1 /* $Id: blend.c,v 1.4 1999/10/08 09:27:10 keithw Exp $ */
4 * Mesa 3-D graphics library
7 * Copyright (C) 1999 Brian Paul All Rights Reserved.
9 * Permission is hereby granted, free of charge, to any person obtaining a
10 * copy of this software and associated documentation files (the "Software"),
11 * to deal in the Software without restriction, including without limitation
12 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
13 * and/or sell copies of the Software, and to permit persons to whom the
14 * Software is furnished to do so, subject to the following conditions:
16 * The above copyright notice and this permission notice shall be included
17 * in all copies or substantial portions of the Software.
19 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
20 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
21 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
22 * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
23 * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
24 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
37 #include "GL/xf86glx.h"
48 #include "GL/xf86glx.h"
53 void gl_BlendFunc( GLcontext
*ctx
, GLenum sfactor
, GLenum dfactor
)
55 ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx
, "glBlendFunc");
57 if (MESA_VERBOSE
& (VERBOSE_API
|VERBOSE_TEXTURE
))
58 fprintf(stderr
, "glBlendFunc %s %s\n",
59 gl_lookup_enum_by_nr(sfactor
),
60 gl_lookup_enum_by_nr(dfactor
));
66 case GL_ONE_MINUS_DST_COLOR
:
68 case GL_ONE_MINUS_SRC_ALPHA
:
70 case GL_ONE_MINUS_DST_ALPHA
:
71 case GL_SRC_ALPHA_SATURATE
:
72 case GL_CONSTANT_COLOR
:
73 case GL_ONE_MINUS_CONSTANT_COLOR
:
74 case GL_CONSTANT_ALPHA
:
75 case GL_ONE_MINUS_CONSTANT_ALPHA
:
76 ctx
->Color
.BlendSrcRGB
= ctx
->Color
.BlendSrcA
= sfactor
;
79 gl_error( ctx
, GL_INVALID_ENUM
, "glBlendFunc(sfactor)" );
87 case GL_ONE_MINUS_SRC_COLOR
:
89 case GL_ONE_MINUS_SRC_ALPHA
:
91 case GL_ONE_MINUS_DST_ALPHA
:
92 case GL_CONSTANT_COLOR
:
93 case GL_ONE_MINUS_CONSTANT_COLOR
:
94 case GL_CONSTANT_ALPHA
:
95 case GL_ONE_MINUS_CONSTANT_ALPHA
:
96 ctx
->Color
.BlendDstRGB
= ctx
->Color
.BlendDstA
= dfactor
;
99 gl_error( ctx
, GL_INVALID_ENUM
, "glBlendFunc(dfactor)" );
103 if (ctx
->Driver
.BlendFunc
) {
104 (*ctx
->Driver
.BlendFunc
)( ctx
, sfactor
, dfactor
);
107 ctx
->Color
.BlendFunc
= NULL
;
108 ctx
->NewState
|= NEW_RASTER_OPS
;
112 /* GL_INGR_blend_func_separate */
114 gl_BlendFuncSeparate( GLcontext
*ctx
, GLenum sfactorRGB
, GLenum dfactorRGB
,
115 GLenum sfactorA
, GLenum dfactorA
)
117 ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx
, "glBlendFuncSeparate");
119 if (MESA_VERBOSE
& (VERBOSE_API
|VERBOSE_TEXTURE
))
120 fprintf(stderr
, "glBlendFuncSeperate %s %s %s %s\n",
121 gl_lookup_enum_by_nr(sfactorRGB
),
122 gl_lookup_enum_by_nr(dfactorRGB
),
123 gl_lookup_enum_by_nr(sfactorA
),
124 gl_lookup_enum_by_nr(dfactorA
));
126 switch (sfactorRGB
) {
130 case GL_ONE_MINUS_DST_COLOR
:
132 case GL_ONE_MINUS_SRC_ALPHA
:
