visualpython-users

[Visualpython-users] New beta version for Python 2.2

[Bruce S. <ba...@an...>]

At http://cil.andrew.cmu.edu/projects/visual is a new beta version of 
VPython for Python 2.2 on Windows. This fixes a bug with the expression 
vector(1,2,3)/2 in the case of invoking "true division" through "from 
__future__ import division".

Bruce Sherwood

[Visualpython-users] whrandom

[Bruce S. <ba...@an...>]

I see in the Python 2.2 documentation the following:

	Deprecated since release 2.1. Use random instead.

Another reason to remove the import of whrandom from Visual.

Bruce Sherwood

Re: [Visualpython-users] Conflict with random

[Bruce S. <ba...@an...>]

It's not exactly an interaction between Visual and Numpy but rather between 
the random function imported through RandomArray and a random function 
imported from whrandom by Visual. I guess the rule is "the last import 
wins" in determining the meaning of a name. If you import RandomArray last, 
it overrules the whrandom definition.

Here is what is imported by Visual (see PythonNN/visual/__init__.py):

from math import *
from Numeric import *
from whrandom import random, randint, uniform
import copy_reg

Note that Visual itself imports Numeric. Visual also imports math, because 
a major use of VPython is by novice programmers doing scientific 
computation and visualization, and it is important that for example "sqrt" 
and "cos" are present without having to invoke them specially.

Frankly, I don't see a good excuse for Visual to import from whrandom. 
Perhaps that's just historical having to do with early testing (Dave 
Scherer, can you comment?). It would probably be clearer to remove that 
import. What do others think?

Bruce Sherwood

--On Monday, November 19, 2001 7:01 PM +0100 Nils Wagner 
<nw...@me...> wrote:

> Hi,
>
> It seems to me that there is a conflict between Vpython and Numpy.
>
> To make this clear check the following example
>
> from Numeric import *
> from visual import *
> from RandomArray import *
> # from visual import *    # conflict with Numpy
> print random((2,3))
>
> Visual-2001-09-24
> [[ 0.82224834  0.79405266  0.1088888 ]
>  [ 0.36729395  0.4097493   0.35424358]]
>
> but if one activates the line just before print random
>
> Visual-2001-09-24
> Traceback (most recent call last):
>   File "random.py", line 5, in ?
>     print random((2,3))
> TypeError: random() takes exactly 1 argument (2 given)
>
>
> Any suggestion ?
>
> Nils

[Visualpython-users] Conflict with random

[Nils W. <nw...@me...>]

Hi,

It seems to me that there is a conflict between Vpython and Numpy.

To make this clear check the following example

from Numeric import *
from visual import *
from RandomArray import *
# from visual import *    # conflict with Numpy
print random((2,3))

Visual-2001-09-24
[[ 0.82224834  0.79405266  0.1088888 ]
 [ 0.36729395  0.4097493   0.35424358]]

but if one activates the line just before print random

Visual-2001-09-24
Traceback (most recent call last):
  File "random.py", line 5, in ?
    print random((2,3))
TypeError: random() takes exactly 1 argument (2 given)


Any suggestion ?

Nils

[Visualpython-users] New features in Python 2.2

[Bruce S. <ba...@an...>]

I should mention that there are some interesting new features in Python 
2.2, and you can read about them at http://www.python.org. Of particular 
interest to those of us doing scientific computations is the following 
example:

from __future__ import division   # two underscores before and after 
"future"
print 3/2

The result is 1.5, whereas without the "from" statement the result is 1.

The intent is that with Python 3.0, some time in the future, this behavior 
of division will be standard, but you can import this behavior "from the 
future" right now. Also as of Python 2.2 if you want the old "integer 
division" behavior you can us two slashes: 3//2 gives 1. People are 
encouraged slowly to change to the new syntax. There will be a warning 
mechanism you can invoke that will tell you of any existing integer 
division cases, so you can decide whether to replace "/" with "//".

This change to Python was prompted in part by observations that novice 
programmers often make the mistake of writing 3/2 when they thought they 
would get the behavior of 3.0/2.0. This was one of the few significant 
problems our own physics students have had with Python syntax, and it's 
often hard to track down the source of the problem when a program 
malfunctions due to this. Frankly, it's a mistake that experienced 
programmers also make sometimes when doing scientific computations.

