This project shows a visualization of the functioning of the algorithm point-in_polygon that determines whether, given a point and a polygon, the point is inside or outside it.
In computational geometry, the point-in-polygon problem asks whether a given point in the plane lies inside or outside a polygon. It is a special case of point location problems and finds applications in areas that deal with processing geometrical data, such as computer graphics.
The number of intersections for a ray passing from the exterior of the polygon to any point; if odd, it shows that the point lies inside the polygon. If it is even, the point lies outside the polygon; this test also works in three dimensions.
If implemented on a computer with finite precision arithmetics, the results may be incorrect if the point lies very close to that boundary, because of rounding errors.
The project is a visualization of the algorithm. The visualization was made with the CANVAS element of JavaScript. The visualization can be displayed here.
It's important to note that the variable precision can be setted to see te problem of the limited precision.
This is a project made as an assignment for the Computer Graphics course of FGV-RJ.