2 * Mesa 3-D graphics library
4 * Copyright (C) 1999-2007 Brian Paul All Rights Reserved.
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the "Software"),
8 * to deal in the Software without restriction, including without limitation
9 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
10 * and/or sell copies of the Software, and to permit persons to whom the
11 * Software is furnished to do so, subject to the following conditions:
13 * The above copyright notice and this permission notice shall be included
14 * in all copies or substantial portions of the Software.
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
17 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
20 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
21 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
22 * 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 for (i
= 0; i
< ctx
->Const
.MaxColorAttachments
; i
++) {
64 mask
|= (BUFFER_BIT_COLOR0
<< i
);
68 /* A window system framebuffer */
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
;
77 else if (fb
->Visual
.doubleBufferMode
) {
78 mask
|= BUFFER_BIT_BACK_LEFT
;
81 for (i
= 0; i
< fb
->Visual
.numAuxBuffers
; i
++) {
82 mask
|= (BUFFER_BIT_AUX0
<< i
);
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.
96 draw_buffer_enum_to_bitmask(const struct gl_context
*ctx
, GLenum buffer
)
102 return BUFFER_BIT_FRONT_LEFT
| BUFFER_BIT_FRONT_RIGHT
;
104 if (_mesa_is_gles3(ctx
)) {
105 /* Page 181 (page 192 of the PDF) in section 4.2.1 of the OpenGL
106 * ES 3.0.1 specification says:
108 * "When draw buffer zero is BACK, color values are written
109 * into the sole buffer for single-buffered contexts, or into
110 * the back buffer for double-buffered contexts."
112 * Since there is no stereo rendering in ES 3.0, only return the
113 * LEFT bits. This also satisfies the "n must be 1" requirement.
115 if (ctx
->DrawBuffer
->Visual
.doubleBufferMode
)
116 return BUFFER_BIT_BACK_LEFT
;
117 return BUFFER_BIT_FRONT_LEFT
;
119 return BUFFER_BIT_BACK_LEFT
| BUFFER_BIT_BACK_RIGHT
;
121 return BUFFER_BIT_FRONT_RIGHT
| BUFFER_BIT_BACK_RIGHT
;
123 return BUFFER_BIT_FRONT_RIGHT
;
125 return BUFFER_BIT_BACK_RIGHT
;
127 return BUFFER_BIT_BACK_LEFT
;
128 case GL_FRONT_AND_BACK
:
129 return BUFFER_BIT_FRONT_LEFT
| BUFFER_BIT_BACK_LEFT
130 | BUFFER_BIT_FRONT_RIGHT
| BUFFER_BIT_BACK_RIGHT
;
132 return BUFFER_BIT_FRONT_LEFT
| BUFFER_BIT_BACK_LEFT
;
134 return BUFFER_BIT_FRONT_LEFT
;
136 return BUFFER_BIT_AUX0
;
140 return 1 << BUFFER_COUNT
; /* invalid, but not BAD_MASK */
141 case GL_COLOR_ATTACHMENT0_EXT
:
142 return BUFFER_BIT_COLOR0
;
143 case GL_COLOR_ATTACHMENT1_EXT
:
144 return BUFFER_BIT_COLOR1
;
145 case GL_COLOR_ATTACHMENT2_EXT
:
146 return BUFFER_BIT_COLOR2
;
147 case GL_COLOR_ATTACHMENT3_EXT
:
148 return BUFFER_BIT_COLOR3
;
149 case GL_COLOR_ATTACHMENT4_EXT
:
150 return BUFFER_BIT_COLOR4
;
151 case GL_COLOR_ATTACHMENT5_EXT
:
152 return BUFFER_BIT_COLOR5
;
153 case GL_COLOR_ATTACHMENT6_EXT
:
154 return BUFFER_BIT_COLOR6
;
155 case GL_COLOR_ATTACHMENT7_EXT
:
156 return BUFFER_BIT_COLOR7
;
165 * Helper routine used by glReadBuffer.
166 * Given a GLenum naming a color buffer, return the index of the corresponding
167 * renderbuffer (a BUFFER_* value).
168 * return -1 for an invalid buffer.
