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    FLUSH_CURRENT(ctx, 0);
 122
 123    if (MESA_VERBOSE & VERBOSE_API)
 124       _mesa_debug(ctx, "glClear 0x%x\n", mask);
 125
 126    if (mask & ~(GL_COLOR_BUFFER_BIT |
 127                 GL_DEPTH_BUFFER_BIT |
 128                 GL_STENCIL_BUFFER_BIT |
 129                 GL_ACCUM_BUFFER_BIT)) {
 130       /* invalid bit set */
 131       _mesa_error( ctx, GL_INVALID_VALUE, "glClear(0x%x)", mask);
 132       return;
 133    }
 134
 135    if (ctx->NewState) {
 136       _mesa_update_state( ctx );        /* update _Xmin, etc */
 137    }
 138
 139    if (ctx->DrawBuffer->_Status != GL_FRAMEBUFFER_COMPLETE_EXT) {
 140       _mesa_error(ctx, GL_INVALID_FRAMEBUFFER_OPERATION_EXT,
 141                   "glClear(incomplete framebuffer)");
 142       return;
 143    }
 144
 145    if (ctx->DrawBuffer->Width == 0 || ctx->DrawBuffer->Height == 0 ||
 146        ctx->DrawBuffer->_Xmin >= ctx->DrawBuffer->_Xmax ||
 147        ctx->DrawBuffer->_Ymin >= ctx->DrawBuffer->_Ymax)
 148       return;
 149
 150    if (ctx->RenderMode == GL_RENDER) {
 151       GLbitfield bufferMask;
 152
 153       /* don't clear depth buffer if depth writing disabled */
 154       if (!ctx->Depth.Mask)
 155          mask &= ~GL_DEPTH_BUFFER_BIT;
 156
 157       /* Build the bitmask to send to device driver's Clear function.
 158        * Note that the GL_COLOR_BUFFER_BIT flag will expand to 0, 1, 2 or 4
 159        * of the BUFFER_BIT_FRONT/BACK_LEFT/RIGHT flags, or one of the
 160        * BUFFER_BIT_COLORn flags.
 161        */
 162       bufferMask = 0;
 163       if (mask & GL_COLOR_BUFFER_BIT) {
 164          GLuint i;
 165          for (i = 0; i < ctx->DrawBuffer->_NumColorDrawBuffers; i++) {
 166             bufferMask |= (1 << ctx->DrawBuffer->_ColorDrawBufferIndexes[i]);
 167          }
 168       }
 169
 170       if ((mask & GL_DEPTH_BUFFER_BIT)
 171           && ctx->DrawBuffer->Visual.haveDepthBuffer) {
 172          bufferMask |= BUFFER_BIT_DEPTH;
 173       }
 174
 175       if ((mask & GL_STENCIL_BUFFER_BIT)
 176           && ctx->DrawBuffer->Visual.haveStencilBuffer) {
 177          bufferMask |= BUFFER_BIT_STENCIL;
 178       }
 179
 180       if ((mask & GL_ACCUM_BUFFER_BIT)
 181           && ctx->DrawBuffer->Visual.haveAccumBuffer) {
 182          bufferMask |= BUFFER_BIT_ACCUM;
 183       }
 184
 185       ASSERT(ctx->Driver.Clear);
 186       ctx->Driver.Clear(ctx, bufferMask);
 187    }
 188 }
 189
 190
 191
 192 /**
 193  * Return bitmask of BUFFER_BIT_* flags indicating which color buffers are
 194  * available to the rendering context (for drawing or reading).
 195  * This depends on the type of framebuffer.  For window system framebuffers
 196  * we look at the framebuffer's visual.  But for user-create framebuffers we
 197  * look at the number of supported color attachments.
