Concepts6
Sweepline Technique
The sweep line technique processes geometric or time-based events in sorted order and maintains an active set that reflects the current state at the sweep position.
Line Sweep
Line sweep (plane sweep) is a technique that processes geometric objects by moving an imaginary line and handling events in sorted order.
Basic Geometry - Lines and Segments
A line can be represented by two points, a point with a direction vector, or the general form ax + by + c = 0, and these forms are interconvertible.
Point in Polygon
Point-in-polygon decides whether a point lies outside, inside, or on the boundary of a polygon.
Orientation and CCW
Orientation (CCW test) tells whether three points make a left turn, right turn, or are collinear by using the sign of a 2D cross product.
Basic Geometry - Points and Vectors
A 2D point can be treated as a vector from the origin, so vector math (addition, scaling, dot, cross) applies directly to points.