buffers.c revision a4d72189b271664501338cc93107845f3d40ae54
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 */ 53static GLbitfield 54supported_buffer_bitmask(const struct gl_context *ctx, const struct gl_framebuffer *fb) 55{ 56 GLbitfield mask = 0x0; 57 58 if (fb->Name > 0) { 59 /* A user-created renderbuffer */ 60 GLuint i; 61 ASSERT(ctx->Extensions.EXT_framebuffer_object); 62 for (i = 0; i < ctx->Const.MaxColorAttachments; i++) { 63 mask |= (BUFFER_BIT_COLOR0 << i); 64 } 65 } 66 else { 67 /* A window system framebuffer */ 68 GLint i; 69 mask = BUFFER_BIT_FRONT_LEFT; /* always have this */ 70 if (fb->Visual.stereoMode) { 71 mask |= BUFFER_BIT_FRONT_RIGHT; 72 if (fb->Visual.doubleBufferMode) { 73 mask |= BUFFER_BIT_BACK_LEFT | BUFFER_BIT_BACK_RIGHT; 74 } 75 } 76 else if (fb->Visual.doubleBufferMode) { 77 mask |= BUFFER_BIT_BACK_LEFT; 78 } 79 80 for (i = 0; i < fb->Visual.numAuxBuffers; i++) { 81 mask |= (BUFFER_BIT_AUX0 << i); 82 } 83 } 84 85 return mask; 86} 87 88 89/** 90 * Helper routine used by glDrawBuffer and glDrawBuffersARB. 91 * Given a GLenum naming one or more color buffers (such as 92 * GL_FRONT_AND_BACK), return the corresponding bitmask of BUFFER_BIT_* flags. 93 */ 94static GLbitfield 95draw_buffer_enum_to_bitmask(GLenum buffer) 96{ 97 switch (buffer) { 98 case GL_NONE: 99 return 0; 100 case GL_FRONT: 101 return BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_FRONT_RIGHT; 102 case GL_BACK: 103 return BUFFER_BIT_BACK_LEFT | BUFFER_BIT_BACK_RIGHT; 104 case GL_RIGHT: 105 return BUFFER_BIT_FRONT_RIGHT | BUFFER_BIT_BACK_RIGHT; 106 case GL_FRONT_RIGHT: 107 return BUFFER_BIT_FRONT_RIGHT; 108 case GL_BACK_RIGHT: 109 return BUFFER_BIT_BACK_RIGHT; 110 case GL_BACK_LEFT: 111 return BUFFER_BIT_BACK_LEFT; 112 case GL_FRONT_AND_BACK: 113 return BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT 114 | BUFFER_BIT_FRONT_RIGHT | BUFFER_BIT_BACK_RIGHT; 115 case GL_LEFT: 116 return BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT; 117 case GL_FRONT_LEFT: 118 return BUFFER_BIT_FRONT_LEFT; 119 case GL_AUX0: 120 return BUFFER_BIT_AUX0; 121 case GL_AUX1: 122 case GL_AUX2: 123 case GL_AUX3: 124 return 1 << BUFFER_COUNT; /* invalid, but not BAD_MASK */ 125 case GL_COLOR_ATTACHMENT0_EXT: 126 return BUFFER_BIT_COLOR0; 127 case GL_COLOR_ATTACHMENT1_EXT: 128 return BUFFER_BIT_COLOR1; 129 case GL_COLOR_ATTACHMENT2_EXT: 130 return BUFFER_BIT_COLOR2; 131 case GL_COLOR_ATTACHMENT3_EXT: 132 return BUFFER_BIT_COLOR3; 133 case GL_COLOR_ATTACHMENT4_EXT: 134 return BUFFER_BIT_COLOR4; 135 case GL_COLOR_ATTACHMENT5_EXT: 136 return BUFFER_BIT_COLOR5; 137 case GL_COLOR_ATTACHMENT6_EXT: 138 return BUFFER_BIT_COLOR6; 139 case GL_COLOR_ATTACHMENT7_EXT: 140 return BUFFER_BIT_COLOR7; 141 default: 142 /* error */ 143 return BAD_MASK; 144 } 145} 146 147 148/** 149 * Helper routine used by glReadBuffer. 150 * Given a GLenum naming a color buffer, return the index of the corresponding 151 * renderbuffer (a BUFFER_* value). 152 * return -1 for an invalid buffer. 