Demo 46 of 68 in category RedBook
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# polyoff.tcl
#
# An example of the OpenGL red book modified to work with Tcl3D.
# The original C sources are Copyright (c) 1993-2003, Silicon Graphics, Inc.
# The Tcl3D sources are Copyright (c) 2005-2022, Paul Obermeier.
# See file LICENSE for complete license information.
#
# This program demonstrates polygon offset to draw a shaded
# polygon and its wireframe counterpart without ugly visual
# artifacts ("stitching").
package require tcl3d
set spinx 0
set spiny 0
set tdist 0.0
set polyfactor 1.0
set polyunits 1.0
# Font to be used in the Tk listbox.
set listFont {-family {Courier} -size 10}
# 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
}
}
# display() draws two spheres, one with a gray, diffuse material,
# the other sphere with a magenta material with a specular highlight.
#
proc DisplayCallback { toglwin } {
set mat_ambient { 0.8 0.8 0.8 1.0 }
set mat_diffuse { 1.0 0.0 0.5 1.0 }
set mat_specular { 1.0 1.0 1.0 1.0 }
set gray { 0.8 0.8 0.8 1.0 }
set black { 0.0 0.0 0.0 1.0 }
glClear [expr $::GL_COLOR_BUFFER_BIT | $::GL_DEPTH_BUFFER_BIT]
# Viewport command is not really needed, but has been inserted for
# Mac OSX. Presentation framework (Tk) does not send a reshape event,
# when switching from one demo to another.
glViewport 0 0 [$toglwin width] [$toglwin height]
glPushMatrix
glTranslatef 0.0 0.0 $::tdist
glRotatef $::spinx 1.0 0.0 0.0
glRotatef $::spiny 0.0 1.0 0.0
glMaterialfv GL_FRONT GL_AMBIENT_AND_DIFFUSE $gray
glMaterialfv GL_FRONT GL_SPECULAR $black
glMaterialf GL_FRONT GL_SHININESS 0.0
glEnable GL_LIGHTING
glEnable GL_LIGHT0
glEnable GL_POLYGON_OFFSET_FILL
glPolygonOffset $::polyfactor $::polyunits
glCallList $::list
glDisable GL_POLYGON_OFFSET_FILL
glDisable GL_LIGHTING
glDisable GL_LIGHT0
glColor3f 1.0 1.0 1.0
glPolygonMode GL_FRONT_AND_BACK GL_LINE
glCallList $::list
glPolygonMode GL_FRONT_AND_BACK GL_FILL
glPopMatrix
glFlush
$toglwin swapbuffers
}
# specify initial properties
# create display list with sphere
# initialize lighting and depth buffer
#
proc CreateCallback { toglwin } {
set light_ambient { 0.0 0.0 0.0 1.0 }
set light_diffuse { 1.0 1.0 1.0 1.0 }
set light_specular { 1.0 1.0 1.0 1.0 }
set light_position { 1.0 1.0 1.0 0.0 }
set global_ambient { 0.2 0.2 0.2 1.0 }
glClearColor 0.0 0.0 0.0 1.0
set ::list [glGenLists 1]
glNewList $::list GL_COMPILE
glutSolidSphere 1.0 20 12
glEndList
glEnable GL_DEPTH_TEST
glLightfv GL_LIGHT0 GL_AMBIENT $light_ambient
glLightfv GL_LIGHT0 GL_DIFFUSE $light_diffuse
glLightfv GL_LIGHT0 GL_SPECULAR $light_specular
glLightfv GL_LIGHT0 GL_POSITION $light_position
glLightModelfv GL_LIGHT_MODEL_AMBIENT $global_ambient
}
proc ReshapeCallback { toglwin { w -1 } { h -1 } } {
set w [$toglwin width]
set h [$toglwin height]
glViewport 0 0 $w $h
glMatrixMode GL_PROJECTION
glLoadIdentity
gluPerspective 45.0 [expr double($w)/double($h)] 1.0 10.0
glMatrixMode GL_MODELVIEW
glLoadIdentity
gluLookAt 0.0 0.0 5.0 0.0 0.0 0.0 0.0 1.0 0.0
}
proc UpdateMsg { str } {
.fr.usage configure -state normal
.fr.usage delete end
.fr.usage insert end $str
.fr.usage configure -state disabled
}
proc IncrPolyUnits {} {
set ::polyunits [expr $::polyunits + 1.0]
UpdateMsg "polyunits is $::polyunits"
.fr.toglwin postredisplay
}
proc DecrPolyUnits {} {
set ::polyunits [expr $::polyunits - 1.0]
UpdateMsg "polyunits is $::polyunits"
.fr.toglwin postredisplay
}
proc IncrPolyFactors {} {
set ::polyfactor [expr $::polyfactor + 0.1]
UpdateMsg "polyfactor is $::polyfactor"
.fr.toglwin postredisplay
}
proc DecrPolyFactors {} {
set ::polyfactor [expr $::polyfactor - 0.1]
UpdateMsg "polyfactor is $::polyfactor"
.fr.toglwin postredisplay
}
proc DecrDistance {} {
if { $::tdist < 4.0 } {
set ::tdist [expr $::tdist + 0.5]
.fr.toglwin postredisplay
}
}
proc IncrDistance {} {
if { $::tdist > -5.0 } {
set ::tdist [expr $::tdist - 0.5]
.fr.toglwin postredisplay
}
}
proc IncrSpinX {} {
set ::spinx [expr ($::spinx + 5) % 360]
.fr.toglwin postredisplay
}
proc IncrSpinY {} {
set ::spiny [expr ($::spiny + 5) % 360]
.fr.toglwin postredisplay
}
frame .fr
pack .fr -expand 1 -fill both
togl .fr.toglwin -double true -depth true \
-createcommand CreateCallback \
-reshapecommand ReshapeCallback \
-displaycommand DisplayCallback
listbox .fr.usage -font $::listFont -height 10
label .fr.info
grid .fr.toglwin -row 0 -column 0 -sticky news
grid .fr.usage -row 1 -column 0 -sticky news
grid .fr.info -row 2 -column 0 -sticky news
grid rowconfigure .fr 0 -weight 1
grid columnconfigure .fr 0 -weight 1
wm title . "Tcl3D demo: OpenGL Red Book example polyoff"
bind . <Key-t> "DecrDistance"
bind . <Key-T> "IncrDistance"
bind . <Key-f> "DecrPolyFactors"
bind . <Key-F> "IncrPolyFactors"
bind . <Key-u> "DecrPolyUnits"
bind . <Key-U> "IncrPolyUnits"
bind . <1> "IncrSpinX"
bind . <2> "IncrSpinY"
bind . <3> "IncrSpinY"
bind . <Control-Button-1> "IncrSpinY"
bind . <Key-Escape> "exit"
.fr.usage insert end "Key-t DecrDistance"
.fr.usage insert end "Key-T IncrDistance"
.fr.usage insert end "Key-f DecrPolyFactors"
.fr.usage insert end "Key-F IncrPolyFactors"
.fr.usage insert end "Key-u DecrPolyUnits"
.fr.usage insert end "Key-U IncrPolyUnits"
.fr.usage insert end "Mouse-L IncrSpinX"
.fr.usage insert end "Mouse-MR IncrSpinY"
.fr.usage insert end "Key-Escape Exit"
.fr.usage insert end "Initialized"
.fr.usage configure -state disabled
PrintInfo [tcl3dOglGetInfoString]
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