dll/opengl/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  * \file buffers.c
  27  * glReadBuffer, DrawBuffer functions.
  28  */
  29
  30 #include <precomp.h>
  31
  32 #define BAD_MASK ~0u
  33
  34 /**
  35  * Return bitmask of BUFFER_BIT_* flags indicating which color buffers are
  36  * available to the rendering context (for drawing or reading).
  37  * This depends on the type of framebuffer.  For window system framebuffers
  38  * we look at the framebuffer's visual.  But for user-create framebuffers we
  39  * look at the number of supported color attachments.
  40  * \param fb  the framebuffer to draw to, or read from
  41  * \return  bitmask of BUFFER_BIT_* flags
  42  */
  43 static GLbitfield
  44 supported_buffer_bitmask(const struct gl_context *ctx, const struct gl_framebuffer *fb)
  45 {
  46    GLbitfield mask = 0x0;
  47
  48    /* A window system framebuffer */
  49    GLint i;
  50    mask = BUFFER_BIT_FRONT_LEFT; /* always have this */
  51    if (fb->Visual.stereoMode) {
  52       mask |= BUFFER_BIT_FRONT_RIGHT;
  53       if (fb->Visual.doubleBufferMode) {
  54          mask |= BUFFER_BIT_BACK_LEFT | BUFFER_BIT_BACK_RIGHT;
  55       }
  56    }
  57    else if (fb->Visual.doubleBufferMode) {
  58       mask |= BUFFER_BIT_BACK_LEFT;
  59    }
  60
  61    for (i = 0; i < fb->Visual.numAuxBuffers; i++) {
  62       mask |= (BUFFER_BIT_AUX0 << i);
  63    }
  64
  65    return mask;
  66 }
  67
  68
  69 /**
  70  * Helper routine used by glDrawBuffer and glDrawBuffersARB.
  71  * Given a GLenum naming one or more color buffers (such as
  72  * GL_FRONT_AND_BACK), return the corresponding bitmask of BUFFER_BIT_* flags.
  73  */
  74 static GLbitfield
  75 draw_buffer_enum_to_bitmask(GLenum buffer)
  76 {
  77    switch (buffer) {
  78       case GL_NONE:
  79          return 0;
  80       case GL_FRONT:
  81          return BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_FRONT_RIGHT;
  82       case GL_BACK:
  83          return BUFFER_BIT_BACK_LEFT | BUFFER_BIT_BACK_RIGHT;
  84       case GL_RIGHT:
  85          return BUFFER_BIT_FRONT_RIGHT | BUFFER_BIT_BACK_RIGHT;
  86       case GL_FRONT_RIGHT:
  87          return BUFFER_BIT_FRONT_RIGHT;
  88       case GL_BACK_RIGHT:
  89          return BUFFER_BIT_BACK_RIGHT;
  90       case GL_BACK_LEFT:
  91          return BUFFER_BIT_BACK_LEFT;
  92       case GL_FRONT_AND_BACK:
  93          return BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT
  94               | BUFFER_BIT_FRONT_RIGHT | BUFFER_BIT_BACK_RIGHT;
  95       case GL_LEFT:
  96          return BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT;
  97       case GL_FRONT_LEFT:
  98          return BUFFER_BIT_FRONT_LEFT;
  99       case GL_AUX0:
 100          return BUFFER_BIT_AUX0;
 101       case GL_AUX1:
 102       case GL_AUX2:
 103       case GL_AUX3:
 104          return 1 << BUFFER_COUNT; /* invalid, but not BAD_MASK */
 105       default:
 106          /* error */
 107          return BAD_MASK;
 108    }
 109 }
 110
 111
 112 /**
 113  * Helper routine used by glReadBuffer.
 114  * Given a GLenum naming a color buffer, return the index of the corresponding
 115  * renderbuffer (a BUFFER_* value).
 116  * return -1 for an invalid buffer.