134 case GL_ONE_MINUS_DST_ALPHA
:
135 case GL_SRC_ALPHA_SATURATE
:
136 case GL_CONSTANT_COLOR
:
137 case GL_ONE_MINUS_CONSTANT_COLOR
:
138 case GL_CONSTANT_ALPHA
:
139 case GL_ONE_MINUS_CONSTANT_ALPHA
:
140 ctx
->Color
.BlendSrcRGB
= sfactorRGB
;
143 gl_error( ctx
, GL_INVALID_ENUM
, "glBlendFuncSeparate(sfactorRGB)" );
147 switch (dfactorRGB
) {
151 case GL_ONE_MINUS_SRC_COLOR
:
153 case GL_ONE_MINUS_SRC_ALPHA
:
155 case GL_ONE_MINUS_DST_ALPHA
:
156 case GL_CONSTANT_COLOR
:
157 case GL_ONE_MINUS_CONSTANT_COLOR
:
158 case GL_CONSTANT_ALPHA
:
159 case GL_ONE_MINUS_CONSTANT_ALPHA
:
160 ctx
->Color
.BlendDstRGB
= dfactorRGB
;
163 gl_error( ctx
, GL_INVALID_ENUM
, "glBlendFuncSeparate(dfactorRGB)" );
171 case GL_ONE_MINUS_DST_COLOR
:
173 case GL_ONE_MINUS_SRC_ALPHA
:
175 case GL_ONE_MINUS_DST_ALPHA
:
176 case GL_SRC_ALPHA_SATURATE
:
177 case GL_CONSTANT_COLOR
:
178 case GL_ONE_MINUS_CONSTANT_COLOR
:
179 case GL_CONSTANT_ALPHA
:
180 case GL_ONE_MINUS_CONSTANT_ALPHA
:
181 ctx
->Color
.BlendSrcA
= sfactorA
;
184 gl_error( ctx
, GL_INVALID_ENUM
, "glBlendFuncSeparate(sfactorA)" );
192 case GL_ONE_MINUS_SRC_COLOR
:
194 case GL_ONE_MINUS_SRC_ALPHA
:
196 case GL_ONE_MINUS_DST_ALPHA
:
197 case GL_CONSTANT_COLOR
:
198 case GL_ONE_MINUS_CONSTANT_COLOR
:
199 case GL_CONSTANT_ALPHA
:
200 case GL_ONE_MINUS_CONSTANT_ALPHA
:
201 ctx
->Color
.BlendDstA
= dfactorA
;
204 gl_error( ctx
, GL_INVALID_ENUM
, "glBlendFuncSeparate(dfactorA)" );
208 ctx
->Color
.BlendFunc
= NULL
;
209 ctx
->NewState
|= NEW_RASTER_OPS
;
211 if (ctx
->Driver
.BlendFuncSeparate
) {
212 (*ctx
->Driver
.BlendFuncSeparate
)( ctx
, sfactorRGB
, dfactorRGB
,
213 sfactorA
, dfactorA
);
219 /* This is really an extension function! */
220 void gl_BlendEquation( GLcontext
*ctx
, GLenum mode
)
222 ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH(ctx
, "glBlendEquation");
224 if (MESA_VERBOSE
& (VERBOSE_API
|VERBOSE_TEXTURE
))
225 fprintf(stderr
, "glBlendEquation %s\n",
226 gl_lookup_enum_by_nr(mode
));
233 case GL_FUNC_ADD_EXT
:
234 case GL_FUNC_SUBTRACT_EXT
:
235 case GL_FUNC_REVERSE_SUBTRACT_EXT
:
236 ctx
->Color
.BlendEquation
= mode
;
239 gl_error( ctx
, GL_INVALID_ENUM
, "glBlendEquation" );
243 /* This is needed to support 1.1's RGB logic ops AND
244 * 1.0's blending logicops.
246 if (mode
==GL_LOGIC_OP
&& ctx
->Color
.BlendEnabled
) {
247 ctx
->Color
.ColorLogicOpEnabled
= GL_TRUE
;
250 ctx
->Color
.ColorLogicOpEnabled
= GL_FALSE
;
253 ctx
->Color
.BlendFunc
= NULL
;
254 ctx
->NewState
|= NEW_RASTER_OPS
;
256 if (ctx
->Driver
.BlendEquation
)
257 ctx
->Driver
.BlendEquation( ctx
, mode
);
262 void gl_BlendColor( GLcontext
*ctx
, GLclampf red
, GLclampf green
,
263 GLclampf blue
, GLclampf alpha
)
265 ctx
->Color
.BlendColor
[0] = CLAMP( red
, 0.0, 1.0 );
266 ctx
->Color
.BlendColor
[1] = CLAMP( green
, 0.0, 1.0 );
267 ctx
->Color
.BlendColor
[2] = CLAMP( blue
, 0.0, 1.0 );
268 ctx
->Color
.BlendColor
[3] = CLAMP( alpha
, 0.0, 1.0 );
274 * Common transparency blending mode.