153 */ 154static GLint 155read_buffer_enum_to_index(GLenum buffer) 156{ 157 switch (buffer) { 158 case GL_FRONT: 159 return BUFFER_FRONT_LEFT; 160 case GL_BACK: 161 return BUFFER_BACK_LEFT; 162 case GL_RIGHT: 163 return BUFFER_FRONT_RIGHT; 164 case GL_FRONT_RIGHT: 165 return BUFFER_FRONT_RIGHT; 166 case GL_BACK_RIGHT: 167 return BUFFER_BACK_RIGHT; 168 case GL_BACK_LEFT: 169 return BUFFER_BACK_LEFT; 170 case GL_LEFT: 171 return BUFFER_FRONT_LEFT; 172 case GL_FRONT_LEFT: 173 return BUFFER_FRONT_LEFT; 174 case GL_AUX0: 175 return BUFFER_AUX0; 176 case GL_AUX1: 177 case GL_AUX2: 178 case GL_AUX3: 179 return BUFFER_COUNT; /* invalid, but not -1 */ 180 case GL_COLOR_ATTACHMENT0_EXT: 181 return BUFFER_COLOR0; 182 case GL_COLOR_ATTACHMENT1_EXT: 183 return BUFFER_COLOR1; 184 case GL_COLOR_ATTACHMENT2_EXT: 185 return BUFFER_COLOR2; 186 case GL_COLOR_ATTACHMENT3_EXT: 187 return BUFFER_COLOR3; 188 case GL_COLOR_ATTACHMENT4_EXT: 189 return BUFFER_COLOR4; 190 case GL_COLOR_ATTACHMENT5_EXT: 191 return BUFFER_COLOR5; 192 case GL_COLOR_ATTACHMENT6_EXT: 193 return BUFFER_COLOR6; 194 case GL_COLOR_ATTACHMENT7_EXT: 195 return BUFFER_COLOR7; 196 default: 197 /* error */ 198 return -1; 199 } 200} 201 202 203/** 204 * Called by glDrawBuffer(). 205 * Specify which renderbuffer(s) to draw into for the first color output. 206 * <buffer> can name zero, one, two or four renderbuffers! 207 * \sa _mesa_DrawBuffersARB 208 * 209 * \param buffer buffer token such as GL_LEFT or GL_FRONT_AND_BACK, etc. 210 * 211 * Note that the behaviour of this function depends on whether the 212 * current ctx->DrawBuffer is a window-system framebuffer (Name=0) or 213 * a user-created framebuffer object (Name!=0). 214 * In the former case, we update the per-context ctx->Color.DrawBuffer 215 * state var _and_ the FB's ColorDrawBuffer state. 216 * In the later case, we update the FB's ColorDrawBuffer state only. 217 * 218 * Furthermore, upon a MakeCurrent() or BindFramebuffer() call, if the 219 * new FB is a window system FB, we need to re-update the FB's 220 * ColorDrawBuffer state to match the context. This is handled in 221 * _mesa_update_framebuffer(). 222 * 223 * See the GL_EXT_framebuffer_object spec for more info. 224 */ 225void GLAPIENTRY 226_mesa_DrawBuffer(GLenum buffer) 227{ 228 GLbitfield destMask; 229 GET_CURRENT_CONTEXT(ctx); 230 ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx); /* too complex... */ 231 232 if (MESA_VERBOSE & VERBOSE_API) { 233 _mesa_debug(ctx, "glDrawBuffer %s\n", _mesa_lookup_enum_by_nr(buffer)); 234 } 235 236 if (buffer == GL_NONE) { 237 destMask = 0x0; 238 } 239 else { 240 const GLbitfield supportedMask 241 = supported_buffer_bitmask(ctx, ctx->DrawBuffer); 242 destMask = draw_buffer_enum_to_bitmask(buffer); 243 if (destMask == BAD_MASK) { 244 /* totally bogus buffer */ 245 _mesa_error(ctx, GL_INVALID_ENUM, "glDrawBuffer(buffer=0x%x)", buffer); 246 return; 247 } 248 destMask &= supportedMask; 249 if (destMask == 0x0) { 250 /* none of the named color buffers exist! */ 251 _mesa_error(ctx, GL_INVALID_OPERATION, 252 "glDrawBuffer(buffer=0x%x)", buffer); 253 return; 254 } 255 } 256 257 /* if we get here, there's no error so set new state */ 258 _mesa_drawbuffers(ctx, 1, &buffer, &destMask); 259 260 /* 261 * Call device driver function. 