visualpython-users

Re: [Visualpython-users] Anyone updating Linux vpython to GTK 2?

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

Two points:

1) Jonathan Brandmeyer is hard at work on making available for testing 
by others his new version that supports transparency, surface textures, 
and sophisticated lighting, and this is based on GTK2.

2) However, it will take some time for this to settle down, so if you 
are able without too much work to offer patches to change the current 
code to be based on GTK2, that would be useful, since as you have found, 
it is difficult to compile the current code on some Linux platforms.

There is another modernization that needs to be carried out, which is to 
move from Numeric (or Numarray) to the new NumPy, which is intended to 
supercede both.

Bruce Sherwood

Hugh Fisher wrote:

>
> I tried building Visual Python from source for our Fedora Core
> 3 Linux PCs. The configure script fell over because it wanted
> GTK 1.2 and didn't recognise GTK 2 as being present.
>
> GTK 2 has been out for a number of years now, so I think it's
> time to bring Visual Python up to date. Is this already being
> planned for some near future release, or would people be
> interested in patches to convert Visual Python to GTK 2 ?
>

[Visualpython-users] Anyone updating Linux vpython to GTK 2?

[Hugh F. <hug...@an...>]

I tried building Visual Python from source for our Fedora Core
3 Linux PCs. The configure script fell over because it wanted
GTK 1.2 and didn't recognise GTK 2 as being present.

GTK 2 has been out for a number of years now, so I think it's
time to bring Visual Python up to date. Is this already being
planned for some near future release, or would people be
interested in patches to convert Visual Python to GTK 2 ?

-- 
	Hugh Fisher
	DCS, ANU

RE: [Visualpython-users] Collision detection with VPython

[Miles J. <mil...@ho...>]

Found solution at http://python.matrix.jp/projects/pyogre/ode_test2.py.
So now example 3 looks like this:

# pyODE example 3: Collision detection

# Originally by Matthias Baas.
# Update by Miles Jacobs to make collision detection work with VPython.
# With thanks to http://python.matrix.jp/projects/pyogre/ode_test2.py.

import sys, os, random, time
from math import *

from visual import *
import ode

# geometric utility functions
def scalp (vec, scal):
    vec[0] *= scal
    vec[1] *= scal
    vec[2] *= scal

def length (vec):
    return sqrt (vec[0]**2 + vec[1]**2 + vec[2]**2)


# create_box
def create_box(world, space, density, lx, ly, lz):
    """Create a box body and its corresponding geom."""

    # Create body
    body = ode.Body(world)
    M = ode.Mass()
    M.setBox(density, lx, ly, lz)
    body.setMass(M)

    # Set parameters for drawing the body
    body.shape = "box"
    body.boxsize = (lx, ly, lz)

    # Create a box geom for collision detection
    geom = ode.GeomBox(space, lengths=body.boxsize)
    geom.setBody(body)

    return body

# drop_object
def drop_object():
    """Drop an object into the scene."""

    global bodies, counter, objcount

    body = create_box(world, space, 1000, 1.0,1.0,1.0)
    body.setPosition((random.gauss(0,0.1),10.0,random.gauss(0,0.1)))
    theta = random.uniform(0,2*pi)
    ct = cos (theta)
    st = sin (theta)
    body.setRotation([ct, 0., -st, 0., 1., 0., st, 0., ct])
    icecube = box(pos=body.getPosition(), axis=(ct,0.,st),
                  length=1.0, height=1.0, width=1.0,
                  
color=(random.gauss(0,1),random.gauss(0,1),random.gauss(0,1)))
    bodies.append(body)
    cubes.append(icecube)
    counter=0
    objcount+=1

# explosion
def explosion():
    """Simulate an explosion.

    Every object is pushed away from the origin.
    The force is dependent on the objects distance from the origin.
    """
    global bodies

    for b in bodies:
        l=b.getPosition ()
        d = length (l)
        a = max(0, 800000*(1.0-0.2*d*d))
        l = [l[0] / 4, l[1], l[2] /4]
        scalp (l, a / length (l))
        b.addForce(l)

# pull
def pull():
    """Pull the objects back to the origin.

    Every object will be pulled back to the origin.
    Every couple of frames there'll be a thrust upwards so that
    the objects won't stick to the ground all the time.
    """
    global bodies, counter

    for b in bodies:
        l=list (b.getPosition ())
        scalp (l, -100000 / length (l))
        b.addForce(l)
        if counter%60==0:
            b.addForce((0,100000,0))

# Collision callback
def near_callback(args, geom1, geom2):
    """Callback function for the collide() method.

    This function checks if the given geoms do collide and
    creates contact joints if they do.
    """

    # Check if the objects do collide
    contacts = ode.collide(geom1, geom2)

    # Create contact joints
    world,contactgroup = args
    for c in contacts:
        c.setBounce(0.2)
        c.setMu(5000)
        j = ode.ContactJoint(world, contactgroup, c)
        j.attach(geom1.getBody(), geom2.getBody())



######################################################################


# Create a world object
world = ode.World()
world.setGravity( (0,-9.81,0) )
world.setERP(0.8)
world.setCFM(1E-5)

# Create a space object
space = ode.Space()

# Create a plane geom which prevent the objects from falling forever
floor = ode.GeomPlane(space, (0,1,0), 0)
ground=box(pos=(0,-0.1,0), width=20, height=0.1, length=20, 
color=color.white)

