Detecting if a point is inside or outside of a path

my favorite way to see if a point is inside or outside a path, is using its winding number🍥

traverse the path from the perspective of a point and add up the amount of turning along the way

if it made a full turn, it's inside
if it wound back to 0, it's outside

it's so neat~💖 pic.twitter.com/oDGxq697cI

— Freya the stray ✈ Dutch Game Day, Oct 4-5 (@FreyaHolmer) February 27, 2020