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Suppose I have a line segment going from (x1,y1) to (x2,y2). How do I calculate the normal vector perpendicular to the line?
I can find lots of stuff about doing this for planes in 3D, but no 2D stuff.
Please go easy on the maths (links to worked examples, diagrams or algorithms are welcome), I’m a programmer more than I’m a mathematician 😉
If we define
dx = x2 - x1anddy = y2 - y1, then the normals are(-dy, dx)and(dy, -dx).Note that no division is required, and so you’re not risking dividing by zero.