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 "state.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 GLcontext *ctx, 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          return BUFFER_BIT_AUX1;
 124       case GL_AUX2:
 125          return BUFFER_BIT_AUX2;
 126       case GL_AUX3:
 127          return BUFFER_BIT_AUX3;
 128       case GL_COLOR_ATTACHMENT0_EXT:
 129          return BUFFER_BIT_COLOR0;
 130       case GL_COLOR_ATTACHMENT1_EXT:
 131          return BUFFER_BIT_COLOR1;
 132       case GL_COLOR_ATTACHMENT2_EXT:
 133          return BUFFER_BIT_COLOR2;
 134       case GL_COLOR_ATTACHMENT3_EXT:
 135          return BUFFER_BIT_COLOR3;
 136       case GL_COLOR_ATTACHMENT4_EXT:
 137          return BUFFER_BIT_COLOR4;
 138       case GL_COLOR_ATTACHMENT5_EXT:
 139          return BUFFER_BIT_COLOR5;
 140       case GL_COLOR_ATTACHMENT6_EXT:
 141          return BUFFER_BIT_COLOR6;
 142       case GL_COLOR_ATTACHMENT7_EXT:
 143          return BUFFER_BIT_COLOR7;
 144       default:
 145          /* error */
 146          return BAD_MASK;
 147    }
 148 }
 149
 150
 151 /**
 152  * Helper routine used by glReadBuffer.
 153  * Given a GLenum naming a color buffer, return the index of the corresponding
 154  * renderbuffer (a BUFFER_* value).
 155  * return -1 for an invalid buffer.
 156  */
 157 static GLint
 158 read_buffer_enum_to_index(GLenum buffer)
 159 {
 160    switch (buffer) {
 161       case GL_FRONT:
 162          return BUFFER_FRONT_LEFT;
 163       case GL_BACK:
 164          return BUFFER_BACK_LEFT;
 165       case GL_RIGHT:
 166          return BUFFER_FRONT_RIGHT;
 167       case GL_FRONT_RIGHT:
 168          return BUFFER_FRONT_RIGHT;
 169       case GL_BACK_RIGHT:
 170          return BUFFER_BACK_RIGHT;
 171       case GL_BACK_LEFT:
 172          return BUFFER_BACK_LEFT;
 173       case GL_LEFT:
 174          return BUFFER_FRONT_LEFT;
 175       case GL_FRONT_LEFT:
 176          return BUFFER_FRONT_LEFT;
 177       case GL_AUX0:
 178          return BUFFER_AUX0;
 179       case GL_AUX1:
 180          return BUFFER_AUX1;
 181       case GL_AUX2:
 182          return BUFFER_AUX2;
 183       case GL_AUX3:
 184          return BUFFER_AUX3;
 185       case GL_COLOR_ATTACHMENT0_EXT:
 186          return BUFFER_COLOR0;
 187       case GL_COLOR_ATTACHMENT1_EXT:
 188          return BUFFER_COLOR1;
 189       case GL_COLOR_ATTACHMENT2_EXT:
 190          return BUFFER_COLOR2;
 191       case GL_COLOR_ATTACHMENT3_EXT:
 192          return BUFFER_COLOR3;
 193       case GL_COLOR_ATTACHMENT4_EXT:
 194          return BUFFER_COLOR4;
 195       case GL_COLOR_ATTACHMENT5_EXT:
 196          return BUFFER_COLOR5;
 197       case GL_COLOR_ATTACHMENT6_EXT:
 198          return BUFFER_COLOR6;
 199       case GL_COLOR_ATTACHMENT7_EXT:
 200          return BUFFER_COLOR7;
 201       default:
 202          /* error */
 203          return -1;
 204    }
 205 }
 206
 207
 208 /**
 209  * Called by glDrawBuffer().
 210  * Specify which renderbuffer(s) to draw into for the first color output.
 211  * <buffer> can name zero, one, two or four renderbuffers!
 212  * \sa _mesa_DrawBuffersARB
 213  *
 214  * \param buffer  buffer token such as GL_LEFT or GL_FRONT_AND_BACK, etc.
 215  *
 216  * Note that the behaviour of this function depends on whether the
 217  * current ctx->DrawBuffer is a window-system framebuffer (Name=0) or
 218  * a user-created framebuffer object (Name!=0).
 219  *   In the former case, we update the per-context ctx->Color.DrawBuffer
 220  *   state var _and_ the FB's ColorDrawBuffer state.
 221  *   In the later case, we update the FB's ColorDrawBuffer state only.
 222  *
 223  * Furthermore, upon a MakeCurrent() or BindFramebuffer() call, if the
 224  * new FB is a window system FB, we need to re-update the FB's
 225  * ColorDrawBuffer state to match the context.  This is handled in
 226  * _mesa_update_framebuffer().