171 read_buffer_enum_to_index(GLenum buffer
)
175 return BUFFER_FRONT_LEFT
;
177 return BUFFER_BACK_LEFT
;
179 return BUFFER_FRONT_RIGHT
;
181 return BUFFER_FRONT_RIGHT
;
183 return BUFFER_BACK_RIGHT
;
185 return BUFFER_BACK_LEFT
;
187 return BUFFER_FRONT_LEFT
;
189 return BUFFER_FRONT_LEFT
;
195 return BUFFER_COUNT
; /* invalid, but not -1 */
196 case GL_COLOR_ATTACHMENT0_EXT
:
197 return BUFFER_COLOR0
;
198 case GL_COLOR_ATTACHMENT1_EXT
:
199 return BUFFER_COLOR1
;
200 case GL_COLOR_ATTACHMENT2_EXT
:
201 return BUFFER_COLOR2
;
202 case GL_COLOR_ATTACHMENT3_EXT
:
203 return BUFFER_COLOR3
;
204 case GL_COLOR_ATTACHMENT4_EXT
:
205 return BUFFER_COLOR4
;
206 case GL_COLOR_ATTACHMENT5_EXT
:
207 return BUFFER_COLOR5
;
208 case GL_COLOR_ATTACHMENT6_EXT
:
209 return BUFFER_COLOR6
;
210 case GL_COLOR_ATTACHMENT7_EXT
:
211 return BUFFER_COLOR7
;
220 * Called by glDrawBuffer().
221 * Specify which renderbuffer(s) to draw into for the first color output.
222 * <buffer> can name zero, one, two or four renderbuffers!
223 * \sa _mesa_DrawBuffers
225 * \param buffer buffer token such as GL_LEFT or GL_FRONT_AND_BACK, etc.
227 * Note that the behaviour of this function depends on whether the
228 * current ctx->DrawBuffer is a window-system framebuffer or a user-created
229 * framebuffer object.
230 * In the former case, we update the per-context ctx->Color.DrawBuffer
231 * state var _and_ the FB's ColorDrawBuffer state.
232 * In the later case, we update the FB's ColorDrawBuffer state only.
234 * Furthermore, upon a MakeCurrent() or BindFramebuffer() call, if the
235 * new FB is a window system FB, we need to re-update the FB's
236 * ColorDrawBuffer state to match the context. This is handled in
237 * _mesa_update_framebuffer().
239 * See the GL_EXT_framebuffer_object spec for more info.
242 _mesa_DrawBuffer(GLenum buffer
)
245 GET_CURRENT_CONTEXT(ctx
);
247 FLUSH_VERTICES(ctx
, 0);
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
);
305 FLUSH_VERTICES(ctx
, 0);
307 /* Turns out n==0 is a valid input that should not produce an error.
308 * The remaining code below correctly handles the n==0 case.
310 * From the OpenGL 3.0 specification, page 258:
311 * "An INVALID_VALUE error is generated if n is greater than
314 if (n
< 0 || n
> (GLsizei
) ctx
->Const
.MaxDrawBuffers
) {
315 _mesa_error(ctx
, GL_INVALID_VALUE
, "glDrawBuffersARB(n)");
319 supportedMask
= supported_buffer_bitmask(ctx
, ctx
->DrawBuffer
);
320 usedBufferMask
= 0x0;
322 /* From the ES 3.0 specification, page 180:
323 * "If the GL is bound to the default framebuffer, then n must be 1
324 * and the constant must be BACK or NONE."
326 if (_mesa_is_gles3(ctx
) && _mesa_is_winsys_fbo(ctx
->DrawBuffer
) &&
327 (n
!= 1 || (buffers
[0] != GL_NONE
&& buffers
[0] != GL_BACK
))) {
328 _mesa_error(ctx
, GL_INVALID_OPERATION
, "glDrawBuffers(buffer)");
332 /* complicated error checking... */
333 for (output
= 0; output
< n
; output
++) {
334 if (buffers
[output
] == GL_NONE
) {
335 destMask
[output
] = 0x0;
338 /* Page 259 (page 275 of the PDF) in section 4.2.1 of the OpenGL 3.0
339 * spec (20080923) says:
341 * "If the GL is bound to a framebuffer object and DrawBuffers is
342 * supplied with [...] COLOR_ATTACHMENTm where m is greater than
343 * or equal to the value of MAX_COLOR_ATTACHMENTS, then the error
344 * INVALID_OPERATION results."
