Select the polygons you wish to convert to triangles:

Open the Tessellate tool by double-clicking "Tessellate"
in the Toolbox.
As soon as Tessellate opens, youll see new, triangular
polygons created for any currently selected polygons:

Note how Tessellate correctly handles non-simple, non-concave
polygons, including polygons with "holes" such as the letter "D".
Youll use Tessellate frequently to convert polygons such as letters of the alphabet
into simple, concave polygons that OpenGL can render.
Note also that Tessellate does not destroy the original polygons,
and that the triangles that are created share the same points as the original polygons.
Thus, any alterations you make to the original polygons will be made to the new triangles,
unless you UnWeld them.