How to create triangle based sensor deployment using NS2?

The network area is formed as a triangle shape. This region act as a cluster that contain sensor nodes. The formula for a region is
Area = (x1*(y2-y3) + x2*(y3-y1) + x3*(y1-y2))/2.0

TCL part :
proc area {a1 b1 a2 b2 a3 b3} {
set ax [expr $b2 – $b3]
set ay [expr $b3 – $b1]
set az [expr $b1 – $b2]
set axx [expr $ax * $a1]
set ayy [expr $ay * $a2]
set azz [expr $az * $a3]
set hx [expr $axx + $ayy + $azz]
set ar [expr $hx / 2.0]
set arr [expr abs($ar)]
puts “Distance between x1 and x2 = $arr”
return $arr
}
proc isinside {c1 d1 c2 d2 c3 d3 c d g} {
global now ns
set inside 0
set A [area $c1 $d1 $c2 $d2 $c3 $d3]
set A1 [area $c $d $c2 $d2 $c3 $d3]
set A2 [area $c1 $d1 $c $d $c3 $d3]
set A3 [area $c1 $d1 $c2 $d2 $c $d]
set AA [expr $A1 + $A2 + $A3]
set diff [expr $AA – $A]
puts “the A and $A yyyyyyyy AA and $AA and $diff”
if {$A == $AA || $diff < 10} {
set inside [expr $inside + 1]
puts “Nodes inside the triangle $g and $inside ”
}
return $inside
}
for {set i 0} {$i < $val(nn) } {incr i } {
set now [$ns now]
if {$xx($i) > 0 && $xx($i) < 200} {
if {$yy($i) < 200} {
set xx1 0
set yy1 0
set xx2 200
set yy2 0
set xx3 100
set yy3 200
set ins [isinside $xx1 $yy1 $xx2 $yy2 $xx3 $yy3 $xx($i) $yy($i) $i]
if {$ins == 1} {
$ns at [expr $now + 0.1] “$node_($i) color darkcyan”
puts “the color of node $i”
}
}
}
}

Screenshot

Triangle based sensor deployment Creation using NS2