visualpython-users

[Visualpython-users] Re: Visualpython-users digest, Vol 1 #736 - 2 msgs

[John B. <jb...@te...>]

----- Original Message -----
> From: Flavio Coelho <fcc...@gm...>
> Hi ,
> I have a PyQT gui that starts a vpython display as part of its functions.
> However, when I close the vpython display it terminates the PyQT as well.
I=
> there a way to avoid this when exiting vpython?

To which J.B. answers:

> From: Jonathan Brandmeyer <jbr...@ea...>
> If you set scene.exit = False, this behavior is supposed to be
> suppressed.
>
> Unfortunately, there is a bug present that keeps this feature from
> working as it should.  It should be fixed soon.

Please advise if this is the same as what I'm experiencing?
I open the Shell, grab a script, run it.  It gives me a stereo (crosseyed)
window and starts showing me my program output (it packs balls; I get to
watch).
When I want to change the conditions, I _used_to_ close the window, make any
changes I want in the script, then run it again.
Now, though, when I close the stereo window, it closes everything and I have
to reload Shell and script in order to run it again.
Is this the _same_ bug as above noted?

Thanks!
(Crosseyed is working *magnificently*, for which implementation I at least
will be forever grateful.
Once I got P2.4 and VP2.4 working on this new machine (AMD Athlon64 3400+;
512MB), everything has been working just as magnificently except for this
above mentioned irritant.)

Peace
JB
Xj...@te...
( REMOVE the 'X' before using ! )
NOTE: due to virus explosion, currently deleting ALL messages over 140kb
from the server without downloading.
http://tetrahedraverse.com

Re: [Visualpython-users] gracefully exiting vpython display

[Jonathan B. <jbr...@ea...>]

On Fri, 2005-10-28 at 10:11 -0200, Flavio Coelho wrote:
> Hi ,
> I have a PyQT gui that starts a vpython display as part of its
> functions. However, when I close the vpython display it terminates the
> PyQT as well. Is there a way to avoid this when exiting vpython?

If you set scene.exit = False, this behavior is supposed to be
suppressed.

Unfortunately, there is a bug present that keeps this feature from
working as it should.  It should be fixed soon.

-Jonathan Brandmeyer

[Visualpython-users] gracefully exiting vpython display

[Flavio C. <fcc...@gm...>]

Hi ,
I have a PyQT gui that starts a vpython display as part of its functions.
However, when I close the vpython display it terminates the PyQT as well. I=
s
there a way to avoid this when exiting vpython?



--
Fl=E1vio Code=E7o Coelho
registered Linux user # 386432
---------------------------
Great spirits have always found violent opposition from mediocrities. The
latter cannot understand it when a man does not thoughtlessly submit to
hereditary prejudices but honestly and courageously uses his intelligence.
Albert Einstein

[Visualpython-users] [Fwd: a debugger for vpython]

[Bruce S. <Bru...@nc...>]

This may be of interest. (Of course, we no longer specially "bundle" 
IDLE but just use what comes with Python.)

-------- Original Message --------
Subject: a debugger for vpython
Date: Sat, 22 Oct 2005 10:05:08 +0200
From: Nir Aides <ni...@di...>
To: bas...@un...

Hi,

I just saw you project vpython, since I am using python for doing some
video animations.
I noticed you bundle Idle in your package and thought you might want to
take a look at Winpdb which is a debugger I recently wrote.
http://www.digitalpeers.com/pythondebugger

Winpdb is much more powerful and usable than the IDLE debugger or PDB,
and I figure your users will benefit from learning about its existence.

Nir

Re: [Visualpython-users] Aqua port - stumped by autoconf

[Jonathan B. <jbr...@ea...>]

On Wed, 2005-10-19 at 21:06 -0700, Dethe Elza wrote:
> On 19-Oct-05, at 4:57 PM, Jonathan Brandmeyer wrote:
> >
> > Are you (or anyone else out there) familiar with Scons?
> 
> What is wrong with using distutils[1], the standard method for  
> building Python extensions?  The new Setuptools[2] package makes it  
> even easier, and supports EasyInstall[3] and Python Eggs[4].
> 
> [1] http://docs.python.org/lib/module-distutils.html
> [2] http://peak.telecommunity.com/DevCenter/setuptools
> [3] http://peak.telecommunity.com/DevCenter/EasyInstall
> [4] http://peak.telecommunity.com/DevCenter/PythonEggs

But it doesn't properly support C++, or the use of a compiler other than
the one that built Python itself.  Those features are absolutely
required for VPython.

