Exponential Shadow Mapping

Never mind, I found how to do it.
For anyone that might be interested, you have to edit at the mainScene.frag, at the material structure, the second property (diffuse) to accept a variable that will be the colour of the object.

from:

material material1 = material(
    vec4(0.075, 0.075, 0.075, 1.0),
    vec4(1.0, 1.0, 1.0, 1.0),
    vec4(1.0, 1.0, 1.0, 1.0),
    250.0
);

to

material material1 = material(
    vec4(0.075, 0.075, 0.075, 1.0),
    u_Colour,
    vec4(1.0, 1.0, 1.0, 1.0),
    250.0
);

and define the u_Colour at the top. Then from your app's code use this to set the color.

m_shader.setUniform4f("u_Colour", it->color ); // set Colour

Yiannis