working car physics

[diedir]

Hi all

i am trying to make "setkey("friction") working but from 0.0 to 1.0, no obvious change seems appear.

 

do we must tweak the chassis or each tire ?

no luck on both.

 

i tried then "object.tire:SetFriction" as seen in the train-trucks scripts don't work at all (give error) works only with chassis

i set it in the main lua script of my car.

 

here my code:

 

require("scripts/class")
require("scripts/loop")
require("scripts/math/math")

local class=CreateClass(...)

function class:CreateObject(model)
       local object=self.super:CreateObject(model)

       function object:UpdateMatrix()
               self:UpdateTires()
       end

       function object:UpdateTires()
               local speed
               for n=0,3 do
                       if self.tire[n]~=nil then
                               self.tire[n]:SetMatrix( self.vehicle:GetTireMatrix(n) )
                               if self.emitter[n]~=nil then
                                       self.emitter[n]:SetMatrix(self.vehicle:GetTireMatrix(n))
                                       self.emitter[n]:Pause()
                                       if self.vehicle:TireIsAirborne(n)==0 then
                                               speed = math.abs(self.model:GetVelocity(0).z)
                                               speed = (speed - 4) * 20.0	--20
                                               speed = Clamp( speed, 0, 1 ) * 0.5
                                               if speed>0.2 then -->0
                                                       self.emitter[n]:Resume()
                                                       self.emitter[n]:SetColorf(1,1,1,speed)
                                               end
                                       end
                               end
                       end
               end
       end

	local couronne
       local pivot
       local suspensionlength=0.2	--0.1
       local springconstant=50	--25
       local springdamper=200	--115

	object.vehicle=CreateVehicle(object.model)
       object.model:SetMass(2.2)	
	object.model:SetFriction(0.4,0.3)
	object.model:SetKey("Gravity",1)

       object.tire={}
       object.emitter={}

	pivot=object.model:FindChild("roueavantg")
        if pivot~=nil then

                tireradius=pivot.aabb.h/2.0
                object.vehicle:AddTire(TFormPoint(pivot.position,pivot.parent,model),tireradius,suspensionlength,springconstant,springdamper)
                object.tire[0]=LoadMesh("abstract::lp_roueavtg.gmf",object.model)
                pivot:Hide()

        end

        pivot=object.model:FindChild("roueavantd")
        if pivot~=nil then
                tireradius=pivot.aabb.h/2.0
                object.vehicle:AddTire(TFormPoint(pivot.position,pivot.parent,model),tireradius,suspensionlength,springconstant,springdamper)
                object.tire[1]=LoadMesh("abstract::lp_roueavtd.gmf",object.model)
                pivot:Hide()

        end     

        pivot=object.model:FindChild("rouearg")
        if pivot~=nil then
                tireradius=pivot.aabb.h/2.0
                object.vehicle:AddTire(TFormPoint(pivot.position,pivot.parent,model),tireradius,suspensionlength,springconstant,springdamper)
                object.tire[2]=LoadMesh("abstract::lp_rouearg.gmf",object.model)
                pivot:Hide()
        end

        pivot=object.model:FindChild("roueard")
        if pivot~=nil then
                tireradius=pivot.aabb.h/2.0
                object.vehicle:AddTire(TFormPoint(pivot.position,pivot.parent,model),tireradius,suspensionlength,springconstant,springdamper)
                object.tire[3]=LoadMesh("abstract::lp_roueard.gmf",object.model)
                pivot:Hide()
        end     


       object.emitter={}
       object:UpdateTires()


               if fw~=nil then
                       SetWorld(fw.transparency.world)
                       for n=0,3 do
                               if object.tire[n]~=nil then --createemitter(50,2000,Vec3...
                                       object.emitter[n]=CreateEmitter(5,2000,Vec3(0,1,0),0,object.tire[n])
                                       object.emitter[n]:SetPosition(Vec3(0,-object.tire[n].aabb.h/2.0,0))
                                       object.emitter[n]:SetParent(model,1)
                                       object.emitter[n]:SetRadius(0,4) --1.6
                                       object.emitter[n]:SetWaver(0.2) --1.0
                                       object.emitter[n]:Paint(LoadMaterial("abstract::roaddust.mat"))
                                       object.emitter[n]:SetRotationSpeed(0.1)
                                       object.emitter[n]:Pause()
                               end
                       end
                       SetWorld(fw.main.world)
               end		

       object.model.buoyant=0
       object.model:SetKey("collisiontype",COLLISION_PROP)
       object:UpdateTires()
end

 

if someone could post a working exemple of friction applied.

thank you

[AggrorJorn]

have you tried something like self.tire?

 

Also try to use higher values for friction. perhaps there is nothing happening because the friction value is too low.

[diedir]

thank you Aggror for answering

 

no i didn't try "self.tire" but i will thanks

 

for the friction i thought it was a float between 0 to 1 but i'm a bit lost with lua commands

because nothing is clear for this language in wiki, not much examples,

but i am playing around with code and sometimes the sky is brighter...

 

i asking me if joints are harder to apply but better (in performance) than an animated mesh, your (or anyone) advice would be great.

 

by the way, i read the very cool guide you made, i discovered a lot ! thanks again.

[AggrorJorn]

You can set friction really high if you want. Drag an oildraum in the scene and try to change it s friction. you can go really high.

I agree with that. I think Lua is really good to understand, at least when the documentation is correct or present. And then there is this problem: http://leadwerks.com/werkspace/index.php?/topic/1582-proper-lua-syntax-highlighting/

 

I assume you have taken a look a the vehicle examples that come with the sdk?

 

Glad that the LUG helped you out!

[diedir]

i am a bit disappointed with lua things,

 

in my pro real life, i'm coding a bit with vbs script, the objects exposed by windows are such easy to grab, name and manipulate that it is a game for me.

 

BUT here in lua all that i can grab from my loaded model is a memory pointer in hexa form that is useless for me,

to be short, i need to retrieve names, position rotation of these "children" of my parent model and "CHANGE" it, but i don't know how, i tried with

 

for k,v in pairs(object) do ...

 

but no luck, is it a security thing that we can't explore a "GMF" model with ease ? (like in model viewer ?)

need to dig in lua "metatables" and "__index", "self" things....

 

sorry to appear

[AggrorJorn]

Class scripts are not my strongest point at the moment.

If you want to retrieve model names or pivots you use the: Finchild()command.

Gettin the name of an object, see this topic: http://leadwerks.com/werkspace/index.php?/topic/1098-get-the-name-of-a-thingoid/

[diedir]

thx for the link, i saw it before but don't remember where, Rick is always an helper.

 

other things, i found the "turret" code thing in viperscout.lua which is handy for what i need, and yes it is by "FindChild" way

 

EDIT:

i put a video on my blog with my running car

Edited March 29, 2010 by diedir