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.
44 * Return bitmask of BUFFER_BIT_* flags indicating which color buffers are
45 * available to the rendering context (for drawing or reading).
46 * This depends on the type of framebuffer. For window system framebuffers
47 * we look at the framebuffer's visual. But for user-create framebuffers we
48 * look at the number of supported color attachments.
49 * \param fb the framebuffer to draw to, or read from
50 * \return bitmask of BUFFER_BIT_* flags
53 supported_buffer_bitmask(const GLcontext
*ctx
, const struct gl_framebuffer
*fb
)
55 GLbitfield mask
= 0x0;
58 /* A user-created renderbuffer */
60 ASSERT(ctx
->Extensions
.EXT_framebuffer_object
);
61 for (i
= 0; i
< ctx
->Const
.MaxColorAttachments
; i
++) {
62 mask
|= (BUFFER_BIT_COLOR0
<< i
);
66 /* A window system framebuffer */
68 mask
= BUFFER_BIT_FRONT_LEFT
; /* always have this */
69 if (fb
->Visual
.stereoMode
) {
70 mask
|= BUFFER_BIT_FRONT_RIGHT
;
71 if (fb
->Visual
.doubleBufferMode
) {
72 mask
|= BUFFER_BIT_BACK_LEFT
| BUFFER_BIT_BACK_RIGHT
;
75 else if (fb
->Visual
.doubleBufferMode
) {
76 mask
|= BUFFER_BIT_BACK_LEFT
;
79 for (i
= 0; i
< fb
->Visual
.numAuxBuffers
; i
++) {
80 mask
|= (BUFFER_BIT_AUX0
<< i
);
89 * Helper routine used by glDrawBuffer and glDrawBuffersARB.
90 * Given a GLenum naming one or more color buffers (such as
91 * GL_FRONT_AND_BACK), return the corresponding bitmask of BUFFER_BIT_* flags.
94 draw_buffer_enum_to_bitmask(GLenum buffer
)
100 return BUFFER_BIT_FRONT_LEFT
| BUFFER_BIT_FRONT_RIGHT
;
102 return BUFFER_BIT_BACK_LEFT
| BUFFER_BIT_BACK_RIGHT
;
104 return BUFFER_BIT_FRONT_RIGHT
| BUFFER_BIT_BACK_RIGHT
;
106 return BUFFER_BIT_FRONT_RIGHT
;
108 return BUFFER_BIT_BACK_RIGHT
;
110 return BUFFER_BIT_BACK_LEFT
;
111 case GL_FRONT_AND_BACK
:
112 return BUFFER_BIT_FRONT_LEFT
| BUFFER_BIT_BACK_LEFT
113 | BUFFER_BIT_FRONT_RIGHT
| BUFFER_BIT_BACK_RIGHT
;
115 return BUFFER_BIT_FRONT_LEFT
| BUFFER_BIT_BACK_LEFT
;
117 return BUFFER_BIT_FRONT_LEFT
;
119 return BUFFER_BIT_AUX0
;
123 return 1 << BUFFER_COUNT
; /* invalid, but not BAD_MASK */
124 case GL_COLOR_ATTACHMENT0_EXT
:
125 return BUFFER_BIT_COLOR0
;
126 case GL_COLOR_ATTACHMENT1_EXT
:
127 return BUFFER_BIT_COLOR1
;
128 case GL_COLOR_ATTACHMENT2_EXT
:
129 return BUFFER_BIT_COLOR2
;
130 case GL_COLOR_ATTACHMENT3_EXT
:
131 return BUFFER_BIT_COLOR3
;
132 case GL_COLOR_ATTACHMENT4_EXT
:
133 return BUFFER_BIT_COLOR4
;
134 case GL_COLOR_ATTACHMENT5_EXT
:
135 return BUFFER_BIT_COLOR5
;
136 case GL_COLOR_ATTACHMENT6_EXT
:
137 return BUFFER_BIT_COLOR6
;
138 case GL_COLOR_ATTACHMENT7_EXT
:
139 return BUFFER_BIT_COLOR7
;
148 * Helper routine used by glReadBuffer.
149 * Given a GLenum naming a color buffer, return the index of the corresponding
150 * renderbuffer (a BUFFER_* value).
151 * return -1 for an invalid buffer.
