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/*
* SOLID - Software Library for Interference Detection
*
* Copyright (C) 2001-2003 Dtecta. All rights reserved.
*
* This library may be distributed under the terms of the Q Public License
* (QPL) as defined by Trolltech AS of Norway and appearing in the file
* LICENSE.QPL included in the packaging of this file.
*
* This library may be distributed and/or modified under the terms of the
* GNU General Public License (GPL) version 2 as published by the Free Software
* Foundation and appearing in the file LICENSE.GPL included in the
* packaging of this file.
*
* This library is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
* WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*
* Commercial use or any other use of this library not covered by either
* the QPL or the GPL requires an additional license from Dtecta.
* Please contact info@dtecta.com for enquiries about the terms of commercial
* use of this library.
*/
#include "RigidBody.h"
static MT_Scalar ContactThreshold = -10.0f;
void RigidBody::setGravity(const MT_Vector3& acceleration)
{
if (m_inv_mass != 0.0f)
{
m_gravity = acceleration * (1.0f / m_inv_mass);
}
}
void RigidBody::setDamping(MT_Scalar lin_damping, MT_Scalar ang_damping)
{
m_lin_damping = GEN_clamped(1.0f - lin_damping, 0.0f, 1.0f);
m_ang_damping = GEN_clamped(1.0f - ang_damping, 0.0f, 1.0f);
}
void RigidBody::reset(const MT_Transform& xform)
{
Dynamic::reset(xform);
}
void RigidBody::applyForces(MT_Scalar step)
{
applyCentralForce(m_gravity);
#if defined (__sun) || defined(__sun__) || defined(__sparc) || defined(__sparc__) || defined (__APPLE)
m_lin_vel *= pow(m_lin_damping, step);
m_ang_vel *= pow(m_ang_damping, step);
#else
m_lin_vel *= powf(m_lin_damping, step);
m_ang_vel *= powf(m_ang_damping, step);
#endif
}
void RigidBody::proceed(MT_Scalar step)
{
m_prev_xform = m_xform;
m_prev_orn = m_orn;
Dynamic::proceed(step);
}
void RigidBody::backup()
{
m_xform = m_prev_xform;
m_orn = m_prev_orn;
updateInertiaTensor();
}
inline MT_Scalar restitutionCurve(MT_Scalar rel_vel, MT_Scalar restitution)
{
return restitution * GEN_min(1.0f, rel_vel / ContactThreshold);
}
void RigidBody::resolveCollision(const MT_Vector3& pos,
MT_Scalar depth, const MT_Vector3& normal,
MT_Scalar restitution, MT_Scalar friction)
{
MT_Vector3 rel_pos = pos - getPosition();
MT_Vector3 vel = getVelocity(rel_pos);
MT_Scalar rel_vel = normal.dot(vel);
if (rel_vel < -MT_EPSILON)
{
MT_Vector3 temp = getInvInertiaTensor() * rel_pos.cross(normal);
MT_Scalar rest = restitutionCurve(rel_vel, restitution);
MT_Scalar impulse = -(1.0f + rest) * rel_vel /
(getInvMass() + normal.dot(temp.cross(rel_pos)));
applyImpulse(normal * impulse, rel_pos);
MT_Vector3 lat_vel = vel - normal * rel_vel;
MT_Scalar lat_rel_vel = lat_vel.length();
if (lat_rel_vel > 0.0f)
{
lat_vel /= lat_rel_vel;
temp = getInvInertiaTensor() * rel_pos.cross(lat_vel);
MT_Scalar friction_impulse = -lat_rel_vel /
(getInvMass() + lat_vel.dot(temp.cross(rel_pos)));
GEN_set_min(friction_impulse, impulse * friction);
applyImpulse(lat_vel * friction_impulse, rel_pos);
}
}
}
void resolveCollision(RigidBody& body1, const MT_Vector3& pos1,
RigidBody& body2, const MT_Vector3& pos2,
MT_Scalar depth, const MT_Vector3& normal, MT_Scalar restitution)
{
MT_Vector3 rel_pos1 = pos1 - body1.getPosition();
MT_Vector3 rel_pos2 = pos2 - body2.getPosition();
MT_Scalar rel_vel = normal.dot(body1.getVelocity(rel_pos1) - body2.getVelocity(rel_pos2));
if (rel_vel < -MT_EPSILON)
{
MT_Vector3 temp1 = body1.getInvInertiaTensor() * rel_pos1.cross(normal);
MT_Vector3 temp2 = body2.getInvInertiaTensor() * rel_pos2.cross(normal);
MT_Scalar rest = restitutionCurve(rel_vel, restitution);
MT_Scalar impulse = -(1.0f + rest) * rel_vel /
(body1.getInvMass() + body2.getInvMass() + normal.dot(temp1.cross(rel_pos1) + temp2.cross(rel_pos2)));
MT_Vector3 impulse_vector = normal * impulse;
body1.applyImpulse(impulse_vector, rel_pos1);
body2.applyImpulse(-impulse_vector, rel_pos2);
}
}
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