262 */ 263 if (ctx->Driver.DrawBuffers) 264 ctx->Driver.DrawBuffers(ctx, 1, &buffer); 265 else if (ctx->Driver.DrawBuffer) 266 ctx->Driver.DrawBuffer(ctx, buffer); 267} 268 269 270/** 271 * Called by glDrawBuffersARB; specifies the destination color renderbuffers 272 * for N fragment program color outputs. 273 * \sa _mesa_DrawBuffer 274 * \param n number of outputs 275 * \param buffers array [n] of renderbuffer names. Unlike glDrawBuffer, the 276 * names cannot specify more than one buffer. For example, 277 * GL_FRONT_AND_BACK is illegal. 278 */ 279void GLAPIENTRY 280_mesa_DrawBuffersARB(GLsizei n, const GLenum *buffers) 281{ 282 GLint output; 283 GLbitfield usedBufferMask, supportedMask; 284 GLbitfield destMask[MAX_DRAW_BUFFERS]; 285 GET_CURRENT_CONTEXT(ctx); 286 ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx); 287 288 /* Turns out n==0 is a valid input that should not produce an error. 289 * The remaining code below correctly handles the n==0 case. 290 */ 291 if (n < 0 || n > (GLsizei) ctx->Const.MaxDrawBuffers) { 292 _mesa_error(ctx, GL_INVALID_VALUE, "glDrawBuffersARB(n)"); 293 return; 294 } 295 296 supportedMask = supported_buffer_bitmask(ctx, ctx->DrawBuffer); 297 usedBufferMask = 0x0; 298 299 /* complicated error checking... */ 300 for (output = 0; output < n; output++) { 301 if (buffers[output] == GL_NONE) { 302 destMask[output] = 0x0; 303 } 304 else { 305 destMask[output] = draw_buffer_enum_to_bitmask(buffers[output]); 306 if (destMask[output] == BAD_MASK 307 || _mesa_bitcount(destMask[output]) > 1) { 308 _mesa_error(ctx, GL_INVALID_ENUM, "glDrawBuffersARB(buffer)"); 309 return; 310 } 311 destMask[output] &= supportedMask; 312 if (destMask[output] == 0) { 313 _mesa_error(ctx, GL_INVALID_OPERATION, 314 "glDrawBuffersARB(unsupported buffer)"); 315 return; 316 } 317 if (destMask[output] & usedBufferMask) { 318 /* can't specify a dest buffer more than once! */ 319 _mesa_error(ctx, GL_INVALID_OPERATION, 320 "glDrawBuffersARB(duplicated buffer)"); 321 return; 322 } 323 324 /* update bitmask */ 325 usedBufferMask |= destMask[output]; 326 } 327 } 328 329 /* OK, if we get here, there were no errors so set the new state */ 330 _mesa_drawbuffers(ctx, n, buffers, destMask); 331 332 /* 333 * Call device driver function. Note that n can be equal to 0, 334 * in which case we don't want to reference buffers[0], which 335 * may not be valid. 336 */ 337 if (ctx->Driver.DrawBuffers) 338 ctx->Driver.DrawBuffers(ctx, n, buffers); 339 else if (ctx->Driver.DrawBuffer) 340 ctx->Driver.DrawBuffer(ctx, n > 0 ? buffers[0] : GL_NONE); 341} 342 343/** 344 * Performs necessary state updates when _mesa_drawbuffers makes an 345 * actual change. 