154 read_buffer_enum_to_index(GLenum buffer
)
158 return BUFFER_FRONT_LEFT
;
160 return BUFFER_BACK_LEFT
;
162 return BUFFER_FRONT_RIGHT
;
164 return BUFFER_FRONT_RIGHT
;
166 return BUFFER_BACK_RIGHT
;
168 return BUFFER_BACK_LEFT
;
170 return BUFFER_FRONT_LEFT
;
172 return BUFFER_FRONT_LEFT
;
178 return BUFFER_COUNT
; /* invalid, but not -1 */
179 case GL_COLOR_ATTACHMENT0_EXT
:
180 return BUFFER_COLOR0
;
181 case GL_COLOR_ATTACHMENT1_EXT
:
182 return BUFFER_COLOR1
;
183 case GL_COLOR_ATTACHMENT2_EXT
:
184 return BUFFER_COLOR2
;
185 case GL_COLOR_ATTACHMENT3_EXT
:
186 return BUFFER_COLOR3
;
187 case GL_COLOR_ATTACHMENT4_EXT
:
188 return BUFFER_COLOR4
;
189 case GL_COLOR_ATTACHMENT5_EXT
:
190 return BUFFER_COLOR5
;
191 case GL_COLOR_ATTACHMENT6_EXT
:
192 return BUFFER_COLOR6
;
193 case GL_COLOR_ATTACHMENT7_EXT
:
194 return BUFFER_COLOR7
;
203 * Called by glDrawBuffer().
204 * Specify which renderbuffer(s) to draw into for the first color output.
205 * <buffer> can name zero, one, two or four renderbuffers!
206 * \sa _mesa_DrawBuffersARB
208 * \param buffer buffer token such as GL_LEFT or GL_FRONT_AND_BACK, etc.
210 * Note that the behaviour of this function depends on whether the
211 * current ctx->DrawBuffer is a window-system framebuffer (Name=0) or
212 * a user-created framebuffer object (Name!=0).
213 * In the former case, we update the per-context ctx->Color.DrawBuffer
214 * state var _and_ the FB's ColorDrawBuffer state.
215 * In the later case, we update the FB's ColorDrawBuffer state only.
217 * Furthermore, upon a MakeCurrent() or BindFramebuffer() call, if the
218 * new FB is a window system FB, we need to re-update the FB's
219 * ColorDrawBuffer state to match the context. This is handled in
220 * _mesa_update_framebuffer().
222 * See the GL_EXT_framebuffer_object spec for more info.
225 _mesa_DrawBuffer(GLenum buffer
)
228 GET_CURRENT_CONTEXT(ctx
);
229 ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx
); /* too complex... */
231 if (MESA_VERBOSE
& VERBOSE_API
) {
232 _mesa_debug(ctx
, "glDrawBuffer %s\n", _mesa_lookup_enum_by_nr(buffer
));
235 if (buffer
== GL_NONE
) {
239 const GLbitfield supportedMask
240 = supported_buffer_bitmask(ctx
, ctx
->DrawBuffer
);
241 destMask
= draw_buffer_enum_to_bitmask(buffer
);
242 if (destMask
== BAD_MASK
) {
243 /* totally bogus buffer */
244 _mesa_error(ctx
, GL_INVALID_ENUM
, "glDrawBuffer(buffer=0x%x)", buffer
);
247 destMask
&= supportedMask
;
248 if (destMask
== 0x0) {
249 /* none of the named color buffers exist! */
250 _mesa_error(ctx
, GL_INVALID_OPERATION
,
251 "glDrawBuffer(buffer=0x%x)", buffer
);
256 /* if we get here, there's no error so set new state */
257 _mesa_drawbuffers(ctx
, 1, &buffer
, &destMask
);
260 * Call device driver function.
262 if (ctx
->Driver
.DrawBuffers
)
263 ctx
->Driver
.DrawBuffers(ctx
, 1, &buffer
);
264 else if (ctx
->Driver
.DrawBuffer
)
265 ctx
->Driver
.DrawBuffer(ctx
, buffer
);
270 * Called by glDrawBuffersARB; specifies the destination color renderbuffers
271 * for N fragment program color outputs.
272 * \sa _mesa_DrawBuffer
273 * \param n number of outputs
274 * \param buffers array [n] of renderbuffer names. Unlike glDrawBuffer, the
275 * names cannot specify more than one buffer. For example,
276 * GL_FRONT_AND_BACK is illegal.
279 _mesa_DrawBuffersARB(GLsizei n
, const GLenum
*buffers
)
282 GLbitfield usedBufferMask
, supportedMask
;
283 GLbitfield destMask
[MAX_DRAW_BUFFERS
];
284 GET_CURRENT_CONTEXT(ctx
);
285 ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx
);
287 /* Turns out n==0 is a valid input that should not produce an error.
