Version 15 of 3dcanvas
Updated 2004-06-30 16:12:16What: 3dcanvas
Where: http://www.ida.liu.se/~petlo/3D_canvas/
Description: This widget implements a three dimensional space in which structured
graphics can be rendered. A 3dcanvas displays any number of items, which may
be things like spheres, polygons, lines and prisms. Items may be manipulated
(e.g. moved or re-colored) and commands may be associated with items in much
the same way that the bind command allows commands to be bound to widgets.
The 3dcanvas also contains a powerful grouping mechanism for manipulating
several spatially related objects as one.
The objects in a 3dcanvas are stored in a hierarchical database together with
associated relations and attributes. This hierarchy is constructed using a
special item type called the group item, which is capable of containing other
items including group items. In the 3dcanvas, all items have their own coordinate
system, which is relative to that of its parent group (this is the group in which
the item is currently placed). All transformations such as scaling or rotating is
performed on this local coordinate system. This means that if a group is rotated,
its coordinate system.
3dcanvas is an old project (Tk4.2) introduced by Peter Loborg.
The small graphics kernel doesn't depend on a third party library.
License: LGPL
Updated: 12/1996 (but v1.0 released 12/2003)
Contact: mailto:[email protected]The 3dcanvas shared library for Tcl8.4.x is available under: - Linux [http://gersoo.free.fr/inform/tcl/3dcanvas/dddcanvas10.so] - Windows [http://gersoo.free.fr/inform/tcl/3dcanvas/dddcanvas10.dll] (compiled by [EB])
Here is a simple demo of 3dcanvas capabilities. It implements an .obj (Alias-Wavefront graphics file format [L1 ]) reader and makes a display in wireframe mode:
.obj file samples and source code below are also available at http://gersoo.free.fr/wiki/w10519/index.html .
# objviz-3dc.tcl
# Author: Gerard Sookahet
# Date: 2004-01-04
# Description: Simple .obj (Alias-Wavefront graphics file format) viewer
load ./libdddcanvas.so
bind all <Escape> { exit }
# Parse .obj file format
proc ObjReader { f } {
global G
if {$f == ""} then return
.c delete all
set nv 0
set nf 0
array set tcoords {}
array set tconnect {}
set fp [open $f r]
set data [read $fp [file size $f]]
close $fp
set data [split $data "\n"]
foreach line $data {
if {[lindex $line 0] == "v"} then {
incr nv
set tcoords($nv) [lrange $line 1 end]
} elseif {[lindex $line 0] == "f"} then {
incr nf
set tconnect($nf) [lrange $line 1 end]
}
}
# Create group items and display lines
set G [.c create group]
for {set i 1} {$i <= $nf} {incr i} {
set lcoords {}
foreach j $tconnect($i) { lappend lcoords $tcoords($j) }
.c addgroup $G items [eval .c create line [join [concat $lcoords] " "] -fill blue]
}
}
# Simple rotation animation for phi and theta angle
proc Animate {} {
global G
.c phirot $G 2
.c thetarot $G 2
after 50 Animate
}
proc BrowseFile { dir filter } {
switch $filter {
obj { set file_types {
{ {Obj files} {.obj} }
{ {all files} * }
}
}
}
set file [tk_getOpenFile -filetypes $file_types \
-initialdir $dir \
-title "$filter File"]
if {$file != ""} { return $file } else { return ""}
}
proc Main {} {
global scx scy scz
global somega sphi stheta
global vdist
global G
set scx 0
set scy 0
set scz -20
set vdist 400
wm title . "Objviz with 3dcanvas"
3dcanvas .c -bg black -width 700 -height 500
pack .c -side top
set f0 [frame .f0]
pack $f0
set f1 [frame $f0.f1]
scale $f1.scx -from 200 -to -200 -length 400 -label "X translation" -orient horiz \
-showvalue true -variable scx -command {.c configure -ox}
scale $f1.scy -from 200 -to -200 -length 400 -label "Y translation" -orient horiz \
-showvalue true -variable scy -command {.c configure -oy}
scale $f1.scz -from 1000 -to -1000 -length 400 -label "Z translation" -orient horiz \
-showvalue true -variable scz -command {.c configure -oz}
scale $f1.vd -from 3000 -to -1000 -length 400 -label "View distance" -orient horiz \
-showvalue true -variable vdist -command {.c configure -viewdistance}
eval pack [winfo children $f1]
set f2 [frame $f0.f2]
scale $f2.scomega -from 180 -to -180 -length 180 -label "Omega angle" -orient horiz \
-showvalue true -variable somega -command {.c configure -omegaangle}
scale $f2.sphi -from 180 -to -180 -length 180 -label "Phi angle" -orient horiz \
-showvalue true -variable sphi -command {.c configure -phiangle}
scale $f2.stheta -from 180 -to -180 -length 180 -label "Theta angle" -orient horiz \
-showvalue true -variable stheta -command {.c configure -thetaangle}
eval pack [winfo children $f2]
set f3 [frame $f0.f3]
button $f3.bloadobj -text "Load obj" -width 9 -command {ObjReader [BrowseFile [pwd] obj]}
button $f3.bromega -text "Omega rotate" -width 9 -command {.c omegarot $G 8}
button $f3.brphi -text "Phi rotate" -width 9 -command {.c phirot $G 8}
button $f3.brtheta -text "Theta rotate" -width 9 -command {.c thetarot $G 8}
button $f3.banim -text Animate -width 9 -command {Animate}
button $f3.babout -text About -width 9 -bg grey -command {About}
button $f3.bquit -text Quit -width 9 -bg grey -command exit
eval pack [winfo children $f3]
pack $f1 $f2 $f3 -side left
}
proc About {} {
set w .about
catch {destroy $w} ; toplevel $w
wm title $w "About this demo"
message $w.msg -justify center -aspect 250 -relief sunken \
-text "3dcanvas demo: a simple .obj viewer\n\nGerard Sookahet\n\
2004-01-04"
button $w.bquit -text Quit -command {destroy .about}
eval pack [winfo children $w]
}
MainGS (040618) Another 3dcanvas demo: the Sierpinski tetrahedron [L2 ]
FW: Does this use any hardware rendering? It almost seems like it.
GS: No. It is based on the same software rendering system as the classical 2D canvas. Apparently, 3dcanvas can be used wherever Tk is used. It just needs to be compiled for the target platform.