Demo 2 of 68 in category RedBook
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# aapoly.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 draws filled polygons with antialiased
# edges. The special GL_SRC_ALPHA_SATURATE blending
# function is used.
# Pressing the 't' key turns the antialiasing on and off.
package require tcl3d
set polySmooth 1
set NFACE 6
# 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
}
}
proc CreateCallback { toglwin } {
glCullFace GL_BACK
glEnable GL_CULL_FACE
glBlendFunc GL_SRC_ALPHA_SATURATE GL_ONE
glClearColor 0.0 0.0 0.0 0.0
}
proc drawCube { x0 x1 y0 y1 z0 z1 } {
# indices of front, top, left, bottom, right, back faces
set indices {
{4 5 6 7} {2 3 7 6} {0 4 7 3}
{0 1 5 4} {1 5 6 2} {0 3 2 1}
}
set v [list \
[list $x0 $y0 $z0 0.0 0.0 0.0 1.0] \
[list $x1 $y0 $z0 1.0 0.0 0.0 1.0] \
[list $x1 $y1 $z0 0.0 1.0 0.0 1.0] \
[list $x0 $y1 $z0 1.0 1.0 0.0 1.0] \
[list $x0 $y0 $z1 0.0 0.0 1.0 1.0] \
[list $x1 $y0 $z1 1.0 0.0 1.0 1.0] \
[list $x1 $y1 $z1 0.0 1.0 1.0 1.0] \
[list $x0 $y1 $z1 1.0 1.0 1.0 1.0] \
]
set va [tcl3dVectorFromList GLfloat [join [join $v]]]
set ca [tcl3dVectorInd $va GLfloat 3]
set ia [tcl3dVectorFromList GLubyte [join [join $indices]]]
glEnableClientState GL_VERTEX_ARRAY
glEnableClientState GL_COLOR_ARRAY
glVertexPointer 3 GL_FLOAT [expr 4*7] $va
glColorPointer 4 GL_FLOAT [expr 4*7] $ca]
glDrawElements GL_QUADS [expr $::NFACE*4] GL_UNSIGNED_BYTE $ia
glDisableClientState GL_VERTEX_ARRAY
glDisableClientState GL_COLOR_ARRAY
}
# Note: polygons must be drawn from front to back for proper blending.
proc DisplayCallback { toglwin } {
# Viewport command is not really needed, but has been inserted for
# Mac OSX. Presentation framework (Tk) does not send a reshape event,
# when switching from one demo to another.
glViewport 0 0 [$toglwin width] [$toglwin height]
if { $::polySmooth } {
glClear GL_COLOR_BUFFER_BIT
glEnable GL_BLEND
glEnable GL_POLYGON_SMOOTH
glDisable GL_DEPTH_TEST
} else {
glClear [expr $::GL_COLOR_BUFFER_BIT | $::GL_DEPTH_BUFFER_BIT]
glDisable GL_BLEND
glDisable GL_POLYGON_SMOOTH
glEnable GL_DEPTH_TEST
}
glPushMatrix
glTranslatef 0.0 0.0 -8.0
glRotatef 30.0 1.0 0.0 0.0
glRotatef 60.0 0.0 1.0 0.0
drawCube -0.5 0.5 -0.5 0.5 -0.5 0.5
glPopMatrix
glFlush
$toglwin swapbuffers
}
proc ReshapeCallback { toglwin { w -1 } { h -1 } } {
set w [$toglwin width]
set h [$toglwin height]
glViewport 0 0 $w $h
glMatrixMode GL_PROJECTION
glLoadIdentity
gluPerspective 30.0 [expr double($w)/double($h)] 1.0 20.0
glMatrixMode GL_MODELVIEW
glLoadIdentity
}
proc ToggleSmooth {} {
set ::polySmooth [expr ! $::polySmooth]
.fr.toglwin postredisplay
}
frame .fr
pack .fr -expand 1 -fill both
togl .fr.toglwin -width 400 -height 400 \
-double true -depth true -alpha true \
-createcommand CreateCallback \
-reshapecommand ReshapeCallback \
-displaycommand DisplayCallback
listbox .fr.usage -font $::listFont -height 2
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 aapolyStride"
bind . <Key-Escape> "exit"
bind . <Key-t> "ToggleSmooth"
.fr.usage insert end "Key-t Toggle smoothing"
.fr.usage insert end "Key-Escape Exit"
.fr.usage configure -state disabled
PrintInfo [tcl3dOglGetInfoString]
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