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 "fbobject.h"
  39 #include "mtypes.h"
  40
  41
  42 #define BAD_MASK ~0u
  43
  44
  45 /**
  46  * Return bitmask of BUFFER_BIT_* flags indicating which color buffers are
  47  * available to the rendering context (for drawing or reading).
  48  * This depends on the type of framebuffer.  For window system framebuffers
  49  * we look at the framebuffer's visual.  But for user-create framebuffers we
  50  * look at the number of supported color attachments.
  51  * \param fb  the framebuffer to draw to, or read from
  52  * \return  bitmask of BUFFER_BIT_* flags
  53  */
  54 static GLbitfield
  55 supported_buffer_bitmask(const struct gl_context *ctx,
  56                          const struct gl_framebuffer *fb)
  57 {
  58    GLbitfield mask = 0x0;
  59
  60    if (_mesa_is_user_fbo(fb)) {
  61       /* A user-created renderbuffer */
  62       GLuint i;
  63       ASSERT(ctx->Extensions.EXT_framebuffer_object);
  64       for (i = 0; i < ctx->Const.MaxColorAttachments; i++) {
  65          mask |= (BUFFER_BIT_COLOR0 << i);
  66       }
  67    }
  68    else {
  69       /* A window system framebuffer */
  70       GLint i;
  71       mask = BUFFER_BIT_FRONT_LEFT; /* always have this */
  72       if (fb->Visual.stereoMode) {
  73          mask |= BUFFER_BIT_FRONT_RIGHT;
  74          if (fb->Visual.doubleBufferMode) {
  75             mask |= BUFFER_BIT_BACK_LEFT | BUFFER_BIT_BACK_RIGHT;
  76          }
  77       }
  78       else if (fb->Visual.doubleBufferMode) {
  79          mask |= BUFFER_BIT_BACK_LEFT;
  80       }
  81
  82       for (i = 0; i < fb->Visual.numAuxBuffers; i++) {
  83          mask |= (BUFFER_BIT_AUX0 << i);
  84       }
  85    }
  86
  87    return mask;
  88 }
  89
  90
  91 /**
  92  * Helper routine used by glDrawBuffer and glDrawBuffersARB.
  93  * Given a GLenum naming one or more color buffers (such as
  94  * GL_FRONT_AND_BACK), return the corresponding bitmask of BUFFER_BIT_* flags.
  95  */
  96 static GLbitfield
  97 draw_buffer_enum_to_bitmask(GLenum buffer)
  98 {
  99    switch (buffer) {
 100       case GL_NONE:
 101          return 0;
 102       case GL_FRONT:
 103          return BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_FRONT_RIGHT;
 104       case GL_BACK:
 105          return BUFFER_BIT_BACK_LEFT | BUFFER_BIT_BACK_RIGHT;
 106       case GL_RIGHT:
 107          return BUFFER_BIT_FRONT_RIGHT | BUFFER_BIT_BACK_RIGHT;
 108       case GL_FRONT_RIGHT:
 109          return BUFFER_BIT_FRONT_RIGHT;
 110       case GL_BACK_RIGHT:
 111          return BUFFER_BIT_BACK_RIGHT;
 112       case GL_BACK_LEFT:
 113          return BUFFER_BIT_BACK_LEFT;
 114       case GL_FRONT_AND_BACK:
 115          return BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT
 116               | BUFFER_BIT_FRONT_RIGHT | BUFFER_BIT_BACK_RIGHT;
 117       case GL_LEFT:
 118          return BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT;
 119       case GL_FRONT_LEFT:
 120          return BUFFER_BIT_FRONT_LEFT;
 121       case GL_AUX0:
 122          return BUFFER_BIT_AUX0;
 123       case GL_AUX1:
 124       case GL_AUX2:
 125       case GL_AUX3:
 126          return 1 << BUFFER_COUNT; /* invalid, but not BAD_MASK */
 127       case GL_COLOR_ATTACHMENT0_EXT:
 128          return BUFFER_BIT_COLOR0;
 129       case GL_COLOR_ATTACHMENT1_EXT:
 130          return BUFFER_BIT_COLOR1;
 131       case GL_COLOR_ATTACHMENT2_EXT:
 132          return BUFFER_BIT_COLOR2;
 133       case GL_COLOR_ATTACHMENT3_EXT:
 134          return BUFFER_BIT_COLOR3;
 135       case GL_COLOR_ATTACHMENT4_EXT:
 136          return BUFFER_BIT_COLOR4;
 137       case GL_COLOR_ATTACHMENT5_EXT:
 138          return BUFFER_BIT_COLOR5;
 139       case GL_COLOR_ATTACHMENT6_EXT:
 140          return BUFFER_BIT_COLOR6;
 141       case GL_COLOR_ATTACHMENT7_EXT:
 142          return BUFFER_BIT_COLOR7;
 143       default:
 144          /* error */
 145          return BAD_MASK;
 146    }
 147 }
 148
 149
 150 /**
 151  * Helper routine used by glReadBuffer.
