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  * glReadBuffer, DrawBuffer functions.
  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 "mtypes.h"
  39
  40
  41 #define BAD_MASK ~0u
  42
  43
  44 /**
  45  * Return bitmask of BUFFER_BIT_* flags indicating which color buffers are
  46  * available to the rendering context (for drawing or reading).
  47  * This depends on the type of framebuffer.  For window system framebuffers
  48  * we look at the framebuffer's visual.  But for user-create framebuffers we
  49  * look at the number of supported color attachments.
  50  * \param fb  the framebuffer to draw to, or read from
  51  * \return  bitmask of BUFFER_BIT_* flags
  52  */
  53 static GLbitfield
  54 supported_buffer_bitmask(const struct gl_context *ctx,
  55                          const struct gl_framebuffer *fb)
  56 {
  57    GLbitfield mask = 0x0;
  58
  59    if (fb->Name > 0) {
  60       /* A user-created renderbuffer */
  61       GLuint i;
  62       ASSERT(ctx->Extensions.EXT_framebuffer_object);
  63       for (i = 0; i < ctx->Const.MaxColorAttachments; i++) {
  64          mask |= (BUFFER_BIT_COLOR0 << i);
  65       }
  66    }
  67    else {
  68       /* A window system framebuffer */
  69       GLint i;
  70       mask = BUFFER_BIT_FRONT_LEFT; /* always have this */
  71       if (fb->Visual.stereoMode) {
  72          mask |= BUFFER_BIT_FRONT_RIGHT;
  73          if (fb->Visual.doubleBufferMode) {
  74             mask |= BUFFER_BIT_BACK_LEFT | BUFFER_BIT_BACK_RIGHT;
  75          }
  76       }
  77       else if (fb->Visual.doubleBufferMode) {
  78          mask |= BUFFER_BIT_BACK_LEFT;
  79       }
  80
  81       for (i = 0; i < fb->Visual.numAuxBuffers; i++) {
  82          mask |= (BUFFER_BIT_AUX0 << i);
  83       }
  84    }
  85
  86    return mask;
  87 }
  88
  89
  90 /**
  91  * Helper routine used by glDrawBuffer and glDrawBuffersARB.
  92  * Given a GLenum naming one or more color buffers (such as
  93  * GL_FRONT_AND_BACK), return the corresponding bitmask of BUFFER_BIT_* flags.
  94  */
  95 static GLbitfield
  96 draw_buffer_enum_to_bitmask(GLenum buffer)
  97 {
  98    switch (buffer) {
  99       case GL_NONE:
 100          return 0;
 101       case GL_FRONT:
 102          return BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_FRONT_RIGHT;
 103       case GL_BACK:
 104          return BUFFER_BIT_BACK_LEFT | BUFFER_BIT_BACK_RIGHT;
 105       case GL_RIGHT:
 106          return BUFFER_BIT_FRONT_RIGHT | BUFFER_BIT_BACK_RIGHT;
 107       case GL_FRONT_RIGHT:
 108          return BUFFER_BIT_FRONT_RIGHT;
 109       case GL_BACK_RIGHT:
 110          return BUFFER_BIT_BACK_RIGHT;
 111       case GL_BACK_LEFT:
 112          return BUFFER_BIT_BACK_LEFT;
 113       case GL_FRONT_AND_BACK:
 114          return BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT
 115               | BUFFER_BIT_FRONT_RIGHT | BUFFER_BIT_BACK_RIGHT;
 116       case GL_LEFT:
 117          return BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT;
 118       case GL_FRONT_LEFT:
 119          return BUFFER_BIT_FRONT_LEFT;
 120       case GL_AUX0:
 121          return BUFFER_BIT_AUX0;
 122       case GL_AUX1:
 123       case GL_AUX2:
 124       case GL_AUX3:
 125          return 1 << BUFFER_COUNT; /* invalid, but not BAD_MASK */
 126       case GL_COLOR_ATTACHMENT0_EXT:
 127          return BUFFER_BIT_COLOR0;
 128       case GL_COLOR_ATTACHMENT1_EXT:
 129          return BUFFER_BIT_COLOR1;
 130       case GL_COLOR_ATTACHMENT2_EXT:
 131          return BUFFER_BIT_COLOR2;
 132       case GL_COLOR_ATTACHMENT3_EXT:
 133          return BUFFER_BIT_COLOR3;
 134       case GL_COLOR_ATTACHMENT4_EXT:
 135          return BUFFER_BIT_COLOR4;
 136       case GL_COLOR_ATTACHMENT5_EXT:
 137          return BUFFER_BIT_COLOR5;
 138       case GL_COLOR_ATTACHMENT6_EXT:
 139          return BUFFER_BIT_COLOR6;
 140       case GL_COLOR_ATTACHMENT7_EXT:
 141          return BUFFER_BIT_COLOR7;
 142       default:
 143          /* error */
 144          return BAD_MASK;
 145    }
 146 }
 147
 148
 149 /**
 150  * Helper routine used by glReadBuffer.
