all of the changes

include/FluidSim/MotorcycleTest.hpp

@@ -10,11 +10,15 @@ class MotorcycleTest {
 public:
     Vehicle vehicle{};
     float load{}, clutch{1.0f};
+    float starter_torque{18.f}; // N m at the crankshaft while held
+    bool starter_engaged{};
+    void set_starter(bool engaged) { starter_engaged=engaged; }
 
 protected:
     void step_motorcycle(Crankshaft& crank, float dt, float maximum_load_torque) {
         crank.load_torque = std::clamp(load, 0.0f, 1.0f) * maximum_load_torque;
         vehicle.clutch_input = std::clamp(clutch, 0.0f, 1.0f);
+        if(starter_engaged) crank.add_torque(std::max(starter_torque,0.f));
         crank.step(dt);
         crank.drivetrain_torque = vehicle.update(crank.omega, crank.inertia, dt);
     }