276 static void blend_transparency( GLcontext
*ctx
, GLuint n
, const GLubyte mask
[],
277 GLubyte rgba
[][4], CONST GLubyte dest
[][4] )
280 ASSERT(ctx
->Color
.BlendEquation
==GL_FUNC_ADD_EXT
);
281 ASSERT(ctx
->Color
.BlendSrcRGB
==GL_SRC_ALPHA
);
282 ASSERT(ctx
->Color
.BlendDstRGB
==GL_ONE_MINUS_SRC_ALPHA
);
287 GLint t
= rgba
[i
][ACOMP
]; /* t in [0,255] */
289 rgba
[i
][RCOMP
] = dest
[i
][RCOMP
];
290 rgba
[i
][GCOMP
] = dest
[i
][GCOMP
];
291 rgba
[i
][BCOMP
] = dest
[i
][BCOMP
];
292 rgba
[i
][ACOMP
] = dest
[i
][ACOMP
];
299 GLint r
= (rgba
[i
][RCOMP
] * t
+ dest
[i
][RCOMP
] * s
) >> 8;
300 GLint g
= (rgba
[i
][GCOMP
] * t
+ dest
[i
][GCOMP
] * s
) >> 8;
301 GLint b
= (rgba
[i
][BCOMP
] * t
+ dest
[i
][BCOMP
] * s
) >> 8;
302 GLint a
= (rgba
[i
][ACOMP
] * t
+ dest
[i
][ACOMP
] * s
) >> 8;
321 static void blend_add( GLcontext
*ctx
, GLuint n
, const GLubyte mask
[],
322 GLubyte rgba
[][4], CONST GLubyte dest
[][4] )
325 ASSERT(ctx
->Color
.BlendEquation
==GL_FUNC_ADD_EXT
);
326 ASSERT(ctx
->Color
.BlendSrcRGB
==GL_ONE
);
327 ASSERT(ctx
->Color
.BlendDstRGB
==GL_ONE
);
332 GLint r
= rgba
[i
][RCOMP
] + dest
[i
][RCOMP
];
333 GLint g
= rgba
[i
][GCOMP
] + dest
[i
][GCOMP
];
334 GLint b
= rgba
[i
][BCOMP
] + dest
[i
][BCOMP
];
335 GLint a
= rgba
[i
][ACOMP
] + dest
[i
][ACOMP
];
336 rgba
[i
][RCOMP
] = MIN2( r
, 255 );
337 rgba
[i
][GCOMP
] = MIN2( g
, 255 );
338 rgba
[i
][BCOMP
] = MIN2( b
, 255 );
339 rgba
[i
][ACOMP
] = MIN2( a
, 255 );
347 * Blend min function (for GL_EXT_blend_minmax)
349 static void blend_min( GLcontext
*ctx
, GLuint n
, const GLubyte mask
[],
350 GLubyte rgba
[][4], CONST GLubyte dest
[][4] )
353 ASSERT(ctx
->Color
.BlendEquation
==GL_MIN_EXT
);
358 rgba
[i
][RCOMP
] = MIN2( rgba
[i
][RCOMP
], dest
[i
][RCOMP
] );
359 rgba
[i
][GCOMP
] = MIN2( rgba
[i
][GCOMP
], dest
[i
][GCOMP
] );
360 rgba
[i
][BCOMP
] = MIN2( rgba
[i
][BCOMP
], dest
[i
][BCOMP
] );
361 rgba
[i
][ACOMP
] = MIN2( rgba
[i
][ACOMP
], dest
[i
][ACOMP
] );
369 * Blend max function (for GL_EXT_blend_minmax)
371 static void blend_max( GLcontext
*ctx
, GLuint n
, const GLubyte mask
[],
372 GLubyte rgba
[][4], CONST GLubyte dest
[][4] )
375 ASSERT(ctx
->Color
.BlendEquation
==GL_MAX_EXT
);
380 rgba
[i
][RCOMP
] = MAX2( rgba
[i
][RCOMP
], dest
[i
][RCOMP
] );
381 rgba
[i
][GCOMP
] = MAX2( rgba
[i
][GCOMP
], dest
[i
][GCOMP
] );
382 rgba
[i
][BCOMP
] = MAX2( rgba
[i
][BCOMP
], dest
