toddat / bhtlua

behaviour trees in lua

#Behaviour Trees in Lua

A first approach to behaviour trees in Lua. Implements Actions, Conditions, Selectors and Sequences. Requires hump.class.

-- Example for turn based game

local TRUE = function() return true end
local FALSE = function() return false end

local isThiefNearTreasure = Condition(FALSE)
local stillStrongEnoughToCarryTreasure = Condition(TRUE)
local updated = false


local makeThiefFlee = Action(function() print("making the thief flee") return false end)
local chooseCastle = Action(function() print("choosing Castle") return true end)
local flyToCastle = Action(function() print("fly to Castle") return true end)
local fightAndEatGuards = Action(function() print("fighting and eating guards") return true end)
local takeGold = Action(function() print("picking up gold") return true end)
local flyHome = Action(function() print("flying home") return true end)
local putTreasureAway = Action(function() print("putting treasure away") return true end)
local postPicturesOfTreasureOnFacebook = Action(function() 
    print("posting pics on facebook")
    return true 
end)

-- testing subtree
local packStuffAndGoHome = Selector{
    Sequence{
        stillStrongEnoughToCarryTreasure,
        takeGold,

    },
    Sequence{
        flyHome,
        putTreasureAway,
    }
}

local simpleBehaviour = Selector{
    Sequence{
        isThiefNearTreasure,
        makeThiefFlee,
    },
    Sequence{
        chooseCastle,
        flyToCastle,
        fightAndEatGuards,
        packStuffAndGoHome

    },
    Sequence{
        postPicturesOfTreasureOnFacebook
    }
}


function exampleLoop()
    for i=1,10 do
        simpleBehaviour:update()
    end
end

exampleLoop()