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        ctx->DrawBuffer->_Xmin >= ctx->DrawBuffer->_Xmax ||
 145        ctx->DrawBuffer->_Ymin >= ctx->DrawBuffer->_Ymax)
 146       return;
 147
 148    if (ctx->RenderMode == GL_RENDER) {
 149       GLbitfield bufferMask;
 150
 151       /* don't clear depth buffer if depth writing disabled */
 152       if (!ctx->Depth.Mask)
 153          mask &= ~GL_DEPTH_BUFFER_BIT;
 154
 155       /* Build the bitmask to send to device driver's Clear function.
 156        * Note that the GL_COLOR_BUFFER_BIT flag will expand to 0, 1, 2 or 4
 157        * of the BUFFER_BIT_FRONT/BACK_LEFT/RIGHT flags, or one of the
 158        * BUFFER_BIT_COLORn flags.
 159        */
 160       bufferMask = 0;
 161       if (mask & GL_COLOR_BUFFER_BIT) {
 162          GLuint i;
 163          for (i = 0; i < ctx->DrawBuffer->_NumColorDrawBuffers; i++) {
 164             bufferMask |= (1 << ctx->DrawBuffer->_ColorDrawBufferIndexes[i]);
 165          }
 166       }
 167
 168       if ((mask & GL_DEPTH_BUFFER_BIT)
 169           && ctx->DrawBuffer->Visual.haveDepthBuffer) {
 170          bufferMask |= BUFFER_BIT_DEPTH;
 171       }
 172
 173       if ((mask & GL_STENCIL_BUFFER_BIT)
 174           && ctx->DrawBuffer->Visual.haveStencilBuffer) {
 175          bufferMask |= BUFFER_BIT_STENCIL;
 176       }
 177
 178       if ((mask & GL_ACCUM_BUFFER_BIT)
 179           && ctx->DrawBuffer->Visual.haveAccumBuffer) {
 180          bufferMask |= BUFFER_BIT_ACCUM;
 181       }
 182
 183       ASSERT(ctx->Driver.Clear);
 184       ctx->Driver.Clear(ctx, bufferMask);
 185    }
 186 }
 187
 188
 189
 190 /**
 191  * Return bitmask of BUFFER_BIT_* flags indicating which color buffers are
 192  * available to the rendering context (for drawing or reading).
 193  * This depends on the type of framebuffer.  For window system framebuffers
 194  * we look at the framebuffer's visual.  But for user-create framebuffers we
 195  * look at the number of supported color attachments.
 196  * \param fb  the framebuffer to draw to, or read from
 197  * \return  bitmask of BUFFER_BIT_* flags
 198  */
 199 static GLbitfield
 200 supported_buffer_bitmask(const GLcontext *ctx, const struct gl_framebuffer *fb)
 201 {
 202    GLbitfield mask = 0x0;
 203
 204    if (fb->Name > 0) {
 205       /* A user-created renderbuffer */
 206       GLuint i;
 207       ASSERT(ctx->Extensions.EXT_framebuffer_object);
 208       for (i = 0; i < ctx->Const.MaxColorAttachments; i++) {
 209          mask |= (BUFFER_BIT_COLOR0 << i);
 210       }
 211    }
 212    else {
 213       /* A window system framebuffer */
 214       GLint i;
 215       mask = BUFFER_BIT_FRONT_LEFT; /* always have this */
 216       if (fb->Visual.stereoMode) {
 217          mask |= BUFFER_BIT_FRONT_RIGHT;
 218          if (fb->Visual.doubleBufferMode) {
 219             mask |= BUFFER_BIT_BACK_LEFT | BUFFER_BIT_BACK_RIGHT;
 220          }
 221       }
 222       else if (fb->Visual.doubleBufferMode) {
 223          mask |= BUFFER_BIT_BACK_LEFT;
 224       }
 225
 226       for (i = 0; i < fb->Visual.numAuxBuffers; i++) {
 227          mask |= (BUFFER_BIT_AUX0 << i);
 228       }
 229    }
 230
 231    return mask;
 232 }
 233
 234
 235 /**
 236  * Helper routine used by glDrawBuffer and glDrawBuffersARB.
