initial commit, 4.5 stable

thirdparty/jolt_physics/Jolt/Physics/Vehicle/VehicleTransmission.h

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+// Jolt Physics Library (https://github.com/jrouwe/JoltPhysics)
+// SPDX-FileCopyrightText: 2021 Jorrit Rouwe
+// SPDX-License-Identifier: MIT
+
+#pragma once
+
+#include <Jolt/ObjectStream/SerializableObject.h>
+#include <Jolt/Core/StreamIn.h>
+#include <Jolt/Core/StreamOut.h>
+#include <Jolt/Physics/StateRecorder.h>
+
+JPH_NAMESPACE_BEGIN
+
+/// How gears are shifted
+enum class ETransmissionMode : uint8
+{
+	Auto,																///< Automatically shift gear up and down
+	Manual,																///< Manual gear shift (call SetTransmissionInput)
+};
+
+/// Configuration for the transmission of a vehicle (gear box)
+class JPH_EXPORT VehicleTransmissionSettings
+{
+	JPH_DECLARE_SERIALIZABLE_NON_VIRTUAL(JPH_EXPORT, VehicleTransmissionSettings)
+
+public:
+	/// Saves the contents in binary form to inStream.
+	void					SaveBinaryState(StreamOut &inStream) const;
+
+	/// Restores the contents in binary form to inStream.
+	void					RestoreBinaryState(StreamIn &inStream);
+
+	ETransmissionMode		mMode = ETransmissionMode::Auto;			///< How to switch gears
+	Array<float>			mGearRatios { 2.66f, 1.78f, 1.3f, 1.0f, 0.74f }; ///< Ratio in rotation rate between engine and gear box, first element is 1st gear, 2nd element 2nd gear etc.
+	Array<float>			mReverseGearRatios { -2.90f };				///< Ratio in rotation rate between engine and gear box when driving in reverse
+	float					mSwitchTime = 0.5f;							///< How long it takes to switch gears (s), only used in auto mode
+	float					mClutchReleaseTime = 0.3f;					///< How long it takes to release the clutch (go to full friction), only used in auto mode
+	float					mSwitchLatency = 0.5f;						///< How long to wait after releasing the clutch before another switch is attempted (s), only used in auto mode
+	float					mShiftUpRPM = 4000.0f;						///< If RPM of engine is bigger then this we will shift a gear up, only used in auto mode
+	float					mShiftDownRPM = 2000.0f;					///< If RPM of engine is smaller then this we will shift a gear down, only used in auto mode
+	float					mClutchStrength = 10.0f;					///< Strength of the clutch when fully engaged. Total torque a clutch applies is Torque = ClutchStrength * (Velocity Engine - Avg Velocity Wheels At Clutch) (units: k m^2 s^-1)
+};
+
+/// Runtime data for transmission
+class JPH_EXPORT VehicleTransmission : public VehicleTransmissionSettings
+{
+public:
+	/// Set input from driver regarding the transmission (only relevant when transmission is set to manual mode)
+	/// @param inCurrentGear Current gear, -1 = reverse, 0 = neutral, 1 = 1st gear etc.
+	/// @param inClutchFriction Value between 0 and 1 indicating how much friction the clutch gives (0 = no friction, 1 = full friction)
+	void					Set(int inCurrentGear, float inClutchFriction) { mCurrentGear = inCurrentGear; mClutchFriction = inClutchFriction; }
+
+	/// Update the current gear and clutch friction if the transmission is in auto mode
+	/// @param inDeltaTime Time step delta time in s
+	/// @param inCurrentRPM Current RPM for engine
+	/// @param inForwardInput Hint if the user wants to drive forward (> 0) or backwards (< 0)
+	/// @param inCanShiftUp Indicates if we want to allow the transmission to shift up (e.g. pass false if wheels are slipping)
+	void					Update(float inDeltaTime, float inCurrentRPM, float inForwardInput, bool inCanShiftUp);
+
+	/// Current gear, -1 = reverse, 0 = neutral, 1 = 1st gear etc.
+	int						GetCurrentGear() const						{ return mCurrentGear; }
+
+	/// Value between 0 and 1 indicating how much friction the clutch gives (0 = no friction, 1 = full friction)
+	float					GetClutchFriction() const					{ return mClutchFriction; }
+
+	/// If the auto box is currently switching gears
+	bool					IsSwitchingGear() const						{ return mGearSwitchTimeLeft > 0.0f; }
+
+	/// Return the transmission ratio based on the current gear (ratio between engine and differential)
+	float					GetCurrentRatio() const;
+
+	/// Only allow sleeping when the transmission is idle
+	bool					AllowSleep() const							{ return mGearSwitchTimeLeft <= 0.0f && mClutchReleaseTimeLeft <= 0.0f && mGearSwitchLatencyTimeLeft <= 0.0f; }
+
+	/// Saving state for replay
+	void					SaveState(StateRecorder &inStream) const;
+	void					RestoreState(StateRecorder &inStream);
+
+private:
+	int						mCurrentGear = 0;							///< Current gear, -1 = reverse, 0 = neutral, 1 = 1st gear etc.
+	float					mClutchFriction = 1.0f;						///< Value between 0 and 1 indicating how much friction the clutch gives (0 = no friction, 1 = full friction)
+	float					mGearSwitchTimeLeft = 0.0f;					///< When switching gears this will be > 0 and will cause the engine to not provide any torque to the wheels for a short time (used for automatic gear switching only)
+	float					mClutchReleaseTimeLeft = 0.0f;				///< After switching gears this will be > 0 and will cause the clutch friction to go from 0 to 1 (used for automatic gear switching only)
+	float					mGearSwitchLatencyTimeLeft = 0.0f;			///< After releasing the clutch this will be > 0 and will prevent another gear switch (used for automatic gear switching only)
+};
+
+JPH_NAMESPACE_END