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Cars – Physics scripts

Ilja Jusupov edited this page Feb 16, 2024 · 3 revisions

With 0.1.77 update it is now possible to use a Lua script to extend car physics. Simply create a “script.lua” in car data folder and it’ll work if extended physics is enabled. And if data is unpacked, it would reload live if script has been edited.

Available functions

  • Basic:
    • Access current car state;
    • Access frequently updating detailed car physics state;
    • Modify car state:
      • Gear grinding flag;
      • Car damage;
      • Engine damage;
      • Gearbox damage;
      • Engine RPM;
      • If stalling is enabled or not;
      • Tyres inflation (set to 0 to blow them up);
    • Modify user controls;
    • Use up to 8 values accessible by dynamic physics controllers and car instrument inputs (for example, a complex logic can be tied to a differential this way);
    • Add extra forces to car body.
  • Added in 0.1.78:
    • Move car box colliders;
    • Set aero wings gain.

More functions will be added soon.

A few short examples

  • Use Extra A switch to toggle between engine power LUTs:

    local carPh = ac.accessCarPhysics()
    local powerBase = ac.DataLUT11.carData(car.index, 'power.lut')
    local powerAlt = ac.DataLUT11.carData(car.index, 'power_alt.lut')
    
    function script.update(dt)
      local activeLUT = car.extraA and powerAlt or powerBase
      ac.overrideEngineTorque(activeLUT:get(carPh.rpm))
    end
  • Exploding engine if engine water temperature exceeds 95 degrees:

    function script.update(dt)
      if car.waterTemperature > 95 then
        ac.accessCarPhysics().engineLifeLeft = 0
      end
    end
  • Rearranging gears in a car with H-shifter so that first gear becomes reverse, for a dog-leg gearbox:

    function script.update(dt)
      local data = ac.accessCarPhysics()
      if data.requestedGearIndex == 2 then
        -- If first gear is requested, change to reverse
        data.requestedGearIndex = 0
      elseif data.requestedGearIndex > 2 then
        -- If above frist gear is requested, bump it one down
        data.requestedGearIndex = data.requestedGearIndex - 1
      else
        -- Otherwise, set it to neutral
        data.requestedGearIndex = 1
      end
    end
  • Kill engine for a second if g-forces get too extreme for more than a second:

    local counter = 0
    local stalledFor = 0
    
    function script.update(dt)
      local data = ac.accessCarPhysics()
      if math.abs(data.gForces.x) > 2 then
        counter = counter + dt
      else
        counter = 0
      end
    
      if counter > 2 then
        -- If g-force was above threshold for more than two seconds, activate stall for a second
        stalledFor = 1
      end
    
      if stalledFor > 0 then
        -- If stalled, lock gas pedal at 0
        stalledFor = stalledFor - dt
        data.gas = 0
      end
    end
  • Jet engine activating with Extra A switch when car drives above 40 km/h (regular car script can add audio and particle effects, also [EXTRA_SWITCHES] SWITCH_A_FLAGS = HOLD_MODE in car config might help):

    function script.update(dt)
      local data = ac.accessCarPhysics()
      local jetActive = car.extraA and car.speedKmh > 40
      data.controllerInputs[0] = jetActive and 1 or 0
      if jetActive then
        ac.addForce(vec3(0, 0, -2), true, vec3(0, 0, 5000), true)
      end
    end

Lua introduction

Here is an introduction in Lua scripting. Some more examples can be found here.

General Information

Car Physics

Track Physics

Car & Track Configs

Car Configs

Instruments
Miscellaneous

Track Configs

Post-processing Filters

Python Apps

Lua Apps

Server Configs

Other Things

Unrelated to Custom Shaders Patch

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