[i
][BCOMP
] );
383 rgba
[i
][ACOMP
] = MAX2( rgba
[i
][ACOMP
], dest
[i
][ACOMP
] );
391 * Modulate: result = src * dest
393 static void blend_modulate( GLcontext
*ctx
, GLuint n
, const GLubyte mask
[],
394 GLubyte rgba
[][4], CONST GLubyte dest
[][4] )
401 GLint r
= (rgba
[i
][RCOMP
] * dest
[i
][RCOMP
]) >> 8;
402 GLint g
= (rgba
[i
][GCOMP
] * dest
[i
][GCOMP
]) >> 8;
403 GLint b
= (rgba
[i
][BCOMP
] * dest
[i
][BCOMP
]) >> 8;
404 GLint a
= (rgba
[i
][ACOMP
] * dest
[i
][ACOMP
]) >> 8;
416 * General case blend pixels.
417 * Input: n - number of pixels
418 * mask - the usual write mask
419 * In/Out: rgba - the incoming and modified pixels
420 * Input: dest - the pixels from the dest color buffer
422 static void blend_general( GLcontext
*ctx
, GLuint n
, const GLubyte mask
[],
423 GLubyte rgba
[][4], CONST GLubyte dest
[][4] )
425 GLfloat rscale
= 1.0F
/ 255.0F
;
426 GLfloat gscale
= 1.0F
/ 255.0F
;
427 GLfloat bscale
= 1.0F
/ 255.0F
;
428 GLfloat ascale
= 1.0F
/ 255.0F
;
433 GLint Rs
, Gs
, Bs
, As
; /* Source colors */
434 GLint Rd
, Gd
, Bd
, Ad
; /* Dest colors */
435 GLfloat sR
, sG
, sB
, sA
; /* Source scaling */
436 GLfloat dR
, dG
, dB
, dA
; /* Dest scaling */
445 /* Frame buffer color */
451 /* Source RGB factor */
452 switch (ctx
->Color
.BlendSrcRGB
) {
460 sR
= (GLfloat
) Rd
* rscale
;
461 sG
= (GLfloat
) Gd
* gscale
;
462 sB
= (GLfloat
) Bd
* bscale
;
464 case GL_ONE_MINUS_DST_COLOR
:
465 sR
= 1.0F
- (GLfloat
) Rd
* rscale
;
466 sG
= 1.0F
- (GLfloat
) Gd
* gscale
;
467 sB
= 1.0F
- (GLfloat
) Bd
* bscale
;
470 sR
= sG
= sB
= (GLfloat
) As
* ascale
;
472 case GL_ONE_MINUS_SRC_ALPHA
:
473 sR
= sG
= sB
= (GLfloat
) 1.0F
- (GLfloat
) As
* ascale
;
476 sR
= sG
= sB
= (GLfloat
) Ad
* ascale
;
478 case GL_ONE_MINUS_DST_ALPHA
:
479 sR
= sG
= sB
= 1.0F
- (GLfloat
) Ad
* ascale
;
481 case GL_SRC_ALPHA_SATURATE
:
482 if (As
< 1.0F
- (GLfloat
) Ad
* ascale
) {
483 sR
= sG
= sB
= (GLfloat
) As
* ascale
;
486 sR
= sG
= sB
= 1.0F
- (GLfloat
) Ad
* ascale
;
489 case GL_CONSTANT_COLOR
:
490 sR
= ctx
->Color
.BlendColor
[0];
491 sG
= ctx
->Color
.BlendColor
[1];
492 sB
= ctx
->Color
.BlendColor
[2];
494 case GL_ONE_MINUS_CONSTANT_COLOR
:
495 sR
= 1.0F
- ctx
->Color
.BlendColor
[0];
496 sG
= 1.0F
- ctx
->Color
.BlendColor
[1];
497 sB
= 1.0F
- ctx
->Color
.BlendColor
[2];
499 case GL_CONSTANT_ALPHA
:
500 sR
= sG
= sB
= ctx
->Color
.BlendColor
[3];
502 case GL_ONE_MINUS_CONSTANT_ALPHA
