Class SoGetMatrixAction


  • public class SoGetMatrixAction
    extends SoAction
    Computes transformation matrix for a subgraph. This action computes transformation matrices for a given subgraph. It computes the cumulative transformation matrix and its inverse, along with a cumulative texture transformation matrix and its inverse. The cumulative transformation matrix transforms the coordinates of a shape from the local object coordinate system to the global world coordinate system.

    When this action is applied to a node, it computes the matrix for just that node. This is currently the easiest way to get the transformation matrix for an SoTransform node. It's not very useful for most other types of nodes.

    The most common scenario is applying this action to a path. In that case it gathers the transformation info for all nodes in the path and those that affect nodes in the path, but it stops when it hits the last node in the path; it does not traverse downwards from it as most other actions (such as rendering) do. This behavior makes the most sense for this action. To get a path to, for example, a specific geometry in the scene graph see SoSearchAction.

    Sets: SoViewportRegionElement

    EXAMPLE

     // Get cumulative matrix using current viewport on screen
     SoPath somePath = ...
     SoGetMatrixAction gma = new SoGetMatrixAction( viewer.getArea().getViewportRegion() );
     gma.apply( somePath );
     SbMatrix matrix = gma.getMatrix();

    See Also:
    SoGetBoundingBoxAction, SoSearchAction
    • Constructor Detail

      • SoGetMatrixAction

        public SoGetMatrixAction​(SbViewportRegion newRegion)
        Constructor.
        Even though the bounding box computation may not involve a window per se, some nodes need the size of the viewport to determine their size in 3D coordinates. For example the size of an SoText2 is a fixed value in device coordinates, but the corresponding size in 3D depends on the current camera.

        Usually it is convenient to get the actual viewport region from the viewer as shown in the example above. However if the scene graph does not contain any viewport dependent nodes then any values can be used.

    • Method Detail

      • getInverse

        public SbMatrix getInverse()
        Returns the inverse of the cumulative transformation matrix. Warning: the matrix returned by this routine should not be changed (unless you are implementing your own transformation nodes).
      • getTextureInverse

        public SbMatrix getTextureInverse()
        Returns the inverse of the cumulative texture transformation matrix. Warning: the matrix returned by this routine should not be changed (unless you are implementing your own transformation nodes).
      • getMatrix

        public SbMatrix getMatrix()
        Returns cumulative transformation matrix. Warning: the matrix returned by this routine should not be changed (unless you are implementing your own transformation nodes).
      • getTextureMatrix

        public SbMatrix getTextureMatrix()
        Returns cumulative texture transformation matrix. Warning: the matrix returned by this routine should not be changed (unless you are implementing your own transformation nodes).
      • enableElement

        public static void enableElement​(java.lang.Class<? extends Inventor> t,
                                         int stkIndex)
      • setViewportRegion

        public void setViewportRegion​(SbViewportRegion newRegion)
        Sets current viewport region to use for action.
      • getViewportRegion

        public SbViewportRegion getViewportRegion()
        Returns current viewport region to use for action.