2 * Mesa 3-D graphics library
5 * Copyright (C) 1999-2007 Brian Paul All Rights Reserved.
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:
14 * The above copyright notice and this permission notice shall be included
15 * in all copies or substantial portions of the Software.
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 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
21 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
22 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
23 * OTHER DEALINGS IN THE SOFTWARE.
29 * glReadBuffer, DrawBuffer functions.
47 * Return bitmask of BUFFER_BIT_* flags indicating which color buffers are
48 * available to the rendering context (for drawing or reading).
49 * This depends on the type of framebuffer. For window system framebuffers
50 * we look at the framebuffer's visual. But for user-create framebuffers we
51 * look at the number of supported color attachments.
52 * \param fb the framebuffer to draw to, or read from
53 * \return bitmask of BUFFER_BIT_* flags
56 supported_buffer_bitmask(const struct gl_context
*ctx
,
57 const struct gl_framebuffer
*fb
)
59 GLbitfield mask
= 0x0;
61 if (_mesa_is_user_fbo(fb
)) {
62 /* A user-created renderbuffer */
64 ASSERT(ctx
->Extensions
.EXT_framebuffer_object
);
65 for (i
= 0; i
< ctx
->Const
.MaxColorAttachments
; i
++) {
66 mask
|= (BUFFER_BIT_COLOR0
<< i
);
70 /* A window system framebuffer */
72 mask
= BUFFER_BIT_FRONT_LEFT
; /* always have this */
73 if (fb
->Visual
.stereoMode
) {
74 mask
|= BUFFER_BIT_FRONT_RIGHT
;
75 if (fb
->Visual
.doubleBufferMode
) {
76 mask
|= BUFFER_BIT_BACK_LEFT
| BUFFER_BIT_BACK_RIGHT
;
79 else if (fb
->Visual
.doubleBufferMode
) {
80 mask
|= BUFFER_BIT_BACK_LEFT
;
83 for (i
= 0; i
< fb
->Visual
.numAuxBuffers
; i
++) {
84 mask
|= (BUFFER_BIT_AUX0
<< i
);
93 * Helper routine used by glDrawBuffer and glDrawBuffersARB.
94 * Given a GLenum naming one or more color buffers (such as
95 * GL_FRONT_AND_BACK), return the corresponding bitmask of BUFFER_BIT_* flags.
98 draw_buffer_enum_to_bitmask(const struct gl_context
*ctx
, GLenum buffer
)
104 return BUFFER_BIT_FRONT_LEFT
| BUFFER_BIT_FRONT_RIGHT
;
106 if (_mesa_is_gles3(ctx
)) {
107 /* Page 181 (page 192 of the PDF) in section 4.2.1 of the OpenGL
108 * ES 3.0.1 specification says:
110 * "When draw buffer zero is BACK, color values are written
111 * into the sole buffer for single-buffered contexts, or into
112 * the back buffer for double-buffered contexts."
114 * Since there is no stereo rendering in ES 3.0, only return the
115 * LEFT bits. This also satisfies the "n must be 1" requirement.