 227  *
 228  * See the GL_EXT_framebuffer_object spec for more info.
 229  */
 230 void GLAPIENTRY
 231 _mesa_DrawBuffer(GLenum buffer)
 232 {
 233    GLbitfield destMask;
 234    GET_CURRENT_CONTEXT(ctx);
 235    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx); /* too complex... */
 236
 237    if (MESA_VERBOSE & VERBOSE_API) {
 238       _mesa_debug(ctx, "glDrawBuffer %s\n", _mesa_lookup_enum_by_nr(buffer));
 239    }
 240
 241    if (buffer == GL_NONE) {
 242       destMask = 0x0;
 243    }
 244    else {
 245       const GLbitfield supportedMask
 246          = supported_buffer_bitmask(ctx, ctx->DrawBuffer);
 247       destMask = draw_buffer_enum_to_bitmask(buffer);
 248       if (destMask == BAD_MASK) {
 249          /* totally bogus buffer */
 250          _mesa_error(ctx, GL_INVALID_ENUM, "glDrawBuffer(buffer=0x%x)", buffer);
 251          return;
 252       }
 253       destMask &= supportedMask;
 254       if (destMask == 0x0) {
 255          /* none of the named color buffers exist! */
 256          _mesa_error(ctx, GL_INVALID_OPERATION,
 257                      "glDrawBuffer(buffer=0x%x)", buffer);
 258          return;
 259       }
 260    }
 261
 262    /* if we get here, there's no error so set new state */
 263    _mesa_drawbuffers(ctx, 1, &buffer, &destMask);
 264
 265    /*
 266     * Call device driver function.
 267     */
 268    if (ctx->Driver.DrawBuffers)
 269       ctx->Driver.DrawBuffers(ctx, 1, &buffer);
 270    else if (ctx->Driver.DrawBuffer)
 271       ctx->Driver.DrawBuffer(ctx, buffer);
 272 }
 273
 274
 275 /**
 276  * Called by glDrawBuffersARB; specifies the destination color renderbuffers
 277  * for N fragment program color outputs.
 278  * \sa _mesa_DrawBuffer
 279  * \param n  number of outputs
 280  * \param buffers  array [n] of renderbuffer names.  Unlike glDrawBuffer, the
 281  *                 names cannot specify more than one buffer.  For example,
 282  *                 GL_FRONT_AND_BACK is illegal.
 283  */
 284 void GLAPIENTRY
 285 _mesa_DrawBuffersARB(GLsizei n, const GLenum *buffers)
 286 {
 287    GLint output;
 288    GLbitfield usedBufferMask, supportedMask;
 289    GLbitfield destMask[MAX_DRAW_BUFFERS];
 290    GET_CURRENT_CONTEXT(ctx);
 291    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx);
 292
 293    if (n < 1 || 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.
 336     */
 337    if (ctx->Driver.DrawBuffers)
 338       ctx->Driver.DrawBuffers(ctx, n, buffers);
 339    else if (ctx->Driver.DrawBuffer)
 340       ctx->Driver.DrawBuffer(ctx, buffers[0]);
 341 }
 342
 343
 344 /**
 345  * Helper function to set the GL_DRAW_BUFFER state in the context and
 346  * current FBO.
 347  *
 348  * All error checking will have been done prior to calling this function
 349  * so nothing should go wrong at this point.
 350  *
 351  * \param ctx  current context
 352  * \param n    number of color outputs to set
 353  * \param buffers  array[n] of colorbuffer names, like GL_LEFT.
 354  * \param destMask  array[n] of BUFFER_BIT_* bitmasks which correspond to the
 355  *                  colorbuffer names.  (i.e. GL_FRONT_AND_BACK =>
 356  *                  BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT).