 237  * Given a GLenum naming one or more color buffers (such as
 238  * GL_FRONT_AND_BACK), return the corresponding bitmask of BUFFER_BIT_* flags.
 239  */
 240 static GLbitfield
 241 draw_buffer_enum_to_bitmask(GLenum buffer)
 242 {
 243    switch (buffer) {
 244       case GL_NONE:
 245          return 0;
 246       case GL_FRONT:
 247          return BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_FRONT_RIGHT;
 248       case GL_BACK:
 249          return BUFFER_BIT_BACK_LEFT | BUFFER_BIT_BACK_RIGHT;
 250       case GL_RIGHT:
 251          return BUFFER_BIT_FRONT_RIGHT | BUFFER_BIT_BACK_RIGHT;
 252       case GL_FRONT_RIGHT:
 253          return BUFFER_BIT_FRONT_RIGHT;
 254       case GL_BACK_RIGHT:
 255          return BUFFER_BIT_BACK_RIGHT;
 256       case GL_BACK_LEFT:
 257          return BUFFER_BIT_BACK_LEFT;
 258       case GL_FRONT_AND_BACK:
 259          return BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT
 260               | BUFFER_BIT_FRONT_RIGHT | BUFFER_BIT_BACK_RIGHT;
 261       case GL_LEFT:
 262          return BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT;
 263       case GL_FRONT_LEFT:
 264          return BUFFER_BIT_FRONT_LEFT;
 265       case GL_AUX0:
 266          return BUFFER_BIT_AUX0;
 267       case GL_AUX1:
 268          return BUFFER_BIT_AUX1;
 269       case GL_AUX2:
 270          return BUFFER_BIT_AUX2;
 271       case GL_AUX3:
 272          return BUFFER_BIT_AUX3;
 273       case GL_COLOR_ATTACHMENT0_EXT:
 274          return BUFFER_BIT_COLOR0;
 275       case GL_COLOR_ATTACHMENT1_EXT:
 276          return BUFFER_BIT_COLOR1;
 277       case GL_COLOR_ATTACHMENT2_EXT:
 278          return BUFFER_BIT_COLOR2;
 279       case GL_COLOR_ATTACHMENT3_EXT:
 280          return BUFFER_BIT_COLOR3;
 281       case GL_COLOR_ATTACHMENT4_EXT:
 282          return BUFFER_BIT_COLOR4;
 283       case GL_COLOR_ATTACHMENT5_EXT:
 284          return BUFFER_BIT_COLOR5;
 285       case GL_COLOR_ATTACHMENT6_EXT:
 286          return BUFFER_BIT_COLOR6;
 287       case GL_COLOR_ATTACHMENT7_EXT:
 288          return BUFFER_BIT_COLOR7;
 289       default:
 290          /* error */
 291          return BAD_MASK;
 292    }
 293 }
 294
 295
 296 /**
 297  * Helper routine used by glReadBuffer.
 298  * Given a GLenum naming a color buffer, return the index of the corresponding
 299  * renderbuffer (a BUFFER_* value).
 300  * return -1 for an invalid buffer.
 301  */
 302 static GLint
 303 read_buffer_enum_to_index(GLenum buffer)
 304 {
 305    switch (buffer) {
 306       case GL_FRONT:
 307          return BUFFER_FRONT_LEFT;
 308       case GL_BACK:
 309          return BUFFER_BACK_LEFT;
 310       case GL_RIGHT:
 311          return BUFFER_FRONT_RIGHT;
 312       case GL_FRONT_RIGHT:
 313          return BUFFER_FRONT_RIGHT;
 314       case GL_BACK_RIGHT:
 315          return BUFFER_BACK_RIGHT;
 316       case GL_BACK_LEFT:
 317          return BUFFER_BACK_LEFT;
 318       case GL_LEFT:
 319          return BUFFER_FRONT_LEFT;
 320       case GL_FRONT_LEFT:
 321          return BUFFER_FRONT_LEFT;
 322       case GL_AUX0:
 323          return BUFFER_AUX0;
 324       case GL_AUX1:
 325          return BUFFER_AUX1;
 326       case GL_AUX2:
 327          return BUFFER_AUX2;
 328       case GL_AUX3:
 329          return BUFFER_AUX3;
 330       case GL_COLOR_ATTACHMENT0_EXT:
 331          return BUFFER_COLOR0;
 332       case GL_COLOR_ATTACHMENT1_EXT:
 333          return BUFFER_COLOR1;
 334       case GL_COLOR_ATTACHMENT2_EXT:
 335          return BUFFER_COLOR2;
 336       case GL_COLOR_ATTACHMENT3_EXT:
 337          return BUFFER_COLOR3;
 338       case GL_COLOR_ATTACHMENT4_EXT:
 339          return BUFFER_COLOR4;
 340       case GL_COLOR_ATTACHMENT5_EXT:
 341          return BUFFER_COLOR5;
 342       case GL_COLOR_ATTACHMENT6_EXT:
 343          return BUFFER_COLOR6;
 344       case GL_COLOR_ATTACHMENT7_EXT:
 345          return BUFFER_COLOR7;
 346       default:
 347          /* error */
 348          return -1;
 349    }
 350 }
 351
 352
 353 /**
 354  * Called by glDrawBuffer().
