Hi :) I want to ask what is the best way to deal with "mini-states" in game? For example I making game like Simcity, i can build buildings, roads, rails, or I can change something in economy. I am making something like:
enum
{
ROAD_CONSTRUCT,
BUILDING_CONSTRUCT
VIEW_MAP
etc..
}
and in the game loop big switch. But the code is getting big. Is there some solution for all popular languages? I am asking because I am writing in C++, AS3 and sometimes in C.
In an OOP language, the standard answer is to use polymorphism:
// Current game state. Should *not* really be a global var.
// This is just for demonstration. The current state can be
// changed by setting this to a new instance of a class that
// inherits State.
State * state;
void gameLoop() {
while (true) {
state->update();
}
}
class State {
public:
virtual void update() = 0;
}
class ConstructRoadState : public State {
public:
virtual void update() {
// Do stuff...
}
}
// Other states...
In C, you can accomplish the same thing using a callback for the current state.
It sounds to me that the problem isn't the states but the way you're handling them.
Why do you need a big switch in the main loop? The only things that generally change are the mouse cursor and the click behaviour. Both of those should be wrapped up in separate functions.
This question may be identical to Game State 'Stack'?, but I'm not sure what you mean by mini-states.
My answer to the question (Game State 'Stack'?) works regardless of how "important" the state is. When states are sets rather than a single global or stack, you don't have to worry about one state unexpectedly excluding another. If you do want a convenient exclusion mechanism for state sets, you can use e.g. the top eight bits of the enumerated value to enforce state uniqueness. Thus states don't need to explicitly know about other states, but just compare their own masked bits to other active states.
