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 * 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.
28 * glReadBuffer, DrawBuffer functions.
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
55 supported_buffer_bitmask(const struct gl_context
*ctx
,
56 const struct gl_framebuffer
*fb
)
58 GLbitfield mask
= 0x0;
60 if (_mesa_is_user_fbo(fb
)) {
61 /* A user-created renderbuffer */
63 ASSERT(ctx
->Extensions
.EXT_framebuffer_object
);
64 for (i
= 0; i
< ctx
->Const
.MaxColorAttachments
; i
++) {
65 mask
|= (BUFFER_BIT_COLOR0
<< i
);
69 /* A window system framebuffer */
71 mask
= BUFFER_BIT_FRONT_LEFT
; /* always have this */
72 if (fb
->Visual
.stereoMode
) {
73 mask
|= BUFFER_BIT_FRONT_RIGHT
;
74 if (fb
->Visual
.doubleBufferMode
) {
75 mask
|= BUFFER_BIT_BACK_LEFT
| BUFFER_BIT_BACK_RIGHT
;
78 else if (fb
->Visual
.doubleBufferMode
) {
79 mask
|= BUFFER_BIT_BACK_LEFT
;
82 for (i
= 0; i
< fb
->Visual
.numAuxBuffers
; i
++) {
83 mask
|= (BUFFER_BIT_AUX0
<< i
);
92 * Helper routine used by glDrawBuffer and glDrawBuffersARB.
93 * Given a GLenum naming one or more color buffers (such as
94 * GL_FRONT_AND_BACK), return the corresponding bitmask of BUFFER_BIT_* flags.
97 draw_buffer_enum_to_bitmask(const struct gl_context
*ctx
, GLenum buffer
)
103 return BUFFER_BIT_FRONT_LEFT
| BUFFER_BIT_FRONT_RIGHT
;
105 if (_mesa_is_gles3(ctx
)) {
106 /* Page 181 (page 192 of the PDF) in section 4.2.1 of the OpenGL
107 * ES 3.0.1 specification says:
109 * "When draw buffer zero is BACK, color values are written
110 * into the sole buffer for single-buffered contexts, or into
111 * the back buffer for double-buffered contexts."
113 * Since there is no stereo rendering in ES 3.0, only return the
114 * LEFT bits. This also satisfies the "n must be 1" requirement.
116 if (ctx
->DrawBuffer
->Visual
.doubleBufferMode
)
117 return BUFFER_BIT_BACK_LEFT
;
118 return BUFFER_BIT_FRONT_LEFT
;
120 return BUFFER_BIT_BACK_LEFT
| BUFFER_BIT_BACK_RIGHT
;
122 return BUFFER_BIT_FRONT_RIGHT
| BUFFER_BIT_BACK_RIGHT
;
124 return BUFFER_BIT_FRONT_RIGHT
;
126 return BUFFER_BIT_BACK_RIGHT
;
128 return BUFFER_BIT_BACK_LEFT
;
129 case GL_FRONT_AND_BACK
:
130 return BUFFER_BIT_FRONT_LEFT
| BUFFER_BIT_BACK_LEFT
131 | BUFFER_BIT_FRONT_RIGHT
| BUFFER_BIT_BACK_RIGHT
;
133 return BUFFER_BIT_FRONT_LEFT
| BUFFER_BIT_BACK_LEFT
;
135 return BUFFER_BIT_FRONT_LEFT
;
137 return BUFFER_BIT_AUX0
;
141 return 1 << BUFFER_COUNT
; /* invalid, but not BAD_MASK */
142 case GL_COLOR_ATTACHMENT0_EXT
:
143 return BUFFER_BIT_COLOR0
;
144 case GL_COLOR_ATTACHMENT1_EXT
:
145 return BUFFER_BIT_COLOR1
;
146 case GL_COLOR_ATTACHMENT2_EXT
:
147 return BUFFER_BIT_COLOR2
;
148 case GL_COLOR_ATTACHMENT3_EXT
:
149 return BUFFER_BIT_COLOR3
;
150 case GL_COLOR_ATTACHMENT4_EXT
:
151 return BUFFER_BIT_COLOR4
;
152 case GL_COLOR_ATTACHMENT5_EXT
:
153 return BUFFER_BIT_COLOR5
;
154 case GL_COLOR_ATTACHMENT6_EXT
:
155 return BUFFER_BIT_COLOR6
;
156 case GL_COLOR_ATTACHMENT7_EXT
:
157 return BUFFER_BIT_COLOR7
;
166 * Helper routine used by glReadBuffer.