 198  * \param fb  the framebuffer to draw to, or read from
 199  * \return  bitmask of BUFFER_BIT_* flags
 200  */
 201 static GLbitfield
 202 supported_buffer_bitmask(const GLcontext *ctx, const struct gl_framebuffer *fb)
 203 {
 204    GLbitfield mask = 0x0;
 205
 206    if (fb->Name > 0) {
 207       /* A user-created renderbuffer */
 208       GLuint i;
 209       ASSERT(ctx->Extensions.EXT_framebuffer_object);
 210       for (i = 0; i < ctx->Const.MaxColorAttachments; i++) {
 211          mask |= (BUFFER_BIT_COLOR0 << i);
 212       }
 213    }
 214    else {
 215       /* A window system framebuffer */
 216       GLint i;
 217       mask = BUFFER_BIT_FRONT_LEFT; /* always have this */
 218       if (fb->Visual.stereoMode) {
 219          mask |= BUFFER_BIT_FRONT_RIGHT;
 220          if (fb->Visual.doubleBufferMode) {
 221             mask |= BUFFER_BIT_BACK_LEFT | BUFFER_BIT_BACK_RIGHT;
 222          }
 223       }
 224       else if (fb->Visual.doubleBufferMode) {
 225          mask |= BUFFER_BIT_BACK_LEFT;
 226       }
 227
 228       for (i = 0; i < fb->Visual.numAuxBuffers; i++) {
 229          mask |= (BUFFER_BIT_AUX0 << i);
 230       }
 231    }
 232
 233    return mask;
 234 }
 235
 236
 237 /**
 238  * Helper routine used by glDrawBuffer and glDrawBuffersARB.
 239  * Given a GLenum naming one or more color buffers (such as
 240  * GL_FRONT_AND_BACK), return the corresponding bitmask of BUFFER_BIT_* flags.
 241  */
 242 static GLbitfield
 243 draw_buffer_enum_to_bitmask(GLenum buffer)
 244 {
 245    switch (buffer) {
 246       case GL_NONE:
 247          return 0;
 248       case GL_FRONT:
 249          return BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_FRONT_RIGHT;
 250       case GL_BACK:
 251          return BUFFER_BIT_BACK_LEFT | BUFFER_BIT_BACK_RIGHT;
 252       case GL_RIGHT:
 253          return BUFFER_BIT_FRONT_RIGHT | BUFFER_BIT_BACK_RIGHT;
 254       case GL_FRONT_RIGHT:
 255          return BUFFER_BIT_FRONT_RIGHT;
 256       case GL_BACK_RIGHT:
 257          return BUFFER_BIT_BACK_RIGHT;
 258       case GL_BACK_LEFT:
 259          return BUFFER_BIT_BACK_LEFT;
 260       case GL_FRONT_AND_BACK:
 261          return BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT
 262               | BUFFER_BIT_FRONT_RIGHT | BUFFER_BIT_BACK_RIGHT;
 263       case GL_LEFT:
 264          return BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT;
 265       case GL_FRONT_LEFT:
 266          return BUFFER_BIT_FRONT_LEFT;
 267       case GL_AUX0:
 268          return BUFFER_BIT_AUX0;
 269       case GL_AUX1:
 270          return BUFFER_BIT_AUX1;
 271       case GL_AUX2:
 272          return BUFFER_BIT_AUX2;
 273       case GL_AUX3:
 274          return BUFFER_BIT_AUX3;
 275       case GL_COLOR_ATTACHMENT0_EXT:
 276          return BUFFER_BIT_COLOR0;
 277       case GL_COLOR_ATTACHMENT1_EXT:
 278          return BUFFER_BIT_COLOR1;
 279       case GL_COLOR_ATTACHMENT2_EXT:
 280          return BUFFER_BIT_COLOR2;
 281       case GL_COLOR_ATTACHMENT3_EXT:
 282          return BUFFER_BIT_COLOR3;
 283       case GL_COLOR_ATTACHMENT4_EXT:
 284          return BUFFER_BIT_COLOR4;
 285       case GL_COLOR_ATTACHMENT5_EXT:
 286          return BUFFER_BIT_COLOR5;
 287       case GL_COLOR_ATTACHMENT6_EXT:
 288          return BUFFER_BIT_COLOR6;
 289       case GL_COLOR_ATTACHMENT7_EXT:
 290          return BUFFER_BIT_COLOR7;
 291       default:
 292          /* error */
 293          return BAD_MASK;
 294    }
 295 }
 296
 297
 298 /**
 299  * Helper routine used by glReadBuffer.
