perf(physics): air flowing along a pipe wakes the physics of a coupled vehicle only when it changes its pressure by more than physics.pipewake (0.001 bar), not with any trickle of it

McZapkie/Mover.cpp

@@ -4720,6 +4720,20 @@ void TMoverParameters::UpdatePipePressure(double dt)
 // Q: 20160713
 // Aktualizacja ciśnienia w przewodzie zasilającym
 // *************************************************************************************************
+namespace
+{
+// whether the air flowing to a coupled vehicle along a pipe wakes its physics: any flow did, but a vehicle standing next to one
+// whose physics is on gets a trickle of it all the time, as their pressures settle, and each wake kept it on for 5 s. with
+// Global.physics_pipewake only a flow which brings its pressure, with what has flown in while it slept, that much away from the
+// pressure of the vehicle the air comes from
+bool pipe_wakes(double const Flow, double const Pressure, TReservoir const &Pipe)
+{
+	if (Flow * Flow <= 0.00000000000001)
+		return false;
+	return (Global.physics_pipewake <= 0.f) || (std::abs(Pressure - Pipe.P_pending()) > Global.physics_pipewake);
+}
+} // namespace
+
 void TMoverParameters::UpdateScndPipePressure(double dt)
 {
 	if (ScndPipePress > 1.0)
@@ -4744,18 +4758,18 @@ void TMoverParameters::UpdateScndPipePressure(double dt)
 	{
 		c = Couplers[0].Connected; // skrot
 		dv1 = 0.5 * dt * PF(ScndPipePress, c->ScndPipePress, Spz * 0.75);
-		if (dv1 * dv1 > 0.00000000000001)
-			c->switch_physics(true, wake_cause::scndpipe);
 		c->Pipe2->Flow(-dv1);
+		if (pipe_wakes(dv1, ScndPipePress, *c->Pipe2))
+			c->switch_physics(true, wake_cause::scndpipe);
 	}
 	// sprzeg 2
 	if (Couplers[1].Connected != nullptr && TestFlag(Couplers[1].CouplingFlag, ctrain_scndpneumatic))
 	{
 		c = Couplers[1].Connected; // skrot
 		dv2 = 0.5 * dt * PF(ScndPipePress, c->ScndPipePress, Spz * 0.75);
-		if (dv2 * dv2 > 0.00000000000001)
-			c->switch_physics(true, wake_cause::scndpipe);
 		c->Pipe2->Flow(-dv2);
+		if (pipe_wakes(dv2, ScndPipePress, *c->Pipe2))
+			c->switch_physics(true, wake_cause::scndpipe);
 	}
 	if (Couplers[1].Connected != nullptr && Couplers[0].Connected != nullptr && TestFlag(Couplers[0].CouplingFlag, ctrain_scndpneumatic) && TestFlag(Couplers[1].CouplingFlag, ctrain_scndpneumatic))
 	{
@@ -4832,18 +4846,18 @@ double TMoverParameters::GetDVc(double dt)
 	{ //*0.85
 		c = Couplers[0].Connected; // skrot           //0.08           //e/D * L/D = e/D^2 * L
 		dv1 = 0.5 * dt * PF(PipePress, c->PipePress, Spg / (1.0 + 0.015 / Spg * Dim.L));
-		if (dv1 * dv1 > 0.00000000000001)
-			c->switch_physics(true, wake_cause::mainpipe);
 		c->Pipe->Flow(-dv1);
+		if (pipe_wakes(dv1, PipePress, *c->Pipe))
+			c->switch_physics(true, wake_cause::mainpipe);
 	}
 	// sprzeg 2
 	if (Couplers[1].Connected != nullptr && TestFlag(Couplers[1].CouplingFlag, ctrain_pneumatic))
 	{
 		c = Couplers[1].Connected; // skrot
 		dv2 = 0.5 * dt * PF(PipePress, c->PipePress, Spg / (1.0 + 0.015 / Spg * Dim.L));
-		if (dv2 * dv2 > 0.00000000000001)
-			c->switch_physics(true, wake_cause::mainpipe);
 		c->Pipe->Flow(-dv2);
+		if (pipe_wakes(dv2, PipePress, *c->Pipe))
+			c->switch_physics(true, wake_cause::mainpipe);
 	}
 	// if ((Couplers[1].Connected != NULL) && (Couplers[0].Connected != NULL))
 	//     if ((TestFlag(Couplers[0].CouplingFlag, ctrain_pneumatic)) &&

McZapkie/hamulce.h

@@ -265,6 +265,14 @@ class TReservoir
 	/// <param name="dv">Volume change to add to dVol.</param>
 	void Flow(double dv);
 	/// <summary>
+	/// Pressure the reservoir will have once the flow accumulated for the step is applied (Vol + dVol) / Cap, in bar.
+	/// Of a vehicle whose physics sleeps, the flow keeps accumulating, as nothing applies it.
+	/// </summary>
+	double P_pending() const
+	{
+		return std::max(0.0, Vol + dVol) / Cap;
+	}
+	/// <summary>
 	/// Applies the accumulated flow (dVol) to the volume and resets dVol.
 	/// Volume is clamped to be non-negative.
 	/// </summary>

application/driveruipanels.cpp

@@ -1516,6 +1516,7 @@ debug_panel::render_section_renderer() {
     // the physics of the vehicles, timed in the section of the main loop
     ImGui::Checkbox( "let vehicles standing still and held by their brakes sleep (physics.sleepheld)", &Global.physics_sleepheld );
     ImGui::Checkbox( "one step of the physics in a frame for road vehicles farther than 1 km (physics.roadlod)", &Global.physics_roadlod );
+    ImGui::SliderFloat( "bar: change of the pressure in a pipe which wakes the physics of a vehicle, 0 any (physics.pipewake)", &Global.physics_pipewake, 0.f, 0.05f, "%.4f" );
     return true;
 }
 

utilities/Globals.cpp

@@ -491,6 +491,12 @@ bool global_settings::ConfigParseSimulation(cParser& Parser, const std::string&
         return true;
     }
 
+    if (token == "physics.pipewake")
+    {
+        ParseOne(Parser, physics_pipewake);
+        return true;
+    }
+
     if (token == "enabletraction")
     {
         ParseOne(Parser, bEnableTraction);
@@ -1901,6 +1907,7 @@ global_settings::export_as_text( std::ostream &Output ) const {
     export_as_text( Output, "fullphysics", FullPhysics );
     export_as_text( Output, "physics.sleepheld", physics_sleepheld );
     export_as_text( Output, "physics.roadlod", physics_roadlod );
+    export_as_text( Output, "physics.pipewake", physics_pipewake );
     export_as_text( Output, "debuglog", iWriteLogEnabled );
     export_as_text( Output, "multiplelogs", MultipleLogs );
     export_as_text( Output, "showsystemconsole", ShowSystemConsole );

utilities/Globals.h

@@ -116,6 +116,7 @@ struct global_settings {
     bool FullPhysics{ true }; // full calculations performed for each simulation step
     bool physics_sleepheld{ true }; // vehicles standing still and held by their brakes let their physics sleep, see TMoverParameters::accelerating()
     bool physics_roadlod{ true }; // road vehicles far from the camera go by one step of the physics in a frame, see vehicle_table::update()
+    float physics_pipewake{ 0.001f }; // bar: air flowing along a pipe wakes the physics of a vehicle when it changes its pressure by more than this. 0: any flow does
     bool bnewAirCouplers{ true };
     float fMoveLight{ 0.f }; // numer dnia w roku albo -1
     bool FakeLight{ false }; // toggle between fixed and dynamic daylight