 152  * Given a GLenum naming a color buffer, return the index of the corresponding
 153  * renderbuffer (a BUFFER_* value).
 154  * return -1 for an invalid buffer.
 155  */
 156 static GLint
 157 read_buffer_enum_to_index(GLenum buffer)
 158 {
 159    switch (buffer) {
 160       case GL_FRONT:
 161          return BUFFER_FRONT_LEFT;
 162       case GL_BACK:
 163          return BUFFER_BACK_LEFT;
 164       case GL_RIGHT:
 165          return BUFFER_FRONT_RIGHT;
 166       case GL_FRONT_RIGHT:
 167          return BUFFER_FRONT_RIGHT;
 168       case GL_BACK_RIGHT:
 169          return BUFFER_BACK_RIGHT;
 170       case GL_BACK_LEFT:
 171          return BUFFER_BACK_LEFT;
 172       case GL_LEFT:
 173          return BUFFER_FRONT_LEFT;
 174       case GL_FRONT_LEFT:
 175          return BUFFER_FRONT_LEFT;
 176       case GL_AUX0:
 177          return BUFFER_AUX0;
 178       case GL_AUX1:
 179       case GL_AUX2:
 180       case GL_AUX3:
 181          return BUFFER_COUNT; /* invalid, but not -1 */
 182       case GL_COLOR_ATTACHMENT0_EXT:
 183          return BUFFER_COLOR0;
 184       case GL_COLOR_ATTACHMENT1_EXT:
 185          return BUFFER_COLOR1;
 186       case GL_COLOR_ATTACHMENT2_EXT:
 187          return BUFFER_COLOR2;
 188       case GL_COLOR_ATTACHMENT3_EXT:
 189          return BUFFER_COLOR3;
 190       case GL_COLOR_ATTACHMENT4_EXT:
 191          return BUFFER_COLOR4;
 192       case GL_COLOR_ATTACHMENT5_EXT:
 193          return BUFFER_COLOR5;
 194       case GL_COLOR_ATTACHMENT6_EXT:
 195          return BUFFER_COLOR6;
 196       case GL_COLOR_ATTACHMENT7_EXT:
 197          return BUFFER_COLOR7;
 198       default:
 199          /* error */
 200          return -1;
 201    }
 202 }
 203
 204
 205 /**
 206  * Called by glDrawBuffer().
 207  * Specify which renderbuffer(s) to draw into for the first color output.
 208  * <buffer> can name zero, one, two or four renderbuffers!
 209  * \sa _mesa_DrawBuffersARB
 210  *
 211  * \param buffer  buffer token such as GL_LEFT or GL_FRONT_AND_BACK, etc.
 212  *
 213  * Note that the behaviour of this function depends on whether the
 214  * current ctx->DrawBuffer is a window-system framebuffer (Name=0) or
 215  * a user-created framebuffer object (Name!=0).
 216  *   In the former case, we update the per-context ctx->Color.DrawBuffer
 217  *   state var _and_ the FB's ColorDrawBuffer state.
 218  *   In the later case, we update the FB's ColorDrawBuffer state only.
 219  *
 220  * Furthermore, upon a MakeCurrent() or BindFramebuffer() call, if the
 221  * new FB is a window system FB, we need to re-update the FB's
 222  * ColorDrawBuffer state to match the context.  This is handled in
 223  * _mesa_update_framebuffer().
 224  *
 225  * See the GL_EXT_framebuffer_object spec for more info.