288 * The remaining code below correctly handles the n==0 case.
290 if (n
< 0 || n
> (GLsizei
) ctx
->Const
.MaxDrawBuffers
) {
291 _mesa_error(ctx
, GL_INVALID_VALUE
, "glDrawBuffersARB(n)");
295 supportedMask
= supported_buffer_bitmask(ctx
, ctx
->DrawBuffer
);
296 usedBufferMask
= 0x0;
298 /* complicated error checking... */
299 for (output
= 0; output
< n
; output
++) {
300 if (buffers
[output
] == GL_NONE
) {
301 destMask
[output
] = 0x0;
304 destMask
[output
] = draw_buffer_enum_to_bitmask(buffers
[output
]);
305 if (destMask
[output
] == BAD_MASK
306 || _mesa_bitcount(destMask
[output
]) > 1) {
307 _mesa_error(ctx
, GL_INVALID_ENUM
, "glDrawBuffersARB(buffer)");
310 destMask
[output
] &= supportedMask
;
311 if (destMask
[output
] == 0) {
312 _mesa_error(ctx
, GL_INVALID_OPERATION
,
313 "glDrawBuffersARB(unsupported buffer)");
316 if (destMask
[output
] & usedBufferMask
) {
317 /* can't specify a dest buffer more than once! */
318 _mesa_error(ctx
, GL_INVALID_OPERATION
,
319 "glDrawBuffersARB(duplicated buffer)");
324 usedBufferMask
|= destMask
[output
];
328 /* OK, if we get here, there were no errors so set the new state */
329 _mesa_drawbuffers(ctx
, n
, buffers
, destMask
);
332 * Call device driver function. Note that n can be equal to 0,
333 * in which case we don't want to reference buffers[0], which
336 if (ctx
->Driver
.DrawBuffers
)
337 ctx
->Driver
.DrawBuffers(ctx
, n
, buffers
);
338 else if (ctx
->Driver
.DrawBuffer
)
339 ctx
->Driver
.DrawBuffer(ctx
, n
> 0 ? buffers
[0] : GL_NONE
);
344 * Helper function to set the GL_DRAW_BUFFER state in the context and
345 * current FBO. Called via glDrawBuffer(), glDrawBuffersARB()
347 * All error checking will have been done prior to calling this function
348 * so nothing should go wrong at this point.
350 * \param ctx current context
351 * \param n number of color outputs to set
352 * \param buffers array[n] of colorbuffer names, like GL_LEFT.
353 * \param destMask array[n] of BUFFER_BIT_* bitmasks which correspond to the
354 * colorbuffer names. (i.e. GL_FRONT_AND_BACK =>
355 * BUFFER_BIT_FRONT_LEFT | BUFFER_BIT_BACK_LEFT).
358 _mesa_drawbuffers(GLcontext
*ctx
, GLuint n
, const GLenum
*buffers
,
359 const GLbitfield
*destMask
)
361 struct gl_framebuffer
*fb
= ctx
->DrawBuffer
;
362 GLbitfield mask
[MAX_DRAW_BUFFERS
];
363 GLboolean newState
= GL_FALSE
;
366 /* compute destMask values now */
367 const GLbitfield supportedMask
= supported_buffer_bitmask(ctx
, fb
);
369 for (output
= 0; output
< n
; output
++) {
370 mask
[output
] = draw_buffer_enum_to_bitmask(buffers
[output
]);
371 ASSERT(mask
[output
] != BAD_MASK
);
372 mask
[output
] &= supportedMask
;
378 * If n==1, destMask[0] may have up to four bits set.
379 * Otherwise, destMask[x] can only have one bit set.
