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_debug.h"
  41 #include "util/u_texture.h"
  42
  43 void util_map_texcoords2d_onto_cubemap(unsigned face,
  44                                        const float *in_st, unsigned in_stride,
  45                                        float *out_str, unsigned out_stride)
  46 {
  47    int i;
  48    float rx, ry, rz;
  49
  50    /* loop over quad verts */
  51    for (i = 0; i < 4; i++) {
  52       /* Compute sc = +/-scale and tc = +/-scale.
  53        * Not +/-1 to avoid cube face selection ambiguity near the edges,
  54        * though that can still sometimes happen with this scale factor...
  55        */
  56       const float scale = 0.9999f;
  57       const float sc = (2 * in_st[0] - 1) * scale;
  58       const float tc = (2 * in_st[1] - 1) * scale;
  59
  60       switch (face) {
  61          case PIPE_TEX_FACE_POS_X:
  62             rx = 1;
  63             ry = -tc;
  64             rz = -sc;
  65             break;
  66          case PIPE_TEX_FACE_NEG_X:
  67             rx = -1;
  68             ry = -tc;
  69             rz = sc;
  70             break;
  71          case PIPE_TEX_FACE_POS_Y:
  72             rx = sc;
  73             ry = 1;
  74             rz = tc;
  75             break;
  76          case PIPE_TEX_FACE_NEG_Y:
  77             rx = sc;
  78             ry = -1;
  79             rz = -tc;
  80             break;
  81          case PIPE_TEX_FACE_POS_Z:
  82             rx = sc;
  83             ry = -tc;
  84             rz = 1;
  85             break;
  86          case PIPE_TEX_FACE_NEG_Z:
  87             rx = -sc;
  88             ry = -tc;
  89             rz = -1;
  90             break;
  91          default:
  92             rx = ry = rz = 0;
  93             assert(0);
  94       }
  95
  96       out_str[0] = rx; /*s*/
  97       out_str[1] = ry; /*t*/
  98       out_str[2] = rz; /*r*/
  99
 100       in_st += in_stride;
 101       out_str += out_stride;
 102    }
 103 }