Bruce Sherwood

[Visualpython-users] VPython 2.2 beta

[Bruce S. <ba...@an...>]

At http://cil.andrew.cmu.edu/projects/visual you can download the second 
beta version of Python 2.2 for Windows (2.2b2, also available at 
http://www.python.org) and a special test version of VPython for Python 
2.2. This test version of VPython has the new zoom convention set 
(scene.newzoom = 1), as will be the case for the regular version of VPython 
starting in mid-December, which is also the time frame for the release of 
the final version of Python 2.2. Zooming is done by depressing both left 
and right buttons on a Windows mouse. The new setting of newzoom has not 
been checked into CVS.

If you are just a bit adventuresome, we encourage you to try this out and 
report any problems. It is not necessary to uninstall the Python 2.1 
version. However, the desktop icon "IDLE for VPython" will be overwritten 
with one that points to the 2.2 version.

One thing to look for is that we think there may be a mouse problem over 
multiple runs, as though mouse status isn't being reset properly at the 
start of each run. A symptom could be for example that on a second run, 
moving the mouse with buttons up rotates the camera! We'd be grateful if 
someone could find and report a reproducible case of this to make it easier 
to test and fix.

Bruce Sherwood

[Visualpython-users] New VPython for Windows

[Bruce S. <ba...@an...>]

There is a new VPython for Windows at 
http://cil.andrew.cmu.edu/projects/visual. All you need to update is the 
new DLL.

This fixes a bug that could create an empty graphics window under certain 
conditions. It was due to a typo in the cvisual file display.cpp and was 
introduced by me on Oct. 31 with the new mouse-handling machinery.

Bruce Sherwood

Re: [Visualpython-users] [Q] Running VPython on IBM ThinkPad (fwd)

[William C. <wc...@an...>]

   In my experience, I have had trouble  S3's Savage 3's and Virges doing 
OpenGL rendering. Though this is a SavageMX, it may be based off of the 
same chipset as one of those two (I've never personally worked with one). 
As professor Sherwood said, I had to bypass hardware and go straight to 
software rendering. D3D never had any problems as far as I could tell, but 
OpenGL was always spotty.
   Also, though this may be a bit of an obvious answer, try checking out 
some alternate drivers (a la driverguide.com, windrivers.com, etc) and 
seeing if there are any drivers for your card there -- if others have had 
the same problem with OpenGL, there may be some patches or fixes.

-- Will Chase
(may some part of this help or inspire!)

--On Thursday, November 15, 2001 10:02 AM -0500 Bruce Sherwood 
<ba...@an...> wrote:

> Does anyone see anything in this diagnostic that might explain the
> problems Lee is having trying to run VPython on a ThinkPad? (The only
> thing I see that is worrisome is the S3 hardware, which as far as I know
> is not very mainstream in terms of modern graphics; I don't know why IBM
> uses this graphics card.)
>
> There is another thing to try, if it is an option. Go to the video
> card/driver controls and turn off graphics acceleration, thereby
> bypassing the graphics card hardware. See whether things then work.
>
> Bruce Sherwood
>
> ---------- Forwarded Message ----------
> Date: Wednesday, November 14, 2001 10:42 PM -0600
> From: Young-Jin Lee <yl...@ui...>
> To: Bruce Sherwood <ba...@an...>
> Subject: Re: [Visualpython-users] [Q] Running VPython on IBM ThinkPad
>
>> My ThinkPad video driver is the latest one available in the IBM web site.
>> Here is the glinfo.py test result.
>> Visual-2001-11-08
>>   d:\program files\python21\dlls\cvisual.dll Thu Nov 08 14:27:12 2001
>>   d:\program files\python21\visual\__init__.py Thu Nov 08 14:21:58 2001
>>   d:\program files\python21\visual\graph.py Wed Aug 29 15:57:16 2001
>>   d:\winnt\system32\opengl32.dll Fri May 04 13:05:02 2001
>> OpenGL renderer active.
>>   Vendor: S3 Graphics, Incorporated
>>   Version: 1.1 2.10.44
>>   Renderer: SavageMX
>>   Extensions:
>>              GL_ARB_texture_compression
>>         GL_EXT_texture_compression_s3tc
>>                             GL_EXT_abgr
>>                             GL_EXT_bgra
>>                 GL_EXT_clip_volume_hint
>>            GL_EXT_compiled_vertex_array
>>                        GL_EXT_fog_coord
>>                    GL_EXT_packed_pixels
>>                 GL_EXT_point_parameters
>>                 GL_EXT_paletted_texture
>>           GL_EXT_shared_texture_palette
>>                 GL_EXT_texture_lod_bias
>>                     GL_EXT_vertex_array
>>                    GL_KTX_buffer_region
>>                              GL_S3_s3tc
>>                        GL_WIN_swap_hint
>>
>> It seems to me that my video driver support OpenGL. I don't know why it
>> does not support VPython.
>> I hope to solve this problem. Thanks.
>>
>> I checked the IBM web site. IBM web site says that the video driver
>> installed on my laptop supports improved OpenGL ICD driver performance. I
>> have no application requiring OpenGL, but I think I can assume my laptop
>> can run an OpenGL based application.
>
> ---------- End Forwarded Message ----------
>
>
>
> _______________________________________________
> Visualpython-users mailing list
> Vis...@li...
> https://lists.sourceforge.net/lists/listinfo/visualpython-users