-Jonathan

Re: [Visualpython-users] Aqua port - stumped by autoconf

[Bruce S. <Bru...@nc...>]

Isn't it the case that to use distutils with modules written in C or C++ 
(such as Visual) there must be a compiler present on the machine? That's 
why we can't use distutils on Windows for example, and for that matter 
isn't it the case that on a Mac there isn't a compiler present if you 
don't install it?

As to why VPython is so difficult to install (especially on the Mac), 
the problems are basically due to not having a component that creates 
native windows and handles native events, so we've had to get by with 
using the Unix/Linux component, which throws even the naive user into 
the scary environments of X11 and fink. I personally have observed that 
the installers on the 10.4 DVD for X11 or Xtools (not sure which it was) 
don't necessarily actually work the first time, and just running the 
installer fixes a problem! And then there's the problem that going from 
10.3 to 10.4 invalidates everything, which is an amazing feature of an 
operating system.

Bottom line, we're all grateful that you're attempting to break through 
to a native-mode version for the Mac, which ought to be vastly easier to 
install.

Bruce Sherwood

Dethe Elza wrote:

>
>
> What is wrong with using distutils[1], the standard method for  
> building Python extensions?  The new Setuptools[2] package makes it  
> even easier, and supports EasyInstall[3] and Python Eggs[4].
>
> [1] http://docs.python.org/lib/module-distutils.html
> [2] http://peak.telecommunity.com/DevCenter/setuptools
> [3] http://peak.telecommunity.com/DevCenter/EasyInstall
> [4] http://peak.telecommunity.com/DevCenter/PythonEggs
>
> I install a lot of programs, and there are three four common methods  
> I encounter:  Untar the app and drag it to /Applications (standard  
> Mac install), untar the installer and run it (for Mac apps which  
> require more than just the Application bundle), type "./ 
> configure;make;sudo make install" at the command line (apps ported  
> from Linux or BSD), and "python setup.py install" (nearly all python  
> extensions and libraries).  I understand that VPython is doing a lot,  
> but why it is so much more complicated than installing PyGame, for  
> instance, is beyond me.
>

Re: [Visualpython-users] Aqua port - stumped by autoconf

[Dethe E. <de...@li...>]

On 19-Oct-05, at 4:57 PM, Jonathan Brandmeyer wrote:
>
> Are you (or anyone else out there) familiar with Scons?

What is wrong with using distutils[1], the standard method for  
building Python extensions?  The new Setuptools[2] package makes it  
even easier, and supports EasyInstall[3] and Python Eggs[4].

[1] http://docs.python.org/lib/module-distutils.html
[2] http://peak.telecommunity.com/DevCenter/setuptools
[3] http://peak.telecommunity.com/DevCenter/EasyInstall
[4] http://peak.telecommunity.com/DevCenter/PythonEggs

I install a lot of programs, and there are three four common methods  
I encounter:  Untar the app and drag it to /Applications (standard  
Mac install), untar the installer and run it (for Mac apps which  
require more than just the Application bundle), type "./ 
configure;make;sudo make install" at the command line (apps ported  
from Linux or BSD), and "python setup.py install" (nearly all python  
extensions and libraries).  I understand that VPython is doing a lot,  
but why it is so much more complicated than installing PyGame, for  
instance, is beyond me.

> I've been considering using it as a replacement for the autotools in
> VPython's source tree.  The last time that I checked, Scons had very
> weak support for actually installing packages, which is why I haven't
> used it for anything other than projects that I haven't actually
> distributed.  On the other hand, the SConstruct build file is very  
> easy
> to read and change.

Easy to read and change would be a plus.  If I could read the  
autoconf file, I could help port it to distutils.  If you're  
interested in moving to distutils, and are willing to explain the  
dependencies to me, I'd be happy to help.  I'd much rather learn more  
about distutils (I've dabbled, but not delved deep yet) than another  
configuration/installation tool which I will only use for this one  
project.

--Dethe

PowerPoint can make almost anything appear good and look  
professional. Quite frankly, I find that a little bit frightening.
  --David Byrne

Re: [Visualpython-users] Aqua port - stumped by autoconf

[Jonathan B. <jbr...@ea...>]

On Wed, 2005-10-19 at 10:49 -0700, Dethe Elza wrote:
>   I think it's do-able, if I can  
> just get through the rather Byzantine configuation.

Are you (or anyone else out there) familiar with Scons?

I've been considering using it as a replacement for the autotools in
VPython's source tree.  The last time that I checked, Scons had very
weak support for actually installing packages, which is why I haven't
used it for anything other than projects that I haven't actually
distributed.  On the other hand, the SConstruct build file is very easy
to read and change.