:
503 sR
= sG
= sB
= 1.0F
- ctx
->Color
.BlendColor
[3];
506 /* this should never happen */
507 gl_problem(ctx
, "Bad blend source RGB factor in do_blend");
511 /* Source Alpha factor */
512 switch (ctx
->Color
.BlendSrcA
) {
520 sA
= (GLfloat
) Ad
* ascale
;
522 case GL_ONE_MINUS_DST_COLOR
:
523 sA
= 1.0F
- (GLfloat
) Ad
* ascale
;
526 sA
= (GLfloat
) As
* ascale
;
528 case GL_ONE_MINUS_SRC_ALPHA
:
529 sA
= (GLfloat
) 1.0F
- (GLfloat
) As
* ascale
;
532 sA
=(GLfloat
) Ad
* ascale
;
534 case GL_ONE_MINUS_DST_ALPHA
:
535 sA
= 1.0F
- (GLfloat
) Ad
* ascale
;
537 case GL_SRC_ALPHA_SATURATE
:
540 case GL_CONSTANT_COLOR
:
541 sA
= ctx
->Color
.BlendColor
[3];
543 case GL_ONE_MINUS_CONSTANT_COLOR
:
544 sA
= 1.0F
- ctx
->Color
.BlendColor
[3];
546 case GL_CONSTANT_ALPHA
:
547 sA
= ctx
->Color
.BlendColor
[3];
549 case GL_ONE_MINUS_CONSTANT_ALPHA
:
550 sA
= 1.0F
- ctx
->Color
.BlendColor
[3];
553 /* this should never happen */
554 gl_problem(ctx
, "Bad blend source A factor in do_blend");
557 /* Dest RGB factor */
558 switch (ctx
->Color
.BlendDstRGB
) {
566 dR
= (GLfloat
) Rs
* rscale
;
567 dG
= (GLfloat
) Gs
* gscale
;
568 dB
= (GLfloat
) Bs
* bscale
;
570 case GL_ONE_MINUS_SRC_COLOR
:
571 dR
= 1.0F
- (GLfloat
) Rs
* rscale
;
572 dG
= 1.0F
- (GLfloat
) Gs
* gscale
;
573 dB
= 1.0F
- (GLfloat
) Bs
* bscale
;
576 dR
= dG
= dB
= (GLfloat
) As
* ascale
;
578 case GL_ONE_MINUS_SRC_ALPHA
:
579 dR
= dG
= dB
= (GLfloat
) 1.0F
- (GLfloat
) As
* ascale
;
582 dR
= dG
= dB
= (GLfloat
) Ad
* ascale
;
584 case GL_ONE_MINUS_DST_ALPHA
:
585 dR
= dG
= dB
= 1.0F
- (GLfloat
) Ad
* ascale
;
587 case GL_CONSTANT_COLOR
:
588 dR
= ctx
->Color
.BlendColor
[0];
589 dG
= ctx
->Color
.BlendColor
[1];
590 dB
= ctx
->Color
.BlendColor
[2];
592 case GL_ONE_MINUS_CONSTANT_COLOR
:
593 dR
= 1.0F
- ctx
->Color
.BlendColor
[0];
594 dG
= 1.0F
- ctx
->Color
.BlendColor
[1];
595 dB
= 1.0F
- ctx
->Color
.BlendColor
[2];
597 case GL_CONSTANT_ALPHA
:
598 dR
= dG
= dB
= ctx
->Color
.BlendColor
[3];
600 case GL_ONE_MINUS_CONSTANT_ALPHA
:
601 dR
= dG
= dB
= 1.0F
- ctx
->Color
.BlendColor
[3] * ascale
;
604 /* this should never happen */
605 gl_problem(ctx
, "Bad blend dest RGB factor in do_blend");
608 /* Dest Alpha factor */
609 switch (ctx
->Color
.BlendDstA
) {
617 dA
= (GLfloat
) As
* ascale
;
619 case GL_ONE_MINUS_SRC_COLOR
:
620 dA
= 1.0F
- (GLfloat
) As
* ascale
;
623 dA
= (GLfloat
) As
* ascale
;
