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All rights reserved. #include "CustomSuspension.h" namespace snippetvehicle { void addCustomSuspensionForce (const PxReal dt, const PxVehicleSuspensionParams& suspParams, const CustomSuspensionParams& customParams, const PxVec3& groundNormal, bool isWheelOnGround, const PxVehicleSuspensionComplianceState& suspComplianceState, const PxVehicleRigidBodyState& rigidBodyState, PxVehicleSuspensionForce& suspForce, CustomSuspensionState& customState) { //Work out the oscillating force magnitude at time t. const PxF32 magnitude = (1.0f + PxCos(customParams.phase + customState.theta))*0.5f*customParams.amplitude; //Compute the custom force and torque. const PxVec3 suspDir = isWheelOnGround ? groundNormal : PxVec3(PxZero); const PxVec3 customForce = suspDir * magnitude; const PxVec3 r = rigidBodyState.pose.rotate(suspParams.suspensionAttachment.transform(suspComplianceState.suspForceAppPoint)); const PxVec3 customTorque = r.cross(customForce); //Increment the phase of the oscillator and clamp it in range (-Pi,Pi) PxReal theta = customState.theta + 2.0f*PxPi*customParams.frequency*dt; if (theta > PxPi) { theta -= 2.0f*PxPi; } else if (theta < -PxPi) { theta += 2.0f*PxPi; } customState.theta = theta; //Add the custom force to the standard suspension force. suspForce.force += customForce; suspForce.torque += customTorque; } bool CustomSuspensionVehicle::initialize(PxPhysics& physics, const PxCookingParams& params, PxMaterial& defaultMaterial, bool addPhysXBeginEndComponents) { if (!DirectDriveVehicle::initialize(physics, params, defaultMaterial, addPhysXBeginEndComponents)) return false; //Set the custom suspension params for all 4 wheels of the vehicle. { CustomSuspensionParams frontLeft; frontLeft.amplitude = 6000.0f*1.25f; frontLeft.frequency = 2.0f; frontLeft.phase = 0.0f; mCustomSuspensionParams[0] = frontLeft; CustomSuspensionParams frontRight; frontRight.amplitude = 6000.0f*1.25f; frontRight.frequency = 2.0f; frontRight.phase = 0.0f; mCustomSuspensionParams[1] = frontRight; CustomSuspensionParams rearLeft; rearLeft.amplitude = 6000.0f*1.25f; rearLeft.frequency = 2.0f; rearLeft.phase = PxPi * 0.5f; mCustomSuspensionParams[2] = rearLeft; CustomSuspensionParams rearRight; rearRight.amplitude = 6000.0f*1.25f; rearRight.frequency = 2.0f; rearRight.phase = PxPi * 0.5f; mCustomSuspensionParams[3] = rearRight; } //Initialise the custom suspension state. mCustomSuspensionStates[0].setToDefault(); mCustomSuspensionStates[1].setToDefault(); mCustomSuspensionStates[2].setToDefault(); mCustomSuspensionStates[3].setToDefault(); return true; } void CustomSuspensionVehicle::destroy() { DirectDriveVehicle::destroy(); } void CustomSuspensionVehicle::initComponentSequence(const bool addPhysXBeginEndComponents) { //Wake up the associated PxRigidBody if it is asleep and the vehicle commands signal an //intent to change state. //Read from the physx actor and write the state (position, velocity etc) to the vehicle. if(addPhysXBeginEndComponents) mComponentSequence.add(static_cast(this)); //Read the input commands (throttle, brake etc) and forward them as torques and angles to the wheels on each axle. mComponentSequence.add(static_cast(this)); //Work out which wheels have a non-zero drive torque and non-zero brake torque. //This is used to determine if any tire is to enter the "sticky" regime that will bring the //vehicle to rest. mComponentSequence.add(static_cast(this)); //Perform a scene query against the physx scene to determine the plane and friction under each wheel. mComponentSequence.add(static_cast(this)); //Start a substep group that can be ticked multiple times per update. //In this example, we perform 3 updates of the suspensions, tires and wheels without recalculating //the plane underneath the wheel. This is useful for stability at low forward speeds and is //computationally cheaper than simulating the entire sequence. mComponentSequenceSubstepGroupHandle = mComponentSequence.beginSubstepGroup(3); //Update the suspension compression given the plane under each wheel. //Update the kinematic compliance from the compression state of each suspension. //Convert suspension state to suspension force and torque. //Add an additional sinusoidal suspension force that will entice the vehicle to //perform a kind of mechanical dance. mComponentSequence.add(static_cast(this)); //Compute the load on the tire, the friction experienced by the tire //and the lateral/longitudinal slip angles. //Convert load/friction/slip to tire force and torque. //If the vehicle is to come rest then compute the "sticky" velocity constraints to apply to the //vehicle. mComponentSequence.add(static_cast(this)); //Apply any velocity constraints to a data buffer that will be consumed by the physx scene //during the next physx scene update. mComponentSequence.add(static_cast(this)); //Apply the tire force, brake force and drive force to each wheel and //forward integrate the rotation speed of each wheel. mComponentSequence.add(static_cast(this)); //Apply the suspension and tire forces to the vehicle's rigid body and forward //integrate the state of the rigid body. mComponentSequence.add(static_cast(this)); //Mark the end of the substep group. mComponentSequence.endSubstepGroup(); //Update the rotation angle of the wheel by forwarding integrating the rotational //speed of each wheel. //Compute the local pose of the wheel in the rigid body frame after accounting //suspension compression and compliance. mComponentSequence.add(static_cast(this)); //Write the local poses of each wheel to the corresponding shapes on the physx actor. //Write the momentum change applied to the vehicle's rigid body to the physx actor. //The physx scene can now try to apply that change to the physx actor. //The physx scene will account for collisions and constraints to be applied to the vehicle //that occur by applying the change. if(addPhysXBeginEndComponents) mComponentSequence.add(static_cast(this)); } }//namespace snippetvehicle