Indices,texture,normal .OBJ file.

Hello, my name is Terry and I’m kinda new to blender.
Anyways, my blender when I export to a .OBJ file, it saves the faces like:
f 1//1 2//1 3//1 4//1

f 5//2 8//2 7//2 6//2

f 1//3 5//3 6//3 2//3

f 2//4 6//4 7//4 3//4

f 3//5 7//5 8//5 4//5

f 5//6 1//6 4//6 8//6

I want it to save in 3’s. so my square would have 2 triangles.
like
-------
| / |
| / |
| / |
--------
not
--------
| |
| |
| |
---------

thx

the .obj exporter in blender already have an option for triangulating faces.