 151  * Given a GLenum naming a color buffer, return the index of the corresponding
 152  * renderbuffer (a BUFFER_* value).
 153  * return -1 for an invalid buffer.
 154  */
 155 static GLint
 156 read_buffer_enum_to_index(GLenum buffer)
 157 {
 158    switch (buffer) {
 159       case GL_FRONT:
 160          return BUFFER_FRONT_LEFT;
 161       case GL_BACK:
 162          return BUFFER_BACK_LEFT;
 163       case GL_RIGHT:
 164          return BUFFER_FRONT_RIGHT;
 165       case GL_FRONT_RIGHT:
 166          return BUFFER_FRONT_RIGHT;
 167       case GL_BACK_RIGHT:
 168          return BUFFER_BACK_RIGHT;
 169       case GL_BACK_LEFT:
 170          return BUFFER_BACK_LEFT;
 171       case GL_LEFT:
 172          return BUFFER_FRONT_LEFT;
 173       case GL_FRONT_LEFT:
 174          return BUFFER_FRONT_LEFT;
 175       case GL_AUX0:
 176          return BUFFER_AUX0;
 177       case GL_AUX1:
 178       case GL_AUX2:
 179       case GL_AUX3:
 180          return BUFFER_COUNT; /* invalid, but not -1 */
 181       case GL_COLOR_ATTACHMENT0_EXT:
 182          return BUFFER_COLOR0;
 183       case GL_COLOR_ATTACHMENT1_EXT:
 184          return BUFFER_COLOR1;
 185       case GL_COLOR_ATTACHMENT2_EXT:
 186          return BUFFER_COLOR2;
 187       case GL_COLOR_ATTACHMENT3_EXT:
 188          return BUFFER_COLOR3;
 189       case GL_COLOR_ATTACHMENT4_EXT:
 190          return BUFFER_COLOR4;
 191       case GL_COLOR_ATTACHMENT5_EXT:
 192          return BUFFER_COLOR5;
 193       case GL_COLOR_ATTACHMENT6_EXT:
 194          return BUFFER_COLOR6;
 195       case GL_COLOR_ATTACHMENT7_EXT:
 196          return BUFFER_COLOR7;
 197       default:
 198          /* error */
 199          return -1;
 200    }
 201 }
 202
 203
 204 /**
 205  * Called by glDrawBuffer().
 206  * Specify which renderbuffer(s) to draw into for the first color output.
 207  * <buffer> can name zero, one, two or four renderbuffers!
 208  * \sa _mesa_DrawBuffersARB
 209  *
 210  * \param buffer  buffer token such as GL_LEFT or GL_FRONT_AND_BACK, etc.
 211  *
 212  * Note that the behaviour of this function depends on whether the
 213  * current ctx->DrawBuffer is a window-system framebuffer (Name=0) or
 214  * a user-created framebuffer object (Name!=0).
 215  *   In the former case, we update the per-context ctx->Color.DrawBuffer
 216  *   state var _and_ the FB's ColorDrawBuffer state.
 217  *   In the later case, we update the FB's ColorDrawBuffer state only.
 218  *
 219  * Furthermore, upon a MakeCurrent() or BindFramebuffer() call, if the
 220  * new FB is a window system FB, we need to re-update the FB's
 221  * ColorDrawBuffer state to match the context.  This is handled in
 222  * _mesa_update_framebuffer().
 223  *
 224  * See the GL_EXT_framebuffer_object spec for more info.