# A list with ODE bodies and Visual objects to see the bodies
bodies = []
cubes = []

# A joint group for the contact joints that are generated whenever
# two bodies collide
contactgroup = ode.JointGroup()

# Some variables used inside the simulation loop
fps = 25
dt = 1.0/fps
running = True
state = 0
counter = 0
objcount = 0
scene.autoscale=0
scene.forward=(-5,-5,-5)

while(1):

    global counter, state

    counter += 1

    if state==0:
        if counter==20:
            drop_object()
        if objcount==10:
            state=1
            counter=0
    # State 1: Explosion and pulling back the objects
    elif state==1:
        if counter==100:
            explosion()
        if counter>300:
            pull()
        if counter==500:
            counter=20

    for b in range(len(bodies)):
        x,y,z = bodies[b].getPosition()
        R = bodies[b].getRotation()
        cubes[b].pos=(x,y,z)
        cubes[b].axis=R[0], R[3], R[6]
        cubes[b].up=R[1], R[4], R[7]

    print state, counter
    # Simulate
    n = 2

    for i in range(n):
        # Detect collisions and create contact joints
        space.collide((world,contactgroup), near_callback)

        # Simulation step
        world.step(dt/n)

        # Remove all contact joints
        contactgroup.empty()

    rate(10)



Miles.

_________________________________________________________________
Express yourself instantly with MSN Messenger! Download today - it's FREE! 
http://messenger.msn.click-url.com/go/onm00200471ave/direct/01/

[Visualpython-users] Pitfall with 'forward' and 'up'

[Thomas P. <tp...@gm...>]

Hi,
I'm still working with version 3.2.1, but judging from the
changelogs, the pitfall should still be present in the
current release.

I tried to setup a scene such that the z axis is pointing
upwards and the camera is looking along the y axis:
#####################################################
from visual import *

# 1 / does not work
scene = display(up=(0, 0, 1), forward=(0, 1, 0))

# 2 / does not work
scene = display(forward=(0, 1, 0), up=(0, 0, 1))

# 3 / works
scene = display(forward=(1, 0, 0), up=(0, 0, 1))
scene.forward = (0, 1, 0)

arrow(pos=(0,0,0), axis=(0,1,0))
#####################################################

The canonical solutions 1 and 2 both do not work, because
the new up direction is colinear with the default forward
direction (1) or the new forward direction is colinear with
the default up direction (2).

Solution 3 works, but it's not really easy to come up with
this solution for a beginner.

A simple fix would be to wait with the colinearity check until
all keywords have been processed.

Cheers,
Tom

-- 
Echte DSL-Flatrate dauerhaft für 0,- Euro*!
"Feel free" mit GMX DSL! http://www.gmx.net/de/go/dsl

Re: [Visualpython-users] Collision detection with VPython

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

Also, in case you didn't spot this, look at the Visual documentation on 
the box object and the accompanying diagram.

Bruce Sherwood

Jonathan Brandmeyer wrote:

>On Mon, 2006-03-27 at 23:20 +0000, Miles Jacobs wrote:
>  
>
>>I've tried to make VPython work with PyODE (http://pyode.sourceforge.net).  
>>The blocks seem to collide properly but they often settle on their edges.  I 
>>probably misunderstand the rotation matrix provided by PyODE or the "up" 
>>method of VPython.
>>    
>>
>
>Both up and axis define the orientation of a VPython body ("angle" is
>not used for anything).  See src/prim.cpp for the full story (there are
>some corner cases that the code follows to avoid degeneration).  The
>following is a reasonable approximation of what happens in there:
>
># Returns the direction cosine matrix of a VPython renderable body
># The result is a right-handed 3x3 orthonormal matrix
>def DCM( renderable):
>	z_axis = renderable.axis.cross( renderable.up).norm()
>	y_axis = z_axis.cross( renderable.axis).norm()
>	x_axis = renderable.axis.norm()
>	# Can probably use Tensor here...
>	ret = Numeric.array( shape=(3,3), type=Numeric.Float64)
>	ret[:,0] = x_axis
>	ret[:,1] = y_axis
>	ret[:,2] = z_axis
>	return ret
>
># Set the orientation of a renderable object from a 3x3 direction 
># cosine matrix, while retaining scaling information on the Visual
># object.
># renderable: A VPython renderable object
># DCM: A right-handed 3x3 orthonormal matrix
># returns: None
>def move_renderable_from_DCM( renderable, DCM):
>	renderable.axis = vector(DCM[:,0]) * renderable.axis.mag
>	renderable.up = vector(DCM[:,1])
>
>  
>
>>  Any help would be appreciated.  The VPython "cubes" get 
>>their positional and angular information from the PyODE "bodies".
>>    
>>
>
>HTH,
>-Jonathan
>
>
>
>
>-------------------------------------------------------
>This SF.Net email is sponsored by xPML, a groundbreaking scripting language
>that extends applications into web and mobile media. Attend the live webcast
>and join the prime developer group breaking into this new coding territory!
>http://sel.as-us.falkag.net/sel?cmd=lnk&kid=110944&bid=241720&dat=121642
>_______________________________________________
>Visualpython-users mailing list
>Vis...@li...
>https://lists.sourceforge.net/lists/listinfo/visualpython-users
>  
>

Re: [Visualpython-users] Collision detection with VPython

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

On Mon, 2006-03-27 at 23:20 +0000, Miles Jacobs wrote:
> I've tried to make VPython work with PyODE (http://pyode.sourceforge.net).  
> The blocks seem to collide properly but they often settle on their edges.  I 
> probably misunderstand the rotation matrix provided by PyODE or the "up" 
> method of VPython.

