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path: root/src/mesa/swrast/s_pixeltex.c
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/* $Id: s_pixeltex.c,v 1.6 2002/01/28 04:25:56 brianp Exp $ */

/*
 * Mesa 3-D graphics library
 * Version:  4.1
 *
 * Copyright (C) 1999-2002  Brian Paul   All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
 * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */


/*
 * This file implements both the GL_SGIX_pixel_texture and
 * GL_SIGS_pixel_texture extensions. Luckily, they pretty much
 * overlap in functionality so we use the same state variables
 * and execution code for both.
 */


#include "glheader.h"
#include "colormac.h"
#include "mem.h"

#include "s_context.h"
#include "s_pixeltex.h"
#include "s_texture.h"


/*
 * Convert RGBA values into strq texture coordinates.
 */
static void
pixeltexgen(GLcontext *ctx, GLuint n, const GLchan rgba[][4],
            GLfloat texcoord[][4])
{
   if (ctx->Pixel.FragmentRgbSource == GL_CURRENT_RASTER_COLOR) {
      GLuint i;
      for (i = 0; i < n; i++) {
         texcoord[i][0] = ctx->Current.RasterColor[RCOMP];
         texcoord[i][1] = ctx->Current.RasterColor[GCOMP];
         texcoord[i][2] = ctx->Current.RasterColor[BCOMP];
      }
   }
   else {
      GLuint i;
      ASSERT(ctx->Pixel.FragmentRgbSource == GL_PIXEL_GROUP_COLOR_SGIS);
      for (i = 0; i < n; i++) {
         texcoord[i][0] = CHAN_TO_FLOAT(rgba[i][RCOMP]);
         texcoord[i][1] = CHAN_TO_FLOAT(rgba[i][GCOMP]);
         texcoord[i][2] = CHAN_TO_FLOAT(rgba[i][BCOMP]);
      }
   }

   if (ctx->Pixel.FragmentAlphaSource == GL_CURRENT_RASTER_COLOR) {
      GLuint i;
      for (i = 0; i < n; i++) {
         texcoord[i][3] = ctx->Current.RasterColor[ACOMP];
      }
   }
   else {
      GLuint i;
      ASSERT(ctx->Pixel.FragmentAlphaSource == GL_PIXEL_GROUP_COLOR_SGIS);
      for (i = 0; i < n; i++) {
         texcoord[i][3] = CHAN_TO_FLOAT(rgba[i][ACOMP]);
      }
   }
}



/*
 * Used byglDraw/CopyPixels: the incoming image colors are treated
 * as texture coordinates.  Use those coords to texture the image.
 * This is for GL_SGIS_pixel_texture / GL_SGIX_pixel_texture.
 */
void
_swrast_pixel_texture(GLcontext *ctx, struct sw_span *span)
{
   if (ctx->Texture._ReallyEnabled & ~TEXTURE0_ANY) {
      /* multitexture! */
      GLchan primary_rgba[MAX_WIDTH][4];
      GLuint unit;

      MEMCPY(primary_rgba, span->color.rgba, 4 * span->end * sizeof(GLchan));
      
      for (unit = 0; unit < ctx->Const.MaxTextureUnits; unit++) {
         if (ctx->Texture.Unit[unit]._ReallyEnabled) {
            pixeltexgen(ctx, span->end,
                        (const GLchan (*)[4]) span->color.rgba,
                        span->texcoords[unit]);
            _swrast_texture_fragments(ctx, unit, span->end,
                                          span->texcoords[unit],
                                          span->lambda[unit],
                                          (CONST GLchan (*)[4]) primary_rgba,
                                          span->color.rgba);
         }
      }
   }
   else {
      /* single texture, unit 0 */
      ASSERT(ctx->Texture._ReallyEnabled & TEXTURE0_ANY);
      pixeltexgen(ctx, span->end,
                  (const GLchan (*)[4]) span->color.rgba,
                  span->texcoords[0]);
      _swrast_texture_fragments(ctx, 0, span->end,
                                    span->texcoords[0], span->lambda[0],
                                    (CONST GLchan (*)[4]) span->color.rgba,
                                    (GLchan (*)[4]) span->color.rgba);
   }
}