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
43void 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}
104