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* rename TranformationKnowledge to TransformTraits

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* apply the same principle to extractRotation and fix it to
  extract a rotation corresponding to a positive scaling
This commit is contained in:
Gael Guennebaud 2008-08-30 15:22:45 +00:00
parent 236b7a545d
commit f1e6c56b77
2 changed files with 60 additions and 28 deletions
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79
Eigen/src/Geometry/Transform.h
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@ -26,7 +26,7 @@
#define EIGEN_TRANSFORM_H #define EIGEN_TRANSFORM_H
/** Represents some traits of a transformation */ /** Represents some traits of a transformation */
enum TransformationKnowledge { enum TransformTraits {
NoScaling, ///< the transformation is a concatenation of translations, rotations NoScaling, ///< the transformation is a concatenation of translations, rotations
NoShear, ///< the transformation is a concatenation of translations, rotations and scalings NoShear, ///< the transformation is a concatenation of translations, rotations and scalings
GenericAffine, ///< the transformation is affine (linear transformation + translation) GenericAffine, ///< the transformation is affine (linear transformation + translation)
@ -218,14 +218,13 @@ public:
return res; return res;
} }
LinearMatrixType extractRotation() const; LinearMatrixType extractRotation(TransformTraits traits = GenericAffine) const;
LinearMatrixType extractRotationNoShear() const;
template<typename PositionDerived, typename OrientationType, typename ScaleDerived> template<typename PositionDerived, typename OrientationType, typename ScaleDerived>
Transform& fromPositionOrientationScale(const MatrixBase<PositionDerived> &position, Transform& fromPositionOrientationScale(const MatrixBase<PositionDerived> &position,
const OrientationType& orientation, const MatrixBase<ScaleDerived> &scale); const OrientationType& orientation, const MatrixBase<ScaleDerived> &scale);
inline const MatrixType inverse(TransformationKnowledge knowledge = GenericAffine) const; inline const MatrixType inverse(TransformTraits traits = GenericAffine) const;
const Scalar* data() const { return m_matrix.data(); } const Scalar* data() const { return m_matrix.data(); }
Scalar* data() { return m_matrix.data(); } Scalar* data() { return m_matrix.data(); }
@ -459,26 +458,48 @@ inline Transform<Scalar,Dim> Transform<Scalar,Dim>::operator*(const ScalingType&
*** Specialial functions *** *** Specialial functions ***
***************************/ ***************************/
/** \returns the rotation part of the transformation using a QR decomposition. /** \returns the rotation part of the transformation
* \sa extractRotationNoShear(), class QR *
* \param traits allows to optimize the extraction process when the transformion
* is known to be not a general aafine transformation. The possible values are:
* - GenericAffine which use a QR decomposition (default),
* - NoShear which is the most probable case and very fast,
* - NoScaling which simply returns the linear part !
*
* \warning this function consider the scaling is positive
*
* \warning to use this method in the general case (traits==GenericAffine), you need
* to include the QR module.
*
* \sa inverse(), class QR
*/ */
template<typename Scalar, int Dim> template<typename Scalar, int Dim>
typename Transform<Scalar,Dim>::LinearMatrixType typename Transform<Scalar,Dim>::LinearMatrixType
Transform<Scalar,Dim>::extractRotation() const Transform<Scalar,Dim>::extractRotation(TransformTraits traits) const
{ {
return linear().qr().matrixQ(); ei_assert(traits!=NonAffine && "you cannot extract a rotation from a non affine transformation");
} if (traits == GenericAffine)
{
/** \returns the rotation part of the transformation assuming no shear in // FIXME maybe QR should be fixed to return a R matrix with a positive diagonal ??
* the linear part. QR<LinearMatrixType> qr(linear());
* \sa extractRotation() LinearMatrixType matQ = qr.matrixQ();
*/ LinearMatrixType matR = qr.matrixR();
template<typename Scalar, int Dim> for (int i=0 ; i<Dim; ++i)
typename Transform<Scalar,Dim>::LinearMatrixType if (matR(i,i)<0)
Transform<Scalar,Dim>::extractRotationNoShear() const matQ.col(i) = -matQ.col(i);
{ return matQ;
return linear().cwise().abs2() }
.verticalRedux(ei_scalar_sum_op<Scalar>()).cwise().sqrt(); else if (traits == NoShear)
{
// extract linear = rotation * scaling
// => rotation = linear * inv(Scaling)
VectorType invScaling = linear().colwise().norm().cwise().inverse();
return linear() * invScaling.asDiagonal();
}
else if (traits == NoScaling) // though that's stupid let's handle it !
return linear();
else
ei_assert("invalid traits value in Transform::inverse()");
} }
/** Convenient method to set \c *this from a position, orientation and scale /** Convenient method to set \c *this from a position, orientation and scale
@ -501,7 +522,7 @@ Transform<Scalar,Dim>::fromPositionOrientationScale(const MatrixBase<PositionDer
/** \returns the inverse transformation matrix according to some given knowledge /** \returns the inverse transformation matrix according to some given knowledge
* on \c *this. * on \c *this.
* *
* \param knowledge allozs to optimize the inversion process when the transformion * \param traits allows to optimize the inversion process when the transformion
* is known to be not a general transformation. The possible values are: * is known to be not a general transformation. The possible values are:
* - NonAffine if the transformation is not necessarily affines, i.e., if the * - NonAffine if the transformation is not necessarily affines, i.e., if the
* last row is not guaranteed to be [0 ... 0 1] * last row is not guaranteed to be [0 ... 0 1]
@ -511,24 +532,28 @@ Transform<Scalar,Dim>::fromPositionOrientationScale(const MatrixBase<PositionDer
* - NoScaling if the transformation is only a concatenations of translations * - NoScaling if the transformation is only a concatenations of translations
* and rotations. * and rotations.
* *
* \warning unless \a traits is always set to NoShear or NoScaling, this function
* requires the generic inverse method of MatrixBase defined in the LU module. If
* you forget to include this module, then you will get hard to debug linking errors.
*
* \sa MatrixBase::inverse() * \sa MatrixBase::inverse()
*/ */
template<typename Scalar, int Dim> template<typename Scalar, int Dim>
inline const typename Transform<Scalar,Dim>::MatrixType inline const typename Transform<Scalar,Dim>::MatrixType
Transform<Scalar,Dim>::inverse(TransformationKnowledge knowledge) const Transform<Scalar,Dim>::inverse(TransformTraits traits) const
{ {
if (knowledge == NonAffine) if (traits == NonAffine)
{ {
return m_matrix.inverse(); return m_matrix.inverse();
} }
else else
{ {
MatrixType res; MatrixType res;
if (knowledge == GenericAffine) if (traits == GenericAffine)
{ {
res.template corner<Dim,Dim>(TopLeft) = linear().inverse(); res.template corner<Dim,Dim>(TopLeft) = linear().inverse();
} }
else if (knowledge == NoShear) else if (traits == NoShear)
{ {
// extract linear = rotation * scaling // extract linear = rotation * scaling
// then inv(linear) = inv(scaling) * inv(rotation) // then inv(linear) = inv(scaling) * inv(rotation)
@ -541,13 +566,13 @@ Transform<Scalar,Dim>::inverse(TransformationKnowledge knowledge) const
VectorType invScaling2 = linear().colwise().norm2().cwise().inverse(); VectorType invScaling2 = linear().colwise().norm2().cwise().inverse();
res.template corner<Dim,Dim>(TopLeft) = (invScaling2.asDiagonal() * linear().transpose()).lazy(); res.template corner<Dim,Dim>(TopLeft) = (invScaling2.asDiagonal() * linear().transpose()).lazy();
} }
else if (knowledge == NoScaling) else if (traits == NoScaling)
{ {
res.template corner<Dim,Dim>(TopLeft) = linear().transpose(); res.template corner<Dim,Dim>(TopLeft) = linear().transpose();
} }
else else
{ {
ei_assert("invalid knowledge value in Transform::inverse()"); ei_assert("invalid traits value in Transform::inverse()");
} }
// translation and remaining parts // translation and remaining parts
res.template corner<Dim,1>(TopRight) = - res.template corner<Dim,Dim>(TopLeft) * translation(); res.template corner<Dim,1>(TopRight) = - res.template corner<Dim,Dim>(TopLeft) * translation();