 355  * Specify which renderbuffer(s) to draw into for the first color output.
 356  * <buffer> can name zero, one, two or four renderbuffers!
 357  * \sa _mesa_DrawBuffersARB
 358  *
 359  * \param buffer  buffer token such as GL_LEFT or GL_FRONT_AND_BACK, etc.
 360  *
 361  * Note that the behaviour of this function depends on whether the
 362  * current ctx->DrawBuffer is a window-system framebuffer (Name=0) or
 363  * a user-created framebuffer object (Name!=0).
 364  *   In the former case, we update the per-context ctx->Color.DrawBuffer
 365  *   state var _and_ the FB's ColorDrawBuffer state.
 366  *   In the later case, we update the FB's ColorDrawBuffer state only.
 367  *
 368  * Furthermore, upon a MakeCurrent() or BindFramebuffer() call, if the
 369  * new FB is a window system FB, we need to re-update the FB's
 370  * ColorDrawBuffer state to match the context.  This is handled in
 371  * _mesa_update_framebuffer().
 372  *
 373  * See the GL_EXT_framebuffer_object spec for more info.
 374  */
 375 void GLAPIENTRY
 376 _mesa_DrawBuffer(GLenum buffer)
 377 {
 378    GLbitfield destMask;
 379    GET_CURRENT_CONTEXT(ctx);
 380    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx); /* too complex... */
 381
 382    if (MESA_VERBOSE & VERBOSE_API) {
 383       _mesa_debug(ctx, "glDrawBuffer %s\n", _mesa_lookup_enum_by_nr(buffer));
 384    }
 385
 386    if (buffer == GL_NONE) {
 387       destMask = 0x0;
 388    }
 389    else {
 390       const GLbitfield supportedMask
 391          = supported_buffer_bitmask(ctx, ctx->DrawBuffer);
 392       destMask = draw_buffer_enum_to_bitmask(buffer);
 393       if (destMask == BAD_MASK) {
 394          /* totally bogus buffer */
 395          _mesa_error(ctx, GL_INVALID_ENUM, "glDrawBuffer(buffer)");
 396          return;
 397       }
 398       destMask &= supportedMask;
 399       if (destMask == 0x0) {
 400          /* none of the named color buffers exist! */
 401          _mesa_error(ctx, GL_INVALID_OPERATION, "glDrawBuffer(buffer)");
 402          return;
 403       }
 404    }
 405
 406    /* if we get here, there's no error so set new state */
 407    _mesa_drawbuffers(ctx, 1, &buffer, &destMask);
 408
 409    /*
 410     * Call device driver function.
 411     */
 412    if (ctx->Driver.DrawBuffers)
 413       ctx->Driver.DrawBuffers(ctx, 1, &buffer);
 414    else if (ctx->Driver.DrawBuffer)
 415       ctx->Driver.DrawBuffer(ctx, buffer);
 416 }
 417
 418
 419 /**
 420  * Called by glDrawBuffersARB; specifies the destination color renderbuffers
 421  * for N fragment program color outputs.