 225  */
 226 void GLAPIENTRY
 227 _mesa_DrawBuffer(GLenum buffer)
 228 {
 229    GLbitfield destMask;
 230    GET_CURRENT_CONTEXT(ctx);
 231    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx); /* too complex... */
 232
 233    if (MESA_VERBOSE & VERBOSE_API) {
 234       _mesa_debug(ctx, "glDrawBuffer %s\n", _mesa_lookup_enum_by_nr(buffer));
 235    }
 236
 237    if (buffer == GL_NONE) {
 238       destMask = 0x0;
 239    }
 240    else {
 241       const GLbitfield supportedMask
 242          = supported_buffer_bitmask(ctx, ctx->DrawBuffer);
 243       destMask = draw_buffer_enum_to_bitmask(buffer);
 244       if (destMask == BAD_MASK) {
 245          /* totally bogus buffer */
 246          _mesa_error(ctx, GL_INVALID_ENUM,
 247                      "glDrawBuffer(buffer=0x%x)", buffer);
 248          return;
 249       }
 250       destMask &= supportedMask;
 251       if (destMask == 0x0) {
 252          /* none of the named color buffers exist! */
 253          _mesa_error(ctx, GL_INVALID_OPERATION,
 254                      "glDrawBuffer(buffer=0x%x)", buffer);
 255          return;
 256       }
 257    }
 258
 259    /* if we get here, there's no error so set new state */
 260    _mesa_drawbuffers(ctx, 1, &buffer, &destMask);
 261
 262    /*
 263     * Call device driver function.
 264     */
 265    if (ctx->Driver.DrawBuffers)
 266       ctx->Driver.DrawBuffers(ctx, 1, &buffer);
 267    else if (ctx->Driver.DrawBuffer)
 268       ctx->Driver.DrawBuffer(ctx, buffer);
 269 }
 270
 271
 272 /**
 273  * Called by glDrawBuffersARB; specifies the destination color renderbuffers
 274  * for N fragment program color outputs.
 275  * \sa _mesa_DrawBuffer
 276  * \param n  number of outputs
 277  * \param buffers  array [n] of renderbuffer names.  Unlike glDrawBuffer, the
 278  *                 names cannot specify more than one buffer.  For example,
 279  *                 GL_FRONT_AND_BACK is illegal.
 280  */
 281 void GLAPIENTRY
 282 _mesa_DrawBuffersARB(GLsizei n, const GLenum *buffers)
 283 {
 284    GLint output;
 285    GLbitfield usedBufferMask, supportedMask;
 286    GLbitfield destMask[MAX_DRAW_BUFFERS];
 287    GET_CURRENT_CONTEXT(ctx);
 288    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx);
 289
 290    /* Turns out n==0 is a valid input that should not produce an error.
 291     * The remaining code below correctly handles the n==0 case.
 292     */
 293    if (n < 0 || n > (GLsizei) ctx->Const.MaxDrawBuffers) {
 294       _mesa_error(ctx, GL_INVALID_VALUE, "glDrawBuffersARB(n)");
 295       return;
 296    }
 297
 298    supportedMask = supported_buffer_bitmask(ctx, ctx->DrawBuffer);
 299    usedBufferMask = 0x0;
 300
 301    /* complicated error checking... */
 302    for (output = 0; output < n; output++) {
 303       if (buffers[output] == GL_NONE) {
 304          destMask[output] = 0x0;
 305       }
 306       else {
 307          destMask[output] = draw_buffer_enum_to_bitmask(buffers[output]);
 308          if (destMask[output] == BAD_MASK
 309              || _mesa_bitcount(destMask[output]) > 1) {
 310             _mesa_error(ctx, GL_INVALID_ENUM, "glDrawBuffersARB(buffer)");
 311             return;
 312          }
 313          destMask[output] &= supportedMask;
 314          if (destMask[output] == 0) {
 315             _mesa_error(ctx, GL_INVALID_OPERATION,
 316                         "glDrawBuffersARB(unsupported buffer)");
 317             return;
 318          }
 319          if (destMask[output] & usedBufferMask) {
 320             /* can't specify a dest buffer more than once! */
 321             _mesa_error(ctx, GL_INVALID_OPERATION,
 322                         "glDrawBuffersARB(duplicated buffer)");
 323             return;
 324          }
 325
 326          /* update bitmask */
 327          usedBufferMask |= destMask[output];
 328       }
 329    }
 330
 331    /* OK, if we get here, there were no errors so set the new state */
 332    _mesa_drawbuffers(ctx, n, buffers, destMask);
 333
 334    /*
 335     * Call device driver function.  Note that n can be equal to 0,
 336     * in which case we don't want to reference buffers[0], which
 337     * may not be valid.
 338     */
 339    if (ctx->Driver.DrawBuffers)
 340       ctx->Driver.DrawBuffers(ctx, n, buffers);
 341    else if (ctx->Driver.DrawBuffer)
 342       ctx->Driver.DrawBuffer(ctx, n > 0 ? buffers[0] : GL_NONE);
 343 }
 344
 345
 346 /**
 347  * Performs necessary state updates when _mesa_drawbuffers makes an
 348  * actual change.
