gtkradiant/tools/quake3/q3map2/brush_primit.c
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git-svn-id: svn://svn.icculus.org/gtkradiant/GtkRadiant/branches/ZeroRadiant@183 8a3a26a2-13c4-0310-b231-cf6edde360e5
2007-11-04 03:34:51 +00:00

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C

/*
Copyright (C) 1999-2007 id Software, Inc. and contributors.
For a list of contributors, see the accompanying CONTRIBUTORS file.
This file is part of GtkRadiant.
GtkRadiant is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
GtkRadiant is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with GtkRadiant; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
----------------------------------------------------------------------------------
This code has been altered significantly from its original form, to support
several games based on the Quake III Arena engine, in the form of "Q3Map2."
------------------------------------------------------------------------------- */
/* marker */
#define BRUSH_PRIMIT_C
/* dependencies */
#include "q3map2.h"
/* -------------------------------------------------------------------------------
functions
------------------------------------------------------------------------------- */
/*
ComputeAxisBase()
computes the base texture axis for brush primitive texturing
note: ComputeAxisBase here and in editor code must always BE THE SAME!
warning: special case behaviour of atan2( y, x ) <-> atan( y / x ) might not be the same everywhere when x == 0
rotation by (0,RotY,RotZ) assigns X to normal
*/
void ComputeAxisBase( vec3_t normal, vec3_t texX, vec3_t texY )
{
vec_t RotY, RotZ;
/* do some cleaning */
if( fabs( normal[ 0 ] ) < 1e-6 )
normal[ 0 ]= 0.0f;
if( fabs( normal[ 1 ] ) < 1e-6 )
normal[ 1 ]=0.0f;
if( fabs( normal[ 2 ] ) < 1e-6 )
normal[ 2 ] = 0.0f;
/* compute the two rotations around y and z to rotate x to normal */
RotY = -atan2( normal[ 2 ], sqrt( normal[ 1 ] * normal[ 1 ] + normal[ 0 ] * normal[ 0 ]) );
RotZ = atan2( normal[ 1 ], normal[ 0 ] );
/* rotate (0,1,0) and (0,0,1) to compute texX and texY */
texX[ 0 ] = -sin( RotZ );
texX[ 1 ] = cos( RotZ );
texX[ 2 ] = 0;
/* the texY vector is along -z (t texture coorinates axis) */
texY[ 0 ] = -sin( RotY ) * cos( RotZ );
texY[ 1 ] = -sin( RotY ) * sin( RotZ );
texY[ 2 ] = -cos( RotY );
}