117 if (ctx
->DrawBuffer
->Visual
.doubleBufferMode
)
118 return BUFFER_BIT_BACK_LEFT
;
119 return BUFFER_BIT_FRONT_LEFT
;
121 return BUFFER_BIT_BACK_LEFT
| BUFFER_BIT_BACK_RIGHT
;
123 return BUFFER_BIT_FRONT_RIGHT
| BUFFER_BIT_BACK_RIGHT
;
125 return BUFFER_BIT_FRONT_RIGHT
;
127 return BUFFER_BIT_BACK_RIGHT
;
129 return BUFFER_BIT_BACK_LEFT
;
130 case GL_FRONT_AND_BACK
:
131 return BUFFER_BIT_FRONT_LEFT
| BUFFER_BIT_BACK_LEFT
132 | BUFFER_BIT_FRONT_RIGHT
| BUFFER_BIT_BACK_RIGHT
;
134 return BUFFER_BIT_FRONT_LEFT
| BUFFER_BIT_BACK_LEFT
;
136 return BUFFER_BIT_FRONT_LEFT
;
138 return BUFFER_BIT_AUX0
;
142 return 1 << BUFFER_COUNT
; /* invalid, but not BAD_MASK */
143 case GL_COLOR_ATTACHMENT0_EXT
:
144 return BUFFER_BIT_COLOR0
;
145 case GL_COLOR_ATTACHMENT1_EXT
:
146 return BUFFER_BIT_COLOR1
;
147 case GL_COLOR_ATTACHMENT2_EXT
:
148 return BUFFER_BIT_COLOR2
;
149 case GL_COLOR_ATTACHMENT3_EXT
:
150 return BUFFER_BIT_COLOR3
;
151 case GL_COLOR_ATTACHMENT4_EXT
:
152 return BUFFER_BIT_COLOR4
;
153 case GL_COLOR_ATTACHMENT5_EXT
:
154 return BUFFER_BIT_COLOR5
;
155 case GL_COLOR_ATTACHMENT6_EXT
:
156 return BUFFER_BIT_COLOR6
;
157 case GL_COLOR_ATTACHMENT7_EXT
:
158 return BUFFER_BIT_COLOR7
;
167 * Helper routine used by glReadBuffer.
168 * Given a GLenum naming a color buffer, return the index of the corresponding
169 * renderbuffer (a BUFFER_* value).
170 * return -1 for an invalid buffer.
173 read_buffer_enum_to_index(GLenum buffer
)
177 return BUFFER_FRONT_LEFT
;
179 return BUFFER_BACK_LEFT
;
181 return BUFFER_FRONT_RIGHT
;
183 return BUFFER_FRONT_RIGHT
;
185 return BUFFER_BACK_RIGHT
;
187 return BUFFER_BACK_LEFT
;
189 return BUFFER_FRONT_LEFT
;
191 return BUFFER_FRONT_LEFT
;
197 return BUFFER_COUNT
; /* invalid, but not -1 */
198 case GL_COLOR_ATTACHMENT0_EXT
:
199 return BUFFER_COLOR0
;
200 case GL_COLOR_ATTACHMENT1_EXT
:
201 return BUFFER_COLOR1
;
202 case GL_COLOR_ATTACHMENT2_EXT
:
203 return BUFFER_COLOR2
;
204 case GL_COLOR_ATTACHMENT3_EXT
:
205 return BUFFER_COLOR3
;
206 case GL_COLOR_ATTACHMENT4_EXT
:
207 return BUFFER_COLOR4
;
208 case GL_COLOR_ATTACHMENT5_EXT
:
209 return BUFFER_COLOR5
;
210 case GL_COLOR_ATTACHMENT6_EXT
:
211 return BUFFER_COLOR6
;
212 case GL_COLOR_ATTACHMENT7_EXT
:
213 return BUFFER_COLOR7
;
222 * Called by glDrawBuffer().
223 * Specify which renderbuffer(s) to draw into for the first color output.
224 * <buffer> can name zero, one, two or four renderbuffers!
225 * \sa _mesa_DrawBuffers
227 * \param buffer buffer token such as GL_LEFT or GL_FRONT_AND_BACK, etc.
229 * Note that the behaviour of this function depends on whether the
230 * current ctx->DrawBuffer is a window-system framebuffer or a user-created
231 * framebuffer object.
232 * In the former case, we update the per-context ctx->Color.DrawBuffer
233 * state var _and_ the FB's ColorDrawBuffer state.
234 * In the later case, we update the FB's ColorDrawBuffer state only.
236 * Furthermore, upon a MakeCurrent() or BindFramebuffer() call, if the
237 * new FB is a window system FB, we need to re-update the FB's
238 * ColorDrawBuffer state to match the context. This is handled in
239 * _mesa_update_framebuffer().
241 * See the GL_EXT_framebuffer_object spec for more info.
