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# movelight.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 demonstrates when to issue lighting and # transformation commands to render a model with a light # which is moved by a modeling transformation (rotate or # translate). The light position is reset after the modeling # transformation is called. The eye position does not change. # # A sphere is drawn using a grey material characteristic. # A single light source illuminates the object. # # Interaction: pressing the left mouse button alters # the modeling transformation (x rotation) by 30 degrees. # The scene is then redrawn with the light in a new position. package require tcl3d 0.4.0 set spin 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 } } # Initialize material property, light source, lighting model, and depth buffer. proc CreateCallback { toglwin } { glClearColor 0.0 0.0 0.0 0.0 glShadeModel GL_SMOOTH glEnable GL_LIGHTING glEnable GL_LIGHT0 glEnable GL_DEPTH_TEST } # Here is where the light position is reset after the modeling # transformation (glRotated) is called. This places the # light at a new position in world coordinates. The cube # represents the position of the light. # proc DisplayCallback { toglwin } { set position { 0.0 0.0 1.5 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 gluLookAt 0.0 0.0 5.0 0.0 0.0 0.0 0.0 1.0 0.0 glPushMatrix glRotated $::spin 1.0 0.0 0.0 glLightfv GL_LIGHT0 GL_POSITION $position glTranslated 0.0 0.0 1.5 glDisable GL_LIGHTING glColor3f 0.0 1.0 1.0 glutWireCube 0.1 glEnable GL_LIGHTING glPopMatrix glutSolidTorus 0.275 0.85 8 15 glPopMatrix glFlush } proc ReshapeCallback { toglwin { w -1 } { h -1 } } { set w [$toglwin width] set h [$toglwin height] glViewport 0 0 $w $h glMatrixMode GL_PROJECTION glLoadIdentity gluPerspective 40.0 [expr double($w)/double($h)] 1.0 20.0 glMatrixMode GL_MODELVIEW glLoadIdentity } proc AddSpin {} { set ::spin [expr ($::spin + 30) % 360] .fr.toglwin postredisplay } 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 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 movelight" bind .fr.toglwin <1> "AddSpin" bind .