625 case GL_ONE_MINUS_SRC_ALPHA
:
626 dA
= (GLfloat
) 1.0F
- (GLfloat
) As
* ascale
;
629 dA
= (GLfloat
) Ad
* ascale
;
631 case GL_ONE_MINUS_DST_ALPHA
:
632 dA
= 1.0F
- (GLfloat
) Ad
* ascale
;
634 case GL_CONSTANT_COLOR
:
635 dA
= ctx
->Color
.BlendColor
[3];
637 case GL_ONE_MINUS_CONSTANT_COLOR
:
638 dA
= 1.0F
- ctx
->Color
.BlendColor
[3];
640 case GL_CONSTANT_ALPHA
:
641 dA
= ctx
->Color
.BlendColor
[3];
643 case GL_ONE_MINUS_CONSTANT_ALPHA
:
644 dA
= 1.0F
- ctx
->Color
.BlendColor
[3] * ascale
;
647 /* this should never happen */
648 gl_problem(ctx
, "Bad blend dest A factor in do_blend");
652 /* Due to round-off problems we have to clamp against zero. */
653 /* Optimization: we don't have to do this for all src & dst factors */
654 if (dA
< 0.0F
) dA
= 0.0F
;
655 if (dR
< 0.0F
) dR
= 0.0F
;
656 if (dG
< 0.0F
) dG
= 0.0F
;
657 if (dB
< 0.0F
) dB
= 0.0F
;
658 if (sA
< 0.0F
) sA
= 0.0F
;
659 if (sR
< 0.0F
) sR
= 0.0F
;
660 if (sG
< 0.0F
) sG
= 0.0F
;
661 if (sB
< 0.0F
) sB
= 0.0F
;
672 /* compute blended color */
673 if (ctx
->Color
.BlendEquation
==GL_FUNC_ADD_EXT
) {
674 r
= Rs
* sR
+ Rd
* dR
;
675 g
= Gs
* sG
+ Gd
* dG
;
676 b
= Bs
* sB
+ Bd
* dB
;
677 a
= As
* sA
+ Ad
* dA
;
679 else if (ctx
->Color
.BlendEquation
==GL_FUNC_SUBTRACT_EXT
) {
680 r
= Rs
* sR
- Rd
* dR
;
681 g
= Gs
* sG
- Gd
* dG
;
682 b
= Bs
* sB
- Bd
* dB
;
683 a
= As
* sA
- Ad
* dA
;
685 else if (ctx
->Color
.BlendEquation
==GL_FUNC_REVERSE_SUBTRACT_EXT
) {
686 r
= Rd
* dR
- Rs
* sR
;
687 g
= Gd
* dG
- Gs
* sG
;
688 b
= Bd
* dB
- Bs
* sB
;
689 a
= Ad
* dA
- As
* sA
;
693 rgba
[i
][RCOMP
] = (GLint
) CLAMP( r
, 0.0F
, 255.0F
);
694 rgba
[i
][GCOMP
] = (GLint
) CLAMP( g
, 0.0F
, 255.0F
);
695 rgba
[i
][BCOMP
] = (GLint
) CLAMP( b
, 0.0F
, 255.0F
);
696 rgba
[i
][ACOMP
] = (GLint
) CLAMP( a
, 0.0F
, 255.0F
);
703 #if defined(USE_MMX_ASM)
705 #include "X86/common_x86asm.h"
710 * Analyze current blending parameters to pick fastest blending function.
711 * Result: the ctx->Color.BlendFunc pointer is updated.
713 static void set_blend_function( GLcontext
*ctx
)
715 const GLenum eq
= ctx
->Color
.BlendEquation
;
716 const GLenum srcRGB
= ctx
->Color
.BlendSrcRGB
;
717 const GLenum dstRGB
= ctx
->Color
.BlendDstRGB
;
718 const GLenum srcA
= ctx
->Color
.BlendSrcA
;
719 const GLenum dstA
= ctx
->Color
.BlendDstA
;
721 #if defined(USE_MMX_ASM)
722 /* Hmm. A table here would have 12^4 == way too many entries.
