point_in_polygon

Draws by checking if point is inside. This requires a "point in polygon" testing.

documented elsewhere ( ??? )

• https://en.wikipedia.org/wiki/Point_in_polygon
  • mentions :
    • Ray casting algorithm .
    • Winding number algorithm .
  • doesn't mention :
    • Concavity-removal algorithm ( this how I named this not sure if it's already discovered and baptized , named somehow ) .

gif-recorded usage demos

DHTML version (HTML5+ES)

• https://github.com/arkenidar/point_in_polygon
• https://arkenidar.github.io/point_in_polygon/index.html
• https://arkenidar.github.io/point_in_polygon/geometric.js
• https://arkenidar.com/web/gh/point_in_polygon/index.html
• https://arkenidar.com/web/gh/point_in_polygon/geometric.js

Lua, Love2D version

https://github.com/arkenidar/Lua_Love2D_PointInPolygon-Algorithm