Home | History | Annotate | Download | only in util 
      1 /**************************************************************************
      2  *
      3  * Copyright 2008 VMware, Inc.
      4  * All Rights Reserved.
      5  * Copyright 2008 VMware, Inc.  All rights reserved.
      6  * Copyright 2009 Marek Olk <maraeo (at) 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 VMWARE 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 Olk
     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                                        boolean allow_scale)
     47 {
     48    int i;
     49    float rx, ry, rz;
     50 
     51    /* loop over quad verts */
     52    for (i = 0; i < 4; i++) {
     53       /* Compute sc = +/-scale and tc = +/-scale.
     54        * Not +/-1 to avoid cube face selection ambiguity near the edges,
     55        * though that can still sometimes happen with this scale factor...
     56        *
     57        * XXX: Yep, there is no safe scale factor that will prevent sampling
     58        * the neighbouring face when stretching out.  A more reliable solution
     59        * would be to clamp (sc, tc) against +/- 1.0-1.0/mipsize, in the shader.
     60        *
     61        * Also, this is not necessary when minifying, or 1:1 blits.
     62        */
     63       const float scale = allow_scale ? 0.9999f : 1.0f;
     64       const float sc = (2 * in_st[0] - 1) * scale;
     65       const float tc = (2 * in_st[1] - 1) * scale;
     66 
     67       switch (face) {
     68          case PIPE_TEX_FACE_POS_X:
     69             rx = 1;
     70             ry = -tc;
     71             rz = -sc;
     72             break;
     73          case PIPE_TEX_FACE_NEG_X:
     74             rx = -1;
     75             ry = -tc;
     76             rz = sc;
     77             break;
     78          case PIPE_TEX_FACE_POS_Y:
     79             rx = sc;
     80             ry = 1;
     81             rz = tc;
     82             break;
     83          case PIPE_TEX_FACE_NEG_Y:
     84             rx = sc;
     85             ry = -1;
     86             rz = -tc;
     87             break;
     88          case PIPE_TEX_FACE_POS_Z:
     89             rx = sc;
     90             ry = -tc;
     91             rz = 1;
     92             break;
     93          case PIPE_TEX_FACE_NEG_Z:
     94             rx = -sc;
     95             ry = -tc;
     96             rz = -1;
     97             break;
     98          default:
     99             rx = ry = rz = 0;
    100             assert(0);
    101       }
    102 
    103       out_str[0] = rx; /*s*/
    104       out_str[1] = ry; /*t*/
    105       out_str[2] = rz; /*r*/
    106 
    107       in_st += in_stride;
    108       out_str += out_stride;
    109    }
    110 }
    111