s_masking.c revision 3998cfa933dcd9134b75d9f0ae2c9cfcd6f2ee45 
1/*
2 * Mesa 3-D graphics library
3 *
4 * Copyright (C) 1999-2006  Brian Paul   All Rights Reserved.
5 *
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:
12 *
13 * The above copyright notice and this permission notice shall be included
14 * in all copies or substantial portions of the Software.
15 *
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.
23 */
24
25
26/*
27 * Implement the effect of glColorMask and glIndexMask in software.
28 */
29
30
31#include "main/glheader.h"
32#include "main/macros.h"
33
34#include "s_context.h"
35#include "s_masking.h"
36#include "s_span.h"
37
38
39/**
40 * Apply the color mask to a span of rgba values.
41 */
42void
43_swrast_mask_rgba_span(struct gl_context *ctx, struct gl_renderbuffer *rb,
44                       SWspan *span, GLuint buf)
45{
46   const GLuint n = span->end;
47   void *rbPixels;
48
49   ASSERT(n < SWRAST_MAX_WIDTH);
50   ASSERT(span->arrayMask & SPAN_RGBA);
51
52   rbPixels = _swrast_get_dest_rgba(ctx, rb, span);
53
54   /*
55    * Do component masking.
56    * Note that we're not using span->array->mask[] here.  We could...
57    */
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;
64      GLuint i;
65      for (i = 0; i < n; i++) {
66         src[i] = (src[i] & srcMask) | (dst[i] & dstMask);
67      }
68   }
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;
78      GLuint i;
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);
84      }
85   }
86   else {
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];
94      GLuint i;
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);
100      }
101   }
102}
103