NAME

       SbLineProjector -

       The SbLineProjector class projects 2D points to 3D points along a line.

       The 3D projection of the 2D coordinates is for this projector class constrained to lie
       along a pre-defined line.

SYNOPSIS

       #include <Inventor/projectors/SbLineProjector.h>

       Inherits SbProjector.

   Public Member Functions
       SbLineProjector (void)
       virtual SbProjector * copy (void) const
       virtual SbVec3f project (const SbVec2f &point)
       virtual SbBool tryProject (const SbVec2f &point, const float epsilon, SbVec3f &result)
       void setLine (const SbLine &line)
       const SbLine & getLine (void) const
       virtual SbVec3f getVector (const SbVec2f &viewpos1, const SbVec2f &viewpos2)
       virtual SbVec3f getVector (const SbVec2f &viewpos)
       void setStartPosition (const SbVec2f &viewpos)
       void setStartPosition (const SbVec3f &point)

   Protected Attributes
       SbLine line
       SbVec3f lastPoint

   Additional Inherited Members

Detailed Description

       The SbLineProjector class projects 2D points to 3D points along a line.

       The 3D projection of the 2D coordinates is for this projector class constrained to lie
       along a pre-defined line.

       Among other places, this is useful within the translation draggers, like for instance
       SoTranslate1Dragger, where we want to move 'pieces' along one or more axes.

Constructor & Destructor Documentation

   SbLineProjector::SbLineProjector (void)
       Constructor. Intializes the projector instance to use a line from <0, 0, 0> to <0, 1, 0>.

Member Function Documentation

   SbProjector * SbLineProjector::copy (void) const [virtual]
       Construct and return a copy of this projector. The caller is responsible for destructing
       the new instance.

       Note that if the Coin library has been built as a DLL under Microsoft Windows and you use
       this method from application code, you must make sure that both the Coin DLL and the
       application executable is using the same instance of a C Run-Time (CRT) library.
       Otherwise, you will get memory heap corruption upon deallocating the returned instances,
       eventually leading to mysterious crashes.

       Implements SbProjector.

   SbVec3f SbLineProjector::project (const SbVec2f &point) [virtual]
       Project the 2D point from normalized viewport coordinates to a 3D point. The mapping will
       be done in accordance with the type of the projector.

       Implements SbProjector.

   SbBool SbLineProjector::tryProject (const SbVec2f &point, const floatepsilon, SbVec3f &result)
       [virtual]
       Try projecting the 2D point from normalized viewport coordinates to a 3D point. The
       mapping will be done in accordance with the type of the projector.

       If the projection can't be done safely (for instance when the projection plane or line is
       parallel to the view volume projection), this function should return FALSE.

       Default implementation will call project() and always return TRUE, but subclasses can
       override this behavior to support safe projections.

       Since:
           Coin 3.0

       Reimplemented from SbProjector.

   void SbLineProjector::setLine (const SbLine &lineref)
       Set a new projection line. 3D points will be mapped to be on this line.

   const SbLine & SbLineProjector::getLine (void) const
       Returns the currently set projection line.

   SbVec3f SbLineProjector::getVector (const SbVec2f &viewpos1, const SbVec2f &viewpos2)
       [virtual]
       Calculates and returns a vector between the projected 3D position of viewpos1 and
       viewpos2.

   SbVec3f SbLineProjector::getVector (const SbVec2f &viewpos) [virtual]
       Returns the 3D vector between the last projection and the one calculated for viewpos.

   void SbLineProjector::setStartPosition (const SbVec2f &viewpos)
       Explicitly set position of initial projection, so we get correct values for later calls to
       getVector() etc.

   void SbLineProjector::setStartPosition (const SbVec3f &point)
       Explicitly set position of initial projection, so we get correct values for later calls to
       getVector() etc.

Member Data Documentation

   SbLineProjector::line [protected]
       The projection line. Projected 3D points will be constrained to be on this line.

   SbLineProjector::lastPoint [protected]
       The last projected point.

Author

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