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
 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    GLbitfield usedBufferMask, supportedMask;
 390    GLbitfield destMask[MAX_DRAW_BUFFERS];
 391    GET_CURRENT_CONTEXT(ctx);
 392    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx);
 393
 394    if (!ctx->Extensions.ARB_draw_buffers) {
 395       _mesa_error(ctx, GL_INVALID_OPERATION, "glDrawBuffersARB");
 396       return;
 397    }
 398    if (n < 1 || n > (GLsizei) ctx->Const.MaxDrawBuffers) {
 399       _mesa_error(ctx, GL_INVALID_VALUE, "glDrawBuffersARB(n)");
 400       return;
 401    }
 402
 403    supportedMask = supported_buffer_bitmask(ctx, ctx->DrawBuffer);
 404    usedBufferMask = 0x0;
 405
 406    /* complicated error checking... */
 407    for (output = 0; output < n; output++) {
 408       if (buffers[output] == GL_NONE) {
 409          destMask[output] = 0x0;
 410       }
 411       else {
 412          destMask[output] = draw_buffer_enum_to_bitmask(buffers[output]);
 413          if (destMask[output] == BAD_MASK
 414              || _mesa_bitcount(destMask[output]) > 1) {
 415             _mesa_error(ctx, GL_INVALID_ENUM, "glDrawBuffersARB(buffer)");
 416             return;
 417          }
 418          destMask[output] &= supportedMask;
 419          if (destMask[output] == 0) {
 420             _mesa_error(ctx, GL_INVALID_OPERATION,
 421                         "glDrawBuffersARB(unsupported buffer)");
 422             return;
 423          }
 424          if (destMask[output] & usedBufferMask) {
 425             /* can't specify a dest buffer more than once! */
 426             _mesa_error(ctx, GL_INVALID_OPERATION,
 427                         "glDrawBuffersARB(duplicated buffer)");
 428             return;
 429          }
 430
 431          /* update bitmask */
 432          usedBufferMask |= destMask[output];
 433       }
 434    }
 435
 436    /* OK, if we get here, there were no errors so set the new state */
 437    _mesa_drawbuffers(ctx, n, buffers, destMask);
 438 }
 439
 440
 441 /**
 442  * Set color output state.  Traditionally, there was only one color
 443  * output, but fragment programs can now have several distinct color
 444  * outputs (see GL_ARB_draw_buffers).  This function sets the state
 445  * for one such color output.
 446  * \param ctx  current context
 447  * \param output  which fragment program output
 448  * \param buffer  buffer to write to (like GL_LEFT)
 449  * \param destMask  BUFFER_* bitmask
 450  *                  (like BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT).
 451  */
 452 static void
 453 set_color_output(GLcontext *ctx, GLuint output, GLenum buffer,
 454                  GLbitfield destMask)
 455 {
 456    struct gl_framebuffer *fb = ctx->DrawBuffer;
 457
 458    ASSERT(output < ctx->Const.MaxDrawBuffers);
 459
 460    /* Set per-FBO state */
 461    fb->ColorDrawBuffer[output] = buffer;
 462    fb->_ColorDrawBufferMask[output] = destMask;
 463    /* not really needed, will be set later */
 464    fb->_NumColorDrawBuffers[output] = 0;
 465
 466    /* Set traditional state var */
 467    ctx->Color.DrawBuffer[output] = buffer;
 468 }
 469
 470
 471 /**
 472  * Helper routine used by _mesa_DrawBuffer, _mesa_DrawBuffersARB and
 473  * _mesa_PopAttrib to set drawbuffer state.
 474  * All error checking will have been done prior to calling this function
 475  * so nothing should go wrong at this point.
 476  * \param ctx  current context
 477  * \param n    number of color outputs to set
 478  * \param buffers  array[n] of colorbuffer names, like GL_LEFT.
 479  * \param destMask  array[n] of BUFFER_* bitmasks which correspond to the
 480  *                  colorbuffer names.  (i.e. GL_FRONT_AND_BACK =>
 481  *                  BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT).
 482  */
 483 void
 484 _mesa_drawbuffers(GLcontext *ctx, GLuint n, const GLenum *buffers,
 485                   const GLbitfield *destMask)
 486 {
 487    GLbitfield mask[MAX_DRAW_BUFFERS];
 488    GLuint output;
 489
 490    if (!destMask) {
 491       /* compute destMask values now */
 492       const GLbitfield supportedMask
 493          = supported_buffer_bitmask(ctx, ctx->DrawBuffer);
 494       for (output = 0; output < n; output++) {
 495          mask[output] = draw_buffer_enum_to_bitmask(buffers[output]);
 496          ASSERT(mask[output] != BAD_MASK);
 497          mask[output] &= supportedMask;
 498       }
 499       destMask = mask;
 500    }
 501
 502    for (output = 0; output < n; output++) {
 503       set_color_output(ctx, output, buffers[output], destMask[output]);
 504    }
 505
 506    /* set remaining color outputs to NONE */
 507    for (output = n; output < ctx->Const.MaxDrawBuffers; output++) {
 508       set_color_output(ctx, output, GL_NONE, 0x0);
 509    }
 510
 511    ctx->NewState |= _NEW_COLOR;
 512
 513    /*
 514     * Call device driver function.
