How do I find the coordinates inside a rectangle or triangle?

How would I go about finding the coordinates for random points inside this rectangle?

This is the code used:

n=20;

x=linspace(-1,1,n);

y=linspace(-1,1,n);

[x,y]=meshgrid(x,y);

z=zeros(n);

for i=1:n

for j=1:n

[N A] = acm_N([x(i,j) y(i,j)],[-1 -1; 1 -1; 1 1; -1 1],acm_def);

z(i,j)=N(10);

end

end

surf(x,y,z);

Answer 1

[Bruno Luong]

INTERP2