Random Numbers in a Domain with unknown function in MATLAB

I want to create an array of random floating-point numbers in MATLAB that are inside D where the boundary D is between

1. ( (0.6+0.1*cos(3t))*cos(t) , (0.6+0.1*cos(3t))*sin(t) ) t \in [0, pi]
2. (x,y) where y=0

How can I create this array in MATLAB?

something like this picture; red points are on the boundary D