Can any of the third-party packagers comment on their experience with
redistributing scons-built packages?

Thanks,
-Jonathan Brandmeyer

Re: [Visualpython-users] Aqua port - stumped by autoconf

[Jonathan B. <jbr...@ea...>]

On Wed, 2005-10-19 at 10:49 -0700, Dethe Elza wrote:
> Hi Jonathan,
> 
> Thanks!  That got me one step further.  Now it is looking for  
> install.sh, which I don't see in the CVS tree.  Where do I find this?

My set of the autotools doesn't look for an install.sh, just install-sh.
That file is symlinked in by automake
from /usr/share/automake-1.9/install-sh on my Debian box.

> I'm sure it would be easier if I installed Fink, but part of the  
> justification for this whole exercise is that I don't want to a)  
> install Fink, or b) run X, just for this one application.  Everything  
> else I use works just fine without Fink or X, so I'd like to use  
> VPython the same way, if possible.

Note that there is a difference between needing Fink to build the
configure scripts, and needing it to actually build or run VPython.
Rebuilding the configure scripts is something that only a developer will
do, and even then only rarely.

I suspect that after you change configure.ac to separately test for
*-apple-darwin* and pull in the OSX-specific files, you won't have to
rebuild the configure scripts again.

>   I think it's do-able, if I can  
> just get through the rather Byzantine configuation.

-Jonathan

Re: [Visualpython-users] Aqua port - stumped by autoconf

[Dethe E. <de...@li...>]

Hi Jonathan,

Thanks!  That got me one step further.  Now it is looking for  
install.sh, which I don't see in the CVS tree.  Where do I find this?

I'm sure it would be easier if I installed Fink, but part of the  
justification for this whole exercise is that I don't want to a)  
install Fink, or b) run X, just for this one application.  Everything  
else I use works just fine without Fink or X, so I'd like to use  
VPython the same way, if possible.  I think it's do-able, if I can  
just get through the rather Byzantine configuation.

Thanks again.

--Dethe

On 19-Oct-05, at 5:17 AM, Jonathan Brandmeyer wrote:

> On Tue, 2005-10-18 at 22:47 -0700, Dethe Elza wrote:
>
>> Hi folks,
>>
>> I've finally gotten some time to look at porting VPython to OS X
>> Aqua.
>>
>
> Excellent!
>
>
>>   I've got Boost.python installed, and stubbed in the platmac.[h|
>> cpp], and the osxgl.[h|cpp], but I'm having no luck getting a working
>> configure file to compile it.  When I run autoconf I get a configure
>> file, but running aclocal tells me:
>>
>> aclocal: macro `AM_PATH_GTK' required but not defined
>>
>> But GTK shouldn't be required, so how do I turn that off?
>>
>
> Generating the configure script is much more difficult than actually
> running it, since it is designed to determine settings on every  
> platform
> that Visual can run on.  Therefore, you actually do need GTK installed
> (or at least its .m4 files).
>
> I face a similar problem when rebuilding configure using MinGW on
> Windows.  To work around it, I have a copy of gtk.m4 and pkg.m4 in
> VPython's CVS.  Look under vpython/share/aclocal.  Copy those files to
> $prefix/share/aclocal.  You will probably have an easier time getting
> autoconf, automake, and libtool to work if you use the packages in  
> Fink.
> In that case, you will want to copy the .m4 files
> into /sw/share/aclocal, but only if they are not already included in
> Fink's GTK 1.2 development package.
>
>
>>   I can
>> delete the offending line from acinclude.m4, but that still leaves me
>> with my next problem, which is that when I run the resulting
>> configure script it complains that in the line:
>>
>> AM_INIT_AUTOMAKE( visual, 3.2.3)
>>
>
> What is the current version of automake and autoconf on your system?
>
>
>> that the symbol "visual" is unknown.
>>
>> I'm not an avid user of autoconf or even configure, and after poking
>> around in it for a day or so, I'm not any more enlightened. Can
>> anyone tell me what I'm doing that's stupid and hosing the build?
>>
>
> I've given a few guesses above, but also see the file autogen.sh in  
> the
> top-level of VPython's source tree (maybe only in CVS).  It is what I
> use to sequence the operation of the autotools when building the
> configure scripts themselves.
>
> -Jonathan
>
>
>
> -------------------------------------------------------
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There are two ways of constructing a software design.  One way is to  
make it so simple there are obviously no deficiencies and the other  
way is to make it so complicated that there are no obvious  
deficiencies.  --C.A.R. Hoare

Re: [Visualpython-users] Aqua port - stumped by autoconf

[Jonathan B. <jbr...@ea...>]

On Tue, 2005-10-18 at 22:47 -0700, Dethe Elza wrote:
> Hi folks,
> 
> I've finally gotten some time to look at porting VPython to OS X  
> Aqua.

