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