346 */ 347static void 348updated_drawbuffers(struct gl_context *ctx) 349{ 350 FLUSH_VERTICES(ctx, _NEW_BUFFERS); 351 352#if FEATURE_GL 353 if (ctx->API == API_OPENGL && !ctx->Extensions.ARB_ES2_compatibility) { 354 struct gl_framebuffer *fb = ctx->DrawBuffer; 355 356 /* Flag the FBO as requiring validation. */ 357 if (fb->Name != 0) { 358 fb->_Status = 0; 359 } 360 } 361#endif 362} 363 364/** 365 * Helper function to set the GL_DRAW_BUFFER state in the context and 366 * current FBO. Called via glDrawBuffer(), glDrawBuffersARB() 367 * 368 * All error checking will have been done prior to calling this function 369 * so nothing should go wrong at this point. 370 * 371 * \param ctx current context 372 * \param n number of color outputs to set 373 * \param buffers array[n] of colorbuffer names, like GL_LEFT. 374 * \param destMask array[n] of BUFFER_BIT_* bitmasks which correspond to the 375 * colorbuffer names. (i.e. GL_FRONT_AND_BACK => 376 * BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT). 377 */ 378void 379_mesa_drawbuffers(struct gl_context *ctx, GLuint n, const GLenum *buffers, 380 const GLbitfield *destMask) 381{ 382 struct gl_framebuffer *fb = ctx->DrawBuffer; 383 GLbitfield mask[MAX_DRAW_BUFFERS]; 384 GLuint buf; 385 386 if (!destMask) { 387 /* compute destMask values now */ 388 const GLbitfield supportedMask = supported_buffer_bitmask(ctx, fb); 389 GLuint output; 390 for (output = 0; output < n; output++) { 391 mask[output] = draw_buffer_enum_to_bitmask(buffers[output]); 392 ASSERT(mask[output] != BAD_MASK); 393 mask[output] &= supportedMask; 394 } 395 destMask = mask; 396 } 397 398 /* 399 * If n==1, destMask[0] may have up to four bits set. 400 * Otherwise, destMask[x] can only have one bit set. 401 */ 402 if (n == 1) { 403 GLuint count = 0, destMask0 = destMask[0]; 404 while (destMask0) { 405 GLint bufIndex = _mesa_ffs(destMask0) - 1; 406 if (fb->_ColorDrawBufferIndexes[count] != bufIndex) { 407 updated_drawbuffers(ctx); 408 fb->_ColorDrawBufferIndexes[count] = bufIndex; 409 } 410 count++; 411 destMask0 &= ~(1 << bufIndex); 412 } 413 fb->ColorDrawBuffer[0] = buffers[0]; 414 fb->_NumColorDrawBuffers = count; 415 } 416 else { 417 GLuint count = 0; 418 for (buf = 0; buf < n; buf++ ) { 419 if (destMask[buf]) { 420 GLint bufIndex = _mesa_ffs(destMask[buf]) - 1; 421 /* only one bit should be set in the destMask[buf] field */ 422 ASSERT(_mesa_bitcount(destMask[buf]) == 1); 423 if (fb->_ColorDrawBufferIndexes[buf] != bufIndex) { 424 updated_drawbuffers(ctx); 425 fb->_ColorDrawBufferIndexes[buf] = bufIndex; 426 } 427 count = buf + 1; 428 } 429 else { 430 if (fb->_ColorDrawBufferIndexes[buf] != -1) { 431 updated_drawbuffers(ctx); 432 fb->_ColorDrawBufferIndexes[buf] = -1; 433 } 434 } 435 fb->ColorDrawBuffer[buf] = buffers[buf]; 436 } 437 fb->_NumColorDrawBuffers = count; 438 } 439 440 /* set remaining outputs to -1 (GL_NONE) */ 441 for (buf = fb->_NumColorDrawBuffers; buf < ctx->Const.MaxDrawBuffers; buf++) { 442 if (fb->_ColorDrawBufferIndexes[buf] != -1) { 443 updated_drawbuffers(ctx); 444 fb->_ColorDrawBufferIndexes[buf] = -1; 445 } 446 } 447 for (buf = n; buf < ctx->Const.MaxDrawBuffers; buf++) { 448 fb->ColorDrawBuffer[buf] = GL_NONE; 449 } 450 451 if (fb->Name == 0) { 452 /* also set context drawbuffer state */ 453 for (buf = 0; buf < ctx->Const.MaxDrawBuffers; buf++) { 454 if (ctx->Color.DrawBuffer[buf] != fb->ColorDrawBuffer[buf]) { 455 updated_drawbuffers(ctx); 456 ctx->Color.DrawBuffer[buf] = fb->ColorDrawBuffer[buf]; 457 } 458 } 459 } 460} 461 462 463/** 464 * Update the current drawbuffer's _ColorDrawBufferIndex[] list, etc. 465 * from the context's Color.DrawBuffer[] state. 