/*
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* Java port of Bullet (c) 2008 Martin Dvorak <jezek2@advel.cz>
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*
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* Bullet Continuous Collision Detection and Physics Library
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* Copyright (c) 2003-2008 Erwin Coumans http://www.bulletphysics.com/
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*
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* This software is provided 'as-is', without any express or implied warranty.
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* In no event will the authors be held liable for any damages arising from
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* the use of this software.
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*
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* Permission is granted to anyone to use this software for any purpose,
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* including commercial applications, and to alter it and redistribute it
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* freely, subject to the following restrictions:
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*
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* 1. The origin of this software must not be misrepresented; you must not
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* claim that you wrote the original software. If you use this software
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* in a product, an acknowledgment in the product documentation would be
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* appreciated but is not required.
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* 2. Altered source versions must be plainly marked as such, and must not be
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* misrepresented as being the original software.
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* 3. This notice may not be removed or altered from any source distribution.
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*/
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package com.bulletphysics.dynamics.vehicle;
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import com.bulletphysics.dynamics.RigidBody;
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import com.bulletphysics.linearmath.Transform;
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import cz.advel.stack.Stack;
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import javax.vecmath.Vector3f;
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/**
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* WheelInfo contains information per wheel about friction and suspension.
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*
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* @author jezek2
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*/
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public class WheelInfo {
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//protected final BulletStack stack = BulletStack.get();
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public final RaycastInfo raycastInfo = new RaycastInfo();
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public final Transform worldTransform = new Transform();
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public final Vector3f chassisConnectionPointCS = new Vector3f(); // const
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public final Vector3f wheelDirectionCS = new Vector3f(); // const
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public final Vector3f wheelAxleCS = new Vector3f(); // const or modified by steering
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public float suspensionRestLength1; // const
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public float maxSuspensionTravelCm;
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public float wheelsRadius; // const
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public float suspensionStiffness; // const
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public float wheelsDampingCompression; // const
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public float wheelsDampingRelaxation; // const
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public float frictionSlip;
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public float steering;
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public float rotation;
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public float deltaRotation;
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public float rollInfluence;
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public float engineForce;
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public float brake;
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public boolean bIsFrontWheel;
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public Object clientInfo; // can be used to store pointer to sync transforms...
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public float clippedInvContactDotSuspension;
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public float suspensionRelativeVelocity;
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// calculated by suspension
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public float wheelsSuspensionForce;
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public float skidInfo;
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public WheelInfo(WheelInfoConstructionInfo ci) {
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suspensionRestLength1 = ci.suspensionRestLength;
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maxSuspensionTravelCm = ci.maxSuspensionTravelCm;
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wheelsRadius = ci.wheelRadius;
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suspensionStiffness = ci.suspensionStiffness;
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wheelsDampingCompression = ci.wheelsDampingCompression;
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wheelsDampingRelaxation = ci.wheelsDampingRelaxation;
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chassisConnectionPointCS.set(ci.chassisConnectionCS);
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wheelDirectionCS.set(ci.wheelDirectionCS);
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wheelAxleCS.set(ci.wheelAxleCS);
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frictionSlip = ci.frictionSlip;
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steering = 0f;
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engineForce = 0f;
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rotation = 0f;
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deltaRotation = 0f;
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brake = 0f;
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rollInfluence = 0.1f;
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bIsFrontWheel = ci.bIsFrontWheel;
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}
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public float getSuspensionRestLength() {
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return suspensionRestLength1;
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}
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public void updateWheel(RigidBody chassis, RaycastInfo raycastInfo) {
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if (raycastInfo.isInContact) {
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float project = raycastInfo.contactNormalWS.dot(raycastInfo.wheelDirectionWS);
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Vector3f chassis_velocity_at_contactPoint = Stack.alloc(Vector3f.class);
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Vector3f relpos = Stack.alloc(Vector3f.class);
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relpos.sub(raycastInfo.contactPointWS, chassis.getCenterOfMassPosition(Stack.alloc(Vector3f.class)));
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chassis.getVelocityInLocalPoint(relpos, chassis_velocity_at_contactPoint);
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float projVel = raycastInfo.contactNormalWS.dot(chassis_velocity_at_contactPoint);
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if (project >= -0.1f) {
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suspensionRelativeVelocity = 0f;
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clippedInvContactDotSuspension = 1f / 0.1f;
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}
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else {
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float inv = -1f / project;
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suspensionRelativeVelocity = projVel * inv;
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clippedInvContactDotSuspension = inv;
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}
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}
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else {
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// Not in contact : position wheel in a nice (rest length) position
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raycastInfo.suspensionLength = getSuspensionRestLength();
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suspensionRelativeVelocity = 0f;
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raycastInfo.contactNormalWS.negate(raycastInfo.wheelDirectionWS);
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clippedInvContactDotSuspension = 1f;
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}
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}
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////////////////////////////////////////////////////////////////////////////
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public static class RaycastInfo {
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// set by raycaster
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public final Vector3f contactNormalWS = new Vector3f(); // contactnormal
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public final Vector3f contactPointWS = new Vector3f(); // raycast hitpoint
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public float suspensionLength;
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public final Vector3f hardPointWS = new Vector3f(); // raycast starting point
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public final Vector3f wheelDirectionWS = new Vector3f(); // direction in worldspace
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public final Vector3f wheelAxleWS = new Vector3f(); // axle in worldspace
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public boolean isInContact;
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public Object groundObject; // could be general void* ptr
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}
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}
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