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Improved the handling of scaled matrices in the Quat::set(Matrix&) method.

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This commit is contained in:
Robert Osfield 2003-05-21 21:32:56 +00:00
parent 72b86dee82
commit fb55f6ffbc
2 changed files with 61 additions and 45 deletions
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5
include/osg/Quat
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@ -280,9 +280,12 @@ class SG_EXPORT Quat
return matrix;
}
friend inline std::ostream& operator << (std::ostream& output, const Quat& vec);
protected:
void _set(const Matrix& m );
}; // end of class prototype
inline std::ostream& operator << (std::ostream& output, const Quat& vec)

95
src/osg/Quat.cpp
View File

@ -198,57 +198,70 @@ void Quat::slerp( float t, const Quat& from, const Quat& to )
void Quat::set( const Matrix& m )
{
// Source: Gamasutra, Rotating Objects Using Quaternions
// Source:
//
//http://www.gamasutra.com/features/programming/19980703/quaternions_01.htm
// http://mccammon.ucsd.edu/~adcock/matrixfaq.html#Q55
float tr, s;
float tq[4];
int i, j, k;
float x_scale = sqrtf(osg::square(m(0,0))+osg::square(m(1,0))+osg::square(m(2,0)));
int nxt[3] = {1, 2, 0};
tr = m(0,0) + m(1,1) + m(2,2);
// check the diagonal
if (tr > 0.0)
if (osg::absolute(x_scale-1.0f)>1e-5)
{
s = (float)sqrt (tr + 1.0);
QW = s / 2.0f;
s = 0.5f / s;
QX = (m(1,2) - m(2,1)) * s;
QY = (m(2,0) - m(0,2)) * s;
QZ = (m(0,1) - m(1,0)) * s;
osg::Matrix new_m(m*osg::Matrix::scale(1.0f/x_scale,1.0f/x_scale,1.0f/x_scale));
_set(new_m);
}
else
{
// diagonal is negative
i = 0;
if (m(1,1) > m(0,0))
i = 1;
if (m(2,2) > m(i,i))
i = 2;
j = nxt[i];
k = nxt[j];
s = (float)sqrt ((m(i,i) - (m(j,j) + m(k,k))) + 1.0);
tq[i] = s * 0.5f;
if (s != 0.0f)
s = 0.5f / s;
tq[3] = (m(j,k) - m(k,j)) * s;
tq[j] = (m(i,j) + m(j,i)) * s;
tq[k] = (m(i,k) + m(k,i)) * s;
QX = tq[0];
QY = tq[1];
QZ = tq[2];
QW = tq[3];
_set(m);
}
}
void Quat::_set(const Matrix& m )
{
//std::cout<<"Matrix scaled "<<m<<std::endl;
double S;
double tr = m(0,0) + m(1,1) + m(2,2) + 1.0;
//cout << "tr="<<tr<<endl;
// check the diagonal
if (tr > 2e-5/*0.00000001*/)
{
//cout << "path one"<<endl;
S = 0.5/sqrt (tr);
QW = 0.25 / S;
QX = (m(1,2) - m(2,1)) * S;
QY = (m(2,0) - m(0,2)) * S;
QZ = (m(0,1) - m(1,0)) * S;
}
else
{
//cout << "path two"<<endl;
if ( m(0,0) > m(1,1) && m(0,0) > m(2,2) ) { // Column 0:
S = sqrt( 1.0 + m(0,0) - m(1,1) - m(2,2) ) * 2.0;
QX = 0.25 * S;
QY = (m(1,0) + m(0,1) ) / S;
QZ = (m(0,2) + m(2,0) ) / S;
QW = (m(2,1) - m(1,2) ) / S;
} else if ( m(1,1) > m(2,2) ) { // Column 1:
S = sqrt( 1.0 + m(1,1) - m(0,0) - m(2,2) ) * 2.0;
QX = (m(1,0) + m(0,1) ) / S;
QY = 0.25 * S;
QZ = (m(2,1) + m(1,2) ) / S;
QW = (m(0,2) - m(2,0) ) / S;
} else { // Column 2:
S = sqrt( 1.0 + m(2,2) - m(0,0) - m(1,1) ) * 2.0;
QX = (m(0,2) + m(2,0) ) / S;
QY = (m(2,1) + m(1,2) ) / S;
QZ = 0.25f * S;
QW = (m(1,0) - m(0,1) ) / S;
}
}
}
void Quat::get( Matrix& m ) const
{