466 * Use when changing contexts. 467 */ 468void 469_mesa_update_draw_buffers(struct gl_context *ctx) 470{ 471 GLenum buffers[MAX_DRAW_BUFFERS]; 472 GLuint i; 473 474 /* should be a window system FBO */ 475 assert(ctx->DrawBuffer->Name == 0); 476 477 for (i = 0; i < ctx->Const.MaxDrawBuffers; i++) 478 buffers[i] = ctx->Color.DrawBuffer[i]; 479 480 _mesa_drawbuffers(ctx, ctx->Const.MaxDrawBuffers, buffers, NULL); 481} 482 483 484/** 485 * Like \sa _mesa_drawbuffers(), this is a helper function for setting 486 * GL_READ_BUFFER state in the context and current FBO. 487 * \param ctx the rendering context 488 * \param buffer GL_FRONT, GL_BACK, GL_COLOR_ATTACHMENT0, etc. 489 * \param bufferIndex the numerical index corresponding to 'buffer' 490 */ 491void 492_mesa_readbuffer(struct gl_context *ctx, GLenum buffer, GLint bufferIndex) 493{ 494 struct gl_framebuffer *fb = ctx->ReadBuffer; 495 496 if (fb->Name == 0) { 497 /* Only update the per-context READ_BUFFER state if we're bound to 498 * a window-system framebuffer. 499 */ 500 ctx->Pixel.ReadBuffer = buffer; 501 } 502 503 fb->ColorReadBuffer = buffer; 504 fb->_ColorReadBufferIndex = bufferIndex; 505 506 ctx->NewState |= _NEW_BUFFERS; 507} 508 509 510 511/** 512 * Called by glReadBuffer to set the source renderbuffer for reading pixels. 513 * \param mode color buffer such as GL_FRONT, GL_BACK, etc. 514 */ 515void GLAPIENTRY 516_mesa_ReadBuffer(GLenum buffer) 517{ 518 struct gl_framebuffer *fb; 519 GLbitfield supportedMask; 520 GLint srcBuffer; 521 GET_CURRENT_CONTEXT(ctx); 522 ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx); 523 524 if (MESA_VERBOSE & VERBOSE_API) 525 _mesa_debug(ctx, "glReadBuffer %s\n", _mesa_lookup_enum_by_nr(buffer)); 526 527 fb = ctx->ReadBuffer; 528 529 if (MESA_VERBOSE & VERBOSE_API) 530 _mesa_debug(ctx, "glReadBuffer %s\n", _mesa_lookup_enum_by_nr(buffer)); 531 532 if (fb->Name > 0 && buffer == GL_NONE) { 533 /* This is legal for user-created framebuffer objects */ 534 srcBuffer = -1; 535 } 536 else { 537 /* general case / window-system framebuffer */ 538 srcBuffer = read_buffer_enum_to_index(buffer); 539 if (srcBuffer == -1) { 540 _mesa_error(ctx, GL_INVALID_ENUM, 541 "glReadBuffer(buffer=0x%x)", buffer); 542 return; 543 } 544 supportedMask = supported_buffer_bitmask(ctx, fb); 545 if (((1 << srcBuffer) & supportedMask) == 0) { 546 _mesa_error(ctx, GL_INVALID_OPERATION, 547 "glReadBuffer(buffer=0x%x)", buffer); 548 return; 549 } 550 } 551 552 /* OK, all error checking has been completed now */ 553 554 _mesa_readbuffer(ctx, buffer, srcBuffer); 555 ctx->NewState |= _NEW_BUFFERS; 556 557 /* 558 * Call device driver function. 559 */ 560 if (ctx->Driver.ReadBuffer) 561 (*ctx->Driver.ReadBuffer)(ctx, buffer); 562} 563