renderbuffer(s) to draw into for the first color output.
 333  * <buffer> can name zero, one, two or four renderbuffers!
 334  * \sa _mesa_DrawBuffersARB
 335  *
 336  * \param buffer  buffer token such as GL_LEFT or GL_FRONT_AND_BACK, etc.
 337  */
 338 void GLAPIENTRY
 339 _mesa_DrawBuffer(GLenum buffer)
 340 {
 341    GLuint bufferID;
 342    GLbitfield destMask;
 343    GET_CURRENT_CONTEXT(ctx);
 344    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx); /* too complex... */
 345
 346    if (MESA_VERBOSE & VERBOSE_API) {
 347       _mesa_debug(ctx, "glDrawBuffer %s\n", _mesa_lookup_enum_by_nr(buffer));
 348    }
 349
 350    bufferID = ctx->DrawBuffer->Name;
 351
 352    if (buffer == GL_NONE) {
 353       destMask = 0x0;
 354    }
 355    else {
 356       const GLbitfield supportedMask = supported_buffer_bitmask(ctx, bufferID);
 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
 376 /**
 377  * Called by glDrawBuffersARB; specifies the destination color renderbuffers
 378  * for N fragment program color outputs.
 379  * \sa _mesa_DrawBuffer
 380  * \param n  number of outputs
 381  * \param buffers  array [n] of renderbuffer names.  Unlike glDrawBuffer, the
 382  *                 names cannot specify more than one buffer.  For example,
 383  *                 GL_FRONT_AND_BACK is illegal.
 384  */
 385 void GLAPIENTRY
 386 _mesa_DrawBuffersARB(GLsizei n, const GLenum *buffers)
 387 {
 388    GLint output;
 389    GLuint bufferID;
 390    GLbitfield usedBufferMask, supportedMask;
 391    GLbitfield destMask[MAX_DRAW_BUFFERS];
 392    GET_CURRENT_CONTEXT(ctx);
 393    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx);
 394
 395    if (!ctx->Extensions.ARB_draw_buffers) {
 396       _mesa_error(ctx, GL_INVALID_OPERATION, "glDrawBuffersARB");
 397       return;
 398    }
 399    if (n < 1 || n > (GLsizei) ctx->Const.MaxDrawBuffers) {
 400       _mesa_error(ctx, GL_INVALID_VALUE, "glDrawBuffersARB(n)");
 401       return;
 402    }
 403
 404    bufferID = ctx->DrawBuffer->Name;
 405
 406    supportedMask = supported_buffer_bitmask(ctx, bufferID);
 407    usedBufferMask = 0x0;
 408
 409    /* complicated error checking... */
 410    for (output = 0; output < n; output++) {
 411       if (buffers[output] == GL_NONE) {
 412          destMask[output] = 0x0;
 413       }
 414       else {
 415          destMask[output] = draw_buffer_enum_to_bitmask(buffers[output]);
 416          if (destMask[output] == BAD_MASK
 417              || _mesa_bitcount(destMask[output]) > 1) {
 418             _mesa_error(ctx, GL_INVALID_ENUM, "glDrawBuffersARB(buffer)");
 419             return;
 420          }
 421          destMask[output] &= supportedMask;
 422          if (destMask[output] == 0) {
 423             _mesa_error(ctx, GL_INVALID_OPERATION,
 424                         "glDrawBuffersARB(unsupported buffer)");
 425             return;
 426          }
 427          if (destMask[output] & usedBufferMask) {
 428             /* can't specify a dest buffer more than once! */
 429             _mesa_error(ctx, GL_INVALID_OPERATION,
 430                         "glDrawBuffersARB(duplicated buffer)");
 431             return;
 432          }
 433
 434          /* update bitmask */
 435          usedBufferMask |= destMask[output];
 436       }
 437    }
 438
 439    /* OK, if we get here, there were no errors so set the new state */
 440    _mesa_drawbuffers(ctx, n, buffers, destMask);
 441 }
 442
 443
 444 /**
 445  * Set color output state.  Traditionally, there was only one color
 446  * output, but fragment programs can now have several distinct color
 447  * outputs (see GL_ARB_draw_buffers).  This function sets the state
 448  * for one such color output.
