Demo 5 of 68 in category RedBook
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# accpersp.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.
#
# Use the accumulation buffer to do full-scene antialiasing
# on a scene with perspective projection, using the special
# routines accFrustum() and accPerspective().
package require tcl3d
source [file join [file dirname [info script]] "jitter.tclinc"]
# 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
}
}
# The first 6 arguments are identical to the glFrustum() call.
#
# pixdx and pixdy are anti-alias jitter in pixels.
# Set both equal to 0.0 for no anti-alias jitter.
# eyedx and eyedy are depth-of field jitter in pixels.
# Set both equal to 0.0 for no depth of field effects.
#
# focus is distance from eye to plane in focus.
# focus must be greater than, but not equal to 0.0.
#
# Note that accFrustum() calls glTranslatef(). You will
# probably want to insure that your ModelView matrix has been
# initialized to identity before calling accFrustum().
#
proc accFrustum { left right bottom top near far \
pixdx pixdy eyedx eyedy focus } {
set viewport [tcl3dOglGetViewport]
set xwsize [expr $right - $left]
set ywsize [expr $top - $bottom]
set dx [expr -($pixdx*$xwsize/double([lindex $viewport 2]) + \
$eyedx*$near/$focus)]
set dy [expr -($pixdy*$ywsize/double([lindex $viewport 3]) + \
$eyedy*$near/$focus)]
glMatrixMode GL_PROJECTION
glLoadIdentity
glFrustum [expr $left + $dx] [expr $right + $dx] \
[expr $bottom + $dy] [expr $top + $dy] $near $far
glMatrixMode GL_MODELVIEW
glLoadIdentity
glTranslatef [expr -1.0 * $eyedx] [expr -1.0 * $eyedy] 0.0
}
# The first 4 arguments are identical to the gluPerspective() call.
# pixdx and pixdy are anti-alias jitter in pixels.
# Set both equal to 0.0 for no anti-alias jitter.
# eyedx and eyedy are depth-of field jitter in pixels.
# Set both equal to 0.0 for no depth of field effects.
#
# focus is distance from eye to plane in focus.
# focus must be greater than, but not equal to 0.0.
#
# Note that accPerspective() calls accFrustum().
#
proc accPerspective { fovy aspect near far pixdx pixdy \
eyedx eyedy focus } {
set PI_ 3.14159265358979323846
set fov2 [expr (($fovy*$PI_) / 180.0) / 2.0]
set top [expr $near / (cos($fov2) / sin($fov2))]
set bottom [expr -1 * $top]
set right [expr $top * $aspect]
set left [expr -1 * $right]
accFrustum $left $right $bottom $top $near $far \
$pixdx $pixdy $eyedx $eyedy $focus
}
# Initialize lighting and other values.
#
proc CreateCallback { toglwin } {
set mat_ambient { 1.0 1.0 1.0 1.0 }
set mat_specular { 1.0 1.0 1.0 1.0 }
set light_position { 0.0 0.0 10.0 1.0 }
set lm_ambient { 0.2 0.2 0.2 1.0 }
glMaterialfv GL_FRONT GL_AMBIENT $mat_ambient
glMaterialfv GL_FRONT GL_SPECULAR $mat_specular
glMaterialf GL_FRONT GL_SHININESS 50.0
glLightfv GL_LIGHT0 GL_POSITION $light_position
glLightModelfv GL_LIGHT_MODEL_AMBIENT $lm_ambient
glEnable GL_LIGHTING
glEnable GL_LIGHT0
glEnable GL_DEPTH_TEST
glShadeModel GL_FLAT
glClearColor 0.0 0.0 0.0 0.0
glClearAccum 0.0 0.0 0.0 0.0
}
proc displayObjects {} {
set torus_diffuse { 0.7 0.7 0.0 1.0 }
set cube_diffuse { 0.0 0.7 0.7 1.0 }
set sphere_diffuse { 0.7 0.0 0.7 1.0 }
set octa_diffuse { 0.7 0.4 0.4 1.0 }
glPushMatrix
glTranslatef 0.0 0.0 -5.0
glRotatef 30.0 1.0 0.0 0.0
glPushMatrix
glTranslatef -0.80 0.35 0.0
glRotatef 100.0 1.0 0.0 0.0
glMaterialfv GL_FRONT GL_DIFFUSE $torus_diffuse
glutSolidTorus 0.275 0.85 16 16
glPopMatrix
glPushMatrix
glTranslatef -0.75 -0.50 0.0
glRotatef 45.0 0.0 0.0 1.0
glRotatef 45.0 1.0 0.0 0.0
glMaterialfv GL_FRONT GL_DIFFUSE $cube_diffuse
glutSolidCube 1.5
glPopMatrix
glPushMatrix
glTranslatef 0.75 0.60 0.0
glRotatef 30.0 1.0 0.0 0.0
glMaterialfv GL_FRONT GL_DIFFUSE $sphere_diffuse
glutSolidSphere 1.0 16 16
glPopMatrix
glPushMatrix
glTranslatef 0.70 -0.90 0.25
glMaterialfv GL_FRONT GL_DIFFUSE $octa_diffuse
glutSolidOctahedron
glPopMatrix
glPopMatrix
}
proc DisplayCallback { toglwin } {
set ACSIZE 8
# Viewport command is not really needed, but has been inserted for
# Mac OSX. Presentation framework (Tk) does not send a reshape event,
# when switching from one demo to another.
glViewport 0 0 [$toglwin width] [$toglwin height]
set viewport [tcl3dOglGetViewport]
glClear GL_ACCUM_BUFFER_BIT
for { set jitter 0 } { $jitter < $ACSIZE } { incr jitter } {
glClear [expr $::GL_COLOR_BUFFER_BIT | $::GL_DEPTH_BUFFER_BIT]
set jitPnt [lindex $::j($ACSIZE) $jitter]
accPerspective 50.0 \
double([lindex $viewport 2])/double([lindex $viewport 3]) \
1.0 15.0 \
[lindex $jitPnt 0] \
[lindex $jitPnt 1] \
0.0 0.0 1.0
displayObjects
glAccum GL_ACCUM [expr 1.0 / $ACSIZE]
}
glAccum GL_RETURN 1.0
glFlush
$toglwin swapbuffers
}
proc ReshapeCallback { toglwin { w -1 } { h -1 } } {
set w [$toglwin width]
set h [$toglwin height]
glViewport 0 0 $w $h
}
frame .fr
pack .fr -expand 1 -fill both
# Create a Togl window using an accumulation buffer.
# Reshape and Display callbacks are configured later after knowing if
# the needed accumulation buffer is available.
set retVal [catch { togl .fr.toglwin \
-width 400 -height 400 \
-double true -accum true -depth true \
-createcommand CreateCallback } errMsg]
if { $retVal != 0 } {
tk_messageBox -icon error -type ok -title "Missing Togl feature" \
-message "Demo needs accumulation buffer: $errMsg"
proc ::Cleanup {} {}
exit 1
return
}
.fr.toglwin configure \
-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 accpersp"
bind . <Key-Escape> "exit"
.fr.usage insert end "Key-Escape Exit"
.fr.usage configure -state disabled
PrintInfo [tcl3dOglGetInfoString]
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