no display name and no $DISPLAY environment variable
    while executing
"load /enadisk/commun/linux/local/ActiveTcl-8.6.11/lib/libtk8.6.so Tk"
    ("package ifneeded Tk 8.6.11" script)
    invoked from within
"package require Tk"
    (in namespace eval "::request" script line 15)
    invoked from within
"namespace eval ::request $script"
    ("::try" body line 12)
OUTPUT BUFFER:
# Copyright:      2006-2010 Paul Obermeier (obermeier@tcl3d.org)
#
#                 See the file "Tcl3D_License.txt" for information on 
#                 usage and redistribution of this file, and for a
#                 DISCLAIMER OF ALL WARRANTIES.
#
# Module:         Tcl3D -> tcl3dOde
# Filename:       odeGravity.tcl
#
# Author:         Paul Obermeier
#
# Description:    Tcl3D Ode example: Bodies influenced by gravity.
#                 Based on PyODE Tutorial 1 By Matthias Baas.

package require Tk
package require tcl3d 0.5.0

if { [info procs tcl3dHaveOde] ne "" } {
    if { ![tcl3dHaveOde] } {
        tk_messageBox -icon error -type ok -title "Error" \
                      -message "You do not have ODE installed."
        exit
    }
}

# Show errors occuring in the Togl callbacks.
proc bgerror { msg } {
    tk_messageBox -icon error -type ok -message "Error: $msg\n\n$::errorInfo"
    exit
}

# Print info message into widget a the bottom of the window.
proc PrintInfo { msg } {
    if { [winfo exists .fr.info] } {
        .fr.info configure -text $msg
    }
}

proc Cleanup {} {
    .fr.toglwin delete $::id1 $::id2
}

proc ExitProg {} {
    exit
}

proc StartAnimation {} {
    if { [info exists ::animateId] } {
        return
    }
    set x1 0
    set y1 2
    set z1 0
    set x2 1
    set y2 2
    set z2 0

    set ::world [dWorldCreate]
    dWorldSetGravity $::world 0 -9.81 0

    set body1 [dBodyCreate $::world]
    set body2 [dBodyCreate $::world]

    set M [new_dMass]
    dMassSetZero $M
    dMassSetSphere $M 2500 0.05
    dMassAdjust $M 1.0
    dBodySetMass $body1 $M

    dMassAdjust $M 1.5
    dBodySetMass $body2 $M

    dBodySetPosition $body1 $x1 $y1 $z1
    dBodyAddForce $body1 0 200 0
    dBodySetPosition $body2 $x2 $y2 $z2
    dBodyAddForce $body2 0 200 0

    set ::total_time 0.0
    set ::dt 0.04

    animate $body1 $body2
}

proc StopAnimation {} {
    if { [info exists ::animateId] } {
        after cancel $::animateId 
        unset ::animateId
    }
}

proc animate { body1 body2 } {
    set pos [dBodyGetPosition $body1]
    set x1 [dReal_getitem $pos 0]
    set y1 [dReal_getitem $pos 1]
    set z1 [dReal_getitem $pos 2]
    .fr.toglwin coords $::id1 \
          [expr 200 + $x1*100-5] [expr 600 - $y1*100-5] \
          [expr 200 + $x1*100+5] [expr 600 - $y1*100+5]
    set pos [dBodyGetPosition $body2]
    set x2 [dReal_getitem $pos 0]
    set y2 [dReal_getitem $pos 1]
    set z2 [dReal_getitem $pos 2]
    .fr.toglwin coords $::id2 \
          [expr 200 + $x2*100-5] [expr 600 - $y2*100-5] \
          [expr 200 + $x2*100+5] [expr 600 - $y2*100+5]

    dWorldStep $::world $::dt
    set ::total_time [expr $::total_time + $::dt]
    update idletasks
    after 100
    if { $y1 < 0.0 || $y2 < 0.0 } {
        StopAnimation
    }
    set ::animateId [tcl3dAfterIdle "animate $body1 $body2"]
}

# Master frame. Needed to integrate demo into Tcl3D Starpack presentation.
frame .fr
pack .fr -expand 1 -fill both

canvas .fr.toglwin -width 400 -height 600 -bg white
label .fr.info
grid .fr.toglwin -row 0 -column 0 -sticky news
grid .fr.info    -row 1 -column 0 -sticky news
grid rowconfigure .fr 0 -weight 1
grid columnconfigure .fr 0 -weight 1

# Watch For ESC Key And Quit Messages
wm protocol . WM_DELETE_WINDOW "ExitProg"
bind .  "ExitProg"
bind . <1> "StartAnimation"
bind . <2> "StopAnimation"
bind . <3> "StopAnimation"
bind .  "StopAnimation"

set id1 [.fr.toglwin create oval -2 -2 -1 -1 -fill red]
set id2 [.fr.toglwin create oval -2 -2 -1 -1 -fill red]
.fr.toglwin create line 0 400 1000 400

wm title . "Tcl3D demo (ODE): Bodies with gravity"

PrintInfo [format "Running on %s with Tcl %s" \
           $tcl_platform(os) [info patchlevel]]

if { [file tail [info script]] == [file tail $::argv0] } {
    # If started directly from tclsh or wish, then start animation.
    update
    StartAnimation
}