Modding the lighting and specular as in idtech

[Radiance]

Is it possible to mod the lighting and specular maps with doom open source engine?
https://github.com/id-Software/DOOM-3-BFG
It's written in C++. I would like to rewrite it just to test it out.
Is this possible?

[A.M Team]

HPL3 has C++ elements but ultimately it's an Angel Script engine. You would have to rewrite it from scratch to achieve the effects you want.

[Abion47]

Like DocPoo said, HPL3 may have C++-like syntax but it is actually a language called AngelScript. You don't have access to any of the C++ deeper capabilities, and in fact, you don't even have access to any functions outside of what is declared in the hps_api.hps file (or in other script files that also ultimately point back to that one file).

That being said, maybe this isn't what you were asking. Was there a particular effect or feature in the Doom engine that you were interested in replicating?

[Radiance]

You don't have access to any of the C++ deeper capabilities, and in fact, you don't even have access to any functions outside of what is declared in the hps_api.hps file (or in other script files that also ultimately point back to that one file).

Why there isn't access of the C++ deeper capabilities?

That being said, maybe this isn't what you were asking. Was there a particular effect or feature in the Doom engine that you were interested in replicating?

Only specular bump map and lighting rendering.

What about particle system ?

[Abion47]

Why there isn't access of the C++ deeper capabilities?

Because it isn't C++. AngelScript is a sandboxed scripting language, meaning that it is only as powerful as the game allows it to be. While FG has made HPL3 pretty damn powerful, it's still just a scripting language at the end of the day, and it cannot be as powerful or as flexible as a compiled language, particularly one like C++.

Only specular bump map and lighting rendering.

What about particle system ?

I'm not sure what you mean by lighting rendering. HPL3 uses light sources and supports specular maps. It also has a fairly hefty support for particle systems, even going so far as to have a dedicated editor for designing them.