Excellent!

>   I've got Boost.python installed, and stubbed in the platmac.[h| 
> cpp], and the osxgl.[h|cpp], but I'm having no luck getting a working  
> configure file to compile it.  When I run autoconf I get a configure  
> file, but running aclocal tells me:
> 
> aclocal: macro `AM_PATH_GTK' required but not defined
> 
> But GTK shouldn't be required, so how do I turn that off?

Generating the configure script is much more difficult than actually
running it, since it is designed to determine settings on every platform
that Visual can run on.  Therefore, you actually do need GTK installed
(or at least its .m4 files).

I face a similar problem when rebuilding configure using MinGW on
Windows.  To work around it, I have a copy of gtk.m4 and pkg.m4 in
VPython's CVS.  Look under vpython/share/aclocal.  Copy those files to
$prefix/share/aclocal.  You will probably have an easier time getting
autoconf, automake, and libtool to work if you use the packages in Fink.
In that case, you will want to copy the .m4 files
into /sw/share/aclocal, but only if they are not already included in
Fink's GTK 1.2 development package.

>   I can  
> delete the offending line from acinclude.m4, but that still leaves me  
> with my next problem, which is that when I run the resulting  
> configure script it complains that in the line:
> 
> AM_INIT_AUTOMAKE( visual, 3.2.3)

What is the current version of automake and autoconf on your system?

> that the symbol "visual" is unknown.
> 
> I'm not an avid user of autoconf or even configure, and after poking  
> around in it for a day or so, I'm not any more enlightened. Can  
> anyone tell me what I'm doing that's stupid and hosing the build?

I've given a few guesses above, but also see the file autogen.sh in the
top-level of VPython's source tree (maybe only in CVS).  It is what I
use to sequence the operation of the autotools when building the
configure scripts themselves.

-Jonathan

[Visualpython-users] Aqua port - stumped by autoconf

[Dethe E. <de...@li...>]

Hi folks,

I've finally gotten some time to look at porting VPython to OS X  
Aqua.  I've got Boost.python installed, and stubbed in the platmac.[h| 
cpp], and the osxgl.[h|cpp], but I'm having no luck getting a working  
configure file to compile it.  When I run autoconf I get a configure  
file, but running aclocal tells me:

aclocal: macro `AM_PATH_GTK' required but not defined

But GTK shouldn't be required, so how do I turn that off?  I can  
delete the offending line from acinclude.m4, but that still leaves me  
with my next problem, which is that when I run the resulting  
configure script it complains that in the line:

AM_INIT_AUTOMAKE( visual, 3.2.3)

that the symbol "visual" is unknown.

I'm not an avid user of autoconf or even configure, and after poking  
around in it for a day or so, I'm not any more enlightened. Can  
anyone tell me what I'm doing that's stupid and hosing the build?

--Dethe

This [the adoption of open source software] isn't just my idea, or  
Brazil's idea. It's the idea of our time. The complexity of our times  
demands it." --Gilberto Gil, Brazilian Minister of Culture

[Visualpython-users] Processor

[Bruce P. <bap...@te...>]

Well I'm not sure this is the same problem; but I've run into conflicts 
when using Pentium processors with Hyper Threading technology . I have a 
Visual/Python application that is multi threaded and it appears that the 
low level hardware threading and the software threading interfere with each 
other. The HT option can be turned off in the bios setup options so it's 
easy enough to check.

Bruce

At 08:28 PM 10/10/2005, you wrote:

>Message: 1
>From: "John Brawley" <jb...@te...>
>To: <vis...@li...>
>Date: Mon, 10 Oct 2005 10:47:48 -0500
>Subject: [Visualpython-users] Processors
>
>Is anybody aware of any _processor-specific_ problems between VPython and
>Python itself?
>
>I some time ago found I could not run Python 2.4 with the VPython for it, on
>one machine with an AMD CPU, but could on the other machine, with an Intel
>CPU.  (In both cases, older processors, 300 and 200 MHz respectively.)
>
>I now find Python/VPython runs perfectly (I _need_ P2.4.1, because it has
>the "crosseyed" keyword for stereo) on a dual-processor XEON machine (Compaq
>Evo W6000 workstation), but does not run on an AMD K62 500 MHz machine.  I'm
>currently building a new AMD Athlon 64 3400+ machine, primarily to run this
>very program of mine, and I'm worried the Pythons won't run on it.
>
>Facts: no difference at all between machines as far as installing Python,
>VPython, and Numeric on them.  The only difference I can figure between
>machines is the type of processor --AMD or Intel.  Older Python/VPython
>installations run fine on both my earlier machines.  2.4 and 2.4.1 do not
>run on the AMD machines.
>
>WHY NOT ?
>
>(I'll dig into the exact error messages and such later, after I have the new
>machine built and running.  I just right now want to know if anybody here
>has run into _any_ CPU-specific problems with Python/VPython 2.4 and later.)
>
>   Any thoughts?
>
>Peace
>JB

Bruce Peterson, Ph.D.
Terastat, Inc
Information Access Systems
Voice (425) 466 7344
Fax (206) 350 3685 

[Visualpython-users] Key release events

[Morgan L. <mo...@gm...>]

Hi, everyone.

I would like to request a way to tell when a key has been released, either
in a similar way to the current scene.kb.getkey() or a function like
kb.ispressed(key). This would be useful for games and similar time-sensitiv=
e
projects.

-Morgan LaMoore

[Visualpython-users] Processors

[John B. <jb...@te...>]

Is anybody aware of any _processor-specific_ problems between VPython and
Python itself?

I some time ago found I could not run Python 2.4 with the VPython for it, on
one machine with an AMD CPU, but could on the other machine, with an Intel
CPU.  (In both cases, older processors, 300 and 200 MHz respectively.)

I now find Python/VPython runs perfectly (I _need_ P2.4.1, because it has
the "crosseyed" keyword for stereo) on a dual-processor XEON machine (Compaq
Evo W6000 workstation), but does not run on an AMD K62 500 MHz machine.  I'm
currently building a new AMD Athlon 64 3400+ machine, primarily to run this
very program of mine, and I'm worried the Pythons won't run on it.

Facts: no difference at all between machines as far as installing Python,
VPython, and Numeric on them.  The only difference I can figure between
machines is the type of processor --AMD or Intel.  Older Python/VPython
installations run fine on both my earlier machines.  2.4 and 2.4.1 do not
run on the AMD machines.

WHY NOT ?

(I'll dig into the exact error messages and such later, after I have the new
machine built and running.  I just right now want to know if anybody here
has run into _any_ CPU-specific problems with Python/VPython 2.4 and later.)

  Any thoughts?

Peace
JB
Xj...@te...
( REMOVE the 'X' before using ! )
NOTE: due to virus explosion, currently deleting ALL messages over 140kb
from the server without downloading.
http://tetrahedraverse.com

[Visualpython-users] problem with VPython on Fedora 4

[paco <fg...@um...>]

I have installed VPython on Fedora 4 and everything seems fine. When I
attempt to execute a demo I get the following error

"Traceback (most recent call last):
  File "bounce.py", line 1, in ?
    from visual import *
  File "/usr/lib/python2.4/site-packages/visual/__init__.py", line 28,
in ?
    from visual.primitives import arrow, cylinder, cone, sphere, box,
ring, label
ImportError: No module named primitives"

Haw can I fix that?

Thanks in advance


Paco

RE: [Visualpython-users] Cast a shadow

[Nick L. <ni...@ja...>]

Many thanks Bruce. No need to apologise though, vpython is excellent as it
is. It's helping me in learning python and damn good fun to boot :)

I'll go have a look at Pov-Ray and see what it's all about.

Thanks again,
Nick .