Re: [Visualpython-users] [Q] Running VPython on IBM ThinkPad (fwd)

[Bruce S. <ba...@an...>]

Does anyone see anything in this diagnostic that might explain the problems 
Lee is having trying to run VPython on a ThinkPad? (The only thing I see 
that is worrisome is the S3 hardware, which as far as I know is not very 
mainstream in terms of modern graphics; I don't know why IBM uses this 
graphics card.)

There is another thing to try, if it is an option. Go to the video 
card/driver controls and turn off graphics acceleration, thereby bypassing 
the graphics card hardware. See whether things then work.

Bruce Sherwood

---------- Forwarded Message ----------
Date: Wednesday, November 14, 2001 10:42 PM -0600
From: Young-Jin Lee <yl...@ui...>
To: Bruce Sherwood <ba...@an...>
Subject: Re: [Visualpython-users] [Q] Running VPython on IBM ThinkPad

> My ThinkPad video driver is the latest one available in the IBM web site.
> Here is the glinfo.py test result.
> Visual-2001-11-08
>   d:\program files\python21\dlls\cvisual.dll Thu Nov 08 14:27:12 2001
>   d:\program files\python21\visual\__init__.py Thu Nov 08 14:21:58 2001
>   d:\program files\python21\visual\graph.py Wed Aug 29 15:57:16 2001
>   d:\winnt\system32\opengl32.dll Fri May 04 13:05:02 2001
> OpenGL renderer active.
>   Vendor: S3 Graphics, Incorporated
>   Version: 1.1 2.10.44
>   Renderer: SavageMX
>   Extensions:
>              GL_ARB_texture_compression
>         GL_EXT_texture_compression_s3tc
>                             GL_EXT_abgr
>                             GL_EXT_bgra
>                 GL_EXT_clip_volume_hint
>            GL_EXT_compiled_vertex_array
>                        GL_EXT_fog_coord
>                    GL_EXT_packed_pixels
>                 GL_EXT_point_parameters
>                 GL_EXT_paletted_texture
>           GL_EXT_shared_texture_palette
>                 GL_EXT_texture_lod_bias
>                     GL_EXT_vertex_array
>                    GL_KTX_buffer_region
>                              GL_S3_s3tc
>                        GL_WIN_swap_hint
>
> It seems to me that my video driver support OpenGL. I don't know why it
> does not support VPython.
> I hope to solve this problem. Thanks.
>
> I checked the IBM web site. IBM web site says that the video driver
> installed on my laptop supports improved OpenGL ICD driver performance. I
> have no application requiring OpenGL, but I think I can assume my laptop
> can run an OpenGL based application.

---------- End Forwarded Message ----------

Re: [Visualpython-users] [Q] Running VPython on IBM ThinkPad

[Bruce S. <ba...@an...>]

My first guess is a problem with the video driver, since you are getting 
something to happen. If I remember correctly, the IBM ThinkPad has a rather 
incompetent graphics card, and so might not do a decent job of supporting 
OpenGL; it would be interesting to know whether anyone has had success 
running VPython or other OpenGL applications on a ThinkPad. You could try 
going to the web page for ThinkPad and downloading the latest video driver.

It might also be useful to run the demo program glinfo.py and report its 
output.

Bruce Sherwood

--On Wednesday, November 14, 2001 21:47 -0600 Young-Jin Lee 
<yl...@ui...> wrote:

> Hi, I have problem running VPython on my IBM ThinkPad.
> When I ran VPython scripts, on my ThinkPad (T22 with Windows 2000
> professional), nothing came up in the scene window. I saw the print
> string, "Visual-2001-11-08" in the windows command tool, but VPython
> display remained black. But VPython seemed to draw something because when
> I move the cursor on top of VPython display, it blinked. Is this known
> problem? How can I run VPython on my laptop?
> Thanks in advance.

