OUTPUT BUFFER:
# select.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 is an illustration of the selection mode and # name stack, which detects whether objects which collide # with a viewing volume. First, four triangles and a # rectangular box representing a viewing volume are drawn # (drawScene routine). The green triangle and yellow # triangles appear to lie within the viewing volume, but # the red triangle appears to lie outside it. Then the # selection mode is entered (selectObjects routine). # Drawing to the screen ceases. To see if any collisions # occur, the four triangles are called. In this example, # the green triangle causes one hit with the name 1, and # the yellow triangles cause one hit with the name 3. package require tcl3d 0.3.1 tcl3dConsoleCreate .tcl3dOutputConsole "# " "Select Output" set BUFSIZE 512 set selectBuffer [tcl3dVector GLuint $::BUFSIZE] # 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" 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 } } # draw a triangle with vertices at (x1, y1), (x2, y2) # and (x3, y3) at z units away from the origin. proc drawTriangle { x1 y1 x2 y2 x3 y3 z } { glBegin GL_TRIANGLES glVertex3f $x1 $y1 $z glVertex3f $x2 $y2 $z glVertex3f $x3 $y3 $z glEnd } # draw a rectangular box with these outer x, y, and z values proc drawViewVolume { x1 x2 y1 y2 z1 z2 } { set negz1 [expr -1.0 * $z1] set negz2 [expr -1.0 * $z2] glColor3f 1.0 1.0 1.0 glBegin GL_LINE_LOOP glVertex3f $x1 $y1 $negz1 glVertex3f $x2 $y1 $negz1 glVertex3f $x2 $y2 $negz1 glVertex3f $x1 $y2 $negz1 glEnd glBegin GL_LINE_LOOP glVertex3f $x1 $y1 $negz2 glVertex3f $x2 $y1 $negz2 glVertex3f $x2 $y2 $negz2 glVertex3f $x1 $y2 $negz2 glEnd glBegin GL_LINES ; # 4 lines glVertex3f $x1 $y1 $negz1 glVertex3f $x1 $y1 $negz2 glVertex3f $x1 $y2 $negz1 glVertex3f $x1 $y2 $negz2 glVertex3f $x2 $y1 $negz1 glVertex3f $x2 $y1 $negz2 glVertex3f $x2 $y2 $negz1 glVertex3f $x2 $y2 $negz2 glEnd } # drawScene draws 4 triangles and a wire frame # which represents the viewing volume. #/ proc drawScene {} { glMatrixMode GL_PROJECTION glLoadIdentity gluPerspective 40.0 [expr 4.0/3.0] 1.0 100.0 glMatrixMode GL_MODELVIEW glLoadIdentity gluLookAt 7.5 7.5 12.5 2.5 2.5 -5.0 0.0 1.0 0.0 glColor3f 0.0 1.0 0.0 ; # green triangle drawTriangle 2.0 2.0 3.0 2.0 2.5 3.0 -5.0 glColor3f 1.0 0.0 0.0 ; # red triangle drawTriangle 2.0 7.0 3.0 7.0 2.5 8.0 -5.0 glColor3f 1.0 1.0 0.0 ; # yellow triangles drawTriangle 2.0 2.0 3.0 2.0 2.5 3.0 0.0 drawTriangle 2.0 2.0 3.0 2.0 2.5 3.0 -10.0 drawViewVolume 0.0 5.0 0.0 5.0 0.0 10.0 } # processHits prints out the contents of the selection array # proc processHits { hits } { set count 0 puts "hits = $hits" for { set i 0 } { $i < $hits } { incr i } { set names [$::selectBuffer get $count] puts " number of names for hit = $names" incr count puts -nonewline [format " z1 is %g;" \ [expr double ([$::selectBuffer get $count]) / 0x7fffffff]] incr count puts [format " z2 is %g" \ [expr double ([$::selectBuffer get $count]) / 0x7fffffff]] incr count puts -nonewline " the name is " for { set j 0 } { $j < $names } { incr j } { puts -nonewline [format "%d " [$::selectBuffer get $count]] incr count } puts "" } } # selectObjects "draws" the triangles in selection mode, # assigning names for the triangles. Note that the third # and fourth triangles share one name, so that if either # or both triangles intersects the viewing/clipping volume, # only one hit will be registered. #/ proc selectObjects {} { glSelectBuffer $::BUFSIZE $::selectBuffer glRenderMode GL_SELECT glInitNames glPushName 0 glPushMatrix glMatrixMode GL_PROJECTION glLoadIdentity glOrtho 0.0 5.0 0.0 5.0 0.0 10.0 glMatrixMode GL_MODELVIEW glLoadIdentity glLoadName 1 drawTriangle 2.0 2.0 3.0 2.0 2.5 3.0 -5.0 glLoadName 2 drawTriangle 2.0 7.0 3.0 7.0 2.5 8.0 -5.0 glLoadName 3 drawTriangle 2.0 2.0 3.0 2.0 2.5 3.0 0.0 drawTriangle 2.0 2.0 3.0 2.0 2.5 3.0 -10.0 glPopMatrix glFlush set hits [glRenderMode GL_RENDER] processHits $hits } proc tclCreateFunc { toglwin } { glEnable GL_DEPTH_TEST glShadeModel GL_FLAT } proc tclReshapeFunc { toglwin w h } { } proc tclDisplayFunc { toglwin } { glClearColor 0.0 0.0 0.0 0.0 glClear [expr $::GL_COLOR_BUFFER_BIT | $::GL_DEPTH_BUFFER_BIT] drawScene selectObjects glFlush } frame .fr pack .fr -expand 1 -fill both togl .fr.toglwin -width 400 -height 400 -double false -depth true \ -createproc tclCreateFunc \ -reshapeproc tclReshapeFunc \ -displayproc tclDisplayFunc 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 select" bind .