167 * Given a GLenum naming a color buffer, return the index of the corresponding
168 * renderbuffer (a BUFFER_* value).
169 * return -1 for an invalid buffer.
172 read_buffer_enum_to_index(GLenum buffer
)
176 return BUFFER_FRONT_LEFT
;
178 return BUFFER_BACK_LEFT
;
180 return BUFFER_FRONT_RIGHT
;
182 return BUFFER_FRONT_RIGHT
;
184 return BUFFER_BACK_RIGHT
;
186 return BUFFER_BACK_LEFT
;
188 return BUFFER_FRONT_LEFT
;
190 return BUFFER_FRONT_LEFT
;
196 return BUFFER_COUNT
; /* invalid, but not -1 */
197 case GL_COLOR_ATTACHMENT0_EXT
:
198 return BUFFER_COLOR0
;
199 case GL_COLOR_ATTACHMENT1_EXT
:
200 return BUFFER_COLOR1
;
201 case GL_COLOR_ATTACHMENT2_EXT
:
202 return BUFFER_COLOR2
;
203 case GL_COLOR_ATTACHMENT3_EXT
:
204 return BUFFER_COLOR3
;
205 case GL_COLOR_ATTACHMENT4_EXT
:
206 return BUFFER_COLOR4
;
207 case GL_COLOR_ATTACHMENT5_EXT
:
208 return BUFFER_COLOR5
;
209 case GL_COLOR_ATTACHMENT6_EXT
:
210 return BUFFER_COLOR6
;
211 case GL_COLOR_ATTACHMENT7_EXT
:
212 return BUFFER_COLOR7
;
221 * Called by glDrawBuffer().
222 * Specify which renderbuffer(s) to draw into for the first color output.
223 * <buffer> can name zero, one, two or four renderbuffers!
224 * \sa _mesa_DrawBuffers
226 * \param buffer buffer token such as GL_LEFT or GL_FRONT_AND_BACK, etc.
228 * Note that the behaviour of this function depends on whether the
229 * current ctx->DrawBuffer is a window-system framebuffer (Name=0) or
230 * a user-created framebuffer object (Name!=0).
231 * In the former case, we update the per-context ctx->Color.DrawBuffer
232 * state var _and_ the FB's ColorDrawBuffer state.
233 * In the later case, we update the FB's ColorDrawBuffer state only.
235 * Furthermore, upon a MakeCurrent() or BindFramebuffer() call, if the
236 * new FB is a window system FB, we need to re-update the FB's
237 * ColorDrawBuffer state to match the context. This is handled in
238 * _mesa_update_framebuffer().
240 * See the GL_EXT_framebuffer_object spec for more info.