244 _mesa_DrawBuffer(GLenum buffer
)
247 GET_CURRENT_CONTEXT(ctx
);
249 FLUSH_VERTICES(ctx
, 0);
251 if (MESA_VERBOSE
& VERBOSE_API
) {
252 _mesa_debug(ctx
, "glDrawBuffer %s\n", _mesa_lookup_enum_by_nr(buffer
));
255 if (buffer
== GL_NONE
) {
259 const GLbitfield supportedMask
260 = supported_buffer_bitmask(ctx
, ctx
->DrawBuffer
);
261 destMask
= draw_buffer_enum_to_bitmask(ctx
, buffer
);
262 if (destMask
== BAD_MASK
) {
263 /* totally bogus buffer */
264 _mesa_error(ctx
, GL_INVALID_ENUM
,
265 "glDrawBuffer(buffer=0x%x)", buffer
);
268 destMask
&= supportedMask
;
269 if (destMask
== 0x0) {
270 /* none of the named color buffers exist! */
271 _mesa_error(ctx
, GL_INVALID_OPERATION
,
272 "glDrawBuffer(buffer=0x%x)", buffer
);
277 /* if we get here, there's no error so set new state */
278 _mesa_drawbuffers(ctx
, 1, &buffer
, &destMask
);
281 * Call device driver function.
283 if (ctx
->Driver
.DrawBuffers
)
284 ctx
->Driver
.DrawBuffers(ctx
, 1, &buffer
);
285 else if (ctx
->Driver
.DrawBuffer
)
286 ctx
->Driver
.DrawBuffer(ctx
, buffer
);
291 * Called by glDrawBuffersARB; specifies the destination color renderbuffers
292 * for N fragment program color outputs.
293 * \sa _mesa_DrawBuffer
294 * \param n number of outputs
295 * \param buffers array [n] of renderbuffer names. Unlike glDrawBuffer, the
296 * names cannot specify more than one buffer. For example,
297 * GL_FRONT_AND_BACK is illegal.
300 _mesa_DrawBuffers(GLsizei n
, const GLenum
*buffers
)
303 GLbitfield usedBufferMask
, supportedMask
;
304 GLbitfield destMask
[MAX_DRAW_BUFFERS
];
305 GET_CURRENT_CONTEXT(ctx
);
307 FLUSH_VERTICES(ctx
, 0);
309 /* Turns out n==0 is a valid input that should not produce an error.
310 * The remaining code below correctly handles the n==0 case.
312 * From the OpenGL 3.0 specification, page 258:
313 * "An INVALID_VALUE error is generated if n is greater than
316 if (n
< 0 || n
> (GLsizei
) ctx
->Const
.MaxDrawBuffers
) {
317 _mesa_error(ctx
, GL_INVALID_VALUE
, "glDrawBuffersARB(n)");
321 supportedMask
= supported_buffer_bitmask(ctx
, ctx
->DrawBuffer
);
322 usedBufferMask
= 0x0;
324 /* From the ES 3.0 specification, page 180:
325 * "If the GL is bound to the default framebuffer, then n must be 1
326 * and the constant must be BACK or NONE."
328 if (_mesa_is_gles3(ctx
) && _mesa_is_winsys_fbo(ctx
->DrawBuffer
) &&
329 (n
!= 1 || (buffers
[0] != GL_NONE
&& buffers
[0] != GL_BACK
))) {
330 _mesa_error(ctx
, GL_INVALID_OPERATION
, "glDrawBuffers(buffer)");
334 /* complicated error checking... */
335 for (output
= 0; output
< n
; output
++) {
336 if (buffers
[output
] == GL_NONE
) {
337 destMask
[output
] = 0x0;
340 /* Page 259 (page 275 of the PDF) in section 4.2.1 of the OpenGL 3.0
341 * spec (20080923) says:
343 * "If the GL is bound to a framebuffer object and DrawBuffers is
344 * supplied with [...] COLOR_ATTACHMENTm where m is greater than
345 * or equal to the value of MAX_COLOR_ATTACHMENTS, then the error
346 * INVALID_OPERATION results."
