reactos/dll/opengl/mesa/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, const struct gl_framebuffer *fb)
  55 {
  56    GLbitfield mask = 0x0;
  57
  58    /* A window system framebuffer */
  59    GLint i;
  60    mask = BUFFER_BIT_FRONT_LEFT; /* always have this */
  61    if (fb->Visual.stereoMode) {
  62       mask |= BUFFER_BIT_FRONT_RIGHT;
  63       if (fb->Visual.doubleBufferMode) {
  64          mask |= BUFFER_BIT_BACK_LEFT | BUFFER_BIT_BACK_RIGHT;
  65       }
  66    }
  67    else if (fb->Visual.doubleBufferMode) {
  68       mask |= BUFFER_BIT_BACK_LEFT;
  69    }
  70
  71    for (i = 0; i < fb->Visual.numAuxBuffers; i++) {
  72       mask |= (BUFFER_BIT_AUX0 << i);
  73    }
  74
  75    return mask;
  76 }
  77
  78
  79 /**
  80  * Helper routine used by glDrawBuffer and glDrawBuffersARB.
  81  * Given a GLenum naming one or more color buffers (such as
  82  * GL_FRONT_AND_BACK), return the corresponding bitmask of BUFFER_BIT_* flags.
  83  */
  84 static GLbitfield
  85 draw_buffer_enum_to_bitmask(GLenum buffer)
  86 {
  87    switch (buffer) {
  88       case GL_NONE:
  89          return 0;
  90       case GL_FRONT:
  91          return BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_FRONT_RIGHT;
  92       case GL_BACK:
  93          return BUFFER_BIT_BACK_LEFT | BUFFER_BIT_BACK_RIGHT;
  94       case GL_RIGHT:
  95          return BUFFER_BIT_FRONT_RIGHT | BUFFER_BIT_BACK_RIGHT;
  96       case GL_FRONT_RIGHT:
  97          return BUFFER_BIT_FRONT_RIGHT;
  98       case GL_BACK_RIGHT:
  99          return BUFFER_BIT_BACK_RIGHT;
 100       case GL_BACK_LEFT:
 101          return BUFFER_BIT_BACK_LEFT;
 102       case GL_FRONT_AND_BACK:
 103          return BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT
 104               | BUFFER_BIT_FRONT_RIGHT | BUFFER_BIT_BACK_RIGHT;
 105       case GL_LEFT:
 106          return BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT;
 107       case GL_FRONT_LEFT:
 108          return BUFFER_BIT_FRONT_LEFT;
 109       case GL_AUX0:
 110          return BUFFER_BIT_AUX0;
 111       case GL_AUX1:
 112       case GL_AUX2:
 113       case GL_AUX3:
 114          return 1 << BUFFER_COUNT; /* invalid, but not BAD_MASK */
 115       default:
 116          /* error */
 117          return BAD_MASK;
 118    }
 119 }
 120
 121
 122 /**
 123  * Helper routine used by glReadBuffer.
 124  * Given a GLenum naming a color buffer, return the index of the corresponding
 125  * renderbuffer (a BUFFER_* value).
 126  * return -1 for an invalid buffer.
 127  */
 128 static GLint
 129 read_buffer_enum_to_index(GLenum buffer)
 130 {
 131    switch (buffer) {
 132       case GL_FRONT:
 133          return BUFFER_FRONT_LEFT;
 134       case GL_BACK:
 135          return BUFFER_BACK_LEFT;
 136       case GL_RIGHT:
 137          return BUFFER_FRONT_RIGHT;
 138       case GL_FRONT_RIGHT:
 139          return BUFFER_FRONT_RIGHT;
 140       case GL_BACK_RIGHT:
 141          return BUFFER_BACK_RIGHT;
 142       case GL_BACK_LEFT:
 143          return BUFFER_BACK_LEFT;
 144       case GL_LEFT:
 145          return BUFFER_FRONT_LEFT;
 146       case GL_FRONT_LEFT:
 147          return BUFFER_FRONT_LEFT;
 148       case GL_AUX0:
 149          return BUFFER_AUX0;
 150       case GL_AUX1:
 151       case GL_AUX2:
 152       case GL_AUX3:
 153          return BUFFER_COUNT; /* invalid, but not -1 */
 154       default:
 155          /* error */
 156          return -1;
 157    }
 158 }
 159
 160
 161 /**
 162  * Called by glDrawBuffer().
