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/**************************************************************************
*
* Copyright 2008 VMware, Inc.
* All Rights Reserved.
* Copyright 2008 VMware, Inc. All rights reserved.
* Copyright 2009 Marek Olšák <maraeo@gmail.com>
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sub license, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice (including the
* next paragraph) shall be included in all copies or substantial portions
* of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
* IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
* ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
**************************************************************************/
/**
* @file
* Texture mapping utility functions.
*
* @author Brian Paul
* Marek Olšák
*/
#include "pipe/p_defines.h"
#include "util/u_debug.h"
#include "util/u_texture.h"
void util_map_texcoords2d_onto_cubemap(unsigned face,
const float *in_st, unsigned in_stride,
float *out_str, unsigned out_stride,
boolean allow_scale)
{
int i;
float rx, ry, rz;
/* loop over quad verts */
for (i = 0; i < 4; i++) {
/* Compute sc = +/-scale and tc = +/-scale.
* Not +/-1 to avoid cube face selection ambiguity near the edges,
* though that can still sometimes happen with this scale factor...
*
* XXX: Yep, there is no safe scale factor that will prevent sampling
* the neighbouring face when stretching out. A more reliable solution
* would be to clamp (sc, tc) against +/- 1.0-1.0/mipsize, in the shader.
*
* Also, this is not necessary when minifying, or 1:1 blits.
*/
const float scale = allow_scale ? 0.9999f : 1.0f;
const float sc = (2 * in_st[0] - 1) * scale;
const float tc = (2 * in_st[1] - 1) * scale;
switch (face) {
case PIPE_TEX_FACE_POS_X:
rx = 1;
ry = -tc;
rz = -sc;
break;
case PIPE_TEX_FACE_NEG_X:
rx = -1;
ry = -tc;
rz = sc;
break;
case PIPE_TEX_FACE_POS_Y:
rx = sc;
ry = 1;
rz = tc;
break;
case PIPE_TEX_FACE_NEG_Y:
rx = sc;
ry = -1;
rz = -tc;
break;
case PIPE_TEX_FACE_POS_Z:
rx = sc;
ry = -tc;
rz = 1;
break;
case PIPE_TEX_FACE_NEG_Z:
rx = -sc;
ry = -tc;
rz = -1;
break;
default:
rx = ry = rz = 0;
assert(0);
}
out_str[0] = rx; /*s*/
out_str[1] = ry; /*t*/
out_str[2] = rz; /*r*/
in_st += in_stride;
out_str += out_stride;
}
}
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