 300  * Given a GLenum naming a color buffer, return the index of the corresponding
 301  * renderbuffer (a BUFFER_* value).
 302  * return -1 for an invalid buffer.
 303  */
 304 static GLint
 305 read_buffer_enum_to_index(GLenum buffer)
 306 {
 307    switch (buffer) {
 308       case GL_FRONT:
 309          return BUFFER_FRONT_LEFT;
 310       case GL_BACK:
 311          return BUFFER_BACK_LEFT;
 312       case GL_RIGHT:
 313          return BUFFER_FRONT_RIGHT;
 314       case GL_FRONT_RIGHT:
 315          return BUFFER_FRONT_RIGHT;
 316       case GL_BACK_RIGHT:
 317          return BUFFER_BACK_RIGHT;
 318       case GL_BACK_LEFT:
 319          return BUFFER_BACK_LEFT;
 320       case GL_LEFT:
 321          return BUFFER_FRONT_LEFT;
 322       case GL_FRONT_LEFT:
 323          return BUFFER_FRONT_LEFT;
 324       case GL_AUX0:
 325          return BUFFER_AUX0;
 326       case GL_AUX1:
 327          return BUFFER_AUX1;
 328       case GL_AUX2:
 329          return BUFFER_AUX2;
 330       case GL_AUX3:
 331          return BUFFER_AUX3;
 332       case GL_COLOR_ATTACHMENT0_EXT:
 333          return BUFFER_COLOR0;
 334       case GL_COLOR_ATTACHMENT1_EXT:
 335          return BUFFER_COLOR1;
 336       case GL_COLOR_ATTACHMENT2_EXT:
 337          return BUFFER_COLOR2;
 338       case GL_COLOR_ATTACHMENT3_EXT:
 339          return BUFFER_COLOR3;
 340       case GL_COLOR_ATTACHMENT4_EXT:
 341          return BUFFER_COLOR4;
 342       case GL_COLOR_ATTACHMENT5_EXT:
 343          return BUFFER_COLOR5;
 344       case GL_COLOR_ATTACHMENT6_EXT:
 345          return BUFFER_COLOR6;
 346       case GL_COLOR_ATTACHMENT7_EXT:
 347          return BUFFER_COLOR7;
 348       default:
 349          /* error */
 350          return -1;
 351    }
 352 }
 353
 354
 355 /**
 356  * Called by glDrawBuffer().
 357  * Specify which renderbuffer(s) to draw into for the first color output.
 358  * <buffer> can name zero, one, two or four renderbuffers!
 359  * \sa _mesa_DrawBuffersARB
 360  *
 361  * \param buffer  buffer token such as GL_LEFT or GL_FRONT_AND_BACK, etc.
 362  *
 363  * Note that the behaviour of this function depends on whether the
 364  * current ctx->DrawBuffer is a window-system framebuffer (Name=0) or
 365  * a user-created framebuffer object (Name!=0).
 366  *   In the former case, we update the per-context ctx->Color.DrawBuffer
 367  *   state var _and_ the FB's ColorDrawBuffer state.
 368  *   In the later case, we update the FB's ColorDrawBuffer state only.
 369  *
 370  * Furthermore, upon a MakeCurrent() or BindFramebuffer() call, if the
 371  * new FB is a window system FB, we need to re-update the FB's
 372  * ColorDrawBuffer state to match the context.  This is handled in
 373  * _mesa_update_framebuffer().
 374  *
 375  * See the GL_EXT_framebuffer_object spec for more info.