 515     */
 516    if (ctx->Driver.DrawBuffers)
 517       ctx->Driver.DrawBuffers(ctx, n, buffers);
 518    else if (ctx->Driver.DrawBuffer)
 519       ctx->Driver.DrawBuffer(ctx, buffers[0]);
 520 }
 521
 522
 523
 524 /**
 525  * Called by glReadBuffer to set the source renderbuffer for reading pixels.
 526  * \param mode color buffer such as GL_FRONT, GL_BACK, etc.
 527  */
 528 void GLAPIENTRY
 529 _mesa_ReadBuffer(GLenum buffer)
 530 {
 531    struct gl_framebuffer *fb;
 532    GLbitfield supportedMask;
 533    GLint srcBuffer;
 534    GET_CURRENT_CONTEXT(ctx);
 535    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx);
 536
 537    fb = ctx->ReadBuffer;
 538
 539    if (MESA_VERBOSE & VERBOSE_API)
 540       _mesa_debug(ctx, "glReadBuffer %s\n", _mesa_lookup_enum_by_nr(buffer));
 541
 542    if (fb->Name > 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=0x%x)", buffer);
 551          return;
 552       }
 553       supportedMask = supported_buffer_bitmask(ctx, fb);
 554       if (((1 << srcBuffer) & supportedMask) == 0) {
 555          _mesa_error(ctx, GL_INVALID_OPERATION, "glReadBuffer(buffer=0x%x)", buffer);
 556          return;
 557       }
 558    }
 559
 560    if (fb->Name == 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  * XXX THIS IS OBSOLETE - drivers should take care of detecting window
 580  * size changes and act accordingly, likely calling _mesa_resize_framebuffer().
 581  *
 582  * GL_MESA_resize_buffers extension.
 583  *
 584  * When this function is called, we'll ask the window system how large
 585  * the current window is.  If it's a new size, we'll call the driver's
 586  * ResizeBuffers function.  The driver will then resize its color buffers
 587  * as needed, and maybe call the swrast's routine for reallocating
 588  * swrast-managed depth/stencil/accum/etc buffers.
 589  * \note This function should only be called through the GL API, not
 590  * from device drivers (as was done in the past).
 591  */
 592
 593 void _mesa_resizebuffers( GLcontext *ctx )
 594 {
 595    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH( ctx );
 596
 597    if (MESA_VERBOSE & VERBOSE_API)
 598       _mesa_debug(ctx, "glResizeBuffersMESA\n");
 599
 600    if (!ctx->Driver.GetBufferSize) {
 601       return;
 602    }
 603
 604    if (ctx->WinSysDrawBuffer) {
 605       GLuint newWidth, newHeight;
 606       GLframebuffer *buffer = ctx->WinSysDrawBuffer;
 607
 608       assert(buffer->Name == 0);
 609
 610       /* ask device driver for size of output buffer */
 611       ctx->Driver.GetBufferSize( buffer, &newWidth, &newHeight );
 612
 613       /* see if size of device driver's color buffer (window) has changed */
 614       if (buffer->Width != newWidth || buffer->Height != newHeight) {
 615          if (ctx->Driver.ResizeBuffers)
 616             ctx->Driver.ResizeBuffers(ctx, buffer, newWidth, newHeight );
 617       }
 618    }
 619
 620    if (ctx->WinSysReadBuffer
 621        && ctx->WinSysReadBuffer != ctx->WinSysDrawBuffer) {
 622       GLuint newWidth, newHeight;
 623       GLframebuffer *buffer = ctx->WinSysReadBuffer;
 624
 625       assert(buffer->Name == 0);
 626
 627       /* ask device driver for size of read buffer */
 628       ctx->Driver.GetBufferSize( buffer, &newWidth, &newHeight );
 629
 630       /* see if size of device driver's color buffer (window) has changed */
 631       if (buffer->Width != newWidth || buffer->Height != newHeight) {
 632          if (ctx->Driver.ResizeBuffers)
 633             ctx->Driver.ResizeBuffers(ctx, buffer, newWidth, newHeight );
 634       }
 635    }
 636
 637    ctx->NewState |= _NEW_BUFFERS;  /* to update scissor / window bounds */
 638 }
 639
 640
 641 /*
 642  * XXX THIS IS OBSOLETE
 643  */
 644 void GLAPIENTRY
 645 _mesa_ResizeBuffersMESA( void )
 646 {
 647    GET_CURRENT_CONTEXT(ctx);
 648
 649    if (ctx->Extensions.MESA_resize_buffers)
 650       _mesa_resizebuffers( ctx );
 651 }
 652
 653
 654 /*
 655  * XXX move somewhere else someday?
