vb01/quaternion.h

#include<cmath>

namespace vb01{
	class quaternion{
		public:
			quaternion(float w,float x,float y,float z){
				this->w=w;
				this->x=x;
				this->y=y;
				this->z=z;
			}
			inline vb01::quaternion operator* (vb01::quaternion q){
				float a1=this->w,a2=q.w,
					  b1=this->x,b2=q.x,
					  c1=this->y,c2=q.y,
					  d1=this->z,d2=q.z;
				float w=a1*a2-b1*b2-c1*c2-d1*d2;
				float x=a1*b2+b1*a2+c1*d2-d1*c2;
				float y=a1*c2-b1*d2+c1*a2+d1*b2;
				float z=a1*d2+b1*c2-c1*b2+d1*a2;
				return quaternion(w,x,y,z);
			}
			//inline vb01::quaternion conj(){return -.5*(*this+vb01::QUAT_I*(*this)*vb01::QUAT_I+vb01::QUAT_J*(*this)*vb01::QUAT_J+vb01::QUAT_K*(*this)*vb01::QUAT_K);}
			inline vb01::quaternion operator/ (float f){return quaternion(w/f,x/f,y/f,z/f);}
			inline vb01::quaternion norm(){return *this/getLength();}
			//inline vb01::quaternion recip(){return conj()/getLengthSq();}
			inline float getLengthSq(){return w*w+x*x+y*y+z*z;}
			inline float getLength(){return std::sqrt(getLengthSq());}

	//static vb01::quaternion QUAT_I=quaternion(0,1,0,0),QUAT_J=quaternion(0,0,1,0),QUAT_K=quaternion(0,0,0,1);
			float w,x,y,z;
		private:
	};
}