 226  */
 227 void GLAPIENTRY
 228 _mesa_DrawBuffer(GLenum buffer)
 229 {
 230    GLbitfield destMask;
 231    GET_CURRENT_CONTEXT(ctx);
 232    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx); /* too complex... */
 233
 234    if (MESA_VERBOSE & VERBOSE_API) {
 235       _mesa_debug(ctx, "glDrawBuffer %s\n", _mesa_lookup_enum_by_nr(buffer));
 236    }
 237
 238    if (buffer == GL_NONE) {
 239       destMask = 0x0;
 240    }
 241    else {
 242       const GLbitfield supportedMask
 243          = supported_buffer_bitmask(ctx, ctx->DrawBuffer);
 244       destMask = draw_buffer_enum_to_bitmask(buffer);
 245       if (destMask == BAD_MASK) {
 246          /* totally bogus buffer */
 247          _mesa_error(ctx, GL_INVALID_ENUM,
 248                      "glDrawBuffer(buffer=0x%x)", buffer);
 249          return;
 250       }
 251       destMask &= supportedMask;
 252       if (destMask == 0x0) {
 253          /* none of the named color buffers exist! */
 254          _mesa_error(ctx, GL_INVALID_OPERATION,
 255                      "glDrawBuffer(buffer=0x%x)", buffer);
 256          return;
 257       }
 258    }
 259
 260    /* if we get here, there's no error so set new state */
 261    _mesa_drawbuffers(ctx, 1, &buffer, &destMask);
 262
 263    /*
 264     * Call device driver function.
 265     */
 266    if (ctx->Driver.DrawBuffers)
 267       ctx->Driver.DrawBuffers(ctx, 1, &buffer);
 268    else if (ctx->Driver.DrawBuffer)
 269       ctx->Driver.DrawBuffer(ctx, buffer);
 270 }
 271
 272
 273 /**
 274  * Called by glDrawBuffersARB; specifies the destination color renderbuffers
 275  * for N fragment program color outputs.
 276  * \sa _mesa_DrawBuffer
 277  * \param n  number of outputs
 278  * \param buffers  array [n] of renderbuffer names.  Unlike glDrawBuffer, the
 279  *                 names cannot specify more than one buffer.  For example,
 280  *                 GL_FRONT_AND_BACK is illegal.
 281  */
 282 void GLAPIENTRY
 283 _mesa_DrawBuffersARB(GLsizei n, const GLenum *buffers)
 284 {
 285    GLint output;
 286    GLbitfield usedBufferMask, supportedMask;
 287    GLbitfield destMask[MAX_DRAW_BUFFERS];
 288    GET_CURRENT_CONTEXT(ctx);
 289    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx);
 290
 291    /* Turns out n==0 is a valid input that should not produce an error.
 292     * The remaining code below correctly handles the n==0 case.
 293     */
 294    if (n < 0 || n > (GLsizei) ctx->Const.MaxDrawBuffers) {
 295       _mesa_error(ctx, GL_INVALID_VALUE, "glDrawBuffersARB(n)");
 296       return;
 297    }
 298
 299    supportedMask = supported_buffer_bitmask(ctx, ctx->DrawBuffer);
 300    usedBufferMask = 0x0;
 301
 302    /* complicated error checking... */
 303    for (output = 0; output < n; output++) {
 304       if (buffers[output] == GL_NONE) {
 305          destMask[output] = 0x0;
 306       }
 307       else {
 308          destMask[output] = draw_buffer_enum_to_bitmask(buffers[output]);
 309          if (destMask[output] == BAD_MASK
 310              || _mesa_bitcount(destMask[output]) > 1) {
 311             _mesa_error(ctx, GL_INVALID_ENUM, "glDrawBuffersARB(buffer)");
 312             return;
 313          }
 314          destMask[output] &= supportedMask;
 315          if (destMask[output] == 0) {
 316             _mesa_error(ctx, GL_INVALID_OPERATION,
 317                         "glDrawBuffersARB(unsupported buffer)");
 318             return;
 319          }
 320          if (destMask[output] & usedBufferMask) {
 321             /* can't specify a dest buffer more than once! */
 322             _mesa_error(ctx, GL_INVALID_OPERATION,
 323                         "glDrawBuffersARB(duplicated buffer)");
 324             return;
 325          }
 326
 327          /* update bitmask */
 328          usedBufferMask |= destMask[output];
 329       }
 330    }
 331
 332    /* OK, if we get here, there were no errors so set the new state */
 333    _mesa_drawbuffers(ctx, n, buffers, destMask);
 334
 335    /*
 336     * Call device driver function.  Note that n can be equal to 0,
 337     * in which case we don't want to reference buffers[0], which
 338     * may not be valid.
 339     */
 340    if (ctx->Driver.DrawBuffers)
 341       ctx->Driver.DrawBuffers(ctx, n, buffers);
 342    else if (ctx->Driver.DrawBuffer)
 343       ctx->Driver.DrawBuffer(ctx, n > 0 ? buffers[0] : GL_NONE);
 344 }
 345
 346
 347 /**
 348  * Performs necessary state updates when _mesa_drawbuffers makes an
 349  * actual change.