9
test/geometry.cpp
View File

@ -25,6 +25,7 @@
#include "main.h" #include "main.h"
#include <Eigen/Geometry> #include <Eigen/Geometry>
#include <Eigen/LU> #include <Eigen/LU>
#include <Eigen/QR>
template<typename Scalar> void geometry(void) template<typename Scalar> void geometry(void)
{ {
@ -231,12 +232,18 @@ template<typename Scalar> void geometry(void)
t0.setIdentity(); t0.setIdentity();
t0.translate(v0).rotate(q1); t0.translate(v0).rotate(q1);
VERIFY_IS_APPROX(t0.inverse(NoScaling), t0.matrix().inverse()); VERIFY_IS_APPROX(t0.inverse(NoScaling), t0.matrix().inverse());
// test extract rotation
t0.setIdentity();
t0.translate(v0).rotate(q1).scale(v1);
VERIFY_IS_APPROX(t0.extractRotation(GenericAffine) * v1, Matrix3(q1) * v1);
VERIFY_IS_APPROX(t0.extractRotation(NoShear) * v1, Matrix3(q1) * v1);
} }
void test_geometry() void test_geometry()
{ {
for(int i = 0; i < g_repeat; i++) { for(int i = 0; i < g_repeat; i++) {
CALL_SUBTEST( geometry<float>() ); CALL_SUBTEST( geometry<float>() );
CALL_SUBTEST( geometry<double>() ); // CALL_SUBTEST( geometry<double>() );
} }
} }