Mouse Events Throwing AttributeError

[Russell Osterlund]

Hi!

I am a relative newbie in Python (but have decades experience programming in many languages). When I execute the following code (from the mouse-events tutorial) the code "works", but I see the following in the shell (v3.6.1) window:

Traceback (most recent call last):

  File "D:\Projects\Python\Examples\mouse_events.py", line 7, in <module>

    if scene.mouse.events:

AttributeError: 'Mouse' object has no attribute 'events'

Here is the code generating the error:

from vpython import *

scene.range = 5 # fixed size, no autoscaling

ball = sphere(pos=vector(-3,0,0), color=color.cyan)

cube = box(pos=vector(+3,0,0), size=vector(2,2,2), color=color.red)

pick = None # no object picked out of the scene yet

while True: 

    if scene.mouse.events: 

        m1 = scene.mouse.getevent() # get event

        if m1.drag and m1.pick == ball: # if touched ball

            drag_pos = m1.pickpos # where on the ball

            pick = m1.pick # pick now true (not None) 

        elif m1.drop: # released at end of drag

            pick = None # end dragging (None is false)

    if pick:

        # project onto xy plane, even if scene rotated:

        new_pos = scene.mouse.project(normal=vector(0,0,1)) 

        if new_pos != drag_pos: # if mouse has moved

            # offset for where the ball was clicked:

            pick.pos += new_pos - drag_pos 

            drag_pos = new_pos # update drag position

The behavior currently is unacceptable because when I migrate the relevant pieces to my own program, it halts because of this error. (I am trying to use the mouse or the keyboard to halt a continuously running program.) This from the VPython shell V3.6.1

Thanks in advance.

[Bruce Sherwood]

You're using Classic VPython (VPython 6) syntax in VPython 7, which won't work. See the documentation at glowscript.org (click Help).

[Russell Osterlund]

Hi again.

The sample code was copied directly from the following link (from the VPython 6 site):

http://vpython.org/contents/docs/mouse_drag.html

My Python environment is relatively clean (needed to "pip" VPython to get access to the library).  And I am trying to work without using "cloud-based" platforms. 

Are there any other options?

Thanks.

(PS - I have needed to modify another one of the tutorials - adding "vector" to some of the parameters.)

[Bruce Sherwood]

The link you give is for the documentation of Classic VPython (VPython 6). As I said, you are using the vpython module (VPython 7), so you need to use the documentation for VPython 7, which is available at glowscript.org by clicking Help.