 117  */
 118 static GLint
 119 read_buffer_enum_to_index(GLenum buffer)
 120 {
 121    switch (buffer) {
 122       case GL_FRONT:
 123          return BUFFER_FRONT_LEFT;
 124       case GL_BACK:
 125          return BUFFER_BACK_LEFT;
 126       case GL_RIGHT:
 127          return BUFFER_FRONT_RIGHT;
 128       case GL_FRONT_RIGHT:
 129          return BUFFER_FRONT_RIGHT;
 130       case GL_BACK_RIGHT:
 131          return BUFFER_BACK_RIGHT;
 132       case GL_BACK_LEFT:
 133          return BUFFER_BACK_LEFT;
 134       case GL_LEFT:
 135          return BUFFER_FRONT_LEFT;
 136       case GL_FRONT_LEFT:
 137          return BUFFER_FRONT_LEFT;
 138       case GL_AUX0:
 139          return BUFFER_AUX0;
 140       case GL_AUX1:
 141       case GL_AUX2:
 142       case GL_AUX3:
 143          return BUFFER_COUNT; /* invalid, but not -1 */
 144       default:
 145          /* error */
 146          return -1;
 147    }
 148 }
 149
 150
 151 /**
 152  * Called by glDrawBuffer().
 153  * Specify which renderbuffer(s) to draw into for the first color output.
 154  * <buffer> can name zero, one, two or four renderbuffers!
 155  * \sa _mesa_DrawBuffersARB
 156  *
 157  * \param buffer  buffer token such as GL_LEFT or GL_FRONT_AND_BACK, etc.
 158  *
 159  * Note that the behaviour of this function depends on whether the
 160  * current ctx->DrawBuffer is a window-system framebuffer (Name=0) or
 161  * a user-created framebuffer object (Name!=0).
 162  *   In the former case, we update the per-context ctx->Color.DrawBuffer
 163  *   state var _and_ the FB's ColorDrawBuffer state.
 164  *   In the later case, we update the FB's ColorDrawBuffer state only.
 165  *
 166  * Furthermore, upon a MakeCurrent() or BindFramebuffer() call, if the
 167  * new FB is a window system FB, we need to re-update the FB's
 168  * ColorDrawBuffer state to match the context.  This is handled in
 169  * _mesa_update_framebuffer().
 170  *
 171  * See the GL_EXT_framebuffer_object spec for more info.
 172  */
 173 void GLAPIENTRY
 174 _mesa_DrawBuffer(GLenum buffer)
 175 {
 176    GLbitfield destMask;
 177    GET_CURRENT_CONTEXT(ctx);
 178    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx); /* too complex... */
 179
 180    if (MESA_VERBOSE & VERBOSE_API) {
 181       _mesa_debug(ctx, "glDrawBuffer %s\n", _mesa_lookup_enum_by_nr(buffer));
 182    }
 183
 184    if (buffer == GL_NONE) {
 185       destMask = 0x0;
 186    }
 187    else {
 188       const GLbitfield supportedMask
 189          = supported_buffer_bitmask(ctx, ctx->DrawBuffer);
 190       destMask = draw_buffer_enum_to_bitmask(buffer);
 191       if (destMask == BAD_MASK) {
 192          /* totally bogus buffer */
 193          _mesa_error(ctx, GL_INVALID_ENUM, "glDrawBuffer(buffer=0x%x)", buffer);
 194          return;
 195       }
 196       destMask &= supportedMask;
 197       if (destMask == 0x0) {
 198          /* none of the named color buffers exist! */
 199          _mesa_error(ctx, GL_INVALID_OPERATION,
 200                      "glDrawBuffer(buffer=0x%x)", buffer);
 201          return;
 202       }
 203    }
 204
 205    /* if we get here, there's no error so set new state */
 206    _mesa_drawbuffer(ctx, buffer, destMask);
 207
 208    /*
 209     * Call device driver function.
 210     */
 211    if (ctx->Driver.DrawBuffer)
 212       ctx->Driver.DrawBuffer(ctx, buffer);
 213 }
 214
 215 /**
 216  * Performs necessary state updates when _mesa_drawbuffers makes an
 217  * actual change.
 218  */
 219 static void
 220 updated_drawbuffers(struct gl_context *ctx)
 221 {
 222    FLUSH_VERTICES(ctx, _NEW_BUFFERS);
 223 }
 224
 225 /**
 226  * Helper function to set the GL_DRAW_BUFFER state in the context and
 227  * current FBO.  Called via glDrawBuffer(), glDrawBuffersARB()
 228  *
 229  * All error checking will have been done prior to calling this function
 230  * so nothing should go wrong at this point.
 231  *
 232  * \param ctx  current context
 233  * \param n    number of color outputs to set
 234  * \param buffers  array[n] of colorbuffer names, like GL_LEFT.
 235  * \param destMask  array[n] of BUFFER_BIT_* bitmasks which correspond to the
 236  *                  colorbuffer names.  (i.e. GL_FRONT_AND_BACK =>
 237  *                  BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT).
