2 Copyright (C) 1999-2007 id Software, Inc. and contributors.
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3 For a list of contributors, see the accompanying CONTRIBUTORS file.
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5 This file is part of GtkRadiant.
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7 GtkRadiant is free software; you can redistribute it and/or modify
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8 it under the terms of the GNU General Public License as published by
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9 the Free Software Foundation; either version 2 of the License, or
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10 (at your option) any later version.
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12 GtkRadiant is distributed in the hope that it will be useful,
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13 but WITHOUT ANY WARRANTY; without even the implied warranty of
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14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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15 GNU General Public License for more details.
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17 You should have received a copy of the GNU General Public License
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18 along with GtkRadiant; if not, write to the Free Software
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19 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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21 ----------------------------------------------------------------------------------
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23 This code has been altered significantly from its original form, to support
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24 several games based on the Quake III Arena engine, in the form of "Q3Map2."
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26 ------------------------------------------------------------------------------- */
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31 #define BRUSH_PRIMIT_C
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40 /* -------------------------------------------------------------------------------
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44 ------------------------------------------------------------------------------- */
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48 computes the base texture axis for brush primitive texturing
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49 note: ComputeAxisBase here and in editor code must always BE THE SAME!
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50 warning: special case behaviour of atan2( y, x ) <-> atan( y / x ) might not be the same everywhere when x == 0
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51 rotation by (0,RotY,RotZ) assigns X to normal
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54 void ComputeAxisBase( vec3_t normal, vec3_t texX, vec3_t texY )
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59 /* do some cleaning */
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60 if( fabs( normal[ 0 ] ) < 1e-6 )
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62 if( fabs( normal[ 1 ] ) < 1e-6 )
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64 if( fabs( normal[ 2 ] ) < 1e-6 )
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67 /* compute the two rotations around y and z to rotate x to normal */
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68 RotY = -atan2( normal[ 2 ], sqrt( normal[ 1 ] * normal[ 1 ] + normal[ 0 ] * normal[ 0 ]) );
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69 RotZ = atan2( normal[ 1 ], normal[ 0 ] );
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71 /* rotate (0,1,0) and (0,0,1) to compute texX and texY */
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72 texX[ 0 ] = -sin( RotZ );
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73 texX[ 1 ] = cos( RotZ );
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76 /* the texY vector is along -z (t texture coorinates axis) */
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77 texY[ 0 ] = -sin( RotY ) * cos( RotZ );
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78 texY[ 1 ] = -sin( RotY ) * sin( RotZ );
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79 texY[ 2 ] = -cos( RotY );
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