 163  * Specify which renderbuffer(s) to draw into for the first color output.
 164  * <buffer> can name zero, one, two or four renderbuffers!
 165  * \sa _mesa_DrawBuffersARB
 166  *
 167  * \param buffer  buffer token such as GL_LEFT or GL_FRONT_AND_BACK, etc.
 168  *
 169  * Note that the behaviour of this function depends on whether the
 170  * current ctx->DrawBuffer is a window-system framebuffer (Name=0) or
 171  * a user-created framebuffer object (Name!=0).
 172  *   In the former case, we update the per-context ctx->Color.DrawBuffer
 173  *   state var _and_ the FB's ColorDrawBuffer state.
 174  *   In the later case, we update the FB's ColorDrawBuffer state only.
 175  *
 176  * Furthermore, upon a MakeCurrent() or BindFramebuffer() call, if the
 177  * new FB is a window system FB, we need to re-update the FB's
 178  * ColorDrawBuffer state to match the context.  This is handled in
 179  * _mesa_update_framebuffer().
 180  *
 181  * See the GL_EXT_framebuffer_object spec for more info.
 182  */
 183 void GLAPIENTRY
 184 _mesa_DrawBuffer(GLenum buffer)
 185 {
 186    GLbitfield destMask;
 187    GET_CURRENT_CONTEXT(ctx);
 188    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx); /* too complex... */
 189
 190    if (MESA_VERBOSE & VERBOSE_API) {
 191       _mesa_debug(ctx, "glDrawBuffer %s\n", _mesa_lookup_enum_by_nr(buffer));
 192    }
 193
 194    if (buffer == GL_NONE) {
 195       destMask = 0x0;
 196    }
 197    else {
 198       const GLbitfield supportedMask
 199          = supported_buffer_bitmask(ctx, ctx->DrawBuffer);
 200       destMask = draw_buffer_enum_to_bitmask(buffer);
 201       if (destMask == BAD_MASK) {
 202          /* totally bogus buffer */
 203          _mesa_error(ctx, GL_INVALID_ENUM, "glDrawBuffer(buffer=0x%x)", buffer);
 204          return;
 205       }
 206       destMask &= supportedMask;
 207       if (destMask == 0x0) {
 208          /* none of the named color buffers exist! */
 209          _mesa_error(ctx, GL_INVALID_OPERATION,
 210                      "glDrawBuffer(buffer=0x%x)", buffer);
 211          return;
 212       }
 213    }
 214
 215    /* if we get here, there's no error so set new state */
 216    _mesa_drawbuffer(ctx, buffer, destMask);
 217
 218    /*
 219     * Call device driver function.
 220     */
 221    if (ctx->Driver.DrawBuffer)
 222       ctx->Driver.DrawBuffer(ctx, buffer);
 223 }
 224
 225 /**
 226  * Performs necessary state updates when _mesa_drawbuffers makes an
 227  * actual change.
 228  */
 229 static void
 230 updated_drawbuffers(struct gl_context *ctx)
 231 {
 232    FLUSH_VERTICES(ctx, _NEW_BUFFERS);
 233 }
 234
 235 /**
 236  * Helper function to set the GL_DRAW_BUFFER state in the context and
 237  * current FBO.  Called via glDrawBuffer(), glDrawBuffersARB()
 238  *
 239  * All error checking will have been done prior to calling this function
 240  * so nothing should go wrong at this point.
 241  *
 242  * \param ctx  current context
 243  * \param n    number of color outputs to set
 244  * \param buffers  array[n] of colorbuffer names, like GL_LEFT.
 245  * \param destMask  array[n] of BUFFER_BIT_* bitmasks which correspond to the
 246  *                  colorbuffer names.  (i.e. GL_FRONT_AND_BACK =>
 247  *                  BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT).
