[SOLVED] Transforming a custom tracker's geometry (coin issue)

[Joel_graff]

I'm trying to sort out how to apply transformations to a custom wire tracker I'm creating. I can generate / regenerate the wire by supplying coordinates, but I cannot apply transforms...

The class I've created thus far:

Code: Select all

class DragTracker(Tracker):
    """
    Customized wire tracker
    """

    def __init__(self, points):
        """
        Constructor
        """

        self.line = coin.SoLineSet()
        self.line.numVertices.setValue(len(points))

        self.coords = coin.SoCoordinate3()

        self.transform = coin.SoTransform()

        self.update(points)

        Tracker.__init__(
            self, children=[self.coords, self.line, self.transform], name="DragTracker"
        )

        self.node = self.switch.getChild(0)
        self.draw_style = self.node.getChild(0)
        self.color = self.node.getChild(1)

        self.color.rgb = (0.0, 0.0, 0.0)

        self.on()

    def update(self, points):
        """
        Update
        """

        if not points:
            return

        self.line.numVertices.setValue(len(points))

        for _i, _pt in enumerate(points):
            self.coords.point.set1Value(_i, list(_pt))

    def set_placement(self, placement):
        """
        Transform the tracker by the passed placement
        """

        vec = placement.Base

        self.transform.translation.setValue(tuple(vec))

The idea is simply to call the tracker's set_placement() method and apply the base vector to the transform node of the tracker. Unfortunately, nothing happens...

[Joel_graff]

Solved by re-ordering the nodes that are added for the tracker. Specifically, transformation and coordinate nodes need to precede the geometry node which they define.

Thus:

Code: Select all

 Tracker.__init__(
            self, children=[self.coords, self.line, self.transform], name="DragTracker"
        )

becomes:

Code: Select all

 Tracker.__init__(
            self, children=[self.coords, self.transform, self.Line], name="DragTracker"
        )