src/gallium/auxiliary/util/u_texture.c

   1 /**************************************************************************
   2  *
   3  * Copyright 2008 Tungsten Graphics, Inc., Cedar Park, Texas.
   4  * All Rights Reserved.
   5  * Copyright 2008 VMware, Inc.  All rights reserved.
   6  * Copyright 2009 Marek Olšák <maraeo@gmail.com>
   7  *
   8  * Permission is hereby granted, free of charge, to any person obtaining a
   9  * copy of this software and associated documentation files (the
  10  * "Software"), to deal in the Software without restriction, including
  11  * without limitation the rights to use, copy, modify, merge, publish,
  12  * distribute, sub license, and/or sell copies of the Software, and to
  13  * permit persons to whom the Software is furnished to do so, subject to
  14  * the following conditions:
  15  *
  16  * The above copyright notice and this permission notice (including the
  17  * next paragraph) shall be included in all copies or substantial portions
  18  * of the Software.
  19  *
  20  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  21  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  22  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
  23  * IN NO EVENT SHALL TUNGSTEN GRAPHICS AND/OR ITS SUPPLIERS BE LIABLE FOR
  24  * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
  25  * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
  26  * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  27  *
  28  **************************************************************************/
  29
  30 /**
  31  * @file
  32  * Texture mapping utility functions.
  33  *
  34  * @author Brian Paul
  35  *         Marek Olšák
  36  */
  37
  38 #include "pipe/p_defines.h"
  39
  40 #include "util/u_texture.h"
  41
  42 void util_map_texcoords2d_onto_cubemap(unsigned face,
  43                                        const float *in_st, unsigned in_stride,
  44                                        float *out_str, unsigned out_stride)
  45 {
  46    int i;
  47    float rx, ry, rz;
  48
  49    /* loop over quad verts */
  50    for (i = 0; i < 4; i++) {
  51       /* Compute sc = +/-scale and tc = +/-scale.
  52        * Not +/-1 to avoid cube face selection ambiguity near the edges,
  53        * though that can still sometimes happen with this scale factor...
  54        */
  55       const float scale = 0.9999f;
  56       const float sc = (2 * in_st[0] - 1) * scale;
  57       const float tc = (2 * in_st[1] - 1) * scale;
  58
  59       switch (face) {
  60          case PIPE_TEX_FACE_POS_X:
  61             rx = 1;
  62             ry = -tc;
  63             rz = -sc;
  64             break;
  65          case PIPE_TEX_FACE_NEG_X:
  66             rx = -1;
  67             ry = -tc;
  68             rz = sc;
  69             break;
  70          case PIPE_TEX_FACE_POS_Y:
  71             rx = sc;
  72             ry = 1;
  73             rz = tc;
  74             break;
  75          case PIPE_TEX_FACE_NEG_Y:
  76             rx = sc;
  77             ry = -1;
  78             rz = -tc;
  79             break;
  80          case PIPE_TEX_FACE_POS_Z:
  81             rx = sc;
  82             ry = -tc;
  83             rz = 1;
  84             break;
  85          case PIPE_TEX_FACE_NEG_Z:
  86             rx = -sc;
  87             ry = -tc;
  88             rz = -1;
  89             break;
  90          default:
  91             rx = ry = rz = 0;
  92             assert(0);
  93       }
  94
  95       out_str[0] = rx; /*s*/
  96       out_str[1] = ry; /*t*/
  97       out_str[2] = rz; /*r*/
  98
  99       in_st += in_stride;
 100       out_str += out_stride;
 101    }
 102 }