[Visualpython-users] [Q] Running VPython on IBM ThinkPad

[Young-Jin L. <yl...@ui...>]

Hi, I have problem running VPython on my IBM ThinkPad.
When I ran VPython scripts, on my ThinkPad (T22 with Windows 2000
professional), nothing came up in the scene window. I saw the print string,
"Visual-2001-11-08" in the windows command tool, but VPython display
remained black. But VPython seemed to draw something because when I move the
cursor on top of VPython display, it blinked. Is this known problem? How can
I run VPython on my laptop?
Thanks in advance.

YJ

[Visualpython-users] new stuff

[Bruce S. <ba...@an...>]

On the VPython web site:

In the visual folder, new visual/factorial.py to fix a bug in error 
reporting in the visual.factorial module.

New VPython for Windows incoroporating a fix by David Andersen to make 
setting scene.forward to scene.up give an error message (because OpenGL 
can't deal with this view of a scene).

Bruce Sherwood

Re: [Visualpython-users] GL issue

[David A. <dm...@an...>]

I've changed display, setattr to give an error if forward = up.

Checked in to CVS.

Re: [Visualpython-users] label behavior

[Gary S. <st...@nm...>]

> Recently I've had reasons to use the label object in various ways. I don't 
> know what the implementation issues might be, but it seems to me that a 
> label should be hidden from view when it is behind an object. The main 
> purpose of the label object is to place a label next to some other object, 
> such as a planet, and have it always readable because it continually faces 
> forward. But if the planet goes behind something, I find it very confusing 
> to see the label in front of the occluding object, as though it applied to 
> the object that is now in front.
> 
> Comments?

Seeing as comments were solicited ... ;-)

I presently use labels for instructions and as trial-markers in a research
setting. For my purposes, therefore, it's necessary to have the current
funcitonality (i.e., to always have labels appear on top of the scene). As
for which behavior is more appropriate generally, I won't guess. I might
suggest, however, that the label object have options with default behavior
(which default wouldn't matter to me). 

Just my $0.02.

Gary

--------------------------------------------------------------
Gary Strangman, PhD        |  Neural Systems Group
Office: 617-724-0662       |  Massachusetts General Hospital
Fax:    617-726-4078       |  13th Street, Bldg 149, Room 9103
st...@nm... |  Charlestown, MA  02129
http://www.nmr.mgh.harvard.edu/Neural_Systems_Group/gary/

[Visualpython-users] gyro.py

[Bruce S. <ba...@an...>]

On the VPython site is a new Demos-2001-11-10.zip containing an improved 
version of the program gyro.py. Also checked in to SourceForge CVS.

Bruce Sherwood

[Visualpython-users] label behavior

[Bruce S. <ba...@an...>]

Recently I've had reasons to use the label object in various ways. I don't 
know what the implementation issues might be, but it seems to me that a 
label should be hidden from view when it is behind an object. The main 
purpose of the label object is to place a label next to some other object, 
such as a planet, and have it always readable because it continually faces 
forward. But if the planet goes behind something, I find it very confusing 
to see the label in front of the occluding object, as though it applied to 
the object that is now in front.

Comments?

Bruce Sherwood

RE: [Visualpython-users] GL issue

[David S. <dsc...@vy...>]

> 	When the .forward scene vector is set to (0,1,0) or 
> (0,-1,0), OpenGL initialization either fails (I've had two 
> machines do this) or the scene window will just be blank. Is 
> this a bug that anyone else can replicate?

More specifically, this happens when scene.forward == scene.up.  The
orientation of the scene cannot be fully constrained by only one vector.
The basis calculation in Display::refreshCache() promptly degenerates:

  Vector Z = forward.norm();
  Vector X = Z.cross( up ).norm();

The ambiguity chould be resolved arbitrarily using code similar to that
in Primitive::refreshCache:

    Vector W = axis->cross(*up);
    if (!W) {
      // Resolve degenerate cases:
      W = axis->cross(Vector(1,0,0));
      if (!W) W = axis->cross(Vector(0,1,0));
    }
    W = W.norm();
    Vector H = W.cross( *axis ).norm();
    Vector L = axis->norm();

Alternatively, we could make it an error to set scene.forward==scene.up,
and enforce that in Display::setattr.

