How to find a random point in a quadrangle?

Question

I have to be able to set a random location for a waypoint for a flight sim. The maths challenge is straightforward:

\"To find a single random location within a quadrangl

Answer 1

So, it depends on how you want your distribution.

If you want the points randomly sampled in your 2d view space, then Jacob's answer is great. If you want the points to be sort of like a perspective view (in your example image, more density in top right than bottom left), then you can use bilinear interpolation.

Bilinear interpolation is pretty easy. Generate two random numbers s and t in the range [0..1]. Then if your input points are p0,p1,p2,p3 the bilinear interpolation is:

bilerp(s,t) = t*(s*p3+(1-s)*p2) + (1-t)*(s*p1+(1-s)*p0)

The main difference is whether you want your distribution to be uniform in your 2d space (Jacob's method) or uniform in parameter space.