Demo 55 of 68 in category RedBook
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# stroke.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 some characters of a
# stroke (vector) font. The characters are represented
# by display lists, which are given numbers which
# correspond to the ASCII values of the characters.
# Use of glCallLists() is demonstrated.
package require tcl3d
set X 0
set Y 1
set TYPE 2
set Adata {
{0 0 PT} {0 9 PT} {1 10 PT} {4 10 PT}
{5 9 PT} {5 0 STROKE} {0 5 PT} {5 5 END}
}
set Edata {
{5 0 PT} {0 0 PT} {0 10 PT} {5 10 STROKE}
{0 5 PT} {4 5 END}
}
set Pdata {
{0 0 PT} {0 10 PT} {4 10 PT} {5 9 PT} {5 6 PT}
{4 5 PT} {0 5 END}
}
set Rdata {
{0 0 PT} {0 10 PT} {4 10 PT} {5 9 PT} {5 6 PT}
{4 5 PT} {0 5 STROKE} {3 5 PT} {5 0 END}
}
set Sdata {
{0 1 PT} {1 0 PT} {4 0 PT} {5 1 PT} {5 4 PT}
{4 5 PT} {1 5 PT} {0 6 PT} {0 9 PT} {1 10 PT}
{4 10 PT} {5 9 END}
}
# 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
}
}
# drawLetter interprets the instructions from the array
# for that letter and renders the letter with line segments.
#
proc drawLetter { letter } {
global X Y TYPE
global PT STROKE END
glBegin GL_LINE_STRIP
foreach l $letter {
switch -exact [lindex $l $TYPE] {
PT {
glVertex2f [lindex $l 0] [lindex $l 1]
}
STROKE {
glVertex2f [lindex $l 0] [lindex $l 1]
glEnd
glBegin GL_LINE_STRIP
}
END {
glVertex2f [lindex $l 0] [lindex $l 1]
glEnd
glTranslatef 8.0 0.0 0.0
return
}
}
}
}
# Create a display list for each of 6 characters
proc CreateCallback { toglwin } {
glShadeModel GL_FLAT
set base [glGenLists 128]
glListBase $base
glNewList [expr $base + [tcl3dCharToNum "A"]] GL_COMPILE
drawLetter $::Adata
glEndList
glNewList [expr $base + [tcl3dCharToNum "E"]] GL_COMPILE
drawLetter $::Edata
glEndList
glNewList [expr $base + [tcl3dCharToNum "P"]] GL_COMPILE
drawLetter $::Pdata
glEndList
glNewList [expr $base + [tcl3dCharToNum "R"]] GL_COMPILE
drawLetter $::Rdata
glEndList
glNewList [expr $base + [tcl3dCharToNum "S"]] GL_COMPILE
drawLetter $::Sdata
glEndList
glNewList [expr $base + [tcl3dCharToNum " "]] GL_COMPILE
glTranslatef 8.0 0.0 0.0
glEndList
}
set test1 "A SPARE SERAPE APPEARS AS"
set test2 "APES PREPARE RARE PEPPERS"
proc printStrokedString { s } {
set len [string length $s]
if { $len > 0 } {
set sa [tcl3dVectorFromString GLubyte $s]
glCallLists $len GL_BYTE $sa
$sa delete
}
}
proc DisplayCallback { toglwin } {
global test1 test2
glClear GL_COLOR_BUFFER_BIT
# Viewport command is not really needed, but has been inserted for
# Mac OSX. Presentation framework (Tk) does not send a reshape event,
# when switching from one demo to another.
glViewport 0 0 [$toglwin width] [$toglwin height]
glColor3f 1.0 1.0 1.0
glPushMatrix
glScalef 2.0 2.0 2.0
glTranslatef 10.0 30.0 0.0
printStrokedString $test1
glPopMatrix
glPushMatrix
glScalef 2.0 2.0 2.0
glTranslatef 10.0 13.0 0.0
printStrokedString $test2
glPopMatrix
glFlush
$toglwin swapbuffers
}
proc ReshapeCallback { toglwin { w -1 } { h -1 } } {
set w [$toglwin width]
set h [$toglwin height]
glViewport 0 0 $w $h
glMatrixMode GL_PROJECTION
glLoadIdentity
gluOrtho2D 0.0 $w 0.0 $h
}
frame .fr
pack .fr -expand 1 -fill both
togl .fr.toglwin -width 440 -height 120 -double true \
-createcommand CreateCallback \
-reshapecommand ReshapeCallback \
-displaycommand DisplayCallback
listbox .fr.usage -font $::listFont -height 1
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 stroke"
bind . <Key-Escape> "exit"
.fr.usage insert end "Key-Escape Exit"
.fr.usage configure -state disabled
PrintInfo [tcl3dOglGetInfoString]
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