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- // SPDX-FileCopyrightText: 2021 Jorrit Rouwe
- // SPDX-License-Identifier: MIT
- #include <Jolt/Jolt.h>
- #include <Jolt/Physics/Vehicle/VehicleEngine.h>
- #include <Jolt/ObjectStream/TypeDeclarations.h>
- #ifdef JPH_DEBUG_RENDERER
- #include <Jolt/Renderer/DebugRenderer.h>
- #endif // JPH_DEBUG_RENDERER
- JPH_NAMESPACE_BEGIN
- JPH_IMPLEMENT_SERIALIZABLE_NON_VIRTUAL(VehicleEngineSettings)
- {
- JPH_ADD_ATTRIBUTE(VehicleEngineSettings, mMaxTorque)
- JPH_ADD_ATTRIBUTE(VehicleEngineSettings, mMinRPM)
- JPH_ADD_ATTRIBUTE(VehicleEngineSettings, mMaxRPM)
- JPH_ADD_ATTRIBUTE(VehicleEngineSettings, mNormalizedTorque)
- }
- VehicleEngineSettings::VehicleEngineSettings()
- {
- mNormalizedTorque.Reserve(3);
- mNormalizedTorque.AddPoint(0.0f, 0.8f);
- mNormalizedTorque.AddPoint(0.66f, 1.0f);
- mNormalizedTorque.AddPoint(1.0f, 0.8f);
- }
- void VehicleEngineSettings::SaveBinaryState(StreamOut &inStream) const
- {
- inStream.Write(mMaxTorque);
- inStream.Write(mMinRPM);
- inStream.Write(mMaxRPM);
- mNormalizedTorque.SaveBinaryState(inStream);
- }
- void VehicleEngineSettings::RestoreBinaryState(StreamIn &inStream)
- {
- inStream.Read(mMaxTorque);
- inStream.Read(mMinRPM);
- inStream.Read(mMaxRPM);
- mNormalizedTorque.RestoreBinaryState(inStream);
- }
- void VehicleEngine::ApplyTorque(float inTorque, float inDeltaTime)
- {
- // Accelerate engine using torque
- mCurrentRPM += cAngularVelocityToRPM * inTorque * inDeltaTime / mInertia;
- ClampRPM();
- }
- void VehicleEngine::ApplyDamping(float inDeltaTime)
- {
- // Angular damping: dw/dt = -c * w
- // Solution: w(t) = w(0) * e^(-c * t) or w2 = w1 * e^(-c * dt)
- // Taylor expansion of e^(-c * dt) = 1 - c * dt + ...
- // Since dt is usually in the order of 1/60 and c is a low number too this approximation is good enough
- mCurrentRPM *= max(0.0f, 1.0f - mAngularDamping * inDeltaTime);
- ClampRPM();
- }
- #ifdef JPH_DEBUG_RENDERER
- void VehicleEngine::DrawRPM(DebugRenderer *inRenderer, Vec3Arg inPosition, Vec3Arg inForward, Vec3Arg inUp, float inSize, float inShiftDownRPM, float inShiftUpRPM) const
- {
- // Function that converts RPM to an angle in radians
- auto rpm_to_angle = [this](float inRPM) { return (-0.75f + 1.5f * (inRPM - mMinRPM) / (mMaxRPM - mMinRPM)) * JPH_PI; };
- // Function to draw part of a pie
- auto draw_pie = [rpm_to_angle, inRenderer, inSize, inPosition, inForward, inUp](float inMinRPM, float inMaxRPM, Color inColor) {
- inRenderer->DrawPie(inPosition, inSize, inForward, inUp, rpm_to_angle(inMinRPM), rpm_to_angle(inMaxRPM), inColor, DebugRenderer::ECastShadow::Off);
- };
- // Draw segment until inShiftDownRPM
- if (mCurrentRPM < inShiftDownRPM)
- {
- draw_pie(mMinRPM, mCurrentRPM, Color::sRed);
- draw_pie(mCurrentRPM, inShiftDownRPM, Color::sDarkRed);
- }
- else
- {
- draw_pie(mMinRPM, inShiftDownRPM, Color::sRed);
- }
- // Draw segment between inShiftDownRPM and inShiftUpRPM
- if (mCurrentRPM > inShiftDownRPM && mCurrentRPM < inShiftUpRPM)
- {
- draw_pie(inShiftDownRPM, mCurrentRPM, Color::sOrange);
- draw_pie(mCurrentRPM, inShiftUpRPM, Color::sDarkOrange);
- }
- else
- {
- draw_pie(inShiftDownRPM, inShiftUpRPM, mCurrentRPM <= inShiftDownRPM? Color::sDarkOrange : Color::sOrange);
- }
- // Draw segment above inShiftUpRPM
- if (mCurrentRPM > inShiftUpRPM)
- {
- draw_pie(inShiftUpRPM, mCurrentRPM, Color::sGreen);
- draw_pie(mCurrentRPM, mMaxRPM, Color::sDarkGreen);
- }
- else
- {
- draw_pie(inShiftUpRPM, mMaxRPM, Color::sDarkGreen);
- }
- }
- #endif // JPH_DEBUG_RENDERER
- void VehicleEngine::SaveState(StateRecorder &inStream) const
- {
- inStream.Write(mCurrentRPM);
- }
- void VehicleEngine::RestoreState(StateRecorder &inStream)
- {
- inStream.Read(mCurrentRPM);
- }
- JPH_NAMESPACE_END
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