 449  * \param ctx  current context
 450  * \param output  which fragment program output
 451  * \param buffer  buffer to write to (like GL_LEFT)
 452  * \param destMask  BUFFER_* bitmask
 453  *                  (like BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT).
 454  */
 455 static void
 456 set_color_output(GLcontext *ctx, GLuint output, GLenum buffer,
 457                  GLbitfield destMask)
 458 {
 459    struct gl_framebuffer *fb = ctx->DrawBuffer;
 460
 461    ASSERT(output < ctx->Const.MaxDrawBuffers);
 462
 463    /* Set per-FBO state */
 464    fb->ColorDrawBuffer[output] = buffer;
 465    fb->_ColorDrawBufferMask[output] = destMask;
 466    /* not really needed, will be set later */
 467    fb->_NumColorDrawBuffers[output] = 0;
 468
 469    /* Set traditional state var */
 470    ctx->Color.DrawBuffer[output] = buffer;
 471 }
 472
 473
 474 /**
 475  * Helper routine used by _mesa_DrawBuffer, _mesa_DrawBuffersARB and
 476  * _mesa_PopAttrib to set drawbuffer state.
 477  * All error checking will have been done prior to calling this function
 478  * so nothing should go wrong at this point.
 479  * \param ctx  current context
 480  * \param n    number of color outputs to set
 481  * \param buffers  array[n] of colorbuffer names, like GL_LEFT.
 482  * \param destMask  array[n] of BUFFER_* bitmasks which correspond to the
 483  *                  colorbuffer names.  (i.e. GL_FRONT_AND_BACK =>
 484  *                  BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT).
 485  */
 486 void
 487 _mesa_drawbuffers(GLcontext *ctx, GLuint n, const GLenum *buffers,
 488                   const GLbitfield *destMask)
 489 {
 490    GLbitfield mask[MAX_DRAW_BUFFERS];
 491    GLuint output;
 492
 493    if (!destMask) {
 494       /* compute destMask values now */
 495       const GLuint bufferID = ctx->DrawBuffer->Name;
 496       const GLbitfield supportedMask = supported_buffer_bitmask(ctx, bufferID);
 497       for (output = 0; output < n; output++) {
 498          mask[output] = draw_buffer_enum_to_bitmask(buffers[output]);
 499          ASSERT(mask[output] != BAD_MASK);
 500          mask[output] &= supportedMask;
 501       }
 502       destMask = mask;
 503    }
 504
 505    for (output = 0; output < n; output++) {
 506       set_color_output(ctx, output, buffers[output], destMask[output]);
 507    }
 508
 509    /* set remaining color outputs to NONE */
 510    for (output = n; output < ctx->Const.MaxDrawBuffers; output++) {
 511       set_color_output(ctx, output, GL_NONE, 0x0);
 512    }
 513
 514    ctx->NewState |= _NEW_COLOR;
 515
 516    /*
 517     * Call device driver function.
 518     */
 519    if (ctx->Driver.DrawBuffers)
 520       ctx->Driver.DrawBuffers(ctx, n, buffers);
 521    else if (ctx->Driver.DrawBuffer)
 522       ctx->Driver.DrawBuffer(ctx, buffers[0]);
 523 }
 524
 525
 526
 527 /**
 528  * Called by glReadBuffer to set the source renderbuffer for reading pixels.
 529  * \param mode color buffer such as GL_FRONT, GL_BACK, etc.