348 if (_mesa_is_user_fbo(ctx
->DrawBuffer
) && buffers
[output
] >=
349 GL_COLOR_ATTACHMENT0
+ ctx
->Const
.MaxDrawBuffers
) {
350 _mesa_error(ctx
, GL_INVALID_OPERATION
, "glDrawBuffersARB(buffer)");
354 destMask
[output
] = draw_buffer_enum_to_bitmask(ctx
, buffers
[output
]);
356 /* From the OpenGL 3.0 specification, page 258:
357 * "Each buffer listed in bufs must be one of the values from tables
358 * 4.5 or 4.6. Otherwise, an INVALID_ENUM error is generated.
360 if (destMask
[output
] == BAD_MASK
) {
361 _mesa_error(ctx
, GL_INVALID_ENUM
, "glDrawBuffersARB(buffer)");
365 /* From the OpenGL 3.0 specification, page 259:
366 * "For both the default framebuffer and framebuffer objects, the
367 * constants FRONT, BACK, LEFT, RIGHT, and FRONT_AND_BACK are not
368 * valid in the bufs array passed to DrawBuffers, and will result in
369 * the error INVALID_OPERATION. This restriction is because these
370 * constants may themselves refer to multiple buffers, as shown in
373 if (_mesa_bitcount(destMask
[output
]) > 1) {
374 _mesa_error(ctx
, GL_INVALID_OPERATION
, "glDrawBuffersARB(buffer)");
378 /* From the OpenGL 3.0 specification, page 259:
379 * "If the GL is bound to the default framebuffer and DrawBuffers is
380 * supplied with a constant (other than NONE) that does not indicate
381 * any of the color buffers allocated to the GL context by the window
382 * system, the error INVALID_OPERATION will be generated.
384 * If the GL is bound to a framebuffer object and DrawBuffers is
385 * supplied with a constant from table 4.6 [...] then the error
386 * INVALID_OPERATION results."
388 destMask
[output
] &= supportedMask
;
389 if (destMask
[output
] == 0) {
390 _mesa_error(ctx
, GL_INVALID_OPERATION
,
391 "glDrawBuffersARB(unsupported buffer)");
395 /* ES 3.0 is even more restrictive. From the ES 3.0 spec, page 180:
396 * "If the GL is bound to a framebuffer object, the ith buffer listed
397 * in bufs must be COLOR_ATTACHMENTi or NONE. [...] INVALID_OPERATION."
399 if (_mesa_is_gles3(ctx
) && _mesa_is_user_fbo(ctx
->DrawBuffer
) &&
400 buffers
[output
] != GL_NONE
&&
401 buffers
[output
] != GL_COLOR_ATTACHMENT0
+ output
) {
402 _mesa_error(ctx
, GL_INVALID_OPERATION
, "glDrawBuffers(buffer)");
406 /* From the OpenGL 3.0 specification, page 258:
407 * "Except for NONE, a buffer may not appear more than once in the
408 * array pointed to by bufs. Specifying a buffer more then once will
409 * result in the error INVALID_OPERATION."
411 if (destMask
[output
] & usedBufferMask
) {
412 _mesa_error(ctx
, GL_INVALID_OPERATION
,
413 "glDrawBuffersARB(duplicated buffer)");
418 usedBufferMask
|= destMask
[output
];
422 /* OK, if we get here, there were no errors so set the new state */
423 _mesa_drawbuffers(ctx
, n
, buffers
, destMask
);
426 * Call device driver function. Note that n can be equal to 0,
427 * in which case we don't want to reference buffers[0], which
430 if (ctx
->Driver
.DrawBuffers
)
431 ctx
->Driver
.DrawBuffers(ctx
, n
, buffers
);
432 else if (ctx
->Driver
.DrawBuffer
)
433 ctx
->Driver
.DrawBuffer(ctx
, n
> 0 ? buffers
[0] : GL_NONE
);
438 * Performs necessary state updates when _mesa_drawbuffers makes an
442 updated_drawbuffers(struct gl_context
*ctx
)
444 FLUSH_VERTICES(ctx
, _NEW_BUFFERS
);
446 if (ctx
->API
== API_OPENGL_COMPAT
&& !ctx
->Extensions
.ARB_ES2_compatibility
) {
447 struct gl_framebuffer
*fb
= ctx
->DrawBuffer
;
449 /* Flag the FBO as requiring validation. */
450 if (_mesa_is_user_fbo(fb
)) {
458 * Helper function to set the GL_DRAW_BUFFER state in the context and
459 * current FBO. Called via glDrawBuffer(), glDrawBuffersARB()
461 * All error checking will have been done prior to calling this function
462 * so nothing should go wrong at this point.
