[Visualpython-users] Major Problems with Latest Windows Release of VPython

This is a BUG REPORT. I found these bugs running the Windows 2000 Pro OS.
Please be patient as you read on.
 
I was trying to get rid of some bugs in a new piece of code I am writing,
which relies heavily on VPython. It was maturing nicely, but I was running
into some problems with the scene.exit = 0 attributes of display (see here
http://vpython.org/webdoc/visual/display.html
<http://vpython.org/webdoc/visual/display.html> ), so I decided to try and
upgrade my VPython, and things stopped working altogether, introducing
problems that I have never experienced before. Thinking the problem might be
with me, I went back to some of my simplest applications and the demo
programs and still noted problems. One of these aspects can be represented
with the following small program modified from the cross product.py demo
program below. If you run this code, it should produce a grid for the plane
that illustrates the visual cross product, but it does not. Please read
further below this small program.
 
________________________ Test Program 1 - Modification of the
CrossProduct.py Demo________________________
from visual import *
# demonstration of vector cross product
 
print """
Vector cross product: Red cross Green = Yellow
Drag to change green vector
Click to toggle fixed angle or fixed length
"""
 
scene.title="Vector Cross Product"
scene.width=600
scene.height=600
R = 0.15*4
plane = curve(pos=[(0, -10, -10), (0, -10, 10), (0, 10,10), (0, 10, -10),
              (0, -10, -10), (0,-6,-10), (0,-6,10), (0, -2, 10), (0, -2,
-10),
              (0,2,-10), (0,2,10), (0,6,10), (0,6,-10),(0,10, -10),

              (0,10,-6), (0,-10,-6), (0,-10,-2), (0,10,-2), (0,10,2),
              (0,-10,2), (0,-10,6), (0,10,6)])
___________________________________End of Test Program
1__________________________________________
 
So, I performed some other tests. This next small program is a slight
modification of the graphtest.py demo. Try running it. Note that no axes are
drawn and that you get an error. If you raise the value of -70 to say about
-50, or lower the 70 to something lower, the errors will go away, but you
still get a problem with no axes being drawn. In fact, with regard to the
axes problem, even the simplest program where you try to use the curve
object will not draw a curve on the screen in 3D.

_________________________________ Modification of graphtest.py demo
__________________________________
from visual.graph import *
 
# Using a graph-plotting module
oscillation = gdisplay(xtitle='t', ytitle='Response')
 
list = []
for t in arange(-70, 70, 1):
    pos=(t, 5.0*cos(-0.2*t)) # )
    list.append(pos)
 
funct1 = gcurve(pos = list, color=color.cyan)
 
________________________________ End of Test Program 2
_____________________________________________
 
Finally, I tried a simple test with the last feature I was struggling with.
First, if I try to run the faces_heightfield.py demo, it will generate an
error and not draw anything. Second, when I run the faces_cone.py, I do not
get a cone. I get a cube, and the following message...
 

Traceback (innermost last)
  File "c:\python22\lib\site-packages\visual\demos\faces_cone.py", line 13,
in ?
    model = faces( pos = zeros( (N*3,3), Float ), frame = f )
TypeError: Array can not be safely cast to required type

Third, if I try to run the most simple face possible, a triangle, I get
nothing drawn at all. Try the program below...
 
________________________________ Simple program to draw a Triangle Face
_____________________________________
from visual import *
 
f = frame()
#scene.background = color.black
VertexList = [(0,0,0),(1,0,0),(1,0,0)]
NormalList = [(0,0,1),(1,0,1),(1,0,1)]
 
surface = faces(pos=VertexList, normal=NormalList, color=color.red)
_________________________________ End of Test Program 3
____________________________________________________
 
I think a download of the previous version of Visual should be made
available until these problems can be fixed.
 
Thom

 
 
 
 
  _____  

 
<http://www.hp.com/Redirect/gw/useng_welcome/logo/=http://welcome.hp.com/cou
ntry/us/eng/welcome.htm> HP logo	 
Thom Ives, Ph.D.

R&D Engineering Scientist	

11413 Chinden Blvd MS 400
Boise, ID.  83714

208.396.6880 Phone
208.396.3587 Fax
tho...@hp...  <mailto:tho...@hp...> 

Home:
5556 N Columbine Pl
Boise, ID 83713
208.412.3971 Phone
413.332.6558 Fax
tw...@ca... <mailto:tw...@ca...> 
  _____