 357  */
 358 void
 359 _mesa_drawbuffers(GLcontext *ctx, GLuint n, const GLenum *buffers,
 360                   const GLbitfield *destMask)
 361 {
 362    struct gl_framebuffer *fb = ctx->DrawBuffer;
 363    GLbitfield mask[MAX_DRAW_BUFFERS];
 364
 365    if (!destMask) {
 366       /* compute destMask values now */
 367       const GLbitfield supportedMask = supported_buffer_bitmask(ctx, fb);
 368       GLuint output;
 369       for (output = 0; output < n; output++) {
 370          mask[output] = draw_buffer_enum_to_bitmask(buffers[output]);
 371          ASSERT(mask[output] != BAD_MASK);
 372          mask[output] &= supportedMask;
 373       }
 374       destMask = mask;
 375    }
 376
 377    if (n == 1) {
 378       GLuint buf, count = 0;
 379       /* init to -1 to help catch errors */
 380       fb->_ColorDrawBufferIndexes[0] = -1;
 381       for (buf = 0; buf < BUFFER_COUNT; buf++) {
 382          if (destMask[0] & (1 << buf)) {
 383             fb->_ColorDrawBufferIndexes[count] = buf;
 384             count++;
 385          }
 386       }
 387       fb->ColorDrawBuffer[0] = buffers[0];
 388       fb->_NumColorDrawBuffers = count;
 389    }
 390    else {
 391       GLuint buf, count = 0;
 392       for (buf = 0; buf < n; buf++ ) {
 393          if (destMask[buf]) {
 394             fb->_ColorDrawBufferIndexes[buf] = _mesa_ffs(destMask[buf]) - 1;
 395             fb->ColorDrawBuffer[buf] = buffers[buf];
 396             count = buf + 1;
 397          }
 398          else {
 399             fb->_ColorDrawBufferIndexes[buf] = -1;
 400          }
 401       }
 402       /* set remaining outputs to -1 (GL_NONE) */
 403       while (buf < ctx->Const.MaxDrawBuffers) {
 404          fb->_ColorDrawBufferIndexes[buf] = -1;
 405          fb->ColorDrawBuffer[buf] = GL_NONE;
 406          buf++;
 407       }
 408       fb->_NumColorDrawBuffers = count;
 409    }
 410
 411    if (fb->Name == 0) {
 412       /* also set context drawbuffer state */
 413       GLuint buf;
 414       for (buf = 0; buf < ctx->Const.MaxDrawBuffers; buf++) {
 415          ctx->Color.DrawBuffer[buf] = fb->ColorDrawBuffer[buf];
 416       }
 417    }
 418
 419    ctx->NewState |= _NEW_BUFFERS;
 420 }
 421
 422
 423 /**
 424  * Like \sa _mesa_drawbuffers(), this is a helper function for setting
 425  * GL_READ_BUFFER state in the context and current FBO.
 426  * \param ctx  the rendering context
 427  * \param buffer  GL_FRONT, GL_BACK, GL_COLOR_ATTACHMENT0, etc.
 428  * \param bufferIndex  the numerical index corresponding to 'buffer'
 429  */
 430 void
 431 _mesa_readbuffer(GLcontext *ctx, GLenum buffer, GLint bufferIndex)
 432 {
 433    struct gl_framebuffer *fb = ctx->ReadBuffer;
 434
 435    if (fb->Name == 0) {
 436       /* Only update the per-context READ_BUFFER state if we're bound to
 437        * a window-system framebuffer.
 438        */
 439       ctx->Pixel.ReadBuffer = buffer;
 440    }
 441
 442    fb->ColorReadBuffer = buffer;
 443    fb->_ColorReadBufferIndex = bufferIndex;
 444
 445    ctx->NewState |= _NEW_PIXEL;
 446 }
 447
 448
 449
 450 /**
 451  * Called by glReadBuffer to set the source renderbuffer for reading pixels.
 452  * \param mode color buffer such as GL_FRONT, GL_BACK, etc.
 453  */
 454 void GLAPIENTRY
 455 _mesa_ReadBuffer(GLenum buffer)
 456 {
 457    struct gl_framebuffer *fb;
 458    GLbitfield supportedMask;
 459    GLint srcBuffer;
 460    GET_CURRENT_CONTEXT(ctx);
 461    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx);
 462
 463    if (MESA_VERBOSE & VERBOSE_API)
 464       _mesa_debug(ctx, "glReadBuffer %s\n", _mesa_lookup_enum_by_nr(buffer));
 465
 466    fb = ctx->ReadBuffer;
 467
 468    if (MESA_VERBOSE & VERBOSE_API)
 469       _mesa_debug(ctx, "glReadBuffer %s\n", _mesa_lookup_enum_by_nr(buffer));
 470
 471    if (fb->Name > 0 && buffer == GL_NONE) {
 472       /* This is legal for user-created framebuffer objects */
 473       srcBuffer = -1;
 474    }
 475    else {
 476       /* general case / window-system framebuffer */
 477       srcBuffer = read_buffer_enum_to_index(buffer);
 478       if (srcBuffer == -1) {
 479          _mesa_error(ctx, GL_INVALID_ENUM,
 480                      "glReadBuffer(buffer=0x%x)", buffer);
 481          return;
 482       }
 483       supportedMask = supported_buffer_bitmask(ctx, fb);
 484       if (((1 << srcBuffer) & supportedMask) == 0) {
 485          _mesa_error(ctx, GL_INVALID_OPERATION,
 486                      "glReadBuffer(buffer=0x%x)", buffer);
 487          return;
 488       }
 489    }
 490
 491    /* OK, all error checking has been completed now */
 492
 493    _mesa_readbuffer(ctx, buffer, srcBuffer);
 494    ctx->NewState |= _NEW_BUFFERS;
 495
 496    /*
 497     * Call device driver function.
 498     */
 499    if (ctx->Driver.ReadBuffer)
 500       (*ctx->Driver.ReadBuffer)(ctx, buffer);
 501 }