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outer product and intertia tensor in vecmat3

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Jiri Pittner 2022-10-28 16:14:13 +02:00
parent 43e53b0bbc
commit 31c45d44ec
2 changed files with 47 additions and 0 deletions
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40
vecmat3.cc
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@ -47,6 +47,46 @@ template<typename T>
Vec3<T>& Vec3<T>::fast_normalize(void) {normalize(); return *this;}; Vec3<T>& Vec3<T>::fast_normalize(void) {normalize(); return *this;};
template<typename T>
Mat3<T> Vec3<T>::outer(const Vec3<T> &rhs) const
{
Mat3<T> m;
m[0][0]=q[0]*rhs.q[0];
m[0][1]=q[0]*rhs.q[1];
m[0][2]=q[0]*rhs.q[2];
m[1][0]=q[1]*rhs.q[0];
m[1][1]=q[1]*rhs.q[1];
m[1][2]=q[1]*rhs.q[2];
m[2][0]=q[2]*rhs.q[0];
m[2][1]=q[2]*rhs.q[1];
m[2][2]=q[2]*rhs.q[2];
return m;
}
template<typename T>
void Vec3<T>::inertia(Mat3<T> &m, const T weight) const
{
T r2 = q[0]*q[0]+q[1]*q[1]+q[2]*q[2];
m[0][0] -= weight*(q[0]*q[0]-r2);
m[0][1] -= weight*q[0]*q[1];
m[0][2] -= weight*q[0]*q[2];
m[1][0] -= weight*q[1]*q[0];
m[1][1] -= weight*(q[1]*q[1]-r2);
m[1][2] -= weight*q[1]*q[2];
m[2][0] -= weight*q[2]*q[0];
m[2][1] -= weight*q[2]*q[1];
m[2][2] -= weight*(q[2]*q[2]-r2);
}
template<typename T> template<typename T>
const Vec3<T> Vec3<T>::operator*(const Mat3<T> &rhs) const const Vec3<T> Vec3<T>::operator*(const Mat3<T> &rhs) const
{ {

7
vecmat3.h
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@ -86,6 +86,9 @@ public:
Vec3& normalize(void) {*this /= norm(); return *this;}; Vec3& normalize(void) {*this /= norm(); return *this;};
Vec3& fast_normalize(void); Vec3& fast_normalize(void);
const Vec3 operator*(const Mat3<T> &rhs) const; const Vec3 operator*(const Mat3<T> &rhs) const;
Mat3<T> outer(const Vec3 &rhs) const; //tensor product
void inertia(Mat3<T> &itensor, const T weight) const; //contribution to inertia tensor
//C-style IO //C-style IO
int fprintf(FILE *f, const char *format) const {return ::fprintf(f,format,q[0],q[1],q[2]);}; int fprintf(FILE *f, const char *format) const {return ::fprintf(f,format,q[0],q[1],q[2]);};
int sprintf(char *f, const char *format) const {return ::sprintf(f,format,q[0],q[1],q[2]);}; int sprintf(char *f, const char *format) const {return ::sprintf(f,format,q[0],q[1],q[2]);};
@ -94,6 +97,10 @@ public:
}; };
template <typename T>
inline T hypot3(const Vec3<T> &c, const Vec3<T> &d) {return((c-d).norm());}
template <typename T> template <typename T>
class Mat3 class Mat3
{ {