243 _mesa_DrawBuffer(GLenum buffer
)
246 GET_CURRENT_CONTEXT(ctx
);
247 ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx
); /* too complex... */
249 if (MESA_VERBOSE
& VERBOSE_API
) {
250 _mesa_debug(ctx
, "glDrawBuffer %s\n", _mesa_lookup_enum_by_nr(buffer
));
253 if (buffer
== GL_NONE
) {
257 const GLbitfield supportedMask
258 = supported_buffer_bitmask(ctx
, ctx
->DrawBuffer
);
259 destMask
= draw_buffer_enum_to_bitmask(ctx
, buffer
);
260 if (destMask
== BAD_MASK
) {
261 /* totally bogus buffer */
262 _mesa_error(ctx
, GL_INVALID_ENUM
,
263 "glDrawBuffer(buffer=0x%x)", buffer
);
266 destMask
&= supportedMask
;
267 if (destMask
== 0x0) {
268 /* none of the named color buffers exist! */
269 _mesa_error(ctx
, GL_INVALID_OPERATION
,
270 "glDrawBuffer(buffer=0x%x)", buffer
);
275 /* if we get here, there's no error so set new state */
276 _mesa_drawbuffers(ctx
, 1, &buffer
, &destMask
);
279 * Call device driver function.
281 if (ctx
->Driver
.DrawBuffers
)
282 ctx
->Driver
.DrawBuffers(ctx
, 1, &buffer
);
283 else if (ctx
->Driver
.DrawBuffer
)
284 ctx
->Driver
.DrawBuffer(ctx
, buffer
);
289 * Called by glDrawBuffersARB; specifies the destination color renderbuffers
290 * for N fragment program color outputs.
291 * \sa _mesa_DrawBuffer
292 * \param n number of outputs
293 * \param buffers array [n] of renderbuffer names. Unlike glDrawBuffer, the
294 * names cannot specify more than one buffer. For example,
295 * GL_FRONT_AND_BACK is illegal.
298 _mesa_DrawBuffers(GLsizei n
, const GLenum
*buffers
)
301 GLbitfield usedBufferMask
, supportedMask
;
302 GLbitfield destMask
[MAX_DRAW_BUFFERS
];
303 GET_CURRENT_CONTEXT(ctx
);
304 ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx
);
306 /* Turns out n==0 is a valid input that should not produce an error.
307 * The remaining code below correctly handles the n==0 case.
309 * From the OpenGL 3.0 specification, page 258:
310 * "An INVALID_VALUE error is generated if n is greater than
313 if (n
< 0 || n
> (GLsizei
) ctx
->Const
.MaxDrawBuffers
) {
314 _mesa_error(ctx
, GL_INVALID_VALUE
, "glDrawBuffersARB(n)");
318 supportedMask
= supported_buffer_bitmask(ctx
, ctx
->DrawBuffer
);
319 usedBufferMask
= 0x0;
321 /* From the ES 3.0 specification, page 180:
322 * "If the GL is bound to the default framebuffer, then n must be 1
323 * and the constant must be BACK or NONE."
325 if (_mesa_is_gles3(ctx
) && _mesa_is_winsys_fbo(ctx
->DrawBuffer
) &&
326 (n
!= 1 || (buffers
[0] != GL_NONE
&& buffers
[0] != GL_BACK
))) {
327 _mesa_error(ctx
, GL_INVALID_OPERATION
, "glDrawBuffers(buffer)");
331 /* complicated error checking... */
332 for (output
= 0; output
< n
; output
++) {
333 if (buffers
[output
] == GL_NONE
) {
334 destMask
[output
] = 0x0;
337 /* Page 259 (page 275 of the PDF) in section 4.2.1 of the OpenGL 3.0
338 * spec (20080923) says:
340 * "If the GL is bound to a framebuffer object and DrawBuffers is
341 * supplied with [...] COLOR_ATTACHMENTm where m is greater than
342 * or equal to the value of MAX_COLOR_ATTACHMENTS, then the error
343 * INVALID_OPERATION results."
345 if (_mesa_is_user_fbo(ctx
->DrawBuffer
) && buffers
[output
] >=
346 GL_COLOR_ATTACHMENT0
+ ctx
->Const
.MaxDrawBuffers
) {
347 _mesa_error(ctx
, GL_INVALID_OPERATION
, "glDrawBuffersARB(buffer)");
351 destMask
[output
] = draw_buffer_enum_to_bitmask(ctx
, buffers
[output
]);
353 /* From the OpenGL 3.0 specification, page 258:
354 * "Each buffer listed in bufs must be one of the values from tables
355 * 4.5 or 4.6. Otherwise, an INVALID_ENUM error is generated.