 530  */
 531 void GLAPIENTRY
 532 _mesa_ReadBuffer(GLenum buffer)
 533 {
 534    struct gl_framebuffer *fb;
 535    GLbitfield supportedMask;
 536    GLint srcBuffer;
 537    GLuint bufferID;
 538    GET_CURRENT_CONTEXT(ctx);
 539    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx);
 540
 541    fb = ctx->ReadBuffer;
 542    bufferID = fb->Name;
 543
 544    if (MESA_VERBOSE & VERBOSE_API)
 545       _mesa_debug(ctx, "glReadBuffer %s\n", _mesa_lookup_enum_by_nr(buffer));
 546
 547    if (bufferID > 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;
 557       }
 558       supportedMask = supported_buffer_bitmask(ctx, bufferID);
 559       if (((1 << srcBuffer) & supportedMask) == 0) {
 560          _mesa_error(ctx, GL_INVALID_OPERATION, "glReadBuffer(buffer=0x%x)", buffer);
 561          return;
 562       }
 563    }
 564
 565    if (bufferID == 0) {
 566       ctx->Pixel.ReadBuffer = buffer;
 567    }
 568    fb->ColorReadBuffer = buffer;
 569    fb->_ColorReadBufferIndex = srcBuffer;
 570
 571    ctx->NewState |= _NEW_PIXEL;
 572
 573    /*
 574     * Call device driver function.
 575     */
 576    if (ctx->Driver.ReadBuffer)
 577       (*ctx->Driver.ReadBuffer)(ctx, buffer);
 578 }
 579
 580
 581 #if _HAVE_FULL_GL
 582
 583 /**
 584  * GL_MESA_resize_buffers extension.
 585  *
 586  * When this function is called, we'll ask the window system how large
 587  * the current window is.  If it's a new size, we'll call the driver's
 588  * ResizeBuffers function.  The driver will then resize its color buffers
 589  * as needed, and maybe call the swrast's routine for reallocating
 590  * swrast-managed depth/stencil/accum/etc buffers.
 591  * \note This function should only be called through the GL API, not
 592  * from device drivers (as was done in the past).
 593  */
 594
 595 void _mesa_resizebuffers( GLcontext *ctx )
 596 {
 597    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH( ctx );
 598
 599    if (MESA_VERBOSE & VERBOSE_API)
 600       _mesa_debug(ctx, "glResizeBuffersMESA\n");
 601
 602    if (ctx->WinSysDrawBuffer) {
 603       GLuint newWidth, newHeight;
 604       GLframebuffer *buffer = ctx->WinSysDrawBuffer;
 605
 606       assert(buffer->Name == 0);
 607
 608       /* ask device driver for size of output buffer */
 609       ctx->Driver.GetBufferSize( buffer, &newWidth, &newHeight );
 610
 611       /* see if size of device driver's color buffer (window) has changed */
 612       if (buffer->Width != newWidth || buffer->Height != newHeight) {
 613          if (ctx->Driver.ResizeBuffers)
 614             ctx->Driver.ResizeBuffers(ctx, buffer, newWidth, newHeight );
 615       }
 616    }
 617
 618    if (ctx->WinSysReadBuffer
 619        && ctx->WinSysReadBuffer != ctx->WinSysDrawBuffer) {
 620       GLuint newWidth, newHeight;
 621       GLframebuffer *buffer = ctx->WinSysReadBuffer;
 622
 623       assert(buffer->Name == 0);
 624
 625       /* ask device driver for size of read buffer */
 626       ctx->Driver.GetBufferSize( buffer, &newWidth, &newHeight );
 627
 628       /* see if size of device driver's color buffer (window) has changed */
 629       if (buffer->Width != newWidth || buffer->Height != newHeight) {
 630          if (ctx->Driver.ResizeBuffers)
 631             ctx->Driver.ResizeBuffers(ctx, buffer, newWidth, newHeight );
 632       }
 633    }
 634
 635    ctx->NewState |= _NEW_BUFFERS;  /* to update scissor / window bounds */
 636 }
 637
 638 void GLAPIENTRY
 639 _mesa_ResizeBuffersMESA( void )
 640 {
 641    GET_CURRENT_CONTEXT(ctx);
 642
 643    _mesa_resizebuffers( ctx );
 644 }
 645
 646
 647 /*
 648  * XXX move somewhere else someday?
