GBLENDER_CHANNEL_VARS(blender,r,g,b);  int                   h        = blit->height;  const unsigned char*  src_line = blit->src_line;  unsigned char*        dst_line = blit->dst_line;  do  {    const unsigned char*  src = src_line + blit->src_x*3;    unsigned char*        dst = dst_line + blit->dst_x*GDST_INCR;    int                   w   = blit->width;    do    {      int  ab = GBLENDER_SHADE_INDEX(src[0]);      int  ag = GBLENDER_SHADE_INDEX(src[1]);      int  ar = GBLENDER_SHADE_INDEX(src[2]);      int  aa = (ar << 16) | (ag << 8) | ab;      if ( aa == 0 )      {        /* nothing */      }      else if ( aa == ((GBLENDER_SHADE_COUNT << 16) |                       (GBLENDER_SHADE_COUNT << 8)  |                       (GBLENDER_SHADE_COUNT)       ) )      {        GDST_COPY(dst);      }      else      {        GBlenderPixel  back;        int            pix_r, pix_g, pix_b;        GDST_READ(dst,back);        {          int  back_r = (back >> 16) & 255;                    GBLENDER_LOOKUP_R( blender, back_r );                    pix_r = _grcells[ar];        }                {          int  back_g = (back >> 8) & 255;                    GBLENDER_LOOKUP_G( blender, back_g );                    pix_g = _ggcells[ag];        }        {          int  back_b = (back) & 255;                    GBLENDER_LOOKUP_B( blender, back_b );                    pix_b = _gbcells[ab];        }        GDST_STOREC(dst,pix_r,pix_g,pix_b);      }      src += 3;      dst += GDST_INCR;    }    while (--w > 0);    src_line += blit->src_pitch;    dst_line += blit->dst_pitch;  }  while (--h > 0);    GBLENDER_CHANNEL_CLOSE(blender);