357 if (destMask
[output
] == BAD_MASK
) {
358 _mesa_error(ctx
, GL_INVALID_ENUM
, "glDrawBuffersARB(buffer)");
362 /* From the OpenGL 3.0 specification, page 259:
363 * "For both the default framebuffer and framebuffer objects, the
364 * constants FRONT, BACK, LEFT, RIGHT, and FRONT_AND_BACK are not
365 * valid in the bufs array passed to DrawBuffers, and will result in
366 * the error INVALID_OPERATION. This restriction is because these
367 * constants may themselves refer to multiple buffers, as shown in
370 if (_mesa_bitcount(destMask
[output
]) > 1) {
371 _mesa_error(ctx
, GL_INVALID_OPERATION
, "glDrawBuffersARB(buffer)");
375 /* From the OpenGL 3.0 specification, page 259:
376 * "If the GL is bound to the default framebuffer and DrawBuffers is
377 * supplied with a constant (other than NONE) that does not indicate
378 * any of the color buffers allocated to the GL context by the window
379 * system, the error INVALID_OPERATION will be generated.
381 * If the GL is bound to a framebuffer object and DrawBuffers is
382 * supplied with a constant from table 4.6 [...] then the error
383 * INVALID_OPERATION results."
385 destMask
[output
] &= supportedMask
;
386 if (destMask
[output
] == 0) {
387 _mesa_error(ctx
, GL_INVALID_OPERATION
,
388 "glDrawBuffersARB(unsupported buffer)");
392 /* ES 3.0 is even more restrictive. From the ES 3.0 spec, page 180:
393 * "If the GL is bound to a framebuffer object, the ith buffer listed
394 * in bufs must be COLOR_ATTACHMENTi or NONE. [...] INVALID_OPERATION."
396 if (_mesa_is_gles3(ctx
) && _mesa_is_user_fbo(ctx
->DrawBuffer
) &&
397 buffers
[output
] != GL_NONE
&&
398 buffers
[output
] != GL_COLOR_ATTACHMENT0
+ output
) {
399 _mesa_error(ctx
, GL_INVALID_OPERATION
, "glDrawBuffers(buffer)");
403 /* From the OpenGL 3.0 specification, page 258:
404 * "Except for NONE, a buffer may not appear more than once in the
405 * array pointed to by bufs. Specifying a buffer more then once will
406 * result in the error INVALID_OPERATION."
408 if (destMask
[output
] & usedBufferMask
) {
409 _mesa_error(ctx
, GL_INVALID_OPERATION
,
410 "glDrawBuffersARB(duplicated buffer)");
415 usedBufferMask
|= destMask
[output
];
419 /* OK, if we get here, there were no errors so set the new state */
420 _mesa_drawbuffers(ctx
, n
, buffers
, destMask
);
423 * Call device driver function. Note that n can be equal to 0,
424 * in which case we don't want to reference buffers[0], which
427 if (ctx
->Driver
.DrawBuffers
)
428 ctx
->Driver
.DrawBuffers(ctx
, n
, buffers
);
429 else if (ctx
->Driver
.DrawBuffer
)
430 ctx
->Driver
.DrawBuffer(ctx
, n
> 0 ? buffers
[0] : GL_NONE
);
435 * Performs necessary state updates when _mesa_drawbuffers makes an
439 updated_drawbuffers(struct gl_context
*ctx
)
441 FLUSH_VERTICES(ctx
, _NEW_BUFFERS
);
443 if (ctx
->API
== API_OPENGL_COMPAT
&& !ctx
->Extensions
.ARB_ES2_compatibility
) {
444 struct gl_framebuffer
*fb
= ctx
->DrawBuffer
;
446 /* Flag the FBO as requiring validation. */
447 if (_mesa_is_user_fbo(fb
)) {
455 * Helper function to set the GL_DRAW_BUFFER state in the context and
456 * current FBO. Called via glDrawBuffer(), glDrawBuffersARB()
458 * All error checking will have been done prior to calling this function
459 * so nothing should go wrong at this point.
