How can I generate a 2D triangular domain for plotting a 3D surf on it?

Hi friends

I want to generate a equilateral triangular domain (attached photo) for plotting a 3D surf.

i used the following code to generate it but it doesn't work! I want a similar code to generate the mentioned domain.

x=linspace(0,0.8660254,30);
y=linspace(-0.5773502692.*x,0.5773502692.*x,30);
[x, y]=meshgrid(x, y);

If you know please answer to my question as simple as you can.

Thanks a lot