Josh's Turret AI Script not working...

[The 4th Doctor]

Good morning All,

 

Just wanted to ask if any of you kind folks happen to know if Josh ever managed to complete his Turret AI script as I had copied it and tried to use it but with errors unfortunately... 

I keep getting the following error on his script -----> " Script Error - attempt to call method 'GetDistance' (a nil value) - Line 83

Does anyone know if Josh ever fixed and completed this script or no?! Or if one of you good gentlemen/ladies might have a turret AI script of your own or know where I might find one to use for a gun turret in my level would be very much appreciated indeed! 


Here is the same code I found on Josh's blog here ------> Building Turret AI: Part 2

As a convenience I have posted Josh's code below also! Thanks and God bless all! 



 

--Public
Script.target = nil--enemy to shoot
Script.range = 20
Script.health=100
Script.projectilepath = "Prefabs/Projectiles/tracer.pfb"

Script.shoot1sound=""--path "Fire 1 sound" "Wav file (*.wav):wav|Sound"
Script.shoot2sound=""--path "Fire 2 sound" "Wav file (*.wav):wav|Sound"
Script.shoot3sound=""--path "Fire 3 sound" "Wav file (*.wav):wav|Sound"

--Private
Script.lastfiretime=0
Script.mode = "idle"
Script.lastsearchtime=0
Script.searchfrequency = 500
Script.firefrequency = 50

function Script:Start()

   --Load sounds
   self.sound = {}

   self.sound.shoot = {}
   if self.shoot1sound~="" then self.sound.shoot[1] = Sound:Load(self.shoot1sound) end
   if self.shoot2sound~="" then self.sound.shoot[2] = Sound:Load(self.shoot2sound) end
   if self.shoot3sound~="" then self.sound.shoot[3] = Sound:Load(self.shoot3sound) end

   self.projectile = Prefab:Load(self.projectilepath)
   if self.projectile~=nil then
       self.projectile:Hide()
   end
   self.turret = self.entity:FindChild("turret")

   --Add muzzleflash to gun
   self.muzzle = self.entity:FindChild("muzzle")
   if self.muzzle~=nil then
       local mtl=Material:Create()
       mtl:SetBlendMode(5)
       self.muzzle:SetMaterial(mtl)
       mtl:Release()
       self.muzzleflash = Sprite:Create()
       self.muzzleflash:SetSize(0.35,0.35)
       local pos=self.muzzle:GetPosition(true)
       self.muzzleflash:SetPosition(pos,true)
       self.muzzleflash:SetParent(self.muzzle,true)
       mtl = Material:Load("Materials/Effects/muzzleflash.mat")
       if mtl then
           self.muzzleflash:SetMaterial(mtl)
           mtl:Release()
           mtl=nil
       end
       local light = PointLight:Create()
       light:SetRange(5)
       light:SetColor(1,0.75,0)
       light:SetParent(self.muzzleflash,flash)
       if light.world:GetLightQuality()<2 then
           light:SetShadowMode(0)    
       end
       self.muzzleflash:Hide()
   end

end

function Script:Release()
   if self.projectile~=nil then
       self.projectile:Release()
       self.projectile = nil
   end
end

function TurretSearchHook(entity,extra)


   if entity~=extra then
       if entity.script~=nil then
           if type(entity.script.health)=="number" then
               if entity.script.health>0 then
                   local d = extra:GetDistance(entity)
                   if d<extra.script.range then
                       if extra.script.target~=nil then
                           if extra.script:GetDistance(extra.script.target)>d then
                               if extra.script:GetTargetVisible(entity.script) then
                                   extra.script.target = entity.script
                               end
                           end
                       else
                           if extra.script:GetTargetVisible(entity.script) then
                               extra.script.target = entity.script
                           end
                       end
                   end
               end
           end
       end
   end
end

function Script:GetTargetVisible(target)
   if target==nil then
       target = self.target
   end
   if target==nil then
       return false
   end
   local pickinfo = PickInfo()
   local p0 = self.entity:GetAABB().center
   local p1 = target.entity:GetAABB().center
   local pickmode0 = self.entity:GetPickMode()
   local pickmode1 = target.entity:GetPickMode()
   self.entity:SetPickMode(0)
   target.entity:SetPickMode(0)
   local result = not self.entity.world:Pick(p0,p1,pickinfo,0,false,Collision.LineOfSight)
   self.entity:SetPickMode(pickmode0)
   target.entity:SetPickMode(pickmode1)    
   return result
end

function Script:UpdateWorld()

   if self.health>=0 then

       local currenttime = Time:GetCurrent()

       --Stop shooting if target is dead
       if self.target~=nil then
           if self.target.health<=0 then
               self.target = nil
           end
       end

       --Search for target
       if self.target==nil then
           if currenttime - self.lastsearchtime > self.searchfrequency then
               self.lastsearchtime = currenttime
               local pos = self.entity:GetPosition(true)
               local aabb = AABB(pos - Vec3(self.range), pos + Vec3(self.range))
               self.entity.world:ForEachEntityInAABBDo(aabb,"TurretSearchHook",self.entity)
           end
       end

       --Continuous visibility test
       if self.target~=nil then
           if currenttime - self.lastsearchtime > self.searchfrequency then
               self.lastsearchtime = currenttime
               if self:GetTargetVisible(self.target)==false then
                   self.target = nil
                   return
               end
           end
       end

       if self.target~=nil then

           --Motion tracking
           if self.turret~=nil then
               local p0 = self.turret:GetPosition(true)
               local p1 = self.target.entity:GetAABB().center
               local yplane = p1 - p0
               yplane.y=0
               self.turret:AlignToVector(yplane,1,0.1 / Time:GetSpeed(),0)
           end

           --Shoot
           if self.muzzle~=nil and self.projectile~=nil then
               if currenttime - self.lastfiretime > self.firefrequency then
                   self.lastfiretime = currenttime
                   local bullet = self.projectile:Instance()

                   self.muzzleflash:Show()
                   self.muzzleflash:EmitSound(self.sound.shoot[#self.sound.shoot])
                   self.muzzleflash:SetAngle(math.random(0,360))
                   self.muzzleflashtime=currenttime

                   if bullet~=nil then
                       bullet:Show()
                       bullet:SetPosition(self.muzzle:GetPosition(true),true)
                       bullet:SetRotation(self.muzzle:GetRotation(true),true)
                       if bullet.script~=nil then
                           bullet.script.owner = self
                           if type(bullet.script.Enable)=="function" then
                               bullet.script:Enable()
                           end
                           bullet:Turn(Math:Random(-3,3),Math:Random(-3,3),0)
                       end
                   end
               end
           end

       end

   end

   self:UpdateMuzzleFlash()

end

function Script:UpdateMuzzleFlash()
   if self.muzzleflashtime then
       if Time:GetCurrent()-self.muzzleflashtime<30 then
           self.muzzleflash:Show()
       else
           self.muzzleflash:Hide()
       end
   end
end

 

[Josh]

Hello, and welcome. If you look at the soldier AI script, that basically acts like a moving turret. I think you might be better off using that as a starting point. You can make a copy of the script and then start modifying it to remove the movement code.

[The 4th Doctor]

I'll give it a try and see what happens. Thanks for your quick reply Josh! God bless..