    } else if (attr == "forward") {
      if (Vector(value)==up)
        throw ValueError("display.forward may not be the same as
display.up");
      forward = Vector(value);

...

    } else if (attr=="up") {
      if (Vector(value)==forward)
        throw ValueError("display.up may not be the same as
display.forward");
      up = Vector(value);      

Dave

[Visualpython-users] GL issue

[Andrew P. W. <ap...@an...>]

Hello,

	When the .forward scene vector is set to (0,1,0) or (0,-1,0),
OpenGL initialization either fails (I've had two machines do this)
or the scene window will just be blank. Is this a bug that anyone else can
replicate?

	Thanks,
	-Andrew

Andrew Widdowson <an...@cm...>
http://www.andrew.cmu.edu/~apw2/
Freshman, School of Comp Sci '05

[Visualpython-users] menus

[Bruce S. <ba...@an...>]

Attached is controls.zip, yet another attempt at a way to provide controls 
for VPython programs. You need a recent version of VPython to be able to 
run this (2001-10-31 or later).

New:

Menus as well as buttons and sliders.
Controls go into a regular Visual window, though presumably one would often 
use a separate regular Visual window for controlling objects in a different 
window.

Bruce Sherwood

[Visualpython-users] bug fix

[Bruce S. <ba...@an...>]

On the VPython web site are new versions for Windows that fix a bug just 
discovered by one of our physics students: sphere.w was treated as though 
it meant sphere.x. (For those of you who know C or C++, the problem was a 
missing "break" in a case statement.)

	Ruth Chabay and Bruce Sherwood

Re: [Visualpython-users] [Q] Can VPython be imbedded into other Python application?

[Bruce S. <ba...@an...>]

Why not just try it? I doubt that anyone has done exactly what you're doing.

--On Thursday, November 08, 2001 12:54 -0600 Young-Jin Lee 
<yl...@ui...> wrote:

> Hi, I'd like to know if VPython can be imbedded into other Python
> application?
> I have a MDI application written in wxPython and I want to VPython as one
> of MDI child frame.
> Is it possible?
> Thanks.
>
> YJ

[Visualpython-users] [Q] Can VPython be imbedded into other Python application?

[Young-Jin L. <yl...@ui...>]

Hi, I'd like to know if VPython can be imbedded into other Python
application?
I have a MDI application written in wxPython and I want to VPython as one of
MDI child frame.
Is it possible?
Thanks.

YJ

[Visualpython-users] better controls

[Bruce S. <ba...@an...>]

Attached is Controls.zip, an improved version of the button and slider 
machinery I posted yesterday.

Two significant changes:

1) Instead of horizontal sliders and vertical sliders, there is just one 
kind of slider, and it can point in any direction, specified by "axis". The 
demo has a vertical slider and a slider at an angle.

2) Instead of a 100 by 100 coordinate system with (0,0) in the lower left 
corner, I reverted to standard Visual conventions. The origin is at the 
center of the screen, and you can use any units you like to set up buttons 
and sliders. For buttons, pos is at the center (like box) and for sliders 
pos is at one end (like cylinder).

Bruce

Re: [Visualpython-users] [Q] Closing a display window

[Bruce S. <ba...@an...>]

Maybe you want to set scene.exit = 0? From the windows section of the 
VPython reference manual:

"If sceneb.exit = 0, the program does not quit when the close box of the 
sceneb display is clicked. The default is sceneb.exit = 1, in which case 
clicking the close box does make the program quit."

If there is only one window at all times, but the contents change, you 
could make the old objects invisible and create new ones in the same window.

On a somewhat related issue, note that sceneb.visible = 0 makes the window 
invisible.

Bruce Sherwood

--On Monday, November 05, 2001 12:46 PM -0600 Young-Jin Lee 
<yl...@ui...> wrote:

> Is there any way just closing a display window?
> I don't want to quit the whole program (or VPython shell) when the
> closing icon is pressed. I want to repeatedly create a different display
> window in one application so that I need to be able to close the display
> window when the closing icon is clicked. I read through the display
> window control page of reference manual, but there is no information.

[Visualpython-users] [Q] Closing a display window

[Young-Jin L. <yl...@ui...>]

Is there any way just closing a display window?
I don't want to quit the whole program (or VPython shell) when the =
closing icon is pressed. I want to repeatedly create a different display =
window in one application so that I need to be able to close the display =
window when the closing icon is clicked. I read through the display =
window control page of reference manual, but there is no information.

Thanks in advance.

YJ