> -----Original Message-----
> From: Bruce Sherwood [mailto:Bru...@nc...]
> Sent: 01 October 2005 19:53
> To: Nick Lunt
> Cc: Vpython
> Subject: Re: [Visualpython-users] Cast a shadow
>
>
> Sorry, currently there's no way to cast shadows. And you can only put
> lights at infinity. Jonathan Brandmeyer is working on a version that
> will let you put lights anywhere, but even with that advance there won't
> be shadows, which typically require ray-tracing, which is slow. A minor
> footnote is that at vpython.org there is a routine for exporting a
> VPython scene to Pov-Ray, a freeware ray tracer, which does
> produce shadows.
>
> Bruce Sherwood
>
> Nick Lunt wrote:
>
> >Hello,
> >
> >I've have just installed vpython and have to say I am loving
> messing around
> >with it.
> >
> >Anyhoo, I've had a look through the archives but unfortunately I
> could not
> >find a search function for past posts, hence my question, which I'm sure
> >must of been asked before ;)
> >
> >Is there anyway to have objects cast a shadow ? I can see that
> when I rotate
> >a box object that there is a shadow but when I move a sphere
> object around
> >inside a box (or between two boxes as in the tutorial) there is
> no shadow of
> >the sphere.
> >
> >I can get the current vectors for the default 2 lights (print
> scene.lights)
> >but I'm unsure of how to manipulate my own lights (or the
> default ones) to
> >get a moving object inside a box to generate a shadow.
> >
> >So basically can anyone please give me a quick rundown on how to
> generate my
> >own lighting to enable shadows on moving objects ?
> >
> >I have attached my code in the hope that it my help to explain what I'm
> >trying to do.
> >
> >Many thanks,
> >Nick .
> >
> >
> >
>
>
>
> --
> No virus found in this incoming message.
> Checked by AVG Anti-Virus.
> Version: 7.0.344 / Virus Database: 267.11.9/116 - Release Date: 30/09/2005
>
>

Re: [Visualpython-users] Cast a shadow

[Bruce S. <Bru...@nc...>]

Sorry, currently there's no way to cast shadows. And you can only put 
lights at infinity. Jonathan Brandmeyer is working on a version that 
will let you put lights anywhere, but even with that advance there won't 
be shadows, which typically require ray-tracing, which is slow. A minor 
footnote is that at vpython.org there is a routine for exporting a 
VPython scene to Pov-Ray, a freeware ray tracer, which does produce shadows.

Bruce Sherwood

Nick Lunt wrote:

>Hello,
>
>I've have just installed vpython and have to say I am loving messing around
>with it.
>
>Anyhoo, I've had a look through the archives but unfortunately I could not
>find a search function for past posts, hence my question, which I'm sure
>must of been asked before ;)
>
>Is there anyway to have objects cast a shadow ? I can see that when I rotate
>a box object that there is a shadow but when I move a sphere object around
>inside a box (or between two boxes as in the tutorial) there is no shadow of
>the sphere.
>
>I can get the current vectors for the default 2 lights (print scene.lights)
>but I'm unsure of how to manipulate my own lights (or the default ones) to
>get a moving object inside a box to generate a shadow.
>
>So basically can anyone please give me a quick rundown on how to generate my
>own lighting to enable shadows on moving objects ?
>
>I have attached my code in the hope that it my help to explain what I'm
>trying to do.
>
>Many thanks,
>Nick .
>
>  
>

Re: [Visualpython-users] Segmentation fault

[Jonathan B. <jbr...@ea...>]

On Fri, 2005-09-30 at 03:12 -0600, Vijay Kumar Suryadevara wrote:
> hi,
> 
> I tried to run demo programs of the visual from command prompt. The
> programs run correctly and i get the visualizations also but i get a
> segmentation fault after i close the display window of the
> visualizations.
> 
> (i.e)"python bounce.py" runs the visualization correctly but there is
> a segmentation fault.

Which version of Visual are you using?

-Jonathan

> Iam running vpython on Suse 9.3. Please post if u have answers.
> 
> Thanks,
> Vijay.

[Visualpython-users] Cast a shadow

[Nick L. <ni...@ja...>]

Hello,

I've have just installed vpython and have to say I am loving messing around
with it.

Anyhoo, I've had a look through the archives but unfortunately I could not
find a search function for past posts, hence my question, which I'm sure
must of been asked before ;)

Is there anyway to have objects cast a shadow ? I can see that when I rotate
a box object that there is a shadow but when I move a sphere object around
inside a box (or between two boxes as in the tutorial) there is no shadow of
the sphere.

I can get the current vectors for the default 2 lights (print scene.lights)
but I'm unsure of how to manipulate my own lights (or the default ones) to
get a moving object inside a box to generate a shadow.

So basically can anyone please give me a quick rundown on how to generate my
own lighting to enable shadows on moving objects ?

I have attached my code in the hope that it my help to explain what I'm
trying to do.

Many thanks,
Nick .

[Visualpython-users] Clipboard trouble with python 2.4

[none n. <gho...@ya...>]

i am having an issue when i try to place information
in the clipboard.  IDLE freezes every time i try to do
so.  Can someone help me resolve this?


		
__________________________________ 
Yahoo! Mail - PC Magazine Editors' Choice 2005 
http://mail.yahoo.com

[Visualpython-users] segmentation fault

[Vijay K. S. <vij...@gm...>]

Sorry, I forgot to mention that the demo programs work correctly without an=
y
segmentation fault in IDLE.