 238  */
 239 void
 240 _mesa_drawbuffer(struct gl_context *ctx, const GLenum buffers, GLbitfield destMask)
 241 {
 242    struct gl_framebuffer *fb = ctx->DrawBuffer;
 243    GLint bufIndex;
 244
 245    if (!destMask) {
 246       /* compute destMask values now */
 247       const GLbitfield supportedMask = supported_buffer_bitmask(ctx, fb);
 248       destMask = draw_buffer_enum_to_bitmask(buffers);
 249       ASSERT(destmask != BAD_MASK);
 250       destMask &= supportedMask;
 251    }
 252
 253    bufIndex = _mesa_ffs(destMask) - 1;
 254
 255    if (fb->_ColorDrawBufferIndex != bufIndex) {
 256       updated_drawbuffers(ctx);
 257       fb->_ColorDrawBufferIndex = bufIndex;
 258    }
 259    fb->ColorDrawBuffer = buffers;
 260
 261    if (ctx->Color.DrawBuffer != fb->ColorDrawBuffer) {
 262       updated_drawbuffers(ctx);
 263       ctx->Color.DrawBuffer = fb->ColorDrawBuffer;
 264    }
 265 }
 266
 267
 268 /**
 269  * Update the current drawbuffer's _ColorDrawBufferIndex[] list, etc.
 270  * from the context's Color.DrawBuffer[] state.
 271  * Use when changing contexts.
 272  */
 273 void
 274 _mesa_update_draw_buffer(struct gl_context *ctx)
 275 {
 276    _mesa_drawbuffer(ctx, ctx->Color.DrawBuffer, 0);
 277 }
 278
 279
 280 /**
 281  * Like \sa _mesa_drawbuffers(), this is a helper function for setting
 282  * GL_READ_BUFFER state in the context and current FBO.
 283  * \param ctx  the rendering context
 284  * \param buffer  GL_FRONT, GL_BACK, GL_COLOR_ATTACHMENT0, etc.
 285  * \param bufferIndex  the numerical index corresponding to 'buffer'
 286  */
 287 void
 288 _mesa_readbuffer(struct gl_context *ctx, GLenum buffer, GLint bufferIndex)
 289 {
 290    struct gl_framebuffer *fb = ctx->ReadBuffer;
 291
 292    ctx->Pixel.ReadBuffer = buffer;
 293
 294    fb->ColorReadBuffer = buffer;
 295    fb->_ColorReadBufferIndex = bufferIndex;
 296
 297    ctx->NewState |= _NEW_BUFFERS;
 298 }
 299
 300
 301
 302 /**
 303  * Called by glReadBuffer to set the source renderbuffer for reading pixels.
 304  * \param mode color buffer such as GL_FRONT, GL_BACK, etc.
 305  */
 306 void GLAPIENTRY
 307 _mesa_ReadBuffer(GLenum buffer)
 308 {
 309    struct gl_framebuffer *fb;
 310    GLbitfield supportedMask;
 311    GLint srcBuffer;
 312    GET_CURRENT_CONTEXT(ctx);
 313    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx);
 314
 315    if (MESA_VERBOSE & VERBOSE_API)
 316       _mesa_debug(ctx, "glReadBuffer %s\n", _mesa_lookup_enum_by_nr(buffer));
 317
 318    fb = ctx->ReadBuffer;
 319
 320    if (MESA_VERBOSE & VERBOSE_API)
 321       _mesa_debug(ctx, "glReadBuffer %s\n", _mesa_lookup_enum_by_nr(buffer));
 322
 323    /* general case / window-system framebuffer */
 324    srcBuffer = read_buffer_enum_to_index(buffer);
 325    if (srcBuffer == -1) {
 326       _mesa_error(ctx, GL_INVALID_ENUM,
 327                   "glReadBuffer(buffer=0x%x)", buffer);
 328       return;
 329    }
 330    supportedMask = supported_buffer_bitmask(ctx, fb);
 331    if (((1 << srcBuffer) & supportedMask) == 0) {
 332       _mesa_error(ctx, GL_INVALID_OPERATION,
 333                   "glReadBuffer(buffer=0x%x)", buffer);
 334       return;
 335    }
 336
 337    /* OK, all error checking has been completed now */
 338
 339    _mesa_readbuffer(ctx, buffer, srcBuffer);
 340    ctx->NewState |= _NEW_BUFFERS;
 341
 342    /*
 343     * Call device driver function.
 344     */
 345    if (ctx->Driver.ReadBuffer)
 346       (*ctx->Driver.ReadBuffer)(ctx, buffer);
 347 }