 376  */
 377 void GLAPIENTRY
 378 _mesa_DrawBuffer(GLenum buffer)
 379 {
 380    GLbitfield destMask;
 381    GET_CURRENT_CONTEXT(ctx);
 382    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx); /* too complex... */
 383
 384    if (MESA_VERBOSE & VERBOSE_API) {
 385       _mesa_debug(ctx, "glDrawBuffer %s\n", _mesa_lookup_enum_by_nr(buffer));
 386    }
 387
 388    if (buffer == GL_NONE) {
 389       destMask = 0x0;
 390    }
 391    else {
 392       const GLbitfield supportedMask
 393          = supported_buffer_bitmask(ctx, ctx->DrawBuffer);
 394       destMask = draw_buffer_enum_to_bitmask(buffer);
 395       if (destMask == BAD_MASK) {
 396          /* totally bogus buffer */
 397          _mesa_error(ctx, GL_INVALID_ENUM, "glDrawBuffer(buffer)");
 398          return;
 399       }
 400       destMask &= supportedMask;
 401       if (destMask == 0x0) {
 402          /* none of the named color buffers exist! */
 403          _mesa_error(ctx, GL_INVALID_OPERATION, "glDrawBuffer(buffer)");
 404          return;
 405       }
 406    }
 407
 408    /* if we get here, there's no error so set new state */
 409    _mesa_drawbuffers(ctx, 1, &buffer, &destMask);
 410
 411    /*
 412     * Call device driver function.
 413     */
 414    if (ctx->Driver.DrawBuffers)
 415       ctx->Driver.DrawBuffers(ctx, 1, &buffer);
 416    else if (ctx->Driver.DrawBuffer)
 417       ctx->Driver.DrawBuffer(ctx, buffer);
 418 }
 419
 420
 421 /**
 422  * Called by glDrawBuffersARB; specifies the destination color renderbuffers
 423  * for N fragment program color outputs.
 424  * \sa _mesa_DrawBuffer
 425  * \param n  number of outputs
 426  * \param buffers  array [n] of renderbuffer names.  Unlike glDrawBuffer, the
 427  *                 names cannot specify more than one buffer.  For example,
 428  *                 GL_FRONT_AND_BACK is illegal.
 429  */
 430 void GLAPIENTRY
 431 _mesa_DrawBuffersARB(GLsizei n, const GLenum *buffers)
 432 {
 433    GLint output;
 434    GLbitfield usedBufferMask, supportedMask;
 435    GLbitfield destMask[MAX_DRAW_BUFFERS];
 436    GET_CURRENT_CONTEXT(ctx);
 437    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx);
 438
 439    if (!ctx->Extensions.ARB_draw_buffers) {
 440       _mesa_error(ctx, GL_INVALID_OPERATION, "glDrawBuffersARB");
 441       return;
 442    }
 443    if (n < 1 || n > (GLsizei) ctx->Const.MaxDrawBuffers) {
 444       _mesa_error(ctx, GL_INVALID_VALUE, "glDrawBuffersARB(n)");
 445       return;
 446    }
 447
 448    supportedMask = supported_buffer_bitmask(ctx, ctx->DrawBuffer);
 449    usedBufferMask = 0x0;
 450
 451    /* complicated error checking... */
 452    for (output = 0; output < n; output++) {
 453       if (buffers[output] == GL_NONE) {
 454          destMask[output] = 0x0;
 455       }
 456       else {
 457          destMask[output] = draw_buffer_enum_to_bitmask(buffers[output]);
 458          if (destMask[output] == BAD_MASK
 459              || _mesa_bitcount(destMask[output]) > 1) {
 460             _mesa_error(ctx, GL_INVALID_ENUM, "glDrawBuffersARB(buffer)");
 461             return;
 462          }
 463          destMask[output] &= supportedMask;
 464          if (destMask[output] == 0) {
 465             _mesa_error(ctx, GL_INVALID_OPERATION,
 466                         "glDrawBuffersARB(unsupported buffer)");
 467             return;
 468          }
 469          if (destMask[output] & usedBufferMask) {
 470             /* can't specify a dest buffer more than once! */
 471             _mesa_error(ctx, GL_INVALID_OPERATION,
 472                         "glDrawBuffersARB(duplicated buffer)");
 473             return;
 474          }
 475
 476          /* update bitmask */
 477          usedBufferMask |= destMask[output];
 478       }
 479    }
 480
 481    /* OK, if we get here, there were no errors so set the new state */
 482    _mesa_drawbuffers(ctx, n, buffers, destMask);
 483
 484    /*
 485     * Call device driver function.