 349  */
 350 static void
 351 updated_drawbuffers(struct gl_context *ctx)
 352 {
 353    FLUSH_VERTICES(ctx, _NEW_BUFFERS);
 354
 355 #if FEATURE_GL
 356    if (ctx->API == API_OPENGL && !ctx->Extensions.ARB_ES2_compatibility) {
 357       struct gl_framebuffer *fb = ctx->DrawBuffer;
 358
 359       /* Flag the FBO as requiring validation. */
 360       if (fb->Name != 0) {
 361          fb->_Status = 0;
 362       }
 363    }
 364 #endif
 365 }
 366
 367
 368 /**
 369  * Helper function to set the GL_DRAW_BUFFER state in the context and
 370  * current FBO.  Called via glDrawBuffer(), glDrawBuffersARB()
 371  *
 372  * All error checking will have been done prior to calling this function
 373  * so nothing should go wrong at this point.
 374  *
 375  * \param ctx  current context
 376  * \param n    number of color outputs to set
 377  * \param buffers  array[n] of colorbuffer names, like GL_LEFT.
 378  * \param destMask  array[n] of BUFFER_BIT_* bitmasks which correspond to the
 379  *                  colorbuffer names.  (i.e. GL_FRONT_AND_BACK =>
 380  *                  BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT).
 381  */
 382 void
 383 _mesa_drawbuffers(struct gl_context *ctx, GLuint n, const GLenum *buffers,
 384                   const GLbitfield *destMask)
 385 {
 386    struct gl_framebuffer *fb = ctx->DrawBuffer;
 387    GLbitfield mask[MAX_DRAW_BUFFERS];
 388    GLuint buf;
 389
 390    if (!destMask) {
 391       /* compute destMask values now */
 392       const GLbitfield supportedMask = supported_buffer_bitmask(ctx, fb);
 393       GLuint output;
 394       for (output = 0; output < n; output++) {
 395          mask[output] = draw_buffer_enum_to_bitmask(buffers[output]);
 396          ASSERT(mask[output] != BAD_MASK);
 397          mask[output] &= supportedMask;
 398       }
 399       destMask = mask;
 400    }
 401
 402    /*
 403     * If n==1, destMask[0] may have up to four bits set.
 404     * Otherwise, destMask[x] can only have one bit set.
 405     */
 406    if (n == 1) {
 407       GLuint count = 0, destMask0 = destMask[0];
 408       while (destMask0) {
 409          GLint bufIndex = ffs(destMask0) - 1;
 410          if (fb->_ColorDrawBufferIndexes[count] != bufIndex) {
 411             updated_drawbuffers(ctx);
 412             fb->_ColorDrawBufferIndexes[count] = bufIndex;
 413          }
 414          count++;
 415          destMask0 &= ~(1 << bufIndex);
 416       }
 417       fb->ColorDrawBuffer[0] = buffers[0];
 418       fb->_NumColorDrawBuffers = count;
 419    }
 420    else {
 421       GLuint count = 0;
 422       for (buf = 0; buf < n; buf++ ) {
 423          if (destMask[buf]) {
 424             GLint bufIndex = ffs(destMask[buf]) - 1;
 425             /* only one bit should be set in the destMask[buf] field */
 426             ASSERT(_mesa_bitcount(destMask[buf]) == 1);
 427             if (fb->_ColorDrawBufferIndexes[buf] != bufIndex) {
 428                updated_drawbuffers(ctx);
 429                fb->_ColorDrawBufferIndexes[buf] = bufIndex;
 430             }
 431             count = buf + 1;
 432          }
 433          else {
 434             if (fb->_ColorDrawBufferIndexes[buf] != -1) {
 435                updated_drawbuffers(ctx);
 436                fb->_ColorDrawBufferIndexes[buf] = -1;
 437             }
 438          }
 439          fb->ColorDrawBuffer[buf] = buffers[buf];
 440       }
 441       fb->_NumColorDrawBuffers = count;
 442    }
 443
 444    /* set remaining outputs to -1 (GL_NONE) */
 445    for (buf = fb->_NumColorDrawBuffers; buf < ctx->Const.MaxDrawBuffers; buf++) {
 446       if (fb->_ColorDrawBufferIndexes[buf] != -1) {
 447          updated_drawbuffers(ctx);
 448          fb->_ColorDrawBufferIndexes[buf] = -1;
 449       }
 450    }
 451    for (buf = n; buf < ctx->Const.MaxDrawBuffers; buf++) {
 452       fb->ColorDrawBuffer[buf] = GL_NONE;
 453    }
 454
 455    if (fb->Name == 0) {
 456       /* also set context drawbuffer state */
 457       for (buf = 0; buf < ctx->Const.MaxDrawBuffers; buf++) {
 458          if (ctx->Color.DrawBuffer[buf] != fb->ColorDrawBuffer[buf]) {
 459             updated_drawbuffers(ctx);
 460             ctx->Color.DrawBuffer[buf] = fb->ColorDrawBuffer[buf];
 461          }
 462       }
 463    }
 464 }
 465
 466
 467 /**
 468  * Update the current drawbuffer's _ColorDrawBufferIndex[] list, etc.