Both up and axis define the orientation of a VPython body ("angle" is
not used for anything).  See src/prim.cpp for the full story (there are
some corner cases that the code follows to avoid degeneration).  The
following is a reasonable approximation of what happens in there:

# Returns the direction cosine matrix of a VPython renderable body
# The result is a right-handed 3x3 orthonormal matrix
def DCM( renderable):
	z_axis = renderable.axis.cross( renderable.up).norm()
	y_axis = z_axis.cross( renderable.axis).norm()
	x_axis = renderable.axis.norm()
	# Can probably use Tensor here...
	ret = Numeric.array( shape=(3,3), type=Numeric.Float64)
	ret[:,0] = x_axis
	ret[:,1] = y_axis
	ret[:,2] = z_axis
	return ret

# Set the orientation of a renderable object from a 3x3 direction 
# cosine matrix, while retaining scaling information on the Visual
# object.
# renderable: A VPython renderable object
# DCM: A right-handed 3x3 orthonormal matrix
# returns: None
def move_renderable_from_DCM( renderable, DCM):
	renderable.axis = vector(DCM[:,0]) * renderable.axis.mag
	renderable.up = vector(DCM[:,1])

>   Any help would be appreciated.  The VPython "cubes" get 
> their positional and angular information from the PyODE "bodies".

HTH,
-Jonathan

[Visualpython-users] Re: Python/C++

[Scott D. D. <Sco...@Ac...>]

John Brawley wrote:
> I realize this is not the list for this question, but some of you might
> know, and I'm not currently on the Python list....
> 
> Can anyone tell me how Python implements C++ in the case of _tuples_?
This question makes no sense.

> I'm assuming Python is built somewhat on C (or C++), and in C++ you can't
> return more than one item from a function, but Python allows one to return
> as many (up to 10?) variables as one wants (this is one reason Python is so
> "powerful"; returning three variables at once makes it a 'natural' for 3D
> space work with lots and lots of x,y,z dealings).

Python functions only ever return a single value, but that value might
be a tuple of values.  There is no limit of 10 (or so) values in that
tuple.  Consider:

     def powers(a):
         return (1, a, a**2, a**3, a**4, a**5, a**6, a**7, a**8, a**9,
                 a**10, a**11, a**12, a**13)

     a,b,c,d,e,f,g,h,i,j,k,l,m,n = powers(1.2)

Or even:

     def pows(a, number):
         return [a ** n for n in range(number)]

     a,b,c,d = pows(1.2, 4)

     a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z = pows(1.1, 26)

Modern C (and C++) similarly allow you to return a struct.

Take a python function that you think produces multiple results, and
simply print the result of that function.  It is a single item which
is "dis-assembled" in the python assignment.  For example, you can do
the following:

     (a, b), (c, d, e) = [(1, 3), [1.1, 2.3, 'f']]


-- 
-- Scott David Daniels
Sco...@Ac...

[Visualpython-users] Collision detection with VPython

[Miles J. <mil...@ho...>]

I've tried to make VPython work with PyODE (http://pyode.sourceforge.net).  
The blocks seem to collide properly but they often settle on their edges.  I 
probably misunderstand the rotation matrix provided by PyODE or the "up" 
method of VPython.  Any help would be appreciated.  The VPython "cubes" get 
their positional and angular information from the PyODE "bodies".


# pyODE example 3: Collision detection

# Originally by Matthias Baas.
# Attempt by Miles Jacobs to make collision detection work with VPython.

import sys, os, random, time
from math import *

from visual import *
import ode

from Scientific.Geometry import *
from Scientific.Geometry.TensorModule import *
from Scientific.Geometry.Transformation import *


# geometric utility functions
def scalp (vec, scal):
    vec[0] *= scal


vec[1] *= scal
    vec[2] *= scal

def length (vec):
    return sqrt (vec[0]**2 + vec[1]**2 + vec[2]**2)


