What do you mean? We already have user events.

That sounds beyond the scope of the library.

There's enough low level machinery to draw some particles, beyond that also might beyond the scope.

You mean physics? Or what? Physics is way beyond the scope... a good physics engine is a lot of work, and is a bit separated from IO things Allegro is aimed at.

If there's any concerete issues, we can resolve them.

We try .

What's there to understand? They multiply matrices. They add the calling transformation to the matrix in use.

The manual explains the difference fairly well imo.

For 2D you n d an orthographic projection. For 3d it depends on what you want. The transformations are tied to a bitmap target.

Sorry I'm on my phone or I'd explain better

EDIT

So if you take a look at the manual on liballeg.org here :

https://liballeg.org/a5docs/trunk/transformations.html#al_use_projection_transform

It shows you how to restore the default 2D orthographic transform so you can draw normally on allegro bitmaps using allegro's drawing routines.

As for 3D, allegro needs a proper perspective or orthographic transform set up.

Then you can play with the view transform to move, rotate and scale things at will.

OpenGL is nice because you can push and pop matrices on and off the stack. With allegro you have to recreate the full transform, or multiply the matrices and save and restore the state yourself.