464 * \param ctx current context
465 * \param n number of color outputs to set
466 * \param buffers array[n] of colorbuffer names, like GL_LEFT.
467 * \param destMask array[n] of BUFFER_BIT_* bitmasks which correspond to the
468 * colorbuffer names. (i.e. GL_FRONT_AND_BACK =>
469 * BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT).
472 _mesa_drawbuffers(struct gl_context
*ctx
, GLuint n
, const GLenum
*buffers
,
473 const GLbitfield
*destMask
)
475 struct gl_framebuffer
*fb
= ctx
->DrawBuffer
;
476 GLbitfield mask
[MAX_DRAW_BUFFERS
];
480 /* compute destMask values now */
481 const GLbitfield supportedMask
= supported_buffer_bitmask(ctx
, fb
);
483 for (output
= 0; output
< n
; output
++) {
484 mask
[output
] = draw_buffer_enum_to_bitmask(ctx
, buffers
[output
]);
485 ASSERT(mask
[output
] != BAD_MASK
);
486 mask
[output
] &= supportedMask
;
492 * If n==1, destMask[0] may have up to four bits set.
493 * Otherwise, destMask[x] can only have one bit set.
496 GLuint count
= 0, destMask0
= destMask
[0];
498 GLint bufIndex
= ffs(destMask0
) - 1;
499 if (fb
->_ColorDrawBufferIndexes
[count
] != bufIndex
) {
500 updated_drawbuffers(ctx
);
501 fb
->_ColorDrawBufferIndexes
[count
] = bufIndex
;
504 destMask0
&= ~(1 << bufIndex
);
506 fb
->ColorDrawBuffer
[0] = buffers
[0];
507 fb
->_NumColorDrawBuffers
= count
;
511 for (buf
= 0; buf
< n
; buf
++ ) {
513 GLint bufIndex
= ffs(destMask
[buf
]) - 1;
514 /* only one bit should be set in the destMask[buf] field */
515 ASSERT(_mesa_bitcount(destMask
[buf
]) == 1);
516 if (fb
->_ColorDrawBufferIndexes
[buf
] != bufIndex
) {
517 updated_drawbuffers(ctx
);
518 fb
->_ColorDrawBufferIndexes
[buf
] = bufIndex
;
523 if (fb
->_ColorDrawBufferIndexes
[buf
] != -1) {
524 updated_drawbuffers(ctx
);
525 fb
->_ColorDrawBufferIndexes
[buf
] = -1;
528 fb
->ColorDrawBuffer
[buf
] = buffers
[buf
];
530 fb
->_NumColorDrawBuffers
= count
;
533 /* set remaining outputs to -1 (GL_NONE) */
534 for (buf
= fb
->_NumColorDrawBuffers
; buf
< ctx
->Const
.MaxDrawBuffers
; buf
++) {
535 if (fb
->_ColorDrawBufferIndexes
[buf
] != -1) {
536 updated_drawbuffers(ctx
);
537 fb
->_ColorDrawBufferIndexes
[buf
] = -1;
540 for (buf
= n
; buf
< ctx
->Const
.MaxDrawBuffers
; buf
++) {
541 fb
->ColorDrawBuffer
[buf
] = GL_NONE
;
544 if (_mesa_is_winsys_fbo(fb
)) {
545 /* also set context drawbuffer state */
546 for (buf
= 0; buf
< ctx
->Const
.MaxDrawBuffers
; buf
++) {
547 if (ctx
->Color
.DrawBuffer
[buf
] != fb
->ColorDrawBuffer
[buf
]) {
548 updated_drawbuffers(ctx
);
549 ctx
->Color
.DrawBuffer
[buf
] = fb
->ColorDrawBuffer
[buf
];
557 * Update the current drawbuffer's _ColorDrawBufferIndex[] list, etc.
