src/mesa/swrast/s_pixeltex.c

   1 /*
   2  * Mesa 3-D graphics library
   3  * Version:  6.3
   4  *
   5  * Copyright (C) 1999-2004  Brian Paul   All Rights Reserved.
   6  *
   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:
  13  *
  14  * The above copyright notice and this permission notice shall be included
  15  * in all copies or substantial portions of the Software.
  16  *
  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.
  23  */
  24
  25
  26 /*
  27  * This file implements both the GL_SGIX_pixel_texture and
  28  * GL_SIGS_pixel_texture extensions. Luckily, they pretty much
  29  * overlap in functionality so we use the same state variables
  30  * and execution code for both.
  31  */
  32
  33
  34 #include "glheader.h"
  35 #include "colormac.h"
  36 #include "imports.h"
  37
  38 #include "s_context.h"
  39 #include "s_pixeltex.h"
  40 #include "s_texture.h"
  41
  42
  43 /*
  44  * Convert RGBA values into strq texture coordinates.
  45  */
  46 static void
  47 pixeltexgen(GLcontext *ctx, GLuint n, const GLchan rgba[][4],
  48             GLfloat texcoord[][4])
  49 {
  50    if (ctx->Pixel.FragmentRgbSource == GL_CURRENT_RASTER_COLOR) {
  51       GLuint i;
  52       for (i = 0; i < n; i++) {
  53          texcoord[i][0] = ctx->Current.RasterColor[RCOMP];
  54          texcoord[i][1] = ctx->Current.RasterColor[GCOMP];
  55          texcoord[i][2] = ctx->Current.RasterColor[BCOMP];
  56       }
  57    }
  58    else {
  59       GLuint i;
  60       ASSERT(ctx->Pixel.FragmentRgbSource == GL_PIXEL_GROUP_COLOR_SGIS);
  61       for (i = 0; i < n; i++) {
  62          texcoord[i][0] = CHAN_TO_FLOAT(rgba[i][RCOMP]);
  63          texcoord[i][1] = CHAN_TO_FLOAT(rgba[i][GCOMP]);
  64          texcoord[i][2] = CHAN_TO_FLOAT(rgba[i][BCOMP]);
  65       }
  66    }
  67
  68    if (ctx->Pixel.FragmentAlphaSource == GL_CURRENT_RASTER_COLOR) {
  69       GLuint i;
  70       for (i = 0; i < n; i++) {
  71          texcoord[i][3] = ctx->Current.RasterColor[ACOMP];
  72       }
  73    }
  74    else {
  75       GLuint i;
  76       ASSERT(ctx->Pixel.FragmentAlphaSource == GL_PIXEL_GROUP_COLOR_SGIS);
  77       for (i = 0; i < n; i++) {
  78          texcoord[i][3] = CHAN_TO_FLOAT(rgba[i][ACOMP]);
  79       }
  80    }
  81 }
  82
  83
  84
  85 /*
  86  * Used by glDraw/CopyPixels: the incoming image colors are treated
  87  * as texture coordinates.  Use those coords to texture the image.
  88  * This is for GL_SGIS_pixel_texture / GL_SGIX_pixel_texture.
  89  */
  90 void
  91 _swrast_pixel_texture(GLcontext *ctx, struct sw_span *span)
  92 {
  93    GLuint unit;
  94
  95    ASSERT(!(span->arrayMask & SPAN_TEXTURE));
  96    span->arrayMask |= SPAN_TEXTURE;
  97    span->interpMask &= ~SPAN_TEXTURE;
  98
  99    /* convert colors into texture coordinates */
 100    pixeltexgen( ctx, span->end,
 101                 (const GLchan (*)[4]) span->array->rgba,
 102                 span->array->texcoords[0] );
 103
 104    /* copy the new texture units for all enabled units */
 105    for (unit = 1; unit < ctx->Const.MaxTextureUnits; unit++) {
 106       if (ctx->Texture.Unit[unit]._ReallyEnabled) {
 107          MEMCPY( span->array->texcoords[unit], span->array->texcoords[0],
 108                  span->end * 4 * sizeof(GLfloat) );
 109       }
 110    }
 111 }