 350  */
 351 static void
 352 updated_drawbuffers(struct gl_context *ctx)
 353 {
 354    FLUSH_VERTICES(ctx, _NEW_BUFFERS);
 355
 356 #if FEATURE_GL
 357    if (ctx->API == API_OPENGL && !ctx->Extensions.ARB_ES2_compatibility) {
 358       struct gl_framebuffer *fb = ctx->DrawBuffer;
 359
 360       /* Flag the FBO as requiring validation. */
 361       if (_mesa_is_user_fbo(fb)) {
 362          fb->_Status = 0;
 363       }
 364    }
 365 #endif
 366 }
 367
 368
 369 /**
 370  * Helper function to set the GL_DRAW_BUFFER state in the context and
 371  * current FBO.  Called via glDrawBuffer(), glDrawBuffersARB()
 372  *
 373  * All error checking will have been done prior to calling this function
 374  * so nothing should go wrong at this point.
 375  *
 376  * \param ctx  current context
 377  * \param n    number of color outputs to set
 378  * \param buffers  array[n] of colorbuffer names, like GL_LEFT.
 379  * \param destMask  array[n] of BUFFER_BIT_* bitmasks which correspond to the
 380  *                  colorbuffer names.  (i.e. GL_FRONT_AND_BACK =>
 381  *                  BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT).
 382  */
 383 void
 384 _mesa_drawbuffers(struct gl_context *ctx, GLuint n, const GLenum *buffers,
 385                   const GLbitfield *destMask)
 386 {
 387    struct gl_framebuffer *fb = ctx->DrawBuffer;
 388    GLbitfield mask[MAX_DRAW_BUFFERS];
 389    GLuint buf;
 390
 391    if (!destMask) {
 392       /* compute destMask values now */
 393       const GLbitfield supportedMask = supported_buffer_bitmask(ctx, fb);
 394       GLuint output;
 395       for (output = 0; output < n; output++) {
 396          mask[output] = draw_buffer_enum_to_bitmask(buffers[output]);
 397          ASSERT(mask[output] != BAD_MASK);
 398          mask[output] &= supportedMask;
 399       }
 400       destMask = mask;
 401    }
 402
 403    /*
 404     * If n==1, destMask[0] may have up to four bits set.
 405     * Otherwise, destMask[x] can only have one bit set.
 406     */
 407    if (n == 1) {
 408       GLuint count = 0, destMask0 = destMask[0];
 409       while (destMask0) {
 410          GLint bufIndex = ffs(destMask0) - 1;
 411          if (fb->_ColorDrawBufferIndexes[count] != bufIndex) {
 412             updated_drawbuffers(ctx);
 413             fb->_ColorDrawBufferIndexes[count] = bufIndex;
 414          }
 415          count++;
 416          destMask0 &= ~(1 << bufIndex);
 417       }
 418       fb->ColorDrawBuffer[0] = buffers[0];
 419       fb->_NumColorDrawBuffers = count;
 420    }
 421    else {
 422       GLuint count = 0;
 423       for (buf = 0; buf < n; buf++ ) {
 424          if (destMask[buf]) {
 425             GLint bufIndex = ffs(destMask[buf]) - 1;
 426             /* only one bit should be set in the destMask[buf] field */
 427             ASSERT(_mesa_bitcount(destMask[buf]) == 1);
 428             if (fb->_ColorDrawBufferIndexes[buf] != bufIndex) {
 429                updated_drawbuffers(ctx);
 430                fb->_ColorDrawBufferIndexes[buf] = bufIndex;
 431             }
 432             count = buf + 1;
 433          }
 434          else {
 435             if (fb->_ColorDrawBufferIndexes[buf] != -1) {
 436                updated_drawbuffers(ctx);
 437                fb->_ColorDrawBufferIndexes[buf] = -1;
 438             }
 439          }
 440          fb->ColorDrawBuffer[buf] = buffers[buf];
 441       }
 442       fb->_NumColorDrawBuffers = count;
 443    }
 444
 445    /* set remaining outputs to -1 (GL_NONE) */
 446    for (buf = fb->_NumColorDrawBuffers; buf < ctx->Const.MaxDrawBuffers; buf++) {
 447       if (fb->_ColorDrawBufferIndexes[buf] != -1) {
 448          updated_drawbuffers(ctx);
 449          fb->_ColorDrawBufferIndexes[buf] = -1;
 450       }
 451    }
 452    for (buf = n; buf < ctx->Const.MaxDrawBuffers; buf++) {
 453       fb->ColorDrawBuffer[buf] = GL_NONE;
 454    }
 455
 456    if (_mesa_is_winsys_fbo(fb)) {
 457       /* also set context drawbuffer state */
 458       for (buf = 0; buf < ctx->Const.MaxDrawBuffers; buf++) {
 459          if (ctx->Color.DrawBuffer[buf] != fb->ColorDrawBuffer[buf]) {
 460             updated_drawbuffers(ctx);
 461             ctx->Color.DrawBuffer[buf] = fb->ColorDrawBuffer[buf];
 462          }
 463       }
 464    }
 465 }
 466
 467
 468 /**
 469  * Update the current drawbuffer's _ColorDrawBufferIndex[] list, etc.
