Technical MMORPG information - EO+ Script engine
EO+ was designed to be a simple 'script language' based on states, actions and rules. Basically an EO+ script is a text file, loaded by the gameserver, which has a buildin safe enviroment to execute all the instructions given inside the script.
EO+ parser / loader
At launch time the gameserver scans for all scripts inside its /quest directory, parses the syntax and creates all needed objects into memory, from that point the server doesnt access the script files anymore to gain speed.
EO+ execution
The moment a player logs on its current quests get loaded into memory and the needed event hooks are attached to the things the player has to do. If a RULE of the quest was satisfied the engine will attach the next state, execute its actions, dettach all the old RULEs events, and attach the new event codes.
EO+ storage
Finally all quest progress gets saves into database again, to allow the player to continue the quest at a later time. The quest engine can keep track up to 20 quest at the same time, so the player is able to work on multiple quests if he/she wants to.
Inside the game itself we created some information windows that can show the player which quests he/she has started, and in what state. So the player knows what he/she is supposed to do to make the quest advance into a next state.
Inside the game itself we created some information windows that can show the player which quests he/she has started, and in what state. So the player knows what he/she is supposed to do to make the quest advance into a next state.
EO+ syntax
Here is a code example of a valid EO+ script, that can be loaded into the gameserver, it uses simple code:
Main
{
questname "Pjedro's Potion Quest"
version 2.0
}
state Begin
{
desc "Talk to Pjedro"
action AddNpcText( 1 , "Hello , I am pjedro the only wizzard" );
action AddNpcText( 1 , "I really need some green potions..");
action AddNpcChat( 1 , "Please help me find 10 green potions?");
action AddNpcInput( 1 , 1 , "No, this stuff scares me");
action AddNpcInput( 1 , 2 , "Sure, i will help you");
rule InputNpc( 1 ) goto Lose
rule InputNpc( 2 ) goto FindPotions
}
state FindPotions
{
desc "Find 10 green potions"
rule GotItems( 'green potion' , 10 ) goto GetReward
}
state GetReward
{
desc "Talk to Pjedro for reward"
action ShowHint("You got all the items needed!");
action AddNpcText( 1 , "Did you find my green potions?");
action AddNpcInput( 1 , 1 , "No thank you, find your own");
action AddNpcInput( 1 , 2 , "Sure, here you are");
rule InputNpc( 1 ) goto Lose;
rule InputNpc( 2 ) goto Reward;
rule LostItems( 'green potion' , 10 ) goto FindPotions
}
state Reward{
action RemoveItem( 'green potion' , 10)
action GiveItem( 'juewel ring' );
action Reset();
}
state Lose{
action ShowHint("You are a coward!");
action Reset();
}
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