461 * \param ctx current context
462 * \param n number of color outputs to set
463 * \param buffers array[n] of colorbuffer names, like GL_LEFT.
464 * \param destMask array[n] of BUFFER_BIT_* bitmasks which correspond to the
465 * colorbuffer names. (i.e. GL_FRONT_AND_BACK =>
466 * BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT).
469 _mesa_drawbuffers(struct gl_context
*ctx
, GLuint n
, const GLenum
*buffers
,
470 const GLbitfield
*destMask
)
472 struct gl_framebuffer
*fb
= ctx
->DrawBuffer
;
473 GLbitfield mask
[MAX_DRAW_BUFFERS
];
477 /* compute destMask values now */
478 const GLbitfield supportedMask
= supported_buffer_bitmask(ctx
, fb
);
480 for (output
= 0; output
< n
; output
++) {
481 mask
[output
] = draw_buffer_enum_to_bitmask(ctx
, buffers
[output
]);
482 ASSERT(mask
[output
] != BAD_MASK
);
483 mask
[output
] &= supportedMask
;
489 * If n==1, destMask[0] may have up to four bits set.
490 * Otherwise, destMask[x] can only have one bit set.
493 GLuint count
= 0, destMask0
= destMask
[0];
495 GLint bufIndex
= ffs(destMask0
) - 1;
496 if (fb
->_ColorDrawBufferIndexes
[count
] != bufIndex
) {
497 updated_drawbuffers(ctx
);
498 fb
->_ColorDrawBufferIndexes
[count
] = bufIndex
;
501 destMask0
&= ~(1 << bufIndex
);
503 fb
->ColorDrawBuffer
[0] = buffers
[0];
504 fb
->_NumColorDrawBuffers
= count
;
508 for (buf
= 0; buf
< n
; buf
++ ) {
510 GLint bufIndex
= ffs(destMask
[buf
]) - 1;
511 /* only one bit should be set in the destMask[buf] field */
512 ASSERT(_mesa_bitcount(destMask
[buf
]) == 1);
513 if (fb
->_ColorDrawBufferIndexes
[buf
] != bufIndex
) {
514 updated_drawbuffers(ctx
);
515 fb
->_ColorDrawBufferIndexes
[buf
] = bufIndex
;
520 if (fb
->_ColorDrawBufferIndexes
[buf
] != -1) {
521 updated_drawbuffers(ctx
);
522 fb
->_ColorDrawBufferIndexes
[buf
] = -1;
525 fb
->ColorDrawBuffer
[buf
] = buffers
[buf
];
527 fb
->_NumColorDrawBuffers
= count
;
530 /* set remaining outputs to -1 (GL_NONE) */
531 for (buf
= fb
->_NumColorDrawBuffers
; buf
< ctx
->Const
.MaxDrawBuffers
; buf
++) {
532 if (fb
->_ColorDrawBufferIndexes
[buf
] != -1) {
533 updated_drawbuffers(ctx
);
534 fb
->_ColorDrawBufferIndexes
[buf
] = -1;
537 for (buf
= n
; buf
< ctx
->Const
.MaxDrawBuffers
; buf
++) {
538 fb
->ColorDrawBuffer
[buf
] = GL_NONE
;
541 if (_mesa_is_winsys_fbo(fb
)) {
542 /* also set context drawbuffer state */
543 for (buf
= 0; buf
< ctx
->Const
.MaxDrawBuffers
; buf
++) {
544 if (ctx
->Color
.DrawBuffer
[buf
] != fb
->ColorDrawBuffer
[buf
]) {
545 updated_drawbuffers(ctx
);
546 ctx
->Color
.DrawBuffer
[buf
] = fb
->ColorDrawBuffer
[buf
];
554 * Update the current drawbuffer's _ColorDrawBufferIndex[] list, etc.