346 if (_mesa_is_user_fbo(ctx
->DrawBuffer
) && buffers
[output
] >=
347 GL_COLOR_ATTACHMENT0
+ ctx
->Const
.MaxDrawBuffers
) {
348 _mesa_error(ctx
, GL_INVALID_OPERATION
, "glDrawBuffersARB(buffer)");
352 destMask
[output
] = draw_buffer_enum_to_bitmask(ctx
, buffers
[output
]);
354 /* From the OpenGL 3.0 specification, page 258:
355 * "Each buffer listed in bufs must be one of the values from tables
356 * 4.5 or 4.6. Otherwise, an INVALID_ENUM error is generated.
358 if (destMask
[output
] == BAD_MASK
) {
359 _mesa_error(ctx
, GL_INVALID_ENUM
, "glDrawBuffersARB(buffer)");
363 /* From the OpenGL 3.0 specification, page 259:
364 * "For both the default framebuffer and framebuffer objects, the
365 * constants FRONT, BACK, LEFT, RIGHT, and FRONT_AND_BACK are not
366 * valid in the bufs array passed to DrawBuffers, and will result in
367 * the error INVALID_OPERATION. This restriction is because these
368 * constants may themselves refer to multiple buffers, as shown in
371 if (_mesa_bitcount(destMask
[output
]) > 1) {
372 _mesa_error(ctx
, GL_INVALID_OPERATION
, "glDrawBuffersARB(buffer)");
376 /* From the OpenGL 3.0 specification, page 259:
377 * "If the GL is bound to the default framebuffer and DrawBuffers is
378 * supplied with a constant (other than NONE) that does not indicate
379 * any of the color buffers allocated to the GL context by the window
380 * system, the error INVALID_OPERATION will be generated.
382 * If the GL is bound to a framebuffer object and DrawBuffers is
383 * supplied with a constant from table 4.6 [...] then the error
384 * INVALID_OPERATION results."
386 destMask
[output
] &= supportedMask
;
387 if (destMask
[output
] == 0) {
388 _mesa_error(ctx
, GL_INVALID_OPERATION
,
389 "glDrawBuffersARB(unsupported buffer)");
393 /* ES 3.0 is even more restrictive. From the ES 3.0 spec, page 180:
394 * "If the GL is bound to a framebuffer object, the ith buffer listed
395 * in bufs must be COLOR_ATTACHMENTi or NONE. [...] INVALID_OPERATION."
397 if (_mesa_is_gles3(ctx
) && _mesa_is_user_fbo(ctx
->DrawBuffer
) &&
398 buffers
[output
] != GL_NONE
&&
399 buffers
[output
] != GL_COLOR_ATTACHMENT0
+ output
) {
400 _mesa_error(ctx
, GL_INVALID_OPERATION
, "glDrawBuffers(buffer)");
404 /* From the OpenGL 3.0 specification, page 258:
405 * "Except for NONE, a buffer may not appear more than once in the
406 * array pointed to by bufs. Specifying a buffer more then once will
407 * result in the error INVALID_OPERATION."
