1/************************************************************************** 2 * 3 * Copyright 2008 VMware, Inc. 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 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 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 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