Thread: Pondering

my name is andrew
i am a student at CSM of La Plata, MD. i am currently studying in C++ and will start the advanced C++ course in spring 2005.
inbetween last and upcoming semester i am working on a consol based game. at first its going to be text based but later im going to make it graphic if posible.

the game is going to be a rpg using the rules of "GURPS."
can any one give me any tips on how to keep track of skills and spells. any other tips on creating games would be nice =D

currently i have a player class that gets, updates, and maintains information about the player. but its the spells and skills that puzzle me because other things beside the player are going to use them as well.

is inheritence the answer... or is there a better way....

Polymorphism is a very useful tool when you have different things that have the same base properties. You could have a generic spell class that has virtual functions to be implemented by any number of spells.

There's tons of tutorials out there for polymorphism, just do a google search.

I would have a Skills class and a Spells class, containing the member functions specific to the class.

thanks guys

Good point FYB.

Polymorphism is your best friend and your worst enemy at the same time. It provides a LOT of functionality that would be very hard to gain without it BUT it also incurs quite a bit of function call overhead.

Frankly, I don't use it much in games because the function call overhead can grow exponentially as you add more and more classes. Normally I limit derivations to a maximum of 3 levels and normally only use the (base - > derived 1) format for my classes. Trying to do (base -> derived 1 -> derived 2) creates more function calls. While this may be appropriate for Windows GUI programs and others, it is not advisable in games especially if its happening inside the main game loop.

There are many articles on this on the net as well as in several books. It's a great feature of C++ just don't overuse it.

Well the derived example was assuming that you had virtual functions in the base and/or derived's. Sorry for the lack of clarity in my post.

I guess I mixed two replies into one. The base/derived 1 argument stems from the fact that most people tend to derive far too often and end up with a huge derived mess that is nearly unusable.

You obviously are not paying attention to what I'm saying. I'm not talking about writing pure C code or anything like that. My advice is this:

If you want FPS, stay away from virtual functions, set/get accessor functions, etc.


I will also explain why get/set functions are not the best. Let's say you have created an uber cool sprite class that handles sprites. Each sprite holds a texture or vector of textures (bad idea). But you want to be super C++ coder so you make the IDirect3DTexture9 interface pointer private or protected. Here is the problem.

Let's say you are rendering from outside of the class object that you are currently drawing. In other words a non-member render function is doing the rendering for your object. That render function must call GetTexture() or something like it to get access to the texture member. Now let's say you have 5000 of these objects on screen. That's 5000 calls without even messing with virtual functions!!! Not a good idea. Make the texture member public - sure its ugly but its much better than hiding it simply for the sake of being C++'ey.

wow didnt mean to start a fight =D lol

thanks for the tips guys! (raises hand) "the answer is inheritance"

and i will look into polymorphism, when i figure it out i might use it.

besides who knows what ill learn in the advanced C++ class =D!
thanks for your adivise guys and wish me luck on my next semister

btw this is a great site.