558 * from the context's Color.DrawBuffer[] state.
559 * Use when changing contexts.
562 _mesa_update_draw_buffers(struct gl_context
*ctx
)
564 GLenum buffers
[MAX_DRAW_BUFFERS
];
567 /* should be a window system FBO */
568 assert(_mesa_is_winsys_fbo(ctx
->DrawBuffer
));
570 for (i
= 0; i
< ctx
->Const
.MaxDrawBuffers
; i
++)
571 buffers
[i
] = ctx
->Color
.DrawBuffer
[i
];
573 _mesa_drawbuffers(ctx
, ctx
->Const
.MaxDrawBuffers
, buffers
, NULL
);
578 * Like \sa _mesa_drawbuffers(), this is a helper function for setting
579 * GL_READ_BUFFER state in the context and current FBO.
580 * \param ctx the rendering context
581 * \param buffer GL_FRONT, GL_BACK, GL_COLOR_ATTACHMENT0, etc.
582 * \param bufferIndex the numerical index corresponding to 'buffer'
585 _mesa_readbuffer(struct gl_context
*ctx
, GLenum buffer
, GLint bufferIndex
)
587 struct gl_framebuffer
*fb
= ctx
->ReadBuffer
;
589 if (_mesa_is_winsys_fbo(fb
)) {
590 /* Only update the per-context READ_BUFFER state if we're bound to
591 * a window-system framebuffer.
593 ctx
->Pixel
.ReadBuffer
= buffer
;
596 fb
->ColorReadBuffer
= buffer
;
597 fb
->_ColorReadBufferIndex
= bufferIndex
;
599 ctx
->NewState
|= _NEW_BUFFERS
;
605 * Called by glReadBuffer to set the source renderbuffer for reading pixels.
606 * \param mode color buffer such as GL_FRONT, GL_BACK, etc.
609 _mesa_ReadBuffer(GLenum buffer
)
611 struct gl_framebuffer
*fb
;
612 GLbitfield supportedMask
;
614 GET_CURRENT_CONTEXT(ctx
);
616 FLUSH_VERTICES(ctx
, 0);
618 if (MESA_VERBOSE
& VERBOSE_API
)
619 _mesa_debug(ctx
, "glReadBuffer %s\n", _mesa_lookup_enum_by_nr(buffer
));
621 fb
= ctx
->ReadBuffer
;
623 if (MESA_VERBOSE
& VERBOSE_API
)
624 _mesa_debug(ctx
, "glReadBuffer %s\n", _mesa_lookup_enum_by_nr(buffer
));
626 if (buffer
== GL_NONE
) {
627 /* This is legal--it means that no buffer should be bound for reading. */
631 /* general case / window-system framebuffer */
632 srcBuffer
= read_buffer_enum_to_index(buffer
);
633 if (srcBuffer
== -1) {
634 _mesa_error(ctx
, GL_INVALID_ENUM
,
635 "glReadBuffer(buffer=0x%x)", buffer
);
638 supportedMask
= supported_buffer_bitmask(ctx
, fb
);
639 if (((1 << srcBuffer
) & supportedMask
) == 0) {
640 _mesa_error(ctx
, GL_INVALID_OPERATION
,
641 "glReadBuffer(buffer=0x%x)", buffer
);
646 /* OK, all error checking has been completed now */
648 _mesa_readbuffer(ctx
, buffer
, srcBuffer
);
651 * Call device driver function.
653 if (ctx
->Driver
.ReadBuffer
)
654 (*ctx
->Driver
.ReadBuffer
)(ctx
, buffer
);