buffers.c revision c7048f9d9f91ef8c3ef35e31976adbf686349c41
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 */ 54static GLbitfield 55supported_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 */ 95static GLbitfield 96draw_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 */ 155static GLint 156read_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 */ 226void 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, "glDrawBuffer(buffer=0x%x)", buffer); 247 return; 248 } 249 destMask &= supportedMask; 250 if (destMask == 0x0) { 251 /* none of the named color buffers exist! */ 252 _mesa_error(ctx, GL_INVALID_OPERATION, 253 "glDrawBuffer(buffer=0x%x)", buffer); 254 return; 255 } 256 } 257 258 /* if we get here, there's no error so set new state */ 259 _mesa_drawbuffers(ctx, 1, &buffer, &destMask); 260 261 /* 262 * Call device driver function. 263 */ 264 if (ctx->Driver.DrawBuffers) 265 ctx->Driver.DrawBuffers(ctx, 1, &buffer); 266 else if (ctx->Driver.DrawBuffer) 267 ctx->Driver.DrawBuffer(ctx, buffer); 268} 269 270 271/** 272 * Called by glDrawBuffersARB; specifies the destination color renderbuffers 273 * for N fragment program color outputs. 274 * \sa _mesa_DrawBuffer 275 * \param n number of outputs 276 * \param buffers array [n] of renderbuffer names. Unlike glDrawBuffer, the 277 * names cannot specify more than one buffer. For example, 278 * GL_FRONT_AND_BACK is illegal. 279 */ 280void GLAPIENTRY 281_mesa_DrawBuffersARB(GLsizei n, const GLenum *buffers) 282{ 283 GLint output; 284 GLbitfield usedBufferMask, supportedMask; 285 GLbitfield destMask[MAX_DRAW_BUFFERS]; 286 GET_CURRENT_CONTEXT(ctx); 287 ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx); 288 289 /* Turns out n==0 is a valid input that should not produce an error. 290 * The remaining code below correctly handles the n==0 case. 291 */ 292 if (n < 0 || n > (GLsizei) ctx->Const.MaxDrawBuffers) { 293 _mesa_error(ctx, GL_INVALID_VALUE, "glDrawBuffersARB(n)"); 294 return; 295 } 296 297 supportedMask = supported_buffer_bitmask(ctx, ctx->DrawBuffer); 298 usedBufferMask = 0x0; 299 300 /* complicated error checking... */ 301 for (output = 0; output < n; output++) { 302 if (buffers[output] == GL_NONE) { 303 destMask[output] = 0x0; 304 } 305 else { 306 destMask[output] = draw_buffer_enum_to_bitmask(buffers[output]); 307 if (destMask[output] == BAD_MASK 308 || _mesa_bitcount(destMask[output]) > 1) { 309 _mesa_error(ctx, GL_INVALID_ENUM, "glDrawBuffersARB(buffer)"); 310 return; 311 } 312 destMask[output] &= supportedMask; 313 if (destMask[output] == 0) { 314 _mesa_error(ctx, GL_INVALID_OPERATION, 315 "glDrawBuffersARB(unsupported buffer)"); 316 return; 317 } 318 if (destMask[output] & usedBufferMask) { 319 /* can't specify a dest buffer more than once! */ 320 _mesa_error(ctx, GL_INVALID_OPERATION, 321 "glDrawBuffersARB(duplicated buffer)"); 322 return; 323 } 324 325 /* update bitmask */ 326 usedBufferMask |= destMask[output]; 327 } 328 } 329 330 /* OK, if we get here, there were no errors so set the new state */ 331 _mesa_drawbuffers(ctx, n, buffers, destMask); 332 333 /* 334 * Call device driver function. Note that n can be equal to 0, 335 * in which case we don't want to reference buffers[0], which 336 * may not be valid. 337 */ 338 if (ctx->Driver.DrawBuffers) 339 ctx->Driver.DrawBuffers(ctx, n, buffers); 340 else if (ctx->Driver.DrawBuffer) 341 ctx->Driver.DrawBuffer(ctx, n>0? buffers[0]:GL_NONE); 342} 343 344 345/** 346 * Helper function to set the GL_DRAW_BUFFER state in the context and 347 * current FBO. Called via glDrawBuffer(), glDrawBuffersARB() 348 * 349 * All error checking will have been done prior to calling this function 350 * so nothing should go wrong at this point. 351 * 352 * \param ctx current context 353 * \param n number of color outputs to set 354 * \param buffers array[n] of colorbuffer names, like GL_LEFT. 355 * \param destMask array[n] of BUFFER_BIT_* bitmasks which correspond to the 356 * colorbuffer names. (i.e. GL_FRONT_AND_BACK => 357 * BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT). 