quaterni.h Source File

00001 /*
00002     Copyright (C) 2000 by Norman Kramer
00003 
00004     This library is free software; you can redistribute it and/or
00005     modify it under the terms of the GNU Library General Public
00006     License as published by the Free Software Foundation; either
00007     version 2 of the License, or (at your option) any later version.
00008 
00009     This library is distributed in the hope that it will be useful,
00010     but WITHOUT ANY WARRANTY; without even the implied warranty of
00011     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00012     Library General Public License for more details.
00013 
00014     You should have received a copy of the GNU Library General Public
00015     License along with this library; if not, write to the Free
00016     Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
00017 */
00018 
00019 #ifndef __CS_QUATERNION_H__
00020 #define __CS_QUATERNION_H__
00021 
00022 #include "csgeom/math3d.h"
00023 #include "qsqrt.h"
00024 
00028 class csQuaternion
00029 {
00030 public:
00032   inline void Init (float theR, float theX, float theY, float theZ)
00033   { r = theR; x = theX; y = theY; z = theZ; }
00034 
00036   csQuaternion () { Init(0, 0, 0, 0 ); }
00038   csQuaternion (float theR, float theX=0.0, float theY=0.0, float theZ=0.0)
00039   { Init (theR, theX, theY, theZ ); }
00041   csQuaternion (const csQuaternion& q) { Init (q.r, q.x, q.y, q.z); }
00043   csQuaternion (const csVector3& q) { Init (0, q.x, q.y, q.z); }
00044 
00046   inline friend csQuaternion operator+ (const csQuaternion& q1, const csQuaternion& q2)
00047   { return csQuaternion (q1.r + q2.r, q1.x + q2.x, q1.y + q2.y, q1.z + q2.z ); }
00049   inline friend csQuaternion operator- (const csQuaternion& q1, const csQuaternion& q2)
00050   { return csQuaternion (q1.r - q2.r, q1.x - q2.x, q1.y - q2.y, q1.z - q2.z ); }
00052   inline friend csQuaternion operator* (const csQuaternion& q1, const csQuaternion& q2)
00053   { return csQuaternion (q1.r*q2.r -  q1.x*q2.x - q1.y*q2.y - q1.z*q2.z,
00054                          q1.y*q2.z -  q1.z*q2.y + q1.r*q2.x + q1.x*q2.r,
00055                          q1.z*q2.x -  q1.x*q2.z + q1.r*q2.y + q1.y*q2.r,
00056                          q1.x*q2.y -  q1.y*q2.x + q1.r*q2.z + q1.z*q2.r); }
00057 
00059   csQuaternion& operator*= (const csQuaternion& q2)
00060   {
00061     Init (r*q2.r -  x*q2.x - y*q2.y - z*q2.z,
00062           y*q2.z -  z*q2.y + r*q2.x + x*q2.r,
00063           z*q2.x -  x*q2.z + r*q2.y + y*q2.r,
00064           x*q2.y -  y*q2.x + r*q2.z + z*q2.r);
00065     return *this;
00066   }
00067 
00069   void Conjugate () { Init (r, -x, -y, -z); }
00070 
00072         void Negate () { Init(-r, -x, -y, -z); }
00073 
00079   void PrepRotation (float angle, csVector3 vec)
00080   {
00081     double theSin = sin (angle / 2.0f);
00082     Init ((float) cos (angle / 2.0f), vec.x * theSin, vec.y * theSin, vec.z * theSin);
00083   }
00084 
00086   csVector3 Rotate (csVector3 vec)
00087   {
00088     csQuaternion p (vec);
00089     csQuaternion qConj (r, -x, -y, -z);
00090 
00091     p = *this * p;
00092     p *= qConj;
00093     return csVector3 (p.x, p.y, p.z);
00094   }
00095 
00097   void Normalize ()
00098   {
00099     if(x*x + y*y + z*z > .999)
00100     {
00101       // Severe problems...
00102       float inverselen = 1.0f / (x*x + y*y + z*z);
00103       x *= inverselen;
00104       y *= inverselen;
00105       z *= inverselen;
00106       r = 0.0f;
00107     }
00108     else
00109     {
00110       r = qsqrt(1.0f - x*x - y*y - z*z);
00111     }
00112   }
00113 
00119   void SetWithEuler(const csVector3 &rot);
00120 
00124   csQuaternion ToAxisAngle() const;
00125 
00131   csQuaternion Slerp (const csQuaternion &quat2, float slerp) const;
00132 
00133 //csQuaternion Lerp(const csQuaternion& quat2, float ratio) const;
00134 
00135   float r,x,y,z;
00136 };
00137 
00138 
00139 #endif // __CS_QUATERNION_H__