Port FluidSim core and scenarios to C++20

include/FluidSim/Scenario.hpp

@@ -0,0 +1,82 @@
+#pragma once
+
+#include "FluidSim/AudioProcessing.hpp"
+#include "FluidSim/Engine.hpp"
+#include "FluidSim/Fluid.hpp"
+#include "FluidSim/MechanicalSoundProcessor.hpp"
+#include "FluidSim/OutdoorExhaustReverb.hpp"
+#include "FluidSim/Solver.hpp"
+#include "FluidSim/Vehicle.hpp"
+#include <array>
+#include <cstdint>
+#include <mutex>
+#include <vector>
+
+namespace fluidsim::port {
+
+struct ScenarioSnapshot {
+    float rpm{}, speed_kmh{}, kinetic_energy{}, average_power{}, average_torque{};
+    float cylinder_pressure1{}, cylinder_pressure2{};
+    float cylinder_temperature1{}, cylinder_temperature2{};
+    float cylinder_piston_fraction1{}, cylinder_piston_fraction2{};
+    float valve1_intake_area{}, valve1_exhaust_area{}, valve2_intake_area{}, valve2_exhaust_area{};
+    float intake_pressure{}, exhaust_pressure{};
+    float throttle{}, clutch{}, intake_flow{}, exhaust_flow{};
+    int gear{};
+    bool rev_limit1{}, rev_limit2{}, mechanical_sound_enabled{};
+    std::array<std::vector<GasState>, 6> pipe_states;
+};
+
+// Active C# SingleCylScenario topology: a 600 cc parallel twin, independent
+// intake runners, separate short exhaust headers, shared collector and tailpipe.
+class FourStrokeTwinScenario {
+public:
+    explicit FourStrokeTwinScenario(int sample_rate = 44100);
+    AudioFrame process();
+    void set_controls(float throttle_value, float load_value, float clutch_value);
+    void toggle_mechanical_sound();
+    void shift_up();
+    void shift_down();
+    void set_neutral();
+    void set_first_gear();
+    ScenarioSnapshot snapshot() const;
+
+    float throttle{};
+    float load{};
+    float clutch{1.0f};
+    bool mechanical_sound_enabled{};
+    float mechanical_mix{0.02f}, reverb_send_gain{1.0f};
+    float exhaust_send{0.5f}, intake_send{0.5f}, mechanical_send{};
+    Crankshaft crankshaft{};
+    FourStrokeCylinder cylinder1{}, cylinder2{};
+    Vehicle vehicle{};
+    Volume0D intake_plenum{1.0e-3f, 101325.0f, 300.0f};
+    Volume0D exhaust_collector{0.15e-3f, 101325.0f, 700.0f};
+    std::vector<Pipe1D> pipes;
+    float intake_flow{}, exhaust_flow{};
+    float last_mix_l{}, last_mix_r{};
+    std::uint64_t sample_count{};
+
+private:
+    Port* throttle_port_{};
+    Port* runner_feed1_{};
+    Port* runner_feed2_{};
+    Port* collector_in1_{};
+    Port* collector_in2_{};
+    Port* collector_out_{};
+    float throttle_area_{}, runner_area_{}, valve1_in_{}, valve2_in_{};
+    float valve1_out_{}, valve2_out_{}, header_area_{}, tail_area_{};
+    float dt_{};
+    BoundarySystem boundaries_;
+    Solver solver_;
+    RadiationSource intake_radiation_;
+    RadiationSource exhaust_radiation_;
+    OutdoorExhaustReverb reverb_;
+    MechanicalSoundProcessor mechanical_sound_;
+    mutable std::mutex mutex_;
+
+    static float area_for_diameter(float diameter);
+    static std::vector<Pipe1D> create_pipes();
+};
+
+} // namespace fluidsim::port