358 */ 359void 360_mesa_drawbuffers(GLcontext *ctx, GLuint n, const GLenum *buffers, 361 const GLbitfield *destMask) 362{ 363 struct gl_framebuffer *fb = ctx->DrawBuffer; 364 GLbitfield mask[MAX_DRAW_BUFFERS]; 365 GLboolean newState = GL_FALSE; 366 367 if (!destMask) { 368 /* compute destMask values now */ 369 const GLbitfield supportedMask = supported_buffer_bitmask(ctx, fb); 370 GLuint output; 371 for (output = 0; output < n; output++) { 372 mask[output] = draw_buffer_enum_to_bitmask(buffers[output]); 373 ASSERT(mask[output] != BAD_MASK); 374 mask[output] &= supportedMask; 375 } 376 destMask = mask; 377 } 378 379 /* 380 * If n==1, destMask[0] may have up to four bits set. 381 * Otherwise, destMask[x] can only have one bit set. 382 */ 383 if (n == 1) { 384 GLuint count = 0, destMask0 = destMask[0]; 385 /* init to -1 to help catch errors */ 386 //fb->_ColorDrawBufferIndexes[0] = -1; 387 while (destMask0) { 388 GLint bufIndex = _mesa_ffs(destMask0) - 1; 389 if (fb->_ColorDrawBufferIndexes[count] != bufIndex) { 390 fb->_ColorDrawBufferIndexes[count] = bufIndex; 391 newState = GL_TRUE; 392 } 393 count++; 394 destMask0 &= ~(1 << bufIndex); 395 } 396 fb->ColorDrawBuffer[0] = buffers[0]; 397 if (fb->_NumColorDrawBuffers != count) { 398 fb->_NumColorDrawBuffers = count; 399 newState = GL_TRUE; 400 } 401 } 402 else { 403 GLuint buf, count = 0; 404 for (buf = 0; buf < n; buf++ ) { 405 if (destMask[buf]) { 406 GLint bufIndex = _mesa_ffs(destMask[buf]) - 1; 407 /* only one bit should be set in the destMask[buf] field */ 408 ASSERT(_mesa_bitcount(destMask[buf]) == 1); 409 if (fb->_ColorDrawBufferIndexes[buf] != bufIndex) { 410 fb->_ColorDrawBufferIndexes[buf] = bufIndex; 411 newState = GL_TRUE; 412 } 413 fb->ColorDrawBuffer[buf] = buffers[buf]; 414 count = buf + 1; 415 } 416 else { 417 if (fb->_ColorDrawBufferIndexes[buf] != -1) { 418 fb->_ColorDrawBufferIndexes[buf] = -1; 419 newState = GL_TRUE; 420 } 421 } 422 } 423 /* set remaining outputs to -1 (GL_NONE) */ 424 while (buf < ctx->Const.MaxDrawBuffers) { 425 if (fb->_ColorDrawBufferIndexes[buf] != -1) { 426 fb->_ColorDrawBufferIndexes[buf] = -1; 427 buf++; 428 } 429 fb->ColorDrawBuffer[buf] = GL_NONE; 430 } 431 fb->_NumColorDrawBuffers = count; 432 } 433 434 if (fb->Name == 0) { 435 /* also set context drawbuffer state */ 436 GLuint buf; 437 for (buf = 0; buf < ctx->Const.MaxDrawBuffers; buf++) { 438 if (ctx->Color.DrawBuffer[buf] != fb->ColorDrawBuffer[buf]) { 439 ctx->Color.DrawBuffer[buf] = fb->ColorDrawBuffer[buf]; 440 newState = GL_TRUE; 441 } 442 } 443 } 444 445 if (newState) 446 FLUSH_VERTICES(ctx, _NEW_BUFFERS); 447} 448 449 450/** 451 * Like \sa _mesa_drawbuffers(), this is a helper function for setting 452 * GL_READ_BUFFER state in the context and current FBO. 453 * \param ctx the rendering context 454 * \param buffer GL_FRONT, GL_BACK, GL_COLOR_ATTACHMENT0, etc. 455 * \param bufferIndex the numerical index corresponding to 'buffer' 456 */ 457void 458_mesa_readbuffer(GLcontext *ctx, GLenum buffer, GLint bufferIndex) 459{ 460 struct gl_framebuffer *fb = ctx->ReadBuffer; 461 462 if (fb->Name == 0) { 463 /* Only update the per-context READ_BUFFER state if we're bound to 464 * a window-system framebuffer. 465 */ 466 ctx->Pixel.ReadBuffer = buffer; 467 } 468 469 fb->ColorReadBuffer = buffer; 470 fb->_ColorReadBufferIndex = bufferIndex; 471 472 ctx->NewState |= _NEW_BUFFERS; 473} 474 475 476 477/** 478 * Called by glReadBuffer to set the source renderbuffer for reading pixels. 479 * \param mode color buffer such as GL_FRONT, GL_BACK, etc. 480 */ 481void GLAPIENTRY 482_mesa_ReadBuffer(GLenum buffer) 483{ 484 struct gl_framebuffer *fb; 485 GLbitfield supportedMask; 486 GLint srcBuffer; 487 GET_CURRENT_CONTEXT(ctx); 488 ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx); 489 490 if (MESA_VERBOSE & VERBOSE_API) 491 _mesa_debug(ctx, "glReadBuffer %s\n", _mesa_lookup_enum_by_nr(buffer)); 492 493 fb = ctx->ReadBuffer; 494 495 if (MESA_VERBOSE & VERBOSE_API) 496 _mesa_debug(ctx, "glReadBuffer %s\n", _mesa_lookup_enum_by_nr(buffer)); 497 498 if (fb->Name > 0 && buffer == GL_NONE) { 499 /* This is legal for user-created framebuffer objects */ 500 srcBuffer = -1; 501 } 502 else { 503 /* general case / window-system framebuffer */ 504 srcBuffer = read_buffer_enum_to_index(buffer); 505 if (srcBuffer == -1) { 506 _mesa_error(ctx, GL_INVALID_ENUM, 507 "glReadBuffer(buffer=0x%x)", buffer); 508 return; 509 } 510 supportedMask = supported_buffer_bitmask(ctx, fb); 511 if (((1 << srcBuffer) & supportedMask) == 0) { 512 _mesa_error(ctx, GL_INVALID_OPERATION, 513 "glReadBuffer(buffer=0x%x)", buffer); 514 return; 515 } 516 } 517 518 /* OK, all error checking has been completed now */ 519 520 _mesa_readbuffer(ctx, buffer, srcBuffer); 521 ctx->NewState |= _NEW_BUFFERS; 522 523 /* 524 * Call device driver function. 525 */ 526 if (ctx->Driver.ReadBuffer) 527 (*ctx->Driver.ReadBuffer)(ctx, buffer); 528} 529