 422  * \sa _mesa_DrawBuffer
 423  * \param n  number of outputs
 424  * \param buffers  array [n] of renderbuffer names.  Unlike glDrawBuffer, the
 425  *                 names cannot specify more than one buffer.  For example,
 426  *                 GL_FRONT_AND_BACK is illegal.
 427  */
 428 void GLAPIENTRY
 429 _mesa_DrawBuffersARB(GLsizei n, const GLenum *buffers)
 430 {
 431    GLint output;
 432    GLbitfield usedBufferMask, supportedMask;
 433    GLbitfield destMask[MAX_DRAW_BUFFERS];
 434    GET_CURRENT_CONTEXT(ctx);
 435    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx);
 436
 437    if (!ctx->Extensions.ARB_draw_buffers) {
 438       _mesa_error(ctx, GL_INVALID_OPERATION, "glDrawBuffersARB");
 439       return;
 440    }
 441    if (n < 1 || n > (GLsizei) ctx->Const.MaxDrawBuffers) {
 442       _mesa_error(ctx, GL_INVALID_VALUE, "glDrawBuffersARB(n)");
 443       return;
 444    }
 445
 446    supportedMask = supported_buffer_bitmask(ctx, ctx->DrawBuffer);
 447    usedBufferMask = 0x0;
 448
 449    /* complicated error checking... */
 450    for (output = 0; output < n; output++) {
 451       if (buffers[output] == GL_NONE) {
 452          destMask[output] = 0x0;
 453       }
 454       else {
 455          destMask[output] = draw_buffer_enum_to_bitmask(buffers[output]);
 456          if (destMask[output] == BAD_MASK
 457              || _mesa_bitcount(destMask[output]) > 1) {
 458             _mesa_error(ctx, GL_INVALID_ENUM, "glDrawBuffersARB(buffer)");
 459             return;
 460          }
 461          destMask[output] &= supportedMask;
 462          if (destMask[output] == 0) {
 463             _mesa_error(ctx, GL_INVALID_OPERATION,
 464                         "glDrawBuffersARB(unsupported buffer)");
 465             return;
 466          }
 467          if (destMask[output] & usedBufferMask) {
 468             /* can't specify a dest buffer more than once! */
 469             _mesa_error(ctx, GL_INVALID_OPERATION,
 470                         "glDrawBuffersARB(duplicated buffer)");
 471             return;
 472          }
 473
 474          /* update bitmask */
 475          usedBufferMask |= destMask[output];
 476       }
 477    }
 478
 479    /* OK, if we get here, there were no errors so set the new state */
 480    _mesa_drawbuffers(ctx, n, buffers, destMask);
 481
 482    /*
 483     * Call device driver function.
 484     */
 485    if (ctx->Driver.DrawBuffers)
 486       ctx->Driver.DrawBuffers(ctx, n, buffers);
 487    else if (ctx->Driver.DrawBuffer)
 488       ctx->Driver.DrawBuffer(ctx, buffers[0]);
 489 }
 490
 491
 492 /**
 493  * Helper function to set the GL_DRAW_BUFFER state in the context and
 494  * current FBO.
 495  *
 496  * All error checking will have been done prior to calling this function
 497  * so nothing should go wrong at this point.
 498  *
 499  * \param ctx  current context
 500  * \param n    number of color outputs to set
 501  * \param buffers  array[n] of colorbuffer names, like GL_LEFT.
 502  * \param destMask  array[n] of BUFFER_BIT_* bitmasks which correspond to the
 503  *                  colorbuffer names.  (i.e. GL_FRONT_AND_BACK =>
 504  *                  BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT).
