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# trim.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, Paul Obermeier. # See file LICENSE for complete license information. # # This program draws a NURBS surface in the shape of a # symmetrical hill, using both a NURBS curve and pwl # (piecewise linear) curve to trim part of the surface. package require tcl3d 0.4.0 # 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 } } # # Initializes the control points of the surface to a small hill. # The control points range from -3 to +3 in x, y, and z # proc init_surface {} { global ctlpoints for { set u 0 } { $u < 4 } { incr u } { for { set v 0 } { $v < 4 } { incr v } { lappend ctlpoints { 0.0 0.0 0.0 } } } for { set u 0 } { $u < 4 } { incr u } { for { set v 0 } { $v < 4 } { incr v } { lset ctlpoints [expr $u * 4 + $v] 0 [expr 2.0*(double($u) - 1.5)] lset ctlpoints [expr $u * 4 + $v] 1 [expr 2.0*(double($v) - 1.5)] if { ($u == 1 || $u == 2) && ($v == 1 || $v == 2) } { lset ctlpoints [expr $u *4 + $v] 2 3.0 } else { lset ctlpoints [expr $u *4 + $v] 2 -3.0 } } } } # Initialize material property and depth buffer. # proc CreateCallback { toglwin } { global theNurb set mat_diffuse { 0.7 0.7 0.7 1.0 } set mat_specular { 1.0 1.0 1.0 1.0 } set mat_shininess { 100.0 } glClearColor 0.0 0.0 0.0 0.0 glMaterialfv GL_FRONT GL_DIFFUSE $mat_diffuse glMaterialfv GL_FRONT GL_SPECULAR $mat_specular glMaterialfv GL_FRONT GL_SHININESS $mat_shininess glEnable GL_LIGHTING glEnable GL_LIGHT0 glEnable GL_DEPTH_TEST glEnable GL_AUTO_NORMAL glEnable GL_NORMALIZE init_surface set theNurb [gluNewNurbsRenderer] gluNurbsProperty $theNurb GLU_SAMPLING_TOLERANCE 25.0 gluNurbsProperty $theNurb GLU_DISPLAY_MODE $::GLU_FILL } proc DisplayCallback { toglwin } { global theNurb global ctlpoints set knots {0.0 0.0 0.0 0.0 1.0 1.0 1.0 1.0} # counter clockwise set edgePt {{0.0 0.0} {1.0 0.0} {1.0 1.0} {0.0 1.0} {0.0 0.0}} # clockwise set curvePt {{0.25 0.5} {0.25 0.75} {0.75 0.75} {0.75 0.5}} set curveKnots {0.0 0.0 0.0 0.0 1.0 1.0 1.0 1.0} # clockwise set pwlPt {{0.75 0.5} {0.5 0.25} {0.25 0.5}} 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 glRotatef 330.0 1.0 0.0 0.0 glScalef 0.5 0.5 0.5 gluBeginSurface $theNurb gluNurbsSurface $theNurb 8 $knots 8 $knots \ [expr 4 * 3] 3 [join $ctlpoints] \ 4 4 GL_MAP2_VERTEX_3 gluBeginTrim $theNurb gluPwlCurve $theNurb 5 [join $edgePt] 2 GLU_MAP1_TRIM_2 gluEndTrim $theNurb gluBeginTrim $theNurb gluNurbsCurve $theNurb 8 $curveKnots 2 \ [join $curvePt] 4 GLU_MAP1_TRIM_2 gluPwlCurve $theNurb 3 [join $pwlPt] 2 GLU_MAP1_TRIM_2 gluEndTrim $theNurb gluEndSurface $theNurb glPopMatrix glFlush } proc ReshapeCallback { toglwin { w -1 } { h -1 } } { set w [$toglwin width] set h [$toglwin height] glViewport 0 0 $w $h glMatrixMode GL_PROJECTION glLoadIdentity gluPerspective 45.0 [expr double($w)/double($h)] 3.0 8.0 glMatrixMode GL_MODELVIEW glLoadIdentity glTranslatef 0.0 0.0 -5.0 } frame .fr pack .fr -expand 1 -fill both togl .fr.toglwin -width 500 -height 500 -double false -depth true \ -createproc CreateCallback \ -reshapeproc ReshapeCallback \ -displayproc 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 trim" bind .