Home/ Questions/Q 1024943
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-05-16T11:51:10+00:00

How can I test whether a line has a point that lies within (not

  • 0

How can I test whether a line has a point that lies within (not on the edge of) a triangle. (All in 2D).

Currently I’m thinking I’ll do this:

  • Define the line, and each side of the triangle as Ax+By+C=0, and have an xrange.
  • Check if the line intersects any of the lines of the triangle.
  • If it does, check that this is NOT at the end of the line.

Is there a better way to do this?

Share

Leave an answer

You must login to add an answer.

Need An Account,

1 Answer

  1. Editorial Team

    1. substitute the 3 points into the line’s equation. e.g. if the line is 4x − 3y + 2 = 0, and the triangle’s vertices are (2, 1), (4, 3), (0, 5), we get the values 7, 9 and -13 respectively.

    2. check if all values are of the same sign. If yes, the line does not intersect the triangle. In the above example, the line intersects the triangle.

      http://www.imgftw.net/img/743059947.png

    • 0