 505  */
 506 void
 507 _mesa_drawbuffers(GLcontext *ctx, GLuint n, const GLenum *buffers,
 508                   const GLbitfield *destMask)
 509 {
 510    struct gl_framebuffer *fb = ctx->DrawBuffer;
 511    GLbitfield mask[MAX_DRAW_BUFFERS];
 512
 513    if (!destMask) {
 514       /* compute destMask values now */
 515       const GLbitfield supportedMask = supported_buffer_bitmask(ctx, fb);
 516       GLuint output;
 517       for (output = 0; output < n; output++) {
 518          mask[output] = draw_buffer_enum_to_bitmask(buffers[output]);
 519          ASSERT(mask[output] != BAD_MASK);
 520          mask[output] &= supportedMask;
 521       }
 522       destMask = mask;
 523    }
 524
 525    if (n == 1) {
 526       GLuint buf, count = 0;
 527       /* init to -1 to help catch errors */
 528       fb->_ColorDrawBufferIndexes[0] = -1;
 529       for (buf = 0; buf < BUFFER_COUNT; buf++) {
 530          if (destMask[0] & (1 << buf)) {
 531             fb->_ColorDrawBufferIndexes[count] = buf;
 532             count++;
 533          }
 534       }
 535       fb->ColorDrawBuffer[0] = buffers[0];
 536       fb->_NumColorDrawBuffers = count;
 537    }
 538    else {
 539       GLuint buf, count = 0;
 540       for (buf = 0; buf < n; buf++ ) {
 541          if (destMask[buf]) {
 542             fb->_ColorDrawBufferIndexes[buf] = _mesa_ffs(destMask[buf]) - 1;
 543             fb->ColorDrawBuffer[buf] = buffers[buf];
 544             count = buf + 1;
 545          }
 546          else {
 547             fb->_ColorDrawBufferIndexes[buf] = -1;
 548          }
 549       }
 550       /* set remaining outputs to -1 (GL_NONE) */
 551       while (buf < ctx->Const.MaxDrawBuffers) {
 552          fb->_ColorDrawBufferIndexes[buf] = -1;
 553          fb->ColorDrawBuffer[buf] = GL_NONE;
 554          buf++;
 555       }
 556       fb->_NumColorDrawBuffers = count;
 557    }
 558
 559    if (fb->Name == 0) {
 560       /* also set context drawbuffer state */
 561       GLuint buf;
 562       for (buf = 0; buf < ctx->Const.MaxDrawBuffers; buf++) {
 563          ctx->Color.DrawBuffer[buf] = fb->ColorDrawBuffer[buf];
 564       }
 565    }
 566
 567    ctx->NewState |= _NEW_COLOR;
 568 }
 569
 570
 571 /**
 572  * Like \sa _mesa_drawbuffers(), this is a helper function for setting
 573  * GL_READ_BUFFER state in the context and current FBO.
 574  * \param ctx  the rendering context
 575  * \param buffer  GL_FRONT, GL_BACK, GL_COLOR_ATTACHMENT0, etc.
 576  * \param bufferIndex  the numerical index corresponding to 'buffer'
 577  */
 578 void
 579 _mesa_readbuffer(GLcontext *ctx, GLenum buffer, GLint bufferIndex)
 580 {
 581    struct gl_framebuffer *fb = ctx->ReadBuffer;
 582
 583    if (fb->Name == 0) {
 584       /* Only update the per-context READ_BUFFER state if we're bound to
 585        * a window-system framebuffer.
 586        */
 587       ctx->Pixel.ReadBuffer = buffer;
 588    }
 589
 590    fb->ColorReadBuffer = buffer;
 591    fb->_ColorReadBufferIndex = bufferIndex;
 592
 593    ctx->NewState |= _NEW_PIXEL;
 594 }
 595
 596
 597
 598 /**
 599  * Called by glReadBuffer to set the source renderbuffer for reading pixels.
 600  * \param mode color buffer such as GL_FRONT, GL_BACK, etc.
 601  */
 602 void GLAPIENTRY
 603 _mesa_ReadBuffer(GLenum buffer)
 604 {
 605    struct gl_framebuffer *fb;
 606    GLbitfield supportedMask;
 607    GLint srcBuffer;
 608    GET_CURRENT_CONTEXT(ctx);
 609    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx);
 610
 611    if (MESA_VERBOSE & VERBOSE_API)
 612       _mesa_debug(ctx, "glReadBuffer %s\n", _mesa_lookup_enum_by_nr(buffer));
 613
 614    fb = ctx->ReadBuffer;
 615
 616    if (MESA_VERBOSE & VERBOSE_API)
 617       _mesa_debug(ctx, "glReadBuffer %s\n", _mesa_lookup_enum_by_nr(buffer));
 618
 619    if (fb->Name > 0 && buffer == GL_NONE) {
 620       /* This is legal for user-created framebuffer objects */
 621       srcBuffer = -1;
 622    }
 623    else {
 624       /* general case / window-system framebuffer */
 625       srcBuffer = read_buffer_enum_to_index(buffer);
 626       if (srcBuffer == -1) {
 627          _mesa_error(ctx, GL_INVALID_ENUM,
 628                      "glReadBuffer(buffer=0x%x)", buffer);
 629          return;
 630       }
 631       supportedMask = supported_buffer_bitmask(ctx, fb);
 632       if (((1 << srcBuffer) & supportedMask) == 0) {
 633          _mesa_error(ctx, GL_INVALID_OPERATION,
 634                      "glReadBuffer(buffer=0x%x)", buffer);
 635          return;
 636       }
 637    }
 638
 639    /* OK, all error checking has been completed now */
 640
 641    _mesa_readbuffer(ctx, buffer, srcBuffer);
 642
 643    /*
 644     * Call device driver function.
