Winding number

Question

What do you understand by the term winding number? Briefly illustrate it.

Answer 1

Winding number technique is employed to check whether a given point is within or outside the polygon. This technique provides a direction number to all the edges that cross the scan line. When the edge begins beneath the line and ends above scan line provides direction as -1. Or else 1. For polygons or two dimensional objects, the point is stated to be within when the value of winding number is non-zero.