# create_box
def create_box(world, space, density, lx, ly, lz):
    """Create a box body and its corresponding geom."""

    # Create body
    body = ode.Body(world)
    M = ode.Mass()
    M.setBox(density, lx, ly, lz)
    body.setMass(M)

    # Set parameters for drawing the body
    body.shape = "box"
    body.boxsize = (lx, ly, lz)

    # Create a box geom for collision detection
    geom = ode.GeomBox(space, lengths=body.boxsize)
    geom.setBody(body)

    return body

# drop_object
def drop_object():
    """Drop an object into the scene."""

    global bodies, counter, objcount

    body = create_box(world, space, 1000, 1.0,1.0,1.0)
    body.setPosition((random.gauss(0,0.1),10.0,random.gauss(0,0.1)))
    theta = random.uniform(0,2*pi)
    ct = cos (theta)
    st = sin (theta)
    body.setRotation([ct, 0., -st, 0., 1., 0., st, 0., ct])
    matpot=Tensor([[ct, 0., -st],[0., 1., 0.],[st, 0., ct]])
    matkettle=Rotation(matpot)
    bodyaxis, bodyangle = matkettle.axisAndAngle()
    icecube = box(pos=body.getPosition(), axis=bodyaxis,
                  length=1.0, height=1.0, width=1.0,
                  
color=(random.gauss(0,1),random.gauss(0,1),random.gauss(0,1)))
    bodies.append(body)
    cubes.append(icecube)
    counter=0
    objcount+=1

# explosion
def explosion():
    """Simulate an explosion.

    Every object is pushed away from the origin.
    The force is dependent on the objects distance from the origin.
    """
    global bodies

    for b in bodies:
        l=b.getPosition ()
        d = length (l)
        a = max(0, 800000*(1.0-0.2*d*d))
        l = [l[0] / 4, l[1], l[2] /4]
        scalp (l, a / length (l))
        b.addForce(l)

# pull
def pull():
    """Pull the objects back to the origin.

    Every object will be pulled back to the origin.
    Every couple of frames there'll be a thrust upwards so that
    the objects won't stick to the ground all the time.
    """
    global bodies, counter

    for b in bodies:
        l=list (b.getPosition ())
        scalp (l, -100000 / length (l))
        b.addForce(l)
        if counter%60==0:
            b.addForce((0,100000,0))

# Collision callback
def near_callback(args, geom1, geom2):
    """Callback function for the collide() method.

    This function checks if the given geoms do collide and
    creates contact joints if they do.
    """

    # Check if the objects do collide
    contacts = ode.collide(geom1, geom2)

    # Create contact joints
    world,contactgroup = args
    for c in contacts:
        c.setBounce(0.2)
        c.setMu(5000)
        j = ode.ContactJoint(world, contactgroup, c)
        j.attach(geom1.getBody(), geom2.getBody())



######################################################################


# Create a world object
world = ode.World()
world.setGravity( (0,-9.81,0) )
world.setERP(0.8)
world.setCFM(1E-5)

# Create a space object
space = ode.Space()

# Create a plane geom which prevent the objects from falling forever
floor = ode.GeomPlane(space, (0,1,0), 0)
ground=box(pos=(0,-0.1,0), width=20, height=0.1, length=20, 
color=color.white)

# A list with ODE bodies and Visual objects to see the bodies
bodies = []
cubes = []

# A joint group for the contact joints that are generated whenever
# two bodies collide
contactgroup = ode.JointGroup()

# Some variables used inside the simulation loop
fps = 25
dt = 1.0/fps
running = True
state = 0
counter = 0
objcount = 0
scene.autoscale=0
scene.forward=(-5,-5,-5)

while(1):

    global counter, state

    counter += 1

    if state==0:
        if counter==20:
            drop_object()
        if objcount==10:
            state=1
            counter=0
    # State 1: Explosion and pulling back the objects
    elif state==1:
        if counter==100:
            explosion()
        if counter>300:
            pull()
        if counter==500:
            counter=20

    for b in range(len(bodies)):
        x,y,z = bodies[b].getPosition()
        R = bodies[b].getRotation()
        pot=Tensor([[R[0],R[3],R[6]],[R[1],R[4],R[7]],[R[2],R[5],R[8]]])
        kettle=Rotation(pot)
        bodyaxis, bodyangle = kettle.axisAndAngle()
        cubes[b].pos=(x,y,z)
        cubes[b].axis=bodyaxis
        cubes[b].angle=bodyangle

    print state, counter
    # Simulate
    n = 2

    for i in range(n):
        # Detect collisions and create contact joints
        space.collide((world,contactgroup), near_callback)

        # Simulation step
        world.step(dt/n)

        # Remove all contact joints
        contactgroup.empty()

    rate(10)


Miles.

_________________________________________________________________
Don’t just search. Find. Check out the new MSN Search! 
http://search.msn.click-url.com/go/onm00200636ave/direct/01/

[Visualpython-users] math teacher need help for Tkinter with Vpython

[Andrey A. <an...@uc...>]

Hi,=20

I am preparing slowly but surely an application based on Tkinter and =
VPython.
How could i tie together VPython window(s) and Tkinter unit(s), in order =
to resize proportionally=20
and move them together on the screen?
I will appreciate any HOWTO's and links, or  *.py samples.

Thanks a lot
Math teacher

Re: [Visualpython-users] building visual-3.2.9, boost include not found

[Vincent P. <vp...@un...>]

Can close this discussion,
I'm just a lame...

The export was incorrect :
-      export CPPFLAGS=3D-I/usr/local/include/boost_1_32
correct one is
-      export CPPFLAGS=3D-I/usr/local/include/boost-1_32

Take care, I suppose I just copy/paste frome the message
http://sourceforge.net/mailarchive/message.php?msg_id=3D10561064
(so a little mistake is in it. Pretty good job for the rest)

Seems to work now.