723 * Provide a hook for MMX instead.
725 if (gl_x86_cpu_features
& GL_CPU_MMX
) {
726 gl_mmx_set_blend_function (ctx
);
729 if (srcRGB
!= srcA
|| dstRGB
!= dstA
) {
730 ctx
->Color
.BlendFunc
= blend_general
;
732 else if (eq
==GL_FUNC_ADD_EXT
&& srcRGB
==GL_SRC_ALPHA
733 && dstRGB
==GL_ONE_MINUS_SRC_ALPHA
) {
734 ctx
->Color
.BlendFunc
= blend_transparency
;
736 else if (eq
==GL_FUNC_ADD_EXT
&& srcRGB
==GL_ONE
&& dstRGB
==GL_ONE
) {
737 ctx
->Color
.BlendFunc
= blend_add
;
739 else if (((eq
==GL_FUNC_ADD_EXT
|| eq
==GL_FUNC_REVERSE_SUBTRACT_EXT
)
740 && (srcRGB
==GL_ZERO
&& dstRGB
==GL_SRC_COLOR
))
742 ((eq
==GL_FUNC_ADD_EXT
|| eq
==GL_FUNC_SUBTRACT_EXT
)
743 && (srcRGB
==GL_DST_COLOR
&& dstRGB
==GL_ZERO
))) {
744 ctx
->Color
.BlendFunc
= blend_modulate
;
746 else if (eq
==GL_MIN_EXT
) {
747 ctx
->Color
.BlendFunc
= blend_min
;
749 else if (eq
==GL_MAX_EXT
) {
750 ctx
->Color
.BlendFunc
= blend_max
;
753 ctx
->Color
.BlendFunc
= blend_general
;
760 * Apply the blending operator to a span of pixels.
761 * Input: n - number of pixels in span
762 * x, y - location of leftmost pixel in span in window coords.
763 * mask - boolean mask indicating which pixels to blend.
764 * In/Out: rgba - pixel values
766 void gl_blend_span( GLcontext
*ctx
, GLuint n
, GLint x
, GLint y
,
767 GLubyte rgba
[][4], const GLubyte mask
[] )
769 GLubyte dest
[MAX_WIDTH
][4];
771 /* Check if device driver can do the work */
772 if (ctx
->Color
.BlendEquation
==GL_LOGIC_OP
&& !ctx
->Color
.SWLogicOpEnabled
) {
776 /* Read span of current frame buffer pixels */
777 gl_read_rgba_span( ctx
, n
, x
, y
, dest
);
779 if (!ctx
->Color
.BlendFunc
)
780 set_blend_function(ctx
);
782 (*ctx
->Color
.BlendFunc
)( ctx
, n
, mask
, rgba
, (const GLubyte (*)[4])dest
);
790 * Apply the blending operator to an array of pixels.
791 * Input: n - number of pixels in span
792 * x, y - array of pixel locations
793 * mask - boolean mask indicating which pixels to blend.
794 * In/Out: rgba - pixel values
796 void gl_blend_pixels( GLcontext
*ctx
,
797 GLuint n
, const GLint x
[], const GLint y
[],
798 GLubyte rgba
[][4], const GLubyte mask
[] )
800 GLubyte dest
[PB_SIZE
][4];
802 /* Check if device driver can do the work */
803 if (ctx
->Color
.BlendEquation
==GL_LOGIC_OP
&& !ctx
->Color
.SWLogicOpEnabled
) {
807 /* Read pixels from current color buffer */
808 (*ctx
->Driver
.ReadRGBAPixels
)( ctx
, n
, x
, y
, dest
, mask
);
809 if (ctx
->RasterMask
& ALPHABUF_BIT
) {
810 gl_read_alpha_pixels( ctx
, n
, x
, y
, dest
, mask
);
813 if (!ctx
->Color
.BlendFunc
)
814 set_blend_function(ctx
);
816 (*ctx
->Color
.BlendFunc
)( ctx
, n
, mask
, rgba
, (const GLubyte (*)[4])dest
);