80 lines
3.6 KiB
C++
80 lines
3.6 KiB
C++
/*
|
|
Bullet Continuous Collision Detection and Physics Library, http://bulletphysics.org
|
|
Copyright (C) 2006, 2007 Sony Computer Entertainment Inc.
|
|
|
|
This software is provided 'as-is', without any express or implied warranty.
|
|
In no event will the authors be held liable for any damages arising from the use of this software.
|
|
Permission is granted to anyone to use this software for any purpose,
|
|
including commercial applications, and to alter it and redistribute it freely,
|
|
subject to the following restrictions:
|
|
|
|
1. The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required.
|
|
2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
|
|
3. This notice may not be removed or altered from any source distribution.
|
|
*/
|
|
|
|
#include "btUniversalConstraint.h"
|
|
#include "BulletDynamics/Dynamics/btRigidBody.h"
|
|
#include "LinearMath/btTransformUtil.h"
|
|
|
|
#define UNIV_EPS btScalar(0.01f)
|
|
|
|
// constructor
|
|
// anchor, axis1 and axis2 are in world coordinate system
|
|
// axis1 must be orthogonal to axis2
|
|
btUniversalConstraint::btUniversalConstraint(btRigidBody& rbA, btRigidBody& rbB, const btVector3& anchor, const btVector3& axis1, const btVector3& axis2)
|
|
: btGeneric6DofConstraint(rbA, rbB, btTransform::getIdentity(), btTransform::getIdentity(), true),
|
|
m_anchor(anchor),
|
|
m_axis1(axis1),
|
|
m_axis2(axis2)
|
|
{
|
|
// build frame basis
|
|
// 6DOF constraint uses Euler angles and to define limits
|
|
// it is assumed that rotational order is :
|
|
// Z - first, allowed limits are (-PI,PI);
|
|
// new position of Y - second (allowed limits are (-PI/2 + epsilon, PI/2 - epsilon), where epsilon is a small positive number
|
|
// used to prevent constraint from instability