Thanks,
Vijay

[Visualpython-users] Segmentation fault

[Vijay K. S. <vij...@gm...>]

hi,

I tried to run demo programs of the visual from command prompt. The program=
s
run correctly and i get the visualizations also but i get a segmentation
fault after i close the display window of the visualizations.

(i.e)"python bounce.py" runs the visualization correctly but there is a
segmentation fault.

Iam running vpython on Suse 9.3. Please post if u have answers.

Thanks,
Vijay.

RE: [Visualpython-users] Can the camera be reset after user zoom? Or else...

[Bill W. <ww...@la...>]

Cheers Bruce, very cool!  I think the joke alone is worth the price of
admission.  Speaking of obvious, studying the stonehenge example was my
first instinct, but that one still baffles me.  How to get anything that
looks like zoom from adjusting only the center is beyond me, at least, for
positions that are there.

There is more to this problem than meets the eye (or the camera), and it's
taken me a good part of the day to figure out what might be going on with
the obvious" script you sent.  I started with the one from the "Contributed"
page figuring it was a little newer.  Here are a couple of buried gotchas:

* Rotating by mouse enough changes scene.forward but can also change
scene.up!  Without saving and restoring that you sometimes get mirror images
on recalling the view.

* Saving/restoring more than one view is trickier, and here is what I think
is happening.  Mouse zoom only changes the camera, not range/scale.  Any
programmatic changes to range, however, do produce a new camera distance,
which breaks any previous relationship.  So the program cannot zoom or even
restore a saved view without throwing everything off for views already
stored.

I've attached a version of your script with modifications to try to
emphasize what's going on and suggest how to compensate.  It doesn't feel
pretty but unless there is some unknown parameter to work with, this is the
only way I see to work it (short of grabbing full mouse control and rolling
your own navigation).  I tried to highlight places I hacked it with triple
###.

Thanks again for the prompt and careful help.

Bill

-----Original Message-----
From: Bruce Sherwood [mailto:Bru...@nc...] 
Sent: Wednesday, September 28, 2005 8:28 PM
To: ww...@la...
Cc: vis...@li...
Subject: Re: [Visualpython-users] Can the camera be reset after user zoom?
Or else...

Here is a little routine that restores a previous view. To try it, zoom and
spin, then click (left button) to save that view. Next zoom and spin some
more, to make a completely different view. Click and you'll see your saved
view restored.

This routine makes me think of the joke about the physics professor who
during a class says, "It's obvious that such and such," then pauses and
muses, "Is that really obvious?" He stands there deep in thought for 20
minutes, then announces, "Yes, it is obvious," and proceeds with the rest of
the lecture without further comment.

It wasn't obvious how to write this program. I've put it in the contributed
section of the vpython.org web site.

I'll also draw attention to a somewhat related routine in the example
program stonehenge.py distributed with VPython, where you fly through a
scene by continual readjustment of scene.center.

Bruce Sherwood

from visual import *
##from time import clock

# If you want to access scene.range before any user adjustments # have been
made (zoom or spin), you need to wait for the scene # to be rendered and
autoscaled. In that case you need to import # the clock() function to make
it possible to wait for 0.1 s (say).
# But if you wait on a mouse click for the user to complete zoom # or spin,
you don't need to pause the 0.1 s.

box(pos=(-1.5,0,0), color=color.red)
box(pos=(1.5,0,0), color=color.blue)
##t = clock()
##while clock() < t+0.1:
##    continue

# Wait while user adjusts the view.
scene.mouse.getclick()
# Determine how wide the scene is.
halfwidth = max(scene.range)
# Determine how far we are from the center of the scene.
distance = mag(scene.mouse.camera-scene.center)
# Keep a copy of current scene.forward.
# Without the adding of the zero vector, "direction"
# would just be another name for the current scene.forward.
direction = scene.forward+vector(0,0,0)

# Wait while user changes the view, then restore the previous view.
scene.mouse.getclick()
# Determine the new distance from the center.
newdistance = mag(scene.mouse.camera-scene.center)
# Adjust the range based on the new distance.
scene.range = halfwidth*distance/newdistance # Reset the viewing direction.
scene.forward = direction

Bill Ward wrote:

> Hi everyone,
>  
> I'm new to the list, so first my gratitude to everyone involved in the 
> creation and enhancement of this package...where has it been all my 
> life?  An outstanding and accessible framework with clear 
> tutorials...except for the following!
>  
> I've gathered from reading archives and the reference manual that 
> direct program control of the camera is not an option.  I have 
> explored scale/range, center, forward, and the mouse.camera attributes 
> to where I have a couple of clues.  But how can I do the following:
>  
> I want to establish a set of fixed views of my scene that can be 
> called up from controls (button or menu).  Ideally, I'd like to mouse 
> my way into the correct view, then save the camera position for 
> recall.  I see the camera position is modified, but when I zoom in by 
> mousing there is no change to "scale" , or center, or forward, or 
> anything else I can set.  Am I running up against a buried 
> "manual_scale" that I can't read or write?
>  
> Even if I can only establish the right scale programmatically, that's 
> fine.  But, if I allow the user to zoom and rotate around the scene, 
> how can I go back to a nominal camera distance to establish those 
> fixed viewpoints that will be designed to illustrate the underlying 
> physics?  Hence the subject line, is there such thing as a camera 
> reset?  Can I get the effect by toggling userzoom, or autoscale? Or do 
> I have to just shut of userzoom entirely?
>  
> Thanks in advance for your suggestions.
>  
> Bill Ward
>  

Re: [Visualpython-users] Can the camera be reset after user zoom? Or else...

[Bruce S. <Bru...@nc...>]

Here is a little routine that restores a previous view. To try it, zoom 
and spin, then click (left button) to save that view. Next zoom and spin 
some more, to make a completely different view. Click and you'll see 
your saved view restored.

This routine makes me think of the joke about the physics professor who 
during a class says, "It's obvious that such and such," then pauses and 
muses, "Is that really obvious?" He stands there deep in thought for 20 
minutes, then announces, "Yes, it is obvious," and proceeds with the 
rest of the lecture without further comment.

It wasn't obvious how to write this program. I've put it in the 
contributed section of the vpython.org web site.

I'll also draw attention to a somewhat related routine in the example 
program stonehenge.py distributed with VPython, where you fly through a 
scene by continual readjustment of scene.center.

Bruce Sherwood

from visual import *
##from time import clock

# If you want to access scene.range before any user adjustments
# have been made (zoom or spin), you need to wait for the scene
# to be rendered and autoscaled. In that case you need to import
# the clock() function to make it possible to wait for 0.1 s (say).
# But if you wait on a mouse click for the user to complete zoom
# or spin, you don't need to pause the 0.1 s.

box(pos=(-1.5,0,0), color=color.red)
box(pos=(1.5,0,0), color=color.blue)
##t = clock()
##while clock() < t+0.1:
##    continue

# Wait while user adjusts the view.
scene.mouse.getclick()
# Determine how wide the scene is.
halfwidth = max(scene.range)
# Determine how far we are from the center of the scene.
distance = mag(scene.mouse.camera-scene.center)
# Keep a copy of current scene.forward.
# Without the adding of the zero vector, "direction"
# would just be another name for the current scene.forward.
direction = scene.forward+vector(0,0,0)

# Wait while user changes the view, then restore the previous view.
scene.mouse.getclick()
# Determine the new distance from the center.
newdistance = mag(scene.mouse.camera-scene.center)
# Adjust the range based on the new distance.
scene.range = halfwidth*distance/newdistance
# Reset the viewing direction.
scene.forward = direction

Bill Ward wrote:

> Hi everyone,
>  
> I'm new to the list, so first my gratitude to everyone involved in the 
> creation and enhancement of this package...where has it been all my 
> life?  An outstanding and accessible framework with clear 
> tutorials...except for the following!
>  
> I've gathered from reading archives and the reference manual that 
> direct program control of the camera is not an option.  I have 
> explored scale/range, center, forward, and the mouse.camera attributes 
> to where I have a couple of clues.  But how can I do the following:
>  
> I want to establish a set of fixed views of my scene that can be 
> called up from controls (button or menu).  Ideally, I'd like to mouse 
> my way into the correct view, then save the camera position for 
> recall.  I see the camera position is modified, but when I zoom in by 
> mousing there is no change to "scale" , or center, or forward, or 
> anything else I can set.  Am I running up against a buried 
> "manual_scale" that I can't read or write?
>  
> Even if I can only establish the right scale programmatically, that's 
> fine.  But, if I allow the user to zoom and rotate around the scene, 
> how can I go back to a nominal camera distance to establish those 
> fixed viewpoints that will be designed to illustrate the underlying 
> physics?  Hence the subject line, is there such thing as a camera 
> reset?  Can I get the effect by toggling userzoom, or autoscale? Or do 
> I have to just shut of userzoom entirely?
>  
> Thanks in advance for your suggestions.
>  
> Bill Ward
>