 649  */
 650 void GLAPIENTRY
 651 _mesa_SampleCoverageARB(GLclampf value, GLboolean invert)
 652 {
 653    GET_CURRENT_CONTEXT(ctx);
 654
 655    if (!ctx->Extensions.ARB_multisample) {
 656       _mesa_error(ctx, GL_INVALID_OPERATION, "glSampleCoverageARB");
 657       return;
 658    }
 659
 660    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH( ctx );
 661    ctx->Multisample.SampleCoverageValue = (GLfloat) CLAMP(value, 0.0, 1.0);
 662    ctx->Multisample.SampleCoverageInvert = invert;
 663    ctx->NewState |= _NEW_MULTISAMPLE;
 664 }
 665
 666 #endif /* _HAVE_FULL_GL */
 667
 668
 669
 670 /**
 671  * Define the scissor box.
 672  *
 673  * \param x, y coordinates of the scissor box lower-left corner.
 674  * \param width width of the scissor box.
 675  * \param height height of the scissor box.
 676  *
 677  * \sa glScissor().
 678  *
 679  * Verifies the parameters and updates __GLcontextRec::Scissor. On a
 680  * change flushes the vertices and notifies the driver via
 681  * the dd_function_table::Scissor callback.
 682  */
 683 void
 684 _mesa_set_scissor(GLcontext *ctx,
 685                   GLint x, GLint y, GLsizei width, GLsizei height)
 686 {
 687    if (x == ctx->Scissor.X &&
 688        y == ctx->Scissor.Y &&
 689        width == ctx->Scissor.Width &&
 690        height == ctx->Scissor.Height)
 691       return;
 692
 693    FLUSH_VERTICES(ctx, _NEW_SCISSOR);
 694    ctx->Scissor.X = x;
 695    ctx->Scissor.Y = y;
 696    ctx->Scissor.Width = width;
 697    ctx->Scissor.Height = height;
 698
 699    if (ctx->Driver.Scissor)
 700       ctx->Driver.Scissor( ctx, x, y, width, height );
 701 }
 702
 703
 704 void GLAPIENTRY
 705 _mesa_Scissor( GLint x, GLint y, GLsizei width, GLsizei height )
 706 {
 707    GET_CURRENT_CONTEXT(ctx);
 708    ASSERT_OUTSIDE_BEGIN_END(ctx);
 709
 710    if (width < 0 || height < 0) {
 711       _mesa_error( ctx, GL_INVALID_VALUE, "glScissor" );
 712       return;
 713    }
 714
 715    if (MESA_VERBOSE & VERBOSE_API)
 716       _mesa_debug(ctx, "glScissor %d %d %d %d\n", x, y, width, height);
 717
 718    _mesa_set_scissor(ctx, x, y, width, height);
 719 }
 720
 721
 722
 723 /**********************************************************************/
 724 /** \name Initialization */
 725 /*@{*/
 726
 727 /**
 728  * Initialize the context's scissor state.
 729  * \param ctx  the GL context.
 730  */
 731 void
 732 _mesa_init_scissor(GLcontext *ctx)
 733 {
 734    /* Scissor group */
 735    ctx->Scissor.Enabled = GL_FALSE;
 736    ctx->Scissor.X = 0;
 737    ctx->Scissor.Y = 0;
 738    ctx->Scissor.Width = 0;
 739    ctx->Scissor.Height = 0;
 740 }
 741
 742
 743 /**
 744  * Initialize the context's multisample state.
 745  * \param ctx  the GL context.
 746  */
 747 void
 748 _mesa_init_multisample(GLcontext *ctx)
 749 {
 750    ctx->Multisample.Enabled = GL_FALSE;
 751    ctx->Multisample.SampleAlphaToCoverage = GL_FALSE;
 752    ctx->Multisample.SampleAlphaToOne = GL_FALSE;
 753    ctx->Multisample.SampleCoverage = GL_FALSE;
 754    ctx->Multisample.SampleCoverageValue = 1.0;
 755    ctx->Multisample.SampleCoverageInvert = GL_FALSE;
 756 }
 757
 758 /*@}*/