An abstract class for Frame Constraints defined by an axis or a plane. More...

#include <QGLViewer/constraint.h>

Inheritance diagram for qglviewer::AxisPlaneConstraint:

Public Types
enum	Type { FREE, AXIS, PLANE, FORBIDDEN }
Public Member Functions
	AxisPlaneConstraint ()
virtual	~AxisPlaneConstraint ()
Translation constraint
virtual void	constrainTranslation (Vec &translation, Frame *const frame)
void	setTranslationConstraint (Type type, const Vec &direction)
void	setTranslationConstraintType (Type type)
void	setTranslationConstraintDirection (const Vec &direction)
Type	translationConstraintType () const
Vec	translationConstraintDirection () const
Rotation constraint
virtual void	constrainRotation (Quaternion &rotation, Frame *const frame)
void	setRotationConstraint (Type type, const Vec &direction)
void	setRotationConstraintType (Type type)
void	setRotationConstraintDirection (const Vec &direction)
Type	rotationConstraintType () const
Vec	rotationConstraintDirection () const
Private Attributes
Vec	rotationConstraintDir_
Type	rotationConstraintType_
Vec	translationConstraintDir_
Type	translationConstraintType_

Detailed Description

An abstract class for Frame Constraints defined by an axis or a plane.

AxisPlaneConstraint is an interface for (translation and/or rotation) Constraint that are defined by a direction. translationConstraintType() and rotationConstraintType() define how this direction should be interpreted: as an axis (AxisPlaneConstraint::AXIS) or as a plane normal (AxisPlaneConstraint::PLANE). See the Type() documentation for details.

The three implementations of this class: LocalConstraint, WorldConstraint and CameraConstraint differ by the coordinate system in which this direction is expressed.

Different implementations of this class are illustrated in the contrainedCamera and constrainedFrame examples.

Attention:: When applied, the rotational Constraint may not intuitively follow the mouse displacement. A solution would be to directly measure the rotation angle in screen coordinates, but that would imply to know the QGLViewer::camera(), so that we can compute the projected coordinates of the rotation center (as is done with the QGLViewer::SCREEN_ROTATE binding). However, adding an extra pointer to the QGLViewer::camera() in all the AxisPlaneConstraint derived classes (which the user would have to update in a multi-viewer application) was judged as an overkill.

Definition at line 168 of file constraint.h.

Member Enumeration Documentation

enum qglviewer::AxisPlaneConstraint::Type

Type lists the different types of translation and rotation constraints that are available.

It specifies the meaning of the constraint direction (see translationConstraintDirection() and rotationConstraintDirection()): as an axis direction (AxisPlaneConstraint::AXIS) or a plane normal (AxisPlaneConstraint::PLANE). AxisPlaneConstraint::FREE means no constraint while AxisPlaneConstraint::FORBIDDEN completely forbids the translation and/or the rotation.

See translationConstraintType() and rotationConstraintType().

Attention:: The AxisPlaneConstraint::PLANE Type is not valid for rotational constraint.

New derived classes can use their own extended enum for specific constraints:

    class MyAxisPlaneConstraint : public AxisPlaneConstraint
    {
    public:
      enum MyType { FREE, AXIS, PLANE, FORBIDDEN, CUSTOM };
      virtual void constrainTranslation(Vec &translation, Frame *const frame)
      {
        // translationConstraintType() is simply an int. CUSTOM Type is handled seamlessly.
        switch (translationConstraintType())
        {
        case MyAxisPlaneConstraint::FREE: ... break;
        case MyAxisPlaneConstraint::CUSTOM: ... break;
        }
      };

      MyAxisPlaneConstraint* c = new MyAxisPlaneConstraint();
      // Note the Type conversion
      c->setTranslationConstraintType(AxisPlaneConstraint::Type(MyAxisPlaneConstraint::CUSTOM));
    };

Enumerator:

FREE
AXIS
PLANE
FORBIDDEN

Definition at line 207 of file constraint.h.

Constructor & Destructor Documentation

AxisPlaneConstraint::AxisPlaneConstraint ( )

Default constructor.

translationConstraintType() and rotationConstraintType() are set to AxisPlaneConstraint::FREE. translationConstraintDirection() and rotationConstraintDirection() are set to (0,0,0).

Definition at line 38 of file constraint.cpp.

virtual qglviewer::AxisPlaneConstraint::~AxisPlaneConstraint ( ) [inline, virtual]

Virtual destructor. Empty.

Definition at line 173 of file constraint.h.

