Hi there,

I am developing a 2D top-down post-apocalyptic shooter and would like there to be a storyline. I have no experience with this and have no clue how to do it...

I would like there to be a primary storyline and then some secondary missions, but how do I keep track of where the player is in the story. What functions do I have to add to my code...? Should I have a different class for the storyline and have a bunch of IFs to see if the player meets the required standards to start the mission? and an int for the mission he is currently in?

Sounds like you need to think of some sort of quest system, and mark some of them as [Story] Quests. this will allow you to have requirments too, so you cant do quest B untill Quest A has been completed, or Quest C requires Quest B to have been completed using The Good Choice. etc.

Yeah well... how do I do that?

How about you spend some time thinking about it what i said?

Sounds like you need to think of some sort of quest system

ok, Quest class.

mark some of them as [Story] Quests

Ok, lets have a field IsStoryMission;

this will allow you to have requirments too

ok, so lets store some Quest Pointers vector<Quest*> _Requirements;

boom, quest system started.

was that hard? did it hurt your brain to read my post?

Ok, lets go deeper, well a quest is given by an NPC or some sort, ok, well lets give that NPC a Pointer to a quest object. Oh, wow, That was hard to think of wasnt it?

How does my NPC give that to the player?

Well,

void SomeFunctionCalledWhenPlayerTalksToNPC()
{
     if(NPCQuest->RequirmentsMet(this)
          this->CurrentQuest = Quest;
}

bool RequirmentsMet(Player *player)
{
     return player->HasCompletedQuest(MyRequiredQuest);
}

hmmm well thats about as far as I can go without having access to your code, and look. that took me 10m to figure out.

A story is a sequence of events happening in the view (to be understood in a wider sense) of the player. To ensure that the player notices the events, they are usually not running detached but being enabled by requirements on the world state, and perhaps being triggered by the player. During happening and at its end, an event often alters the world state, so being able to enable or disable other (not yet happened) events. This way a sequence or even branches can be defined.

The world state is the entirety of variables describing, err, the state in which the game world is. E.g. a boolean flag for the life/death of an opponent belonging to the story, a counter for how often the player has hit a target, a flag whether or not a specific NPC has told the player about the hidden secret, ... whatever.

Triggers can be any action a player is able to perform. Colliding with a collision volume can be used as a location based trigger, or the death by shot of an NPC can be a trigger. On the other hand, the expiration of a timer can be a trigger, too, e.g. allowing for deferred events. Triggers can be implemented as a mechanism which alters the world state.

The player usually needs be hinted at how to trigger enabled events, or else s/he may not realize what to do next. How to do this depends on the type and style of the game. Briefings, books, journals, gossip, talks, ... by NPCs, a companion, the HUD, ... and so on. This can also be implemented as events in the way described above.

There isn't necessarily the need to explicitly track the current chapter in the story. The world state already reflects this.

@andy474: I think you are forgetting that this forum is the "for begginers forum". Yes it is hard to interpret such a poorly elaborated answer.

@Bcullis: I know, I'ts just that I'm making the framework of my game still as my graphic designer hasn't caught up to me. I can't carry on the basics and I don't have a map yet. I'll try some methods, but I was just asking if there was a good accepted method to do this. Thanks for the advice though :)

@haegarr: Very good explanation, it kind of gives me an idea of what I need to implement into my game. I ill start having a class "World" with all these flags and simply have another class for the storyline that takes in a reference to the world and has a series of if statements an an int to keep track of the mission the player's in. Kind of like:

- IF( mission == 4 && 6700 < playerX > 6650 && 8700 < playerY > 8650 && playerAbilityConversation > 50) bla bla bla

You think thats OK?

@haegarr: Very good explanation, it kind of gives me an idea of what I need to implement into my game. I ill start having a class "World" with all these flags and simply have another class for the storyline that takes in a reference to the world and has a series of if statements an an int to keep track of the mission the player's in. Kind of like:

- IF( mission == 4 && 6700 < playerX > 6650 && 8700 < playerY > 8650 && playerAbilityConversation > 50) bla bla bla

You think thats OK?

That is a question of experience and of personal preference. Although it is a valid way (until reaching some complexity), I would not implement it that way. I prefer a data driven way with concentrated responsibility (a.k.a. sub-systems, or "services" as they are generally called in my engine).

A way in-between would be where the individual events of the story are stored each one into an own object. The (base) class of that objects would support handling the requirements (probably data driven), and the effects of the event onto the world state (probably data driven, too). They could be separated, combined, or shared in different structures where meaningful (e.g. list of past events, list of running events, list of deferred/pending events, lists of listeners, a spatial structure when depending on locations, ...).