src/mesa/swrast/s_masking.c

   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  */
  42 void
  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       const GLubyte colormask[4] = {
  60          GET_COLORMASK_BIT(ctx->Color.ColorMask, buf, 0) ? 0xff : 0,
  61          GET_COLORMASK_BIT(ctx->Color.ColorMask, buf, 1) ? 0xff : 0,
  62          GET_COLORMASK_BIT(ctx->Color.ColorMask, buf, 2) ? 0xff : 0,
  63          GET_COLORMASK_BIT(ctx->Color.ColorMask, buf, 3) ? 0xff : 0,
  64       };
  65       GLuint srcMask;
  66       memcpy(&srcMask, colormask, sizeof(srcMask));
  67       const GLuint dstMask = ~srcMask;
  68       const GLuint *dst = (const GLuint *) rbPixels;
  69       GLuint *src = (GLuint *) span->array->rgba8;
  70       GLuint i;
  71       for (i = 0; i < n; i++) {
  72          src[i] = (src[i] & srcMask) | (dst[i] & dstMask);
  73       }
  74    }
  75    else if (span->array->ChanType == GL_UNSIGNED_SHORT) {
  76       /* 2-byte components */
  77       /* XXX try to use 64-bit arithmetic someday */
  78       const GLushort rMask = GET_COLORMASK_BIT(ctx->Color.ColorMask, buf, 0) ? 0xffff : 0x0;
  79       const GLushort gMask = GET_COLORMASK_BIT(ctx->Color.ColorMask, buf, 1) ? 0xffff : 0x0;
  80       const GLushort bMask = GET_COLORMASK_BIT(ctx->Color.ColorMask, buf, 2) ? 0xffff : 0x0;
  81       const GLushort aMask = GET_COLORMASK_BIT(ctx->Color.ColorMask, buf, 3) ? 0xffff : 0x0;
  82       const GLushort (*dst)[4] = (const GLushort (*)[4]) rbPixels;
  83       GLushort (*src)[4] = span->array->rgba16;
  84       GLuint i;
  85       for (i = 0; i < n; i++) {
  86          src[i][RCOMP] = (src[i][RCOMP] & rMask) | (dst[i][RCOMP] & ~rMask);
  87          src[i][GCOMP] = (src[i][GCOMP] & gMask) | (dst[i][GCOMP] & ~gMask);
  88          src[i][BCOMP] = (src[i][BCOMP] & bMask) | (dst[i][BCOMP] & ~bMask);
  89          src[i][ACOMP] = (src[i][ACOMP] & aMask) | (dst[i][ACOMP] & ~aMask);
  90       }
  91    }
  92    else {
  93       /* 4-byte components */
  94       const GLuint rMask = GET_COLORMASK_BIT(ctx->Color.ColorMask, buf, 0) ? ~0x0 : 0x0;
  95       const GLuint gMask = GET_COLORMASK_BIT(ctx->Color.ColorMask, buf, 1) ? ~0x0 : 0x0;
  96       const GLuint bMask = GET_COLORMASK_BIT(ctx->Color.ColorMask, buf, 2) ? ~0x0 : 0x0;
  97       const GLuint aMask = GET_COLORMASK_BIT(ctx->Color.ColorMask, buf, 3) ? ~0x0 : 0x0;
  98       const GLuint (*dst)[4] = (const GLuint (*)[4]) rbPixels;
  99       GLuint (*src)[4] = (GLuint (*)[4]) span->array->attribs[VARYING_SLOT_COL0];
 100       GLuint i;
 101       for (i = 0; i < n; i++) {
 102          src[i][RCOMP] = (src[i][RCOMP] & rMask) | (dst[i][RCOMP] & ~rMask);
 103          src[i][GCOMP] = (src[i][GCOMP] & gMask) | (dst[i][GCOMP] & ~gMask);
 104          src[i][BCOMP] = (src[i][BCOMP] & bMask) | (dst[i][BCOMP] & ~bMask);
 105          src[i][ACOMP] = (src[i][ACOMP] & aMask) | (dst[i][ACOMP] & ~aMask);
 106       }
 107    }
 108 }