 486     */
 487    if (ctx->Driver.DrawBuffers)
 488       ctx->Driver.DrawBuffers(ctx, n, buffers);
 489    else if (ctx->Driver.DrawBuffer)
 490       ctx->Driver.DrawBuffer(ctx, buffers[0]);
 491 }
 492
 493
 494 /**
 495  * Helper function to set the GL_DRAW_BUFFER state in the context and
 496  * current FBO.
 497  *
 498  * All error checking will have been done prior to calling this function
 499  * so nothing should go wrong at this point.
 500  *
 501  * \param ctx  current context
 502  * \param n    number of color outputs to set
 503  * \param buffers  array[n] of colorbuffer names, like GL_LEFT.
 504  * \param destMask  array[n] of BUFFER_BIT_* bitmasks which correspond to the
 505  *                  colorbuffer names.  (i.e. GL_FRONT_AND_BACK =>
 506  *                  BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT).
 507  */
 508 void
 509 _mesa_drawbuffers(GLcontext *ctx, GLuint n, const GLenum *buffers,
 510                   const GLbitfield *destMask)
 511 {
 512    struct gl_framebuffer *fb = ctx->DrawBuffer;
 513    GLbitfield mask[MAX_DRAW_BUFFERS];
 514
 515    if (!destMask) {
 516       /* compute destMask values now */
 517       const GLbitfield supportedMask = supported_buffer_bitmask(ctx, fb);
 518       GLuint output;
 519       for (output = 0; output < n; output++) {
 520          mask[output] = draw_buffer_enum_to_bitmask(buffers[output]);
 521          ASSERT(mask[output] != BAD_MASK);
 522          mask[output] &= supportedMask;
 523       }
 524       destMask = mask;
 525    }
 526
 527    if (n == 1) {
 528       GLuint buf, count = 0;
 529       /* init to -1 to help catch errors */
 530       fb->_ColorDrawBufferIndexes[0] = -1;
 531       for (buf = 0; buf < BUFFER_COUNT; buf++) {
 532          if (destMask[0] & (1 << buf)) {
 533             fb->_ColorDrawBufferIndexes[count] = buf;
 534             count++;
 535          }
 536       }
 537       fb->ColorDrawBuffer[0] = buffers[0];
 538       fb->_NumColorDrawBuffers = count;
 539    }
 540    else {
 541       GLuint buf, count = 0;
 542       for (buf = 0; buf < n; buf++ ) {
 543          if (destMask[buf]) {
 544             fb->_ColorDrawBufferIndexes[buf] = _mesa_ffs(destMask[buf]) - 1;
 545             fb->ColorDrawBuffer[buf] = buffers[buf];
 546             count = buf + 1;
 547          }
 548          else {
 549             fb->_ColorDrawBufferIndexes[buf] = -1;
 550          }
 551       }
 552       /* set remaining outputs to -1 (GL_NONE) */
 553       while (buf < ctx->Const.MaxDrawBuffers) {
 554          fb->_ColorDrawBufferIndexes[buf] = -1;
 555          fb->ColorDrawBuffer[buf] = GL_NONE;
 556          buf++;
 557       }
 558       fb->_NumColorDrawBuffers = count;
 559    }
 560
 561    if (fb->Name == 0) {
 562       /* also set context drawbuffer state */
 563       GLuint buf;
 564       for (buf = 0; buf < ctx->Const.MaxDrawBuffers; buf++) {
 565          ctx->Color.DrawBuffer[buf] = fb->ColorDrawBuffer[buf];
 566       }
 567    }
 568
 569    ctx->NewState |= _NEW_COLOR;
 570 }
 571
 572
 573 /**
 574  * Like \sa _mesa_drawbuffers(), this is a helper function for setting
 575  * GL_READ_BUFFER state in the context and current FBO.