 656  */
 657 void GLAPIENTRY
 658 _mesa_SampleCoverageARB(GLclampf value, GLboolean invert)
 659 {
 660    GET_CURRENT_CONTEXT(ctx);
 661
 662    if (!ctx->Extensions.ARB_multisample) {
 663       _mesa_error(ctx, GL_INVALID_OPERATION, "glSampleCoverageARB");
 664       return;
 665    }
 666
 667    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH( ctx );
 668    ctx->Multisample.SampleCoverageValue = (GLfloat) CLAMP(value, 0.0, 1.0);
 669    ctx->Multisample.SampleCoverageInvert = invert;
 670    ctx->NewState |= _NEW_MULTISAMPLE;
 671 }
 672
 673 #endif /* _HAVE_FULL_GL */
 674
 675
 676
 677 /**
 678  * Define the scissor box.
 679  *
 680  * \param x, y coordinates of the scissor box lower-left corner.
 681  * \param width width of the scissor box.
 682  * \param height height of the scissor box.
 683  *
 684  * \sa glScissor().
 685  *
 686  * Verifies the parameters and updates __GLcontextRec::Scissor. On a
 687  * change flushes the vertices and notifies the driver via
 688  * the dd_function_table::Scissor callback.
 689  */
 690 void
 691 _mesa_set_scissor(GLcontext *ctx,
 692                   GLint x, GLint y, GLsizei width, GLsizei height)
 693 {
 694    if (x == ctx->Scissor.X &&
 695        y == ctx->Scissor.Y &&
 696        width == ctx->Scissor.Width &&
 697        height == ctx->Scissor.Height)
 698       return;
 699
 700    FLUSH_VERTICES(ctx, _NEW_SCISSOR);
 701    ctx->Scissor.X = x;
 702    ctx->Scissor.Y = y;
 703    ctx->Scissor.Width = width;
 704    ctx->Scissor.Height = height;
 705
 706    if (ctx->Driver.Scissor)
 707       ctx->Driver.Scissor( ctx, x, y, width, height );
 708 }
 709
 710
 711 void GLAPIENTRY
 712 _mesa_Scissor( GLint x, GLint y, GLsizei width, GLsizei height )
 713 {
 714    GET_CURRENT_CONTEXT(ctx);
 715    ASSERT_OUTSIDE_BEGIN_END(ctx);
 716
 717    if (width < 0 || height < 0) {
 718       _mesa_error( ctx, GL_INVALID_VALUE, "glScissor" );
 719       return;
 720    }
 721
 722    if (MESA_VERBOSE & VERBOSE_API)
 723       _mesa_debug(ctx, "glScissor %d %d %d %d\n", x, y, width, height);
 724
 725    _mesa_set_scissor(ctx, x, y, width, height);
 726 }
 727
 728
 729
 730 /**********************************************************************/
 731 /** \name Initialization */
 732 /*@{*/
 733
 734 /**
 735  * Initialize the context's scissor state.
 736  * \param ctx  the GL context.
 737  */
 738 void
 739 _mesa_init_scissor(GLcontext *ctx)
 740 {
 741    /* Scissor group */
 742    ctx->Scissor.Enabled = GL_FALSE;
 743    ctx->Scissor.X = 0;
 744    ctx->Scissor.Y = 0;
 745    ctx->Scissor.Width = 0;
 746    ctx->Scissor.Height = 0;
 747 }
 748
 749
 750 /**
 751  * Initialize the context's multisample state.
 752  * \param ctx  the GL context.
 753  */
 754 void
 755 _mesa_init_multisample(GLcontext *ctx)
 756 {
 757    ctx->Multisample.Enabled = GL_FALSE;
 758    ctx->Multisample.SampleAlphaToCoverage = GL_FALSE;
 759    ctx->Multisample.SampleAlphaToOne = GL_FALSE;
 760    ctx->Multisample.SampleCoverage = GL_FALSE;
 761    ctx->Multisample.SampleCoverageValue = 1.0;
 762    ctx->Multisample.SampleCoverageInvert = GL_FALSE;
 763 }
 764
 765 /*@}*/