Sorry for the noise.

Vincent Pag=E9.


Vincent Page a =E9crit :

> Hi,
>
> I'll try to be precise enough to define my problem :
> I'm trying to build and instal visual python and have the following=20
> problem :
>
> (from src/build.log) :
> ------------
> In file included from ../include/vector.h:8,
>                 from ../include/xgl.h:10,
>                 from xgl.cpp:4:
> ../include/cvisual.h:8:47: boost/python/detail/wrap_python.hpp: No=20
> such file or directory

[Visualpython-users] building visual-3.2.9, boost include not found

[Vincent P. <vp...@un...>]

Hi,

I'll try to be precise enough to define my problem :
I'm trying to build and instal visual python and have the following=20
problem :

(from src/build.log) :
------------
In file included from ../include/vector.h:8,
                 from ../include/xgl.h:10,
                 from xgl.cpp:4:
../include/cvisual.h:8:47: boost/python/detail/wrap_python.hpp: No such=20
file or directory
------------
The compilation command was (from src/build log also)

g++ -I/usr/include/python2.4 -DHAVE_CONFIG_H -I../include -I..//include=20
-I/usr/include/gtk-1.2 -I/usr/include/glib-1.2 -I/usr/lib64/glib/include=20
-I/usr/X11R6/include -I/usr/include/gtk-1.2 -I/usr/include/glib-1.2=20
-I/usr/lib64/glib/include -I/usr/X11R6/include -D_REENTRANT=20
-I/usr/include/glib-1.2 -I/usr/lib64/glib/include -I/usr/include/gtk-1.2=20
-I/usr/include/glib-1.2 -I/usr/lib64/glib/include -I/usr/X11R6/include=20
-fpic -DPIC -g -O2 -ftemplate-depth-120 -g0 -MM -MT xgl.lo xgl.d -MF=20
xgl.d xgl.cpp
------------

Indeed, this file can be found there :
/usr/local/include/boost-1_32/boost/python/detail/wrap_python.hpp

I've looked through the archive and found some tips from
http://sourceforge.net/mailarchive/message.php?msg_id=3D10561064

so I did :
-      ln -s /usr/local/lib/libboost-python.so=20
/usr/local/lib/libboost-python-gcc-mt-1_32.so
(don't know was proposed as part of the solution)
-      export CPPFLAGS=3D-I/usr/local/include/boost_1_32
-      export LDFLAGS=3D-L/usr/local/lib

I also checked the location of python (/usr/bin/python)

so I run configure as follows :
./configure --prefix=3D/usr

I also looked to the makefile generated by configure and see :
CPPFLAGS =3D -I/usr/local/include/boost_1_32 -I/usr/include/gtk-1.2=20
-I/usr/include/glib-1.2 -I/usr/lib64/glib/include-I/usr/X11R6/include
LDFLAGS =3D -L/usr/local/lib

So the modifs have been taken into account

Still the same error.
I would appreciate som help !

Thanks a lot to everyone

Vincent Pag=E9.

Ps : I use
Python 2.4
scipy-0.4.6/
boost_1_32_0/
And trying to use visual-3.2.9/

[Visualpython-users] Fix to fields program

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

Thanks to feedback, I attach a revised version of the little fields 
program I posted. The one I posted originally would work only with the 
very latest VPython, due to a recent fix to the "faces" object. The 
attached version will work with both older and newer versions.

Bruce Sherwood

[Visualpython-users] Mac documentation

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

I've updated the Mac installation instructions at vpython.org with a 
minimalist set of steps adequate to install the latest Fink version of 
VPython packaged by Martin Costabel. I'm hoping this is fairly 
foolproof; I tried lots of variants and this seems to work in a robust 
fashion (though it takes forever to work through all the compilations).

Bruce Sherwood

[Visualpython-users] Field program

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

Attached is a VPython program that is a useful lecture demo tool for 
displaying various aspects of electric and magnetic fields, which you 
might find interesting (and I'd appreciate critical comments if you play 
with it).

It is based on the features in a program "EM Field" by David Trowbridge 
and me, which won a national prize and has been distributed by Physics 
Academic Software. That program, which was written in the cT language 
(see the cT archives at vpython.org)  is showing its age, and in 
particular there isn't a Mac version that runs on OSX, nor a Linux 
version, so it seemed time to make a modern version. Ultimately it would 
be good to provide a 3D version of the Gauss's law visualization, but 
that's for the future.

Bruce

[Visualpython-users] Re: Again from Andrio, the math teacher

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

On 3/7/06, Andrey Antonov <an...@uc...> wrote:
> Dear Lady Elza,

Um, not even close, but I'll let that slide.

> Your letter impressed me much, because it is obvious that you are (from m=
y
> PoV) a programmer,
> or closely connected with programming.

I'm a professional programmer at my day job, a hobbyist programmer in
my spare time.

> I am not a professional programmer, but I have some experience in
> programming.
> I mean, up to a certain extent I could think :)) in algorithmic way. Mayb=
e
> because I am a math teacher, or for other reasons, I don't know...

There are similarities between programming and math.