 470  * from the context's Color.DrawBuffer[] state.
 471  * Use when changing contexts.
 472  */
 473 void
 474 _mesa_update_draw_buffers(struct gl_context *ctx)
 475 {
 476    GLenum buffers[MAX_DRAW_BUFFERS];
 477    GLuint i;
 478
 479    /* should be a window system FBO */
 480    assert(_mesa_is_winsys_fbo(ctx->DrawBuffer));
 481
 482    for (i = 0; i < ctx->Const.MaxDrawBuffers; i++)
 483       buffers[i] = ctx->Color.DrawBuffer[i];
 484
 485    _mesa_drawbuffers(ctx, ctx->Const.MaxDrawBuffers, buffers, NULL);
 486 }
 487
 488
 489 /**
 490  * Like \sa _mesa_drawbuffers(), this is a helper function for setting
 491  * GL_READ_BUFFER state in the context and current FBO.
 492  * \param ctx  the rendering context
 493  * \param buffer  GL_FRONT, GL_BACK, GL_COLOR_ATTACHMENT0, etc.
 494  * \param bufferIndex  the numerical index corresponding to 'buffer'
 495  */
 496 void
 497 _mesa_readbuffer(struct gl_context *ctx, GLenum buffer, GLint bufferIndex)
 498 {
 499    struct gl_framebuffer *fb = ctx->ReadBuffer;
 500
 501    if (_mesa_is_winsys_fbo(fb)) {
 502       /* Only update the per-context READ_BUFFER state if we're bound to
 503        * a window-system framebuffer.
 504        */
 505       ctx->Pixel.ReadBuffer = buffer;
 506    }
 507
 508    fb->ColorReadBuffer = buffer;
 509    fb->_ColorReadBufferIndex = bufferIndex;
 510
 511    ctx->NewState |= _NEW_BUFFERS;
 512 }
 513
 514
 515
 516 /**
 517  * Called by glReadBuffer to set the source renderbuffer for reading pixels.
 518  * \param mode color buffer such as GL_FRONT, GL_BACK, etc.
 519  */
 520 void GLAPIENTRY
 521 _mesa_ReadBuffer(GLenum buffer)
 522 {
 523    struct gl_framebuffer *fb;
 524    GLbitfield supportedMask;
 525    GLint srcBuffer;
 526    GET_CURRENT_CONTEXT(ctx);
 527    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx);
 528
 529    if (MESA_VERBOSE & VERBOSE_API)
 530       _mesa_debug(ctx, "glReadBuffer %s\n", _mesa_lookup_enum_by_nr(buffer));
 531
 532    fb = ctx->ReadBuffer;
 533
 534    if (MESA_VERBOSE & VERBOSE_API)
 535       _mesa_debug(ctx, "glReadBuffer %s\n", _mesa_lookup_enum_by_nr(buffer));
 536
 537    if (_mesa_is_user_fbo(fb) && buffer == GL_NONE) {
 538       /* This is legal for user-created framebuffer objects */
 539       srcBuffer = -1;
 540    }
 541    else {
 542       /* general case / window-system framebuffer */
 543       srcBuffer = read_buffer_enum_to_index(buffer);
 544       if (srcBuffer == -1) {
 545          _mesa_error(ctx, GL_INVALID_ENUM,
 546                      "glReadBuffer(buffer=0x%x)", buffer);
 547          return;
 548       }
 549       supportedMask = supported_buffer_bitmask(ctx, fb);
 550       if (((1 << srcBuffer) & supportedMask) == 0) {
 551          _mesa_error(ctx, GL_INVALID_OPERATION,
 552                      "glReadBuffer(buffer=0x%x)", buffer);
 553          return;
 554       }
 555    }
 556
 557    /* OK, all error checking has been completed now */
 558
 559    _mesa_readbuffer(ctx, buffer, srcBuffer);
 560    ctx->NewState |= _NEW_BUFFERS;
 561
 562    /*
 563     * Call device driver function.
 564     */
 565    if (ctx->Driver.ReadBuffer)
 566       (*ctx->Driver.ReadBuffer)(ctx, buffer);
 567 }