 645     */
 646    if (ctx->Driver.ReadBuffer)
 647       (*ctx->Driver.ReadBuffer)(ctx, buffer);
 648 }
 649
 650
 651 #if _HAVE_FULL_GL
 652
 653 /**
 654  * XXX THIS IS OBSOLETE - drivers should take care of detecting window
 655  * size changes and act accordingly, likely calling _mesa_resize_framebuffer().
 656  *
 657  * GL_MESA_resize_buffers extension.
 658  *
 659  * When this function is called, we'll ask the window system how large
 660  * the current window is.  If it's a new size, we'll call the driver's
 661  * ResizeBuffers function.  The driver will then resize its color buffers
 662  * as needed, and maybe call the swrast's routine for reallocating
 663  * swrast-managed depth/stencil/accum/etc buffers.
 664  * \note This function should only be called through the GL API, not
 665  * from device drivers (as was done in the past).
 666  */
 667
 668 void _mesa_resizebuffers( GLcontext *ctx )
 669 {
 670    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH( ctx );
 671
 672    if (MESA_VERBOSE & VERBOSE_API)
 673       _mesa_debug(ctx, "glResizeBuffersMESA\n");
 674
 675    if (!ctx->Driver.GetBufferSize) {
 676       return;
 677    }
 678
 679    if (ctx->WinSysDrawBuffer) {
 680       GLuint newWidth, newHeight;
 681       GLframebuffer *buffer = ctx->WinSysDrawBuffer;
 682
 683       assert(buffer->Name == 0);
 684
 685       /* ask device driver for size of output buffer */
 686       ctx->Driver.GetBufferSize( buffer, &newWidth, &newHeight );
 687
 688       /* see if size of device driver's color buffer (window) has changed */
 689       if (buffer->Width != newWidth || buffer->Height != newHeight) {
 690          if (ctx->Driver.ResizeBuffers)
 691             ctx->Driver.ResizeBuffers(ctx, buffer, newWidth, newHeight );
 692       }
 693    }
 694
 695    if (ctx->WinSysReadBuffer
 696        && ctx->WinSysReadBuffer != ctx->WinSysDrawBuffer) {
 697       GLuint newWidth, newHeight;
 698       GLframebuffer *buffer = ctx->WinSysReadBuffer;
 699
 700       assert(buffer->Name == 0);
 701
 702       /* ask device driver for size of read buffer */
 703       ctx->Driver.GetBufferSize( buffer, &newWidth, &newHeight );
 704
 705       /* see if size of device driver's color buffer (window) has changed */
 706       if (buffer->Width != newWidth || buffer->Height != newHeight) {
 707          if (ctx->Driver.ResizeBuffers)
 708             ctx->Driver.ResizeBuffers(ctx, buffer, newWidth, newHeight );
 709       }
 710    }
 711
 712    ctx->NewState |= _NEW_BUFFERS;  /* to update scissor / window bounds */
 713 }
 714
 715
 716 /*
 717  * XXX THIS IS OBSOLETE
 718  */
 719 void GLAPIENTRY
 720 _mesa_ResizeBuffersMESA( void )
 721 {
 722    GET_CURRENT_CONTEXT(ctx);
 723
 724    if (ctx->Extensions.MESA_resize_buffers)
 725       _mesa_resizebuffers( ctx );
 726 }
 727
 728
 729 /*
 730  * XXX move somewhere else someday?