 576  * \param ctx  the rendering context
 577  * \param buffer  GL_FRONT, GL_BACK, GL_COLOR_ATTACHMENT0, etc.
 578  * \param bufferIndex  the numerical index corresponding to 'buffer'
 579  */
 580 void
 581 _mesa_readbuffer(GLcontext *ctx, GLenum buffer, GLint bufferIndex)
 582 {
 583    struct gl_framebuffer *fb = ctx->ReadBuffer;
 584
 585    if (fb->Name == 0) {
 586       /* Only update the per-context READ_BUFFER state if we're bound to
 587        * a window-system framebuffer.
 588        */
 589       ctx->Pixel.ReadBuffer = buffer;
 590    }
 591
 592    fb->ColorReadBuffer = buffer;
 593    fb->_ColorReadBufferIndex = bufferIndex;
 594
 595    ctx->NewState |= _NEW_PIXEL;
 596 }
 597
 598
 599
 600 /**
 601  * Called by glReadBuffer to set the source renderbuffer for reading pixels.
 602  * \param mode color buffer such as GL_FRONT, GL_BACK, etc.
 603  */
 604 void GLAPIENTRY
 605 _mesa_ReadBuffer(GLenum buffer)
 606 {
 607    struct gl_framebuffer *fb;
 608    GLbitfield supportedMask;
 609    GLint srcBuffer;
 610    GET_CURRENT_CONTEXT(ctx);
 611    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx);
 612
 613    if (MESA_VERBOSE & VERBOSE_API)
 614       _mesa_debug(ctx, "glReadBuffer %s\n", _mesa_lookup_enum_by_nr(buffer));
 615
 616    fb = ctx->ReadBuffer;
 617
 618    if (MESA_VERBOSE & VERBOSE_API)
 619       _mesa_debug(ctx, "glReadBuffer %s\n", _mesa_lookup_enum_by_nr(buffer));
 620
 621    if (fb->Name > 0 && buffer == GL_NONE) {
 622       /* This is legal for user-created framebuffer objects */
 623       srcBuffer = -1;
 624    }
 625    else {
 626       /* general case / window-system framebuffer */
 627       srcBuffer = read_buffer_enum_to_index(buffer);
 628       if (srcBuffer == -1) {
 629          _mesa_error(ctx, GL_INVALID_ENUM,
 630                      "glReadBuffer(buffer=0x%x)", buffer);
 631          return;
 632       }
 633       supportedMask = supported_buffer_bitmask(ctx, fb);
 634       if (((1 << srcBuffer) & supportedMask) == 0) {
 635          _mesa_error(ctx, GL_INVALID_OPERATION,
 636                      "glReadBuffer(buffer=0x%x)", buffer);
 637          return;
 638       }
 639    }
 640
 641    /* OK, all error checking has been completed now */
 642
 643    _mesa_readbuffer(ctx, buffer, srcBuffer);
 644
 645    /*
 646     * Call device driver function.
 647     */
 648    if (ctx->Driver.ReadBuffer)
 649       (*ctx->Driver.ReadBuffer)(ctx, buffer);
 650 }
 651
 652
 653 #if _HAVE_FULL_GL
 654
 655 /**
 656  * XXX THIS IS OBSOLETE - drivers should take care of detecting window
 657  * size changes and act accordingly, likely calling _mesa_resize_framebuffer().
 658  *
 659  * GL_MESA_resize_buffers extension.
 660  *
 661  * When this function is called, we'll ask the window system how large
 662  * the current window is.  If it's a new size, we'll call the driver's
 663  * ResizeBuffers function.  The driver will then resize its color buffers
 664  * as needed, and maybe call the swrast's routine for reallocating
 665  * swrast-managed depth/stencil/accum/etc buffers.
 666  * \note This function should only be called through the GL API, not
 667  * from device drivers (as was done in the past).
