Hello Piola,
I am glad to see your interest in using OpenGL fonctions of BGRABitmap.

When you create the
IBGLFont using the
BGLFont function and supply your own font renderer, there is an additional parameter to specify whether the renderer is owned by the font. It is perfectly find to share the renderer. To do so, you need to set the
ARendererOwned parameter to
False so that it won't get freed multiple times.
Regarding memory, there will be slightly less memory used when sharing the rendered, so it is advisable to share it. The instance of a renderer though doesn't use much memory.
The textures of the letters are created and stored by the
IBGLFont object. What matters most is to have fewer
IBGLFont object. This will use less memory and require less texture creations.
So if possible, when labels use the same font, it is better that they use the same
IBGLFont object. If you need various fonts but do not know in advance which ones, I suggest to have list of cached fonts.
Indeed, there isn't much documentation on this subject. You can find some examples in the
test/test4lcl_opengl folder, where they basically have only one
IBGLFont instance.
Warm regards