382 GLuint count
= 0, destMask0
= destMask
[0];
384 GLint bufIndex
= _mesa_ffs(destMask0
) - 1;
385 if (fb
->_ColorDrawBufferIndexes
[count
] != bufIndex
) {
386 fb
->_ColorDrawBufferIndexes
[count
] = bufIndex
;
390 destMask0
&= ~(1 << bufIndex
);
392 fb
->ColorDrawBuffer
[0] = buffers
[0];
393 if (fb
->_NumColorDrawBuffers
!= count
) {
394 fb
->_NumColorDrawBuffers
= count
;
399 GLuint buf
, count
= 0;
400 for (buf
= 0; buf
< n
; buf
++ ) {
402 GLint bufIndex
= _mesa_ffs(destMask
[buf
]) - 1;
403 /* only one bit should be set in the destMask[buf] field */
404 ASSERT(_mesa_bitcount(destMask
[buf
]) == 1);
405 if (fb
->_ColorDrawBufferIndexes
[buf
] != bufIndex
) {
406 fb
->_ColorDrawBufferIndexes
[buf
] = bufIndex
;
409 fb
->ColorDrawBuffer
[buf
] = buffers
[buf
];
413 if (fb
->_ColorDrawBufferIndexes
[buf
] != -1) {
414 fb
->_ColorDrawBufferIndexes
[buf
] = -1;
419 /* set remaining outputs to -1 (GL_NONE) */
420 while (buf
< ctx
->Const
.MaxDrawBuffers
) {
421 if (fb
->_ColorDrawBufferIndexes
[buf
] != -1) {
422 fb
->_ColorDrawBufferIndexes
[buf
] = -1;
425 fb
->ColorDrawBuffer
[buf
] = GL_NONE
;
428 fb
->_NumColorDrawBuffers
= count
;
432 /* also set context drawbuffer state */
434 for (buf
= 0; buf
< ctx
->Const
.MaxDrawBuffers
; buf
++) {
435 if (ctx
->Color
.DrawBuffer
[buf
] != fb
->ColorDrawBuffer
[buf
]) {
436 ctx
->Color
.DrawBuffer
[buf
] = fb
->ColorDrawBuffer
[buf
];
443 FLUSH_VERTICES(ctx
, _NEW_BUFFERS
);
448 * Like \sa _mesa_drawbuffers(), this is a helper function for setting
449 * GL_READ_BUFFER state in the context and current FBO.
450 * \param ctx the rendering context
451 * \param buffer GL_FRONT, GL_BACK, GL_COLOR_ATTACHMENT0, etc.
452 * \param bufferIndex the numerical index corresponding to 'buffer'
455 _mesa_readbuffer(GLcontext
*ctx
, GLenum buffer
, GLint bufferIndex
)
457 struct gl_framebuffer
*fb
= ctx
->ReadBuffer
;
460 /* Only update the per-context READ_BUFFER state if we're bound to
461 * a window-system framebuffer.
463 ctx
->Pixel
.ReadBuffer
= buffer
;
466 fb
->ColorReadBuffer
= buffer
;
467 fb
->_ColorReadBufferIndex
= bufferIndex
;
469 ctx
->NewState
|= _NEW_BUFFERS
;
475 * Called by glReadBuffer to set the source renderbuffer for reading pixels.
476 * \param mode color buffer such as GL_FRONT, GL_BACK, etc.
479 _mesa_ReadBuffer(GLenum buffer
)
481 struct gl_framebuffer
*fb
;
482 GLbitfield supportedMask
;
484 GET_CURRENT_CONTEXT(ctx
);
485 ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx
);
487 if (MESA_VERBOSE
& VERBOSE_API
)
488 _mesa_debug(ctx
, "glReadBuffer %s\n", _mesa_lookup_enum_by_nr(buffer
));
490 fb
= ctx
->ReadBuffer
;
492 if (MESA_VERBOSE
& VERBOSE_API
)
493 _mesa_debug(ctx
, "glReadBuffer %s\n", _mesa_lookup_enum_by_nr(buffer
));
495 if (fb
->Name
> 0 && buffer
== GL_NONE
) {
496 /* This is legal for user-created framebuffer objects */
500 /* general case / window-system framebuffer */
501 srcBuffer
= read_buffer_enum_to_index(buffer
);
502 if (srcBuffer
== -1) {
503 _mesa_error(ctx
, GL_INVALID_ENUM
,
504 "glReadBuffer(buffer=0x%x)", buffer
);
507 supportedMask
= supported_buffer_bitmask(ctx
, fb
);
508 if (((1 << srcBuffer
) & supportedMask
) == 0) {
509 _mesa_error(ctx
, GL_INVALID_OPERATION
,
510 "glReadBuffer(buffer=0x%x)", buffer
);
515 /* OK, all error checking has been completed now */
517 _mesa_readbuffer(ctx
, buffer
, srcBuffer
);
518 ctx
->NewState
|= _NEW_BUFFERS
;
521 * Call device driver function.
523 if (ctx
->Driver
.ReadBuffer
)
524 (*ctx
->Driver
.ReadBuffer
)(ctx
, buffer
);