409 if (destMask
[output
] & usedBufferMask
) {
410 _mesa_error(ctx
, GL_INVALID_OPERATION
,
411 "glDrawBuffersARB(duplicated buffer)");
416 usedBufferMask
|= destMask
[output
];
420 /* OK, if we get here, there were no errors so set the new state */
421 _mesa_drawbuffers(ctx
, n
, buffers
, destMask
);
424 * Call device driver function. Note that n can be equal to 0,
425 * in which case we don't want to reference buffers[0], which
428 if (ctx
->Driver
.DrawBuffers
)
429 ctx
->Driver
.DrawBuffers(ctx
, n
, buffers
);
430 else if (ctx
->Driver
.DrawBuffer
)
431 ctx
->Driver
.DrawBuffer(ctx
, n
> 0 ? buffers
[0] : GL_NONE
);
436 * Performs necessary state updates when _mesa_drawbuffers makes an
440 updated_drawbuffers(struct gl_context
*ctx
)
442 FLUSH_VERTICES(ctx
, _NEW_BUFFERS
);
444 if (ctx
->API
== API_OPENGL_COMPAT
&& !ctx
->Extensions
.ARB_ES2_compatibility
) {
445 struct gl_framebuffer
*fb
= ctx
->DrawBuffer
;
447 /* Flag the FBO as requiring validation. */
448 if (_mesa_is_user_fbo(fb
)) {
456 * Helper function to set the GL_DRAW_BUFFER state in the context and
457 * current FBO. Called via glDrawBuffer(), glDrawBuffersARB()
459 * All error checking will have been done prior to calling this function
460 * so nothing should go wrong at this point.
462 * \param ctx current context
463 * \param n number of color outputs to set
464 * \param buffers array[n] of colorbuffer names, like GL_LEFT.
465 * \param destMask array[n] of BUFFER_BIT_* bitmasks which correspond to the
466 * colorbuffer names. (i.e. GL_FRONT_AND_BACK =>
467 * BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT).
470 _mesa_drawbuffers(struct gl_context
*ctx
, GLuint n
, const GLenum
*buffers
,
471 const GLbitfield
*destMask
)
473 struct gl_framebuffer
*fb
= ctx
->DrawBuffer
;
474 GLbitfield mask
[MAX_DRAW_BUFFERS
];
478 /* compute destMask values now */
479 const GLbitfield supportedMask
= supported_buffer_bitmask(ctx
, fb
);
481 for (output
= 0; output
< n
; output
++) {
482 mask
[output
] = draw_buffer_enum_to_bitmask(ctx
, buffers
[output
]);
483 ASSERT(mask
[output
] != BAD_MASK
);
484 mask
[output
] &= supportedMask
;
490 * If n==1, destMask[0] may have up to four bits set.
491 * Otherwise, destMask[x] can only have one bit set.
494 GLuint count
= 0, destMask0
= destMask
[0];
496 GLint bufIndex
= ffs(destMask0
) - 1;
497 if (fb
->_ColorDrawBufferIndexes
[count
] != bufIndex
) {
498 updated_drawbuffers(ctx
);
499 fb
->_ColorDrawBufferIndexes
[count
] = bufIndex
;
502 destMask0
&= ~(1 << bufIndex
);
504 fb
->ColorDrawBuffer
[0] = buffers
[0];
505 fb
->_NumColorDrawBuffers
= count
;
509 for (buf
= 0; buf
< n
; buf
++ ) {
511 GLint bufIndex
= ffs(destMask
[buf
]) - 1;
512 /* only one bit should be set in the destMask[buf] field */
513 ASSERT(_mesa_bitcount(destMask
[buf
]) == 1);
514 if (fb
->_ColorDrawBufferIndexes
[buf
] != bufIndex
) {
515 updated_drawbuffers(ctx
);
516 fb
->_ColorDrawBufferIndexes
[buf
] = bufIndex
;
521 if (fb
->_ColorDrawBufferIndexes
[buf
] != -1) {
522 updated_drawbuffers(ctx
);
523 fb
->_ColorDrawBufferIndexes
[buf
] = -1;
526 fb
->ColorDrawBuffer
[buf
] = buffers
[buf
];
528 fb
->_NumColorDrawBuffers
= count
;
531 /* set remaining outputs to -1 (GL_NONE) */
532 for (buf
= fb
->_NumColorDrawBuffers
; buf
< ctx
->Const
.MaxDrawBuffers
; buf
++) {
533 if (fb
->_ColorDrawBufferIndexes
[buf
] != -1) {
534 updated_drawbuffers(ctx
);
535 fb
->_ColorDrawBufferIndexes
[buf
] = -1;
538 for (buf
= n
; buf
< ctx
->Const
.MaxDrawBuffers
; buf
++) {
539 fb
->ColorDrawBuffer
[buf
] = GL_NONE
;
542 if (_mesa_is_winsys_fbo(fb
)) {
543 /* also set context drawbuffer state */
544 for (buf
= 0; buf
< ctx
->Const
.MaxDrawBuffers
; buf
++) {
545 if (ctx
->Color
.DrawBuffer
[buf
] != fb
->ColorDrawBuffer
[buf
]) {
546 updated_drawbuffers(ctx
);
547 ctx
->Color
.DrawBuffer
[buf
] = fb
->ColorDrawBuffer
[buf
];
555 * Update the current drawbuffer's _ColorDrawBufferIndex[] list, etc.