Member Function Documentation

virtual void qglviewer::AxisPlaneConstraint::constrainRotation	(	Quaternion &	rotation,
		Frame *const	frame
	)		`[inline, virtual]`

Overloading of Constraint::constrainRotation(). Empty.

Reimplemented from qglviewer::Constraint.

Reimplemented in qglviewer::CameraConstraint, qglviewer::WorldConstraint, and qglviewer::LocalConstraint.

Definition at line 244 of file constraint.h.

virtual void qglviewer::AxisPlaneConstraint::constrainTranslation	(	Vec &	translation,
		Frame *const	frame
	)		`[inline, virtual]`

Overloading of Constraint::constrainTranslation(). Empty

Reimplemented from qglviewer::Constraint.

Reimplemented in qglviewer::CameraConstraint, qglviewer::WorldConstraint, and qglviewer::LocalConstraint.

Definition at line 212 of file constraint.h.

Vec qglviewer::AxisPlaneConstraint::rotationConstraintDirection ( ) const [inline]

Returns the axis direction used by the rotation constraint.

This direction is defined only when rotationConstraintType() is AxisPlaneConstraint::AXIS.

The AxisPlaneConstraint derived classes express this direction in different coordinate system (camera for CameraConstraint, local for LocalConstraint, and world for WorldConstraint). This value can be modified with setRotationConstraintDirection().

Definition at line 259 of file constraint.h.

Type qglviewer::AxisPlaneConstraint::rotationConstraintType ( ) const [inline]

Returns the rotation constraint Type().

Definition at line 251 of file constraint.h.

void AxisPlaneConstraint::setRotationConstraint	(	Type	type,
		const Vec &	direction
	)

Simply calls setRotationConstraintType() and setRotationConstraintDirection().

Definition at line 68 of file constraint.cpp.

void AxisPlaneConstraint::setRotationConstraintDirection ( const Vec & direction )

Defines the rotationConstraintDirection(). The coordinate system where direction is expressed depends on your class implementation.

Definition at line 75 of file constraint.cpp.

void AxisPlaneConstraint::setRotationConstraintType ( Type type )

Set the Type() of the rotationConstraintType(). Default is AxisPlaneConstraint::FREE.

Depending on this value, the Frame will freely rotate (AxisPlaneConstraint::FREE), will only be able to rotate around an axis (AxisPlaneConstraint::AXIS), or will not able to rotate at all (AxisPlaneConstraint::FORBIDDEN).

Use Frame::setOrientation() to define the orientation of the constrained Frame before it gets constrained.

Attention:: An AxisPlaneConstraint::PLANE Type() is not meaningful for rotational constraints and will be ignored.

Definition at line 101 of file constraint.cpp.

void AxisPlaneConstraint::setTranslationConstraint	(	Type	type,
		const Vec &	direction
	)

Simply calls setTranslationConstraintType() and setTranslationConstraintDirection().

Definition at line 45 of file constraint.cpp.

void AxisPlaneConstraint::setTranslationConstraintDirection ( const Vec & direction )

Defines the translationConstraintDirection(). The coordinate system where direction is expressed depends on your class implementation.

Definition at line 52 of file constraint.cpp.

void qglviewer::AxisPlaneConstraint::setTranslationConstraintType ( Type type ) [inline]

Sets the Type() of the translationConstraintType(). Default is AxisPlaneConstraint::FREE.

Definition at line 216 of file constraint.h.

Vec qglviewer::AxisPlaneConstraint::translationConstraintDirection ( ) const [inline]

Returns the direction used by the translation constraint.

It represents the axis direction (AxisPlaneConstraint::AXIS) or the plane normal (AxisPlaneConstraint::PLANE) depending on the translationConstraintType(). It is undefined for AxisPlaneConstraint::FREE or AxisPlaneConstraint::FORBIDDEN.

The AxisPlaneConstraint derived classes express this direction in different coordinate system (camera for CameraConstraint, local for LocalConstraint, and world for WorldConstraint). This value can be modified with setTranslationConstraintDirection().

Definition at line 238 of file constraint.h.

Type qglviewer::AxisPlaneConstraint::translationConstraintType ( ) const [inline]

Returns the translation constraint Type().

Depending on this value, the Frame will freely translate (AxisPlaneConstraint::FREE), will only be able to translate along an axis direction (AxisPlaneConstraint::AXIS), will be forced to stay into a plane (AxisPlaneConstraint::PLANE) or will not able to translate at all (AxisPlaneConstraint::FORBIDDEN).

Use Frame::setPosition() to define the position of the constrained Frame before it gets constrained.

Definition at line 228 of file constraint.h.