mirror of
https://github.com/id-Software/Wolf3D-iOS.git
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172 lines
3.6 KiB
C
172 lines
3.6 KiB
C
/*
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Copyright (C) 2005 Michael Liebscher <johnnycanuck@users.sourceforge.net>
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Copyright (C) 1997-2001 Id Software, Inc.
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License
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as published by the Free Software Foundation; either version 2
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of the License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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/*
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* angle.h: Angle math routines.
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*
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* Author: Michael Liebscher <johnnycanuck@users.sourceforge.net>
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*
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* Acknowledgement:
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* Portion of this code was derived from Quake II, and was originally
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* written by Id Software, Inc.
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*
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*/
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#include "../wolfiphone.h"
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/*
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-----------------------------------------------------------------------------
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Function: angle_diff -Finds the difference between two angles.
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Parameters: angle1, angle2 -[in] Angles in Radians.
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Returns:
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Returns the absolute difference between two angles, this will always
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be between 0 and 180 degrees.
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Notes:
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-----------------------------------------------------------------------------
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*/
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INLINECALL float angle_diff( float angle1, float angle2 )
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{
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float d;
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if( angle1 > angle2 )
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{
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d = angle1 - angle2;
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}
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else
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{
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d = angle2 - angle1;
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}
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if( d > M_PI )
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{
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return 2 * M_PI - d;
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}
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else
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{
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return d;
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}
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}
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/*
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-----------------------------------------------------------------------------
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Function: angle_wise -Clockwise distance between two angles.
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Parameters: angle1, angle2 -[in] Angles in Radians.
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Returns:
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Returns the clockwise distance from angle2 to angle1, this may be
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greater than 180 degrees.
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Notes:
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-----------------------------------------------------------------------------
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*/
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INLINECALL float angle_wise( float angle1, float angle2 )
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{
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if( angle1 > angle2 )
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{
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return angle1 - angle2;
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}
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else
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{
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return angle1 + 2 * M_PI - angle2;
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}
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}
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/*
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-----------------------------------------------------------------------------
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Function: interpolate_angle -Linear interpolate between angle A and B by
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fraction 'f'.
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Parameters:
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Returns:
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Notes:
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-----------------------------------------------------------------------------
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*/
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INLINECALL float interpolate_angle( float from, float to, float fraction )
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{
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float diff = angle_diff( from, to ) * fraction;
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if( angle_wise( to, from ) >= M_PI )
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{
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return from - diff;
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}
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else
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{
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return from + diff;
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}
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}
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/*
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-----------------------------------------------------------------------------
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Function: normalize_angle -
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Parameters:
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Returns: Nothing.
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Notes:
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-----------------------------------------------------------------------------
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*/
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INLINECALL float normalize_angle( float angle )
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{
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while( angle < 0 )
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{
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angle += (2 * M_PI);
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}
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while( angle >= (2 * M_PI) )
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{
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angle -= (2 * M_PI);
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}
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return angle;
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}
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/*
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-----------------------------------------------------------------------------
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Function: LerpAngle -Linear interpolate allowing for the Modulo 360 problem.
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Parameters:
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Returns:
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Notes:
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-----------------------------------------------------------------------------
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*/
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INLINECALL float LerpAngle( float from, float to, float frac )
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{
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if( to - from > 180 )
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{
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to -= 360;
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}
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if( to - from < -180 )
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{
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to += 360;
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}
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return from + frac * (to - from);
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}
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