Finds the area of a triangle

This function will return the area of a triangle. Call it with the coordinates of the points of the triangle.

                                    ` This code was downloaded from The Game Creators
                                    ` It is reproduced here with full permission
                                    ` http://www.thegamecreators.com
                                    
                                    sync on
sync rate 30
hide mouse
do
   cls
   text 0, 0, "Area = " + str$(TriangleArea(0, 0, 300, 200, mousex(), mousey()))
   line 0, 0, 300, 200
   line 300, 200, mousex(), mousey()
   line mousex(), mousey(), 0, 0
   text mousex(), mousey(), str$(mousex()) + ", " + str$(mousey())
   sync
loop

function TriangleArea(x1 as float, y1 as float, x2 as float, y2 as float, x3 as float, y3 as float)
   local area as float
   area = abs(x1 * y2 + y1 * x3 + x2 * y3 - y2 * x3 - x1 * y3 - y1 * x2) / 2
endfunction area