555 * from the context's Color.DrawBuffer[] state.
556 * Use when changing contexts.
559 _mesa_update_draw_buffers(struct gl_context
*ctx
)
561 GLenum buffers
[MAX_DRAW_BUFFERS
];
564 /* should be a window system FBO */
565 assert(_mesa_is_winsys_fbo(ctx
->DrawBuffer
));
567 for (i
= 0; i
< ctx
->Const
.MaxDrawBuffers
; i
++)
568 buffers
[i
] = ctx
->Color
.DrawBuffer
[i
];
570 _mesa_drawbuffers(ctx
, ctx
->Const
.MaxDrawBuffers
, buffers
, NULL
);
575 * Like \sa _mesa_drawbuffers(), this is a helper function for setting
576 * GL_READ_BUFFER state in the context and current FBO.
577 * \param ctx the rendering context
578 * \param buffer GL_FRONT, GL_BACK, GL_COLOR_ATTACHMENT0, etc.
579 * \param bufferIndex the numerical index corresponding to 'buffer'
582 _mesa_readbuffer(struct gl_context
*ctx
, GLenum buffer
, GLint bufferIndex
)
584 struct gl_framebuffer
*fb
= ctx
->ReadBuffer
;
586 if (_mesa_is_winsys_fbo(fb
)) {
587 /* Only update the per-context READ_BUFFER state if we're bound to
588 * a window-system framebuffer.
590 ctx
->Pixel
.ReadBuffer
= buffer
;
593 fb
->ColorReadBuffer
= buffer
;
594 fb
->_ColorReadBufferIndex
= bufferIndex
;
596 ctx
->NewState
|= _NEW_BUFFERS
;
602 * Called by glReadBuffer to set the source renderbuffer for reading pixels.
603 * \param mode color buffer such as GL_FRONT, GL_BACK, etc.
606 _mesa_ReadBuffer(GLenum buffer
)
608 struct gl_framebuffer
*fb
;
609 GLbitfield supportedMask
;
611 GET_CURRENT_CONTEXT(ctx
);
612 ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx
);
614 if (MESA_VERBOSE
& VERBOSE_API
)
615 _mesa_debug(ctx
, "glReadBuffer %s\n", _mesa_lookup_enum_by_nr(buffer
));
617 fb
= ctx
->ReadBuffer
;
619 if (MESA_VERBOSE
& VERBOSE_API
)
620 _mesa_debug(ctx
, "glReadBuffer %s\n", _mesa_lookup_enum_by_nr(buffer
));
622 if (buffer
== GL_NONE
) {
623 /* This is legal--it means that no buffer should be bound for reading. */
627 /* general case / window-system framebuffer */
628 srcBuffer
= read_buffer_enum_to_index(buffer
);
629 if (srcBuffer
== -1) {
630 _mesa_error(ctx
, GL_INVALID_ENUM
,
631 "glReadBuffer(buffer=0x%x)", buffer
);
634 supportedMask
= supported_buffer_bitmask(ctx
, fb
);
635 if (((1 << srcBuffer
) & supportedMask
) == 0) {
636 _mesa_error(ctx
, GL_INVALID_OPERATION
,
637 "glReadBuffer(buffer=0x%x)", buffer
);
642 /* OK, all error checking has been completed now */
644 _mesa_readbuffer(ctx
, buffer
, srcBuffer
);
645 ctx
->NewState
|= _NEW_BUFFERS
;
648 * Call device driver function.
650 if (ctx
->Driver
.ReadBuffer
)
651 (*ctx
->Driver
.ReadBuffer
)(ctx
, buffer
);