For each line (edge) of the polyhedron you can write it's equation as
(y - y1) = (y1 - y2)(x - x1)/(x1 - x2)
So in case of edge from vertex (0, 2) to (1, 0) you can generate it as -
x = (1 - 0) * rand(n,1) + 0 ; %(x2-x1)*(n random number)+x1
y = (2 - 0)/(0 - 1) * (x - 0) + 2 ; % (y1-y2)/(x1-x2)*(x-x1) + y1
Here 'n' is the number points you need to generate on the edge. You can do it for each pair of adjacent vertices in a loop.