 668  */
 669
 670 void _mesa_resizebuffers( GLcontext *ctx )
 671 {
 672    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH( ctx );
 673
 674    if (MESA_VERBOSE & VERBOSE_API)
 675       _mesa_debug(ctx, "glResizeBuffersMESA\n");
 676
 677    if (!ctx->Driver.GetBufferSize) {
 678       return;
 679    }
 680
 681    if (ctx->WinSysDrawBuffer) {
 682       GLuint newWidth, newHeight;
 683       GLframebuffer *buffer = ctx->WinSysDrawBuffer;
 684
 685       assert(buffer->Name == 0);
 686
 687       /* ask device driver for size of output buffer */
 688       ctx->Driver.GetBufferSize( buffer, &newWidth, &newHeight );
 689
 690       /* see if size of device driver's color buffer (window) has changed */
 691       if (buffer->Width != newWidth || buffer->Height != newHeight) {
 692          if (ctx->Driver.ResizeBuffers)
 693             ctx->Driver.ResizeBuffers(ctx, buffer, newWidth, newHeight );
 694       }
 695    }
 696
 697    if (ctx->WinSysReadBuffer
 698        && ctx->WinSysReadBuffer != ctx->WinSysDrawBuffer) {
 699       GLuint newWidth, newHeight;
 700       GLframebuffer *buffer = ctx->WinSysReadBuffer;
 701
 702       assert(buffer->Name == 0);
 703
 704       /* ask device driver for size of read buffer */
 705       ctx->Driver.GetBufferSize( buffer, &newWidth, &newHeight );
 706
 707       /* see if size of device driver's color buffer (window) has changed */
 708       if (buffer->Width != newWidth || buffer->Height != newHeight) {
 709          if (ctx->Driver.ResizeBuffers)
 710             ctx->Driver.ResizeBuffers(ctx, buffer, newWidth, newHeight );
 711       }
 712    }
 713
 714    ctx->NewState |= _NEW_BUFFERS;  /* to update scissor / window bounds */
 715 }
 716
 717
 718 /*
 719  * XXX THIS IS OBSOLETE
 720  */
 721 void GLAPIENTRY
 722 _mesa_ResizeBuffersMESA( void )
 723 {
 724    GET_CURRENT_CONTEXT(ctx);
 725
 726    if (ctx->Extensions.MESA_resize_buffers)
 727       _mesa_resizebuffers( ctx );
 728 }
 729
 730
 731 /*
 732  * XXX move somewhere else someday?
 733  */
 734 void GLAPIENTRY
 735 _mesa_SampleCoverageARB(GLclampf value, GLboolean invert)
 736 {
 737    GET_CURRENT_CONTEXT(ctx);
 738
 739    if (!ctx->Extensions.ARB_multisample) {
 740       _mesa_error(ctx, GL_INVALID_OPERATION, "glSampleCoverageARB");
 741       return;
 742    }
 743
 744    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH( ctx );
 745    ctx->Multisample.SampleCoverageValue = (GLfloat) CLAMP(value, 0.0, 1.0);
 746    ctx->Multisample.SampleCoverageInvert = invert;
 747    ctx->NewState |= _NEW_MULTISAMPLE;
 748 }
 749
 750 #endif /* _HAVE_FULL_GL */
 751
 752
 753
 754 /**
 755  * Initialize the context's multisample state.
 756  * \param ctx  the GL context.
 757  */
 758 void
 759 _mesa_init_multisample(GLcontext *ctx)
 760 {
 761    ctx->Multisample.Enabled = GL_TRUE;
 762    ctx->Multisample.SampleAlphaToCoverage = GL_FALSE;
 763    ctx->Multisample.SampleAlphaToOne = GL_FALSE;
 764    ctx->Multisample.SampleCoverage = GL_FALSE;
 765    ctx->Multisample.SampleCoverageValue = 1.0;
 766    ctx->Multisample.SampleCoverageInvert = GL_FALSE;
 767 }