Problem with LineSegs when clearModelNodes+flattenStrong

General Discussion
1

Hi,
I found what I think is a bug when adding a model and a LineSegs to a nodepath and using clearModelNodes and flattenStrong, both. If you do not use both or use just one of them, the result is good.
Here is the code to reproduce it:

from direct.showbase.ShowBase import ShowBase,LineSegs, PandaNode
from math import pi, sin, cos


class MyApp(ShowBase):
    def __init__(self):
        # Open Panda3D
        ShowBase.__init__(self)
        
        nodepath = self.render.attachNewNode("Nodepath")
         
        # camera model
        model = self.loader.loadModel("cone.bam")
        model.setScale(0.2, 0.2, 0.2)
        model.setColor(0,0,0,1)
        model.reparentTo(nodepath) 
        
        # Create Segs
        segs = LineSegs() 
        segs.setThickness(3.0) 
        segs.setColor(0.0,0.0,0.0,1.0)
        
        fov = 40
        fovr = fov * (pi / 180.0)
        
        ratio =  1.2

        xmin = 1
        xmax = 2 
        ymin = cos(fovr) * xmin * ratio
        ymax = cos(fovr) * xmax * ratio
        zmin = cos(fovr) * xmin
        zmax = cos(fovr) * xmax 

        # Lens min plane
        segs.moveTo(xmin, ymin,   -zmin)
        segs.drawTo(xmin, ymin,   zmin)
        segs.drawTo(xmax, ymax,   zmax)
        segs.moveTo(xmin, ymin,   zmin)
        segs.drawTo(xmin, -ymin,   zmin)
        segs.drawTo(xmax, -ymax,   zmax)
        segs.moveTo(xmin, -ymin,   zmin)
        segs.drawTo(xmin, -ymin,   -zmin)
        segs.drawTo(xmax, -ymax,   -zmax)
        segs.moveTo(xmin, -ymin,   -zmin)
        segs.drawTo(xmin, ymin,   -zmin)
        segs.drawTo(xmax, ymax,   -zmax)
        
        # Lens max plane
        segs.moveTo(xmax, ymax,   zmax)
        segs.drawTo(xmax, -ymax,   zmax)
        segs.drawTo(xmax, -ymax,   -zmax)
        segs.drawTo(xmax, ymax,   -zmax)
        segs.drawTo(xmax, ymax,   zmax)
        
        # Create segs
        gridnode = nodepath.attachNewNode(PandaNode("Lens"))
        gridnode.attachNewNode(segs.create())

        # Flatten Node
        nodepath.clearModelNodes()
        nodepath.flattenStrong()
       
        # Add the spinCameraTask procedure to the task manager.
        self.setFrameRateMeter(True)
        self.taskMgr.add(self.spinCameraTask, "SpinCameraTask")
 
    # Define a procedure to move the camera.
    def spinCameraTask(self, task):
        angleDegrees = task.time * 6.0
        angleRadians = angleDegrees * (pi / 180.0)
        self.camera.setPos(10 * sin(angleRadians), -10.0 * cos(angleRadians), 1)
        self.camera.setHpr(angleDegrees, 0, 0)
        return task.cont

if __name__ == '__main__':
    App = MyApp()
    App.run()
2

Could you attach cone.bam?

3

Yes!
cone.bam (3.01 KB)