 731  */
 732 void GLAPIENTRY
 733 _mesa_SampleCoverageARB(GLclampf value, GLboolean invert)
 734 {
 735    GET_CURRENT_CONTEXT(ctx);
 736
 737    if (!ctx->Extensions.ARB_multisample) {
 738       _mesa_error(ctx, GL_INVALID_OPERATION, "glSampleCoverageARB");
 739       return;
 740    }
 741
 742    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH( ctx );
 743    ctx->Multisample.SampleCoverageValue = (GLfloat) CLAMP(value, 0.0, 1.0);
 744    ctx->Multisample.SampleCoverageInvert = invert;
 745    ctx->NewState |= _NEW_MULTISAMPLE;
 746 }
 747
 748 #endif /* _HAVE_FULL_GL */
 749
 750
 751
 752 /**
 753  * Define the scissor box.
 754  *
 755  * \param x, y coordinates of the scissor box lower-left corner.
 756  * \param width width of the scissor box.
 757  * \param height height of the scissor box.
 758  *
 759  * \sa glScissor().
 760  *
 761  * Verifies the parameters and updates __GLcontextRec::Scissor. On a
 762  * change flushes the vertices and notifies the driver via
 763  * the dd_function_table::Scissor callback.
 764  */
 765 void
 766 _mesa_set_scissor(GLcontext *ctx,
 767                   GLint x, GLint y, GLsizei width, GLsizei height)
 768 {
 769    if (x == ctx->Scissor.X &&
 770        y == ctx->Scissor.Y &&
 771        width == ctx->Scissor.Width &&
 772        height == ctx->Scissor.Height)
 773       return;
 774
 775    FLUSH_VERTICES(ctx, _NEW_SCISSOR);
 776    ctx->Scissor.X = x;
 777    ctx->Scissor.Y = y;
 778    ctx->Scissor.Width = width;
 779    ctx->Scissor.Height = height;
 780
 781    if (ctx->Driver.Scissor)
 782       ctx->Driver.Scissor( ctx, x, y, width, height );
 783 }
 784
 785
 786 void GLAPIENTRY
 787 _mesa_Scissor( GLint x, GLint y, GLsizei width, GLsizei height )
 788 {
 789    GET_CURRENT_CONTEXT(ctx);
 790    ASSERT_OUTSIDE_BEGIN_END(ctx);
 791
 792    if (width < 0 || height < 0) {
 793       _mesa_error( ctx, GL_INVALID_VALUE, "glScissor" );
 794       return;
 795    }
 796
 797    if (MESA_VERBOSE & VERBOSE_API)
 798       _mesa_debug(ctx, "glScissor %d %d %d %d\n", x, y, width, height);
 799
 800    _mesa_set_scissor(ctx, x, y, width, height);
 801 }
 802
 803
 804
 805 /**********************************************************************/
 806 /** \name Initialization */
 807 /*@{*/
 808
 809 /**
 810  * Initialize the context's scissor state.
 811  * \param ctx  the GL context.
 812  */
 813 void
 814 _mesa_init_scissor(GLcontext *ctx)
 815 {
 816    /* Scissor group */
 817    ctx->Scissor.Enabled = GL_FALSE;
 818    ctx->Scissor.X = 0;
 819    ctx->Scissor.Y = 0;
 820    ctx->Scissor.Width = 0;
 821    ctx->Scissor.Height = 0;
 822 }
 823
 824
 825 /**
 826  * Initialize the context's multisample state.
 827  * \param ctx  the GL context.
 828  */
 829 void
 830 _mesa_init_multisample(GLcontext *ctx)
 831 {
 832    ctx->Multisample.Enabled = GL_TRUE;
 833    ctx->Multisample.SampleAlphaToCoverage = GL_FALSE;
 834    ctx->Multisample.SampleAlphaToOne = GL_FALSE;
 835    ctx->Multisample.SampleCoverage = GL_FALSE;
 836    ctx->Multisample.SampleCoverageValue = 1.0;
 837    ctx->Multisample.SampleCoverageInvert = GL_FALSE;
 838 }
 839
 840 /*@}*/