556 * from the context's Color.DrawBuffer[] state.
557 * Use when changing contexts.
560 _mesa_update_draw_buffers(struct gl_context
*ctx
)
562 GLenum buffers
[MAX_DRAW_BUFFERS
];
565 /* should be a window system FBO */
566 assert(_mesa_is_winsys_fbo(ctx
->DrawBuffer
));
568 for (i
= 0; i
< ctx
->Const
.MaxDrawBuffers
; i
++)
569 buffers
[i
] = ctx
->Color
.DrawBuffer
[i
];
571 _mesa_drawbuffers(ctx
, ctx
->Const
.MaxDrawBuffers
, buffers
, NULL
);
576 * Like \sa _mesa_drawbuffers(), this is a helper function for setting
577 * GL_READ_BUFFER state in the context and current FBO.
578 * \param ctx the rendering context
579 * \param buffer GL_FRONT, GL_BACK, GL_COLOR_ATTACHMENT0, etc.
580 * \param bufferIndex the numerical index corresponding to 'buffer'
583 _mesa_readbuffer(struct gl_context
*ctx
, GLenum buffer
, GLint bufferIndex
)
585 struct gl_framebuffer
*fb
= ctx
->ReadBuffer
;
587 if (_mesa_is_winsys_fbo(fb
)) {
588 /* Only update the per-context READ_BUFFER state if we're bound to
589 * a window-system framebuffer.
591 ctx
->Pixel
.ReadBuffer
= buffer
;
594 fb
->ColorReadBuffer
= buffer
;
595 fb
->_ColorReadBufferIndex
= bufferIndex
;
597 ctx
->NewState
|= _NEW_BUFFERS
;
603 * Called by glReadBuffer to set the source renderbuffer for reading pixels.
604 * \param mode color buffer such as GL_FRONT, GL_BACK, etc.
607 _mesa_ReadBuffer(GLenum buffer
)
609 struct gl_framebuffer
*fb
;
610 GLbitfield supportedMask
;
612 GET_CURRENT_CONTEXT(ctx
);
614 FLUSH_VERTICES(ctx
, 0);
616 if (MESA_VERBOSE
& VERBOSE_API
)
617 _mesa_debug(ctx
, "glReadBuffer %s\n", _mesa_lookup_enum_by_nr(buffer
));
619 fb
= ctx
->ReadBuffer
;
621 if (MESA_VERBOSE
& VERBOSE_API
)
622 _mesa_debug(ctx
, "glReadBuffer %s\n", _mesa_lookup_enum_by_nr(buffer
));
624 if (buffer
== GL_NONE
) {
625 /* This is legal--it means that no buffer should be bound for reading. */
629 /* general case / window-system framebuffer */
630 srcBuffer
= read_buffer_enum_to_index(buffer
);
631 if (srcBuffer
== -1) {
632 _mesa_error(ctx
, GL_INVALID_ENUM
,
633 "glReadBuffer(buffer=0x%x)", buffer
);
636 supportedMask
= supported_buffer_bitmask(ctx
, fb
);
637 if (((1 << srcBuffer
) & supportedMask
) == 0) {
638 _mesa_error(ctx
, GL_INVALID_OPERATION
,
639 "glReadBuffer(buffer=0x%x)", buffer
);
644 /* OK, all error checking has been completed now */
646 _mesa_readbuffer(ctx
, buffer
, srcBuffer
);
649 * Call device driver function.
651 if (ctx
->Driver
.ReadBuffer
)
652 (*ctx
->Driver
.ReadBuffer
)(ctx
, buffer
);