I've run into a problem using Quaternion rotation with osg::Matrixd that I
can't seem to figure out. Consider the following test example and resulting
output:
#define DEG2RAD(d) d*(2*M_PI/360.0)
#define RAD2DEG(r) r*360.0/2*M_PI
void testQuaternionRotation()
{
osg::Matrixd osgTrans;
osgTrans.set(osg::Matrix::identity());
osg::Vec3f axis(0.0,0.0,1.0);
double osgTransAngle,osgQuatAngle;
printf("\n*** Doing a 360 deg quaternion rotation about z-axis using
OSG ***\n");
for(int i = 0; i < 360; ++i)
{
double angle = DEG2RAD(i);
osg::Quat quat(angle,axis);
quat.getRotate(osgQuatAngle,axis);
//Set the quat rotation on matrix
osgTrans.setRotate(quat);
quat = osgTrans.getRotate();
quat.getRotate(osgTransAngle,axis);
printf("Rot: %.1f osgQang: %.1f osgTransAng:
%.1f\n",RAD2DEG(angle),RAD2DEG(osgQuatAngle),RAD2DEG(osgTransAngle));
}
}
Output:
Rot: 268.0 osgQang: 268.0 osgTransAng: 268.0
Rot: 269.0 osgQang: 269.0 osgTransAng: 269.0
Rot: 270.0 osgQang: 270.0 osgTransAng: 90.0
Rot: 271.0 osgQang: 271.0 osgTransAng: 89.0
Reading back rotation angles in the 4'th quadrant gives me invalid values. I
would have expected to either get negative angle or the angle that I used to
rotate about the z-axis. Am I missing a elementary consept here or is this an
actual bug in the implementation?
Setting the matrix using a quaternion with angles from the 4'th quaderant seems
to be working just fine, it's only reading it back that doesn't work.
Thanks for any help on this,
Filip
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