 248  */
 249 void
 250 _mesa_drawbuffer(struct gl_context *ctx, const GLenum buffers, GLbitfield destMask)
 251 {
 252    struct gl_framebuffer *fb = ctx->DrawBuffer;
 253    GLint bufIndex;
 254
 255    if (!destMask) {
 256       /* compute destMask values now */
 257       const GLbitfield supportedMask = supported_buffer_bitmask(ctx, fb);
 258       destMask = draw_buffer_enum_to_bitmask(buffers);
 259       ASSERT(destmask != BAD_MASK);
 260       destMask &= supportedMask;
 261    }
 262
 263    bufIndex = _mesa_ffs(destMask) - 1;
 264
 265    if (fb->_ColorDrawBufferIndex != bufIndex) {
 266       updated_drawbuffers(ctx);
 267       fb->_ColorDrawBufferIndex = bufIndex;
 268    }
 269    fb->ColorDrawBuffer = buffers;
 270
 271    if (ctx->Color.DrawBuffer != fb->ColorDrawBuffer) {
 272       updated_drawbuffers(ctx);
 273       ctx->Color.DrawBuffer = fb->ColorDrawBuffer;
 274    }
 275 }
 276
 277
 278 /**
 279  * Update the current drawbuffer's _ColorDrawBufferIndex[] list, etc.
 280  * from the context's Color.DrawBuffer[] state.
 281  * Use when changing contexts.
 282  */
 283 void
 284 _mesa_update_draw_buffer(struct gl_context *ctx)
 285 {
 286    _mesa_drawbuffer(ctx, ctx->Color.DrawBuffer, 0);
 287 }
 288
 289
 290 /**
 291  * Like \sa _mesa_drawbuffers(), this is a helper function for setting
 292  * GL_READ_BUFFER state in the context and current FBO.
 293  * \param ctx  the rendering context
 294  * \param buffer  GL_FRONT, GL_BACK, GL_COLOR_ATTACHMENT0, etc.
 295  * \param bufferIndex  the numerical index corresponding to 'buffer'
 296  */
 297 void
 298 _mesa_readbuffer(struct gl_context *ctx, GLenum buffer, GLint bufferIndex)
 299 {
 300    struct gl_framebuffer *fb = ctx->ReadBuffer;
 301
 302    ctx->Pixel.ReadBuffer = buffer;
 303
 304    fb->ColorReadBuffer = buffer;
 305    fb->_ColorReadBufferIndex = bufferIndex;
 306
 307    ctx->NewState |= _NEW_BUFFERS;
 308 }
 309
 310
 311
 312 /**
 313  * Called by glReadBuffer to set the source renderbuffer for reading pixels.
 314  * \param mode color buffer such as GL_FRONT, GL_BACK, etc.
 315  */
 316 void GLAPIENTRY
 317 _mesa_ReadBuffer(GLenum buffer)
 318 {
 319    struct gl_framebuffer *fb;
 320    GLbitfield supportedMask;
 321    GLint srcBuffer;
 322    GET_CURRENT_CONTEXT(ctx);
 323    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx);
 324
 325    if (MESA_VERBOSE & VERBOSE_API)
 326       _mesa_debug(ctx, "glReadBuffer %s\n", _mesa_lookup_enum_by_nr(buffer));
 327
 328    fb = ctx->ReadBuffer;
 329
 330    if (MESA_VERBOSE & VERBOSE_API)
 331       _mesa_debug(ctx, "glReadBuffer %s\n", _mesa_lookup_enum_by_nr(buffer));
 332
 333    /* general case / window-system framebuffer */
 334    srcBuffer = read_buffer_enum_to_index(buffer);
 335    if (srcBuffer == -1) {
 336       _mesa_error(ctx, GL_INVALID_ENUM,
 337                   "glReadBuffer(buffer=0x%x)", buffer);
 338       return;
 339    }
 340    supportedMask = supported_buffer_bitmask(ctx, fb);
 341    if (((1 << srcBuffer) & supportedMask) == 0) {
 342       _mesa_error(ctx, GL_INVALID_OPERATION,
 343                   "glReadBuffer(buffer=0x%x)", buffer);
 344       return;
 345    }
 346
 347    /* OK, all error checking has been completed now */
 348
 349    _mesa_readbuffer(ctx, buffer, srcBuffer);
 350    ctx->NewState |= _NEW_BUFFERS;
 351
 352    /*
 353     * Call device driver function.
 354     */
 355    if (ctx->Driver.ReadBuffer)
 356       (*ctx->Driver.ReadBuffer)(ctx, buffer);
 357 }