2 * Mesa 3-D graphics library
4 * Copyright (C) 1999-2006 Brian Paul All Rights Reserved.
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27 * Implement the effect of glColorMask and glIndexMask in software.
31 #include "main/glheader.h"
32 #include "main/macros.h"
34 #include "s_context.h"
35 #include "s_masking.h"
40 * Apply the color mask to a span of rgba values.
43 _swrast_mask_rgba_span(struct gl_context
*ctx
, struct gl_renderbuffer
*rb
,
44 SWspan
*span
, GLuint buf
)
46 const GLuint n
= span
->end
;
49 assert(n
< SWRAST_MAX_WIDTH
);
50 assert(span
->arrayMask
& SPAN_RGBA
);
52 rbPixels
= _swrast_get_dest_rgba(ctx
, rb
, span
);
55 * Do component masking.
56 * Note that we're not using span->array->mask[] here. We could...
58 if (span
->array
->ChanType
== GL_UNSIGNED_BYTE
) {
59 /* treat 4xGLubyte as 1xGLuint */
60 const GLuint srcMask
= *((GLuint
*) ctx
->Color
.ColorMask
[buf
]);
61 const GLuint dstMask
= ~srcMask
;
62 const GLuint
*dst
= (const GLuint
*) rbPixels
;
63 GLuint
*src
= (GLuint
*) span
->array
->rgba8
;
65 for (i
= 0; i
< n
; i
++) {
66 src
[i
] = (src
[i
] & srcMask
) | (dst
[i
] & dstMask
);
69 else if (span
->array
->ChanType
== GL_UNSIGNED_SHORT
) {
70 /* 2-byte components */
71 /* XXX try to use 64-bit arithmetic someday */
72 const GLushort rMask
= ctx
->Color
.ColorMask
[buf
][RCOMP
] ? 0xffff : 0x0;
73 const GLushort gMask
= ctx
->Color
.ColorMask
[buf
][GCOMP
] ? 0xffff : 0x0;
74 const GLushort bMask
= ctx
->Color
.ColorMask
[buf
][BCOMP
] ? 0xffff : 0x0;
75 const GLushort aMask
= ctx
->Color
.ColorMask
[buf
][ACOMP
] ? 0xffff : 0x0;
76 const GLushort (*dst
)[4] = (const GLushort (*)[4]) rbPixels
;
77 GLushort (*src
)[4] = span
->array
->rgba16
;
79 for (i
= 0; i
< n
; i
++) {
80 src
[i
][RCOMP
] = (src
[i
][RCOMP
] & rMask
) | (dst
[i
][RCOMP
] & ~rMask
);
81 src
[i
][GCOMP
] = (src
[i
][GCOMP
] & gMask
) | (dst
[i
][GCOMP
] & ~gMask
);
82 src
[i
][BCOMP
] = (src
[i
][BCOMP
] & bMask
) | (dst
[i
][BCOMP
] & ~bMask
);
83 src
[i
][ACOMP
] = (src
[i
][ACOMP
] & aMask
) | (dst
[i
][ACOMP
] & ~aMask
);
87 /* 4-byte components */
88 const GLuint rMask
= ctx
->Color
.ColorMask
[buf
][RCOMP
] ? ~0x0 : 0x0;
89 const GLuint gMask
= ctx
->Color
.ColorMask
[buf
][GCOMP
] ? ~0x0 : 0x0;
90 const GLuint bMask
= ctx
->Color
.ColorMask
[buf
][BCOMP
] ? ~0x0 : 0x0;
91 const GLuint aMask
= ctx
->Color
.ColorMask
[buf
][ACOMP
] ? ~0x0 : 0x0;
92 const GLuint (*dst
)[4] = (const GLuint (*)[4]) rbPixels
;
93 GLuint (*src
)[4] = (GLuint (*)[4]) span
->array
->attribs
[VARYING_SLOT_COL0
];
95 for (i
= 0; i
< n
; i
++) {
96 src
[i
][RCOMP
] = (src
[i
][RCOMP
] & rMask
) | (dst
[i
][RCOMP
] & ~rMask
);
97 src
[i
][GCOMP
] = (src
[i
][GCOMP
] & gMask
) | (dst
[i
][GCOMP
] & ~gMask
);
98 src
[i
][BCOMP
] = (src
[i
][BCOMP
] & bMask
) | (dst
[i
][BCOMP
] & ~bMask
);
99 src
[i
][ACOMP
] = (src
[i
][ACOMP
] & aMask
) | (dst
[i
][ACOMP
] & ~aMask
);