#!/usr/bin/tclsh
#
# This scripts parses a series of tecplot style files of triangles and displays them via VMD's graphics interface

# fname is the filename prefix of the tecplot .dat files, e.g. "convex" for "convex-0.dat"
proc convexizing { fname steps} {
	global framesteps
	global fileprefix
	set framesteps $steps
	set fileprefix $fname

	# avoid some 'animate dup' bug
	set molid [molinfo top]
	if {$steps < 2} {
		error "steps should be greater than 2."
	}
	# make tcount-1 copies of current frame
	for {set i 0} {$i <$steps} {incr i} {
		animate dup frame 0 $molid
	}
	animate goto 0

	global vmd_frame
	trace variable vmd_frame([molinfo top]) w update_current_surface
	display update
	return
}	

proc update_current_surface {name index op} { 
	global fileprefix

	set frame [molinfo $index get frame]
	set oldncount 0
	set oldtriangles {}
	if {$frame > 0} {
		# open file
		set previousframe [expr $frame - 1]
		set fname "$fileprefix-$previousframe.dat"
		#puts "Opening old file $fname."
		set file [open $fname r]
		gets $file title
		gets $file variables
		gets $file zone
		# parse nodes
		set ncount 1
		gets $file line
		while { $line != {} } {
			set nodes($ncount) $line
			incr ncount
			gets $file line
		}
		set ncount [ expr $ncount -1 ]
		set oldncount $ncount
		#puts "There are $ncount nodes."
		# there's a blank line in between
		# parse triangles
		set tcount 0
		gets $file line
		while { $line != {} } {
			set triangles [ split $line " "]
			set oldtriangles [lappend oldtriangles $triangles]
			incr tcount
			gets $file line
		}
		close $file
	}
	# open file
	set fname "$fileprefix-$frame.dat"
	#puts "Opening new file $fname."
	set file [open $fname r]
	gets $file title
	gets $file variables
	gets $file zone
	# parse nodes
	set ncount 1
	gets $file line
	while { $line != {} } {
		set nodes($ncount) $line
		incr ncount
		gets $file line
	}
	set ncount [ expr $ncount -1 ]
	puts "There are $ncount nodes, and $oldncount old ones."
	# there's a blank line in between
	# parse triangles
	set tcount 0
	gets $file line
	set newtriangles {}
	set commontriangles {}
	while { $line != {} } {
		set triangles [ split $line " "]
		if {$ncount == $oldncount} {
			# search in oldtriangles
			set index [lsearch $oldtriangles $triangles]
			if {$index == -1} {
				# not present, then mind in new ones
				#puts "$triangles not present in old ones."
				set newtriangles [lappend newtriangles $triangles]
			} else {
				# present in both, hence remove in old ones
				#puts "$triangles present in old ones."
				set commontriangles [lappend commontriangles $triangles]
				set oldtriangles [lreplace $oldtriangles[set oldtriangles {}] $index $index]
			}
		} else {
			set newtriangles [lappend newtriangles $triangles]
		}
		incr tcount
		gets $file line
	}
	close $file
	#puts "There are $tcount triangles."
	
	# draw all remaining old and new ones
	draw delete all
	foreach triangles $commontriangles {
		set first [ lrange $nodes([ lindex $triangles 0 ]) 0 2 ]
		set second [ lrange $nodes([ lindex $triangles 1 ]) 0 2 ]
		set third [ lrange $nodes([ lindex $triangles 2 ]) 0 2 ]
		draw color green
		draw material Transparent
		#puts "common: $first $second $third"
		#draw line $first $second style dashed
		#draw line $first $third style dashed
		#draw line $second $third style dashed
		draw triangle $first $second $third
	}	

	if {$ncount == $oldncount} {
		foreach triangles $oldtriangles {
			set first [ lrange $nodes([ lindex $triangles 0 ]) 0 2 ]
			set second [ lrange $nodes([ lindex $triangles 1 ]) 0 2 ]
			set third [ lrange $nodes([ lindex $triangles 2 ]) 0 2 ]
			draw color blue
			draw material Diffuse
			#puts "old: $first $second $third"
			draw triangle $first $second $third
		}
	}
	foreach triangles $newtriangles {
		set first [ lrange $nodes([ lindex $triangles 0 ]) 0 2 ]
		set second [ lrange $nodes([ lindex $triangles 1 ]) 0 2 ]
		set third [ lrange $nodes([ lindex $triangles 2 ]) 0 2 ]
		draw color red
		draw material Transparent
		#puts "new: $first $second $third"
		draw triangle $first $second $third
	}	

	return
}

proc convexizing_off {} {
	global vmd_frame
	global framesteps
	trace vdelete vmd_frame([molinfo top]) w update_current_surface
	draw delete all
	animate delete beg 1 end $framesteps skip 0 [molinfo top]
	return
}