 469  * from the context's Color.DrawBuffer[] state.
 470  * Use when changing contexts.
 471  */
 472 void
 473 _mesa_update_draw_buffers(struct gl_context *ctx)
 474 {
 475    GLenum buffers[MAX_DRAW_BUFFERS];
 476    GLuint i;
 477
 478    /* should be a window system FBO */
 479    assert(ctx->DrawBuffer->Name == 0);
 480
 481    for (i = 0; i < ctx->Const.MaxDrawBuffers; i++)
 482       buffers[i] = ctx->Color.DrawBuffer[i];
 483
 484    _mesa_drawbuffers(ctx, ctx->Const.MaxDrawBuffers, buffers, NULL);
 485 }
 486
 487
 488 /**
 489  * Like \sa _mesa_drawbuffers(), this is a helper function for setting
 490  * GL_READ_BUFFER state in the context and current FBO.
 491  * \param ctx  the rendering context
 492  * \param buffer  GL_FRONT, GL_BACK, GL_COLOR_ATTACHMENT0, etc.
 493  * \param bufferIndex  the numerical index corresponding to 'buffer'
 494  */
 495 void
 496 _mesa_readbuffer(struct gl_context *ctx, GLenum buffer, GLint bufferIndex)
 497 {
 498    struct gl_framebuffer *fb = ctx->ReadBuffer;
 499
 500    if (fb->Name == 0) {
 501       /* Only update the per-context READ_BUFFER state if we're bound to
 502        * a window-system framebuffer.
 503        */
 504       ctx->Pixel.ReadBuffer = buffer;
 505    }
 506
 507    fb->ColorReadBuffer = buffer;
 508    fb->_ColorReadBufferIndex = bufferIndex;
 509
 510    ctx->NewState |= _NEW_BUFFERS;
 511 }
 512
 513
 514
 515 /**
 516  * Called by glReadBuffer to set the source renderbuffer for reading pixels.
 517  * \param mode color buffer such as GL_FRONT, GL_BACK, etc.
 518  */
 519 void GLAPIENTRY
 520 _mesa_ReadBuffer(GLenum buffer)
 521 {
 522    struct gl_framebuffer *fb;
 523    GLbitfield supportedMask;
 524    GLint srcBuffer;
 525    GET_CURRENT_CONTEXT(ctx);
 526    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx);
 527
 528    if (MESA_VERBOSE & VERBOSE_API)
 529       _mesa_debug(ctx, "glReadBuffer %s\n", _mesa_lookup_enum_by_nr(buffer));
 530
 531    fb = ctx->ReadBuffer;
 532
 533    if (MESA_VERBOSE & VERBOSE_API)
 534       _mesa_debug(ctx, "glReadBuffer %s\n", _mesa_lookup_enum_by_nr(buffer));
 535
 536    if (fb->Name > 0 && buffer == GL_NONE) {
 537       /* This is legal for user-created framebuffer objects */
 538       srcBuffer = -1;
 539    }
 540    else {
 541       /* general case / window-system framebuffer */
 542       srcBuffer = read_buffer_enum_to_index(buffer);
 543       if (srcBuffer == -1) {
 544          _mesa_error(ctx, GL_INVALID_ENUM,
 545                      "glReadBuffer(buffer=0x%x)", buffer);
 546          return;
 547       }
 548       supportedMask = supported_buffer_bitmask(ctx, fb);
 549       if (((1 << srcBuffer) & supportedMask) == 0) {
 550          _mesa_error(ctx, GL_INVALID_OPERATION,
 551                      "glReadBuffer(buffer=0x%x)", buffer);
 552          return;
 553       }
 554    }
 555
 556    /* OK, all error checking has been completed now */
 557
 558    _mesa_readbuffer(ctx, buffer, srcBuffer);
 559    ctx->NewState |= _NEW_BUFFERS;
 560
 561    /*
 562     * Call device driver function.
 563     */
 564    if (ctx->Driver.ReadBuffer)
 565       (*ctx->Driver.ReadBuffer)(ctx, buffer);
 566 }