Generation of triangle wave

This function allows the generation of a triangular wave.

The usage is the same as sin(2*pi*f*t), but the triangular wave is generated with an amplitude between 0 and 1.
So to generate one second of a triangle wave of amplitude 2 with frequency 5 Hz (sampled each millisecond)

f = 5;
t = 0:0.001:1;
A = 2;
wave = A*triangle(2*pi*f*t);

Note: the wave is generated with positive amplitude (i.e. centered around half of the amplitude). Check the comment in the code to easily change this behaviour.