> Your idea :
> """
> You would probably have to walk the tree of objects and convert the
> state of each object to   a string which, when run, would restore the
> original object.  Tedious, but not difficult."""
>
> is very brilliant and frankly speaking it was the first that came to my m=
ind

Not really brilliant, pretty much a standard approach.

> trying to search my way to
> solve the the problem I asked about. It is strange now, after receiving t=
he
> letter from Bruce, that this topic
> haven't been discussed yet between VPython users.

For the most part I think people test small bits of code at the
command-line and write programs to create larger amounts of code.=20
What I think you want is to build up small bits of code, then to save
the state of all of it?  There are several approaches which would
work, for one, you could just save each line of code to a file before
executing it, to have a log of commands which could be re-run to
recreate your state.  You could have undo by dropping commands off the
end of the file.  Or, as in my previous post, you could build up a
scene, then walk the tree of objects and write out equivalent
commands.  VPython object constructors can take arguments for pretty
much any aspect of their state, so if you have a sphere which is
green, with a radius of 2 at location (4,7,8) in the scene, you could
write out
   from visual import *
   sphere(color=3D(0,1,0), radius=3D2, pos=3D(4,7,8))

Of course, you would have to do this for every type of object that
VPython supports, and for every property of each object--and I'm not
positive that they are all covered by named arguments.

Overall it would be easier to write the files as you go.

> Going ahead I ask myself questions for:
> 1)  bulding the tree of objects and relations between them from the point=
 of
> view of "children and parents objects".

Not sure what you mean here.  Is what I mention above what you mean?

> 2) Also it is closely related to the problem for executing a list of UNDO
> commands in order the reach the beginning state of the program or in my c=
ase
> it is equal in restoring the starting state of the scene.

Undo support would almost certainly be influenced by what mechanism
you're using to build the environment.  I do most of my work on OS X
using its Cocoa framework, and Cocoa already has a notion of
documents.  Working with the standard Cocoa documents you can get a
lot of behaviour (loading, saving, prompting to save before exit,
undo/redo, etc.) without much work.  Implementing it all from scratch
is do-able, but much more work, and runs the substantial risk of it
not working like other programs (which defeats user expectations).

> Could you give me some links to e-books or web sources for mentioned abov=
e
> questions.

I don't have a clear enough idea of what you're trying to do.  The
python.org website has good pointers for improving your python skills.
 If you want to create a UI for your students, you'll need to pick a
user interface toolkit.  This could be Tkinter, which has a good book
on it, or wxPython (I think a book is in progress, but not sure of the
status).  I use Cocoa, but it is OS X only and has no book (yet).=20
There are other options...

I don't think VPython integrates with any of the UI frameworks, but
I've written VPython programs which communicate to a Tkinter UI via
sockets.

I hope that helps.

--Dethe

> Of course looking for the answers is for the next version of the program.=
 If
> the first version wll see the world :))
>
> Thank you again
> Andrio
>
>

Re: [Visualpython-users] Help for saving the scene in a file for future opening and reusing

[<bas...@nc...>]

As can be seen by the differing responses, it isn't clear whether you are
trying to save images (which on Windows can be done by pressing
Alt-PrintScreen, which put a bitmap image in the copy buffer, from which
it can be pasted into a word processor) or you are trying to save object
information (which as explained would require a lot of programming).

I'm left wondering exactly what problem you're trying to solve. Presumably
students have access to their previous programs, which contain all of the
information. They can be run again to regenerate images, and they
obviously contain all the object information. Please offer a bit more
context for what the issue is. Thanks.

Bruce Sherwood

> Dear Friends,
>
> All of us enjoy the VPython environment. Little by little gaining the
> experience we want to create some scripts in Python for building one or
> more
> scenes full of objects.
> I am a math high school teacher. It would be better for my (or our)
> students
> to save their scenes and use them in their next lessons. To be more
> specific
> I mean saving the scene in a file for example using the output  of the
> command:
>     scene.objects
> Could anyone help me to solve this problem. Any hints, links ang
> suggestions
> are welcome.
> I joined the VPython user list from last May 2005 and didn't meet
> discussions on this topic.
>
> ThX in advance
>
> Andrio
> Math teacher
>
>
>
> -------------------------------------------------------
> This SF.Net email is sponsored by xPML, a groundbreaking scripting
> language
> that extends applications into web and mobile media. Attend the live
> webcast
> and join the prime developer group breaking into this new coding
> territory!
> http://sel.as-us.falkag.net/sel?cmd=lnk&kid=110944&bid=241720&dat=121642
> _______________________________________________
> Visualpython-users mailing list
> Vis...@li...
> https://lists.sourceforge.net/lists/listinfo/visualpython-users
>

Re: [Visualpython-users] Help for saving the scene in a file for future opening and reusing

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

VPython doesn't have a built-in way to save the state as a python
program.  It shouldn't be terribly hard to create one, but there isn't
anything built-in as far as I know.

Unfortunately, VPython objects don't appear to be picklable (because
the underlying Boost objects are not pickleable), so you can't even
use the shortcut method of saving your state with the shelve module.

You would probably have to walk the tree of objects and convert the
state of each object to   a string which, when run, would restore the
original object.  Tedious, but not difficult.

-Dethe

On 3/6/06, Andrey Antonov <an...@uc...> wrote:
> Dear Friends,
>
> All of us enjoy the VPython environment. Little by little gaining the
> experience we want to create some scripts in Python for building one or m=
ore
> scenes full of objects.
> I am a math high school teacher. It would be better for my (or our) stude=
nts
> to save their scenes and use them in their next lessons. To be more speci=
fic
> I mean saving the scene in a file for example using the output  of the
> command:
>     scene.objects
> Could anyone help me to solve this problem. Any hints, links ang suggesti=
ons
> are welcome.
> I joined the VPython user list from last May 2005 and didn't meet
> discussions on this topic.
>
> ThX in advance
>
> Andrio
> Math teacher
>
>
>
> -------------------------------------------------------
> This SF.Net email is sponsored by xPML, a groundbreaking scripting langua=
ge
> that extends applications into web and mobile media. Attend the live webc=
ast
> and join the prime developer group breaking into this new coding territor=
y!
> http://sel.as-us.falkag.net/sel?cmd=3Dlnk&kid=3D110944&bid=3D241720&dat=
=3D121642
> _______________________________________________
> Visualpython-users mailing list
> Vis...@li...
> https://lists.sourceforge.net/lists/listinfo/visualpython-users
>

Re: [Visualpython-users] Help for saving the scene in a file for future opening and reusing

[Dr P H B. <P.H...@bh...>]

You do not say what system you are using, but MS has the PrtScr key (to right
of F12), which saves the whole screen to the clipboard, whence you can save
it to a file. Alt/PrtScr saves the current window

This may be too obvious, but PrtScr is one of the better hidden features of
the keyboard.

Regards

Peter



In message <001001c6413f$57dffd00$93e61ec1@mitkoandrey>
          "Andrey Antonov" <an...@uc...> wrote:

> Dear Friends,
> 
> All of us enjoy the VPython environment. Little by little gaining the 
> experience we want to create some scripts in Python for building one or more 
> scenes full of objects.
> I am a math high school teacher. It would be better for my (or our) students 
> to save their scenes and use them in their next lessons. To be more specific 
> I mean saving the scene in a file for example using the output  of the 
> command:
>     scene.objects
> Could anyone help me to solve this problem. Any hints, links ang suggestions 
> are welcome.
> I joined the VPython user list from last May 2005 and didn't meet 
> discussions on this topic.
> 
> ThX in advance
> 
> Andrio
> Math teacher 
> 
> 
> 
> -------------------------------------------------------
> This SF.Net email is sponsored by xPML, a groundbreaking scripting language
> that extends applications into web and mobile media. Attend the live webcast
> and join the prime developer group breaking into this new coding territory!
> http://sel.as-us.falkag.net/sel?cmd=lnk&kid=110944&bid=241720&dat=121642
> _______________________________________________
> Visualpython-users mailing list
> Vis...@li...
> https://lists.sourceforge.net/lists/listinfo/visualpython-users


-- 


Dr P H Borcherds	|<mailto:P.H...@bh...>
			|phone 	0044 (0)121 475 3029

[Visualpython-users] Help for saving the scene in a file for future opening and reusing

[Andrey A. <an...@uc...>]

Dear Friends,

All of us enjoy the VPython environment. Little by little gaining the 
experience we want to create some scripts in Python for building one or more 
scenes full of objects.
I am a math high school teacher. It would be better for my (or our) students 
to save their scenes and use them in their next lessons. To be more specific 
I mean saving the scene in a file for example using the output  of the 
command:
    scene.objects
Could anyone help me to solve this problem. Any hints, links ang suggestions 
are welcome.
I joined the VPython user list from last May 2005 and didn't meet 
discussions on this topic.

ThX in advance

Andrio
Math teacher 

Re: [Visualpython-users] Problems running configure

[Colin K. <te...@ge...>]

Colin Kingsley wrote:
> On 2/23/06, Keegan Carruthers-Smith <kee...@gm...> wrote:
>  > Hi
>  > I have been trying to compile VPython on my Gentoo Linux system.
>  > It keeps on dying on the configure trying to configure libgtkglarea.
>  > I have attached the config.log
>  >
>  > This is the output of the command:
>  >         emerge -p boost gcc python gtk+ gtkglarea numeric
>  >
>  >         [ebuild   R   ] dev-libs/boost-1.31.0
>  >         [ebuild   R   ] sys-devel/gcc-3.3.5-r1
>  >         [ebuild   R   ] dev-lang/python-2.3.4-r1
>  >         [ebuild   R   ] x11-libs/gtk+-2.6.4-r1
>  >         [ebuild   R   ] x11-libs/gtkglarea-1.99.0
>  >         [ebuild   R   ] dev-python/numeric-23.1
>  >
>  > So I do have all the dependencies required. I have also tried remerging
>  > gtkglarea. Also all the version numbers of the packages are above or 
> equal to
>  > the required versions.
>  >
>  > Thanks in advance with any assistance.
>  > Keegan Carruthers-Smith
> 
> 
> It seems, from the config log, that you are trying to build version 
> 3.2.8, for which I have not yet committed an ebuild. Therefore, if this 
> is a gentoo/ebuild issue, I cant really be much help because I don't 
> know anything about the ebuild you are using.
> 
> If nobody figures out the problem, then see if my ebuild works any 
> better, when I commit it. That should happen within a week.
> 
> Good Luck
> Tercel

I just committed version 3.2.9. See if your problem persists with this 
version. I if it does, please post a bug on bugs.gentoo.org, and assign 
it to me (te...@ge...). I'll fix it if its a gentoo problem, and 
if its a visual problem I'll bring it to the vpython devs.

Thanks
Colin

[Visualpython-users] Version 3.2.9

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

Version 3.2.9: Corrects a bug in the helix object (initial specification 
of an axis didn't treat the length properly) and in the faces object 
(didn't "broadcast" a single vector across all normals). Improved 
documentation of label and of stereo options.

The Linux version is available at vpython.org and would normally also be 
available at sourceforge.net, but that site is currently not functioning 
fully.

Bruce Sherwood

Re: [Visualpython-users] Problems running configure

[Colin K. <te...@ge...>]

On 2/23/06, Keegan Carruthers-Smith <kee...@gm...> wrote:
 > Hi
 > I have been trying to compile VPython on my Gentoo Linux system.
 > It keeps on dying on the configure trying to configure libgtkglarea.
 > I have attached the config.log
 >
 > This is the output of the command:
 >         emerge -p boost gcc python gtk+ gtkglarea numeric
 >
 >         [ebuild   R   ] dev-libs/boost-1.31.0
 >         [ebuild   R   ] sys-devel/gcc-3.3.5-r1
 >         [ebuild   R   ] dev-lang/python-2.3.4-r1
 >         [ebuild   R   ] x11-libs/gtk+-2.6.4-r1
 >         [ebuild   R   ] x11-libs/gtkglarea-1.99.0
 >         [ebuild   R   ] dev-python/numeric-23.1
 >
 > So I do have all the dependencies required. I have also tried remerging
 > gtkglarea. Also all the version numbers of the packages are above or 
equal to
 > the required versions.
 >
 > Thanks in advance with any assistance.
 > Keegan Carruthers-Smith


It seems, from the config log, that you are trying to build version 
3.2.8, for which I have not yet committed an ebuild. Therefore, if this 
is a gentoo/ebuild issue, I cant really be much help because I don't 
know anything about the ebuild you are using.

If nobody figures out the problem, then see if my ebuild works any 
better, when I commit it. That should happen within a week.

Good Luck
Tercel

[Visualpython-users] Problems running configure

[Keegan Carruthers-S. <kee...@gm...>]

Hi
I have been trying to compile VPython on my Gentoo Linux system.
It keeps on dying on the configure trying to configure libgtkglarea.
I have attached the config.log

This is the output of the command:
=09emerge -p boost gcc python gtk+ gtkglarea numeric

=09[ebuild   R   ] dev-libs/boost-1.31.0
=09[ebuild   R   ] sys-devel/gcc-3.3.5-r1
=09[ebuild   R   ] dev-lang/python-2.3.4-r1
=09[ebuild   R   ] x11-libs/gtk+-2.6.4-r1
=09[ebuild   R   ] x11-libs/gtkglarea-1.99.0
=09[ebuild   R   ] dev-python/numeric-23.1

So I do have all the dependicies required. I have also tried remerging
gtkglarea. Also all the version numbers of the packages are above or equal =
to
the required versions.

Thanks in advance with any assistance.
Keegan Carruthers-Smith

[Visualpython-users] Re: Python/C++

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

I realize this is not the list for this question, but some of you might
know, and I'm not currently on the Python list....

Can anyone tell me how Python implements C++ in the case of _tuples_?

I'm assuming Python is built somewhat on C (or C++), and in C++ you can't
return more than one item from a function, but Python allows one to return
as many (up to 10?) variables as one wants (this is one reason Python is so
"powerful"; returning three variables at once makes it a 'natural' for 3D
space work with lots and lots of x,y,z dealings).

I'm primarily curious (I don't have a problem in C++ other than lots more
code to do the same things as I did in Python).  I just would like to know
if Python is 'behind the scenes' implementing something like a struct or a
class and/or using ' return *this ' -type C++ things, in order to allow
multiple outputs from functions.

(Thanks, if anyone knows, and thanks, if I'm just stupid and Python isn't
based on C anyway.)

Peace
JB
jb...@te...
Web: http://tetrahedraverse.com

[Visualpython-users] failure to import visual

[James F. <fo...@ys...>]

I have eventually managed to install VPython.
When, though, I type "import visual" in a Python shell, I get the following 
message error:

Traceback (most recent call last):
  File "<stdin>", line 1, in ?
  File "/home/james/binPYTHON/lib/python2.4/site-packages/visual/__init__.py", 
line 15, in ?
    import array_backend
  File 
"/home/james/binPYTHON/lib/python2.4/site-packages/visual/array_backend.py", 
line 1, in ?
    import cvisual
ImportError: /usr/lib/libboost_python.so.1: undefined symbol: 
PyUnicodeUCS4_FromEncodedObject


Anyone knows how I could solve this problem?

Thank you!

J
-- 
Dr James Foadi PhD
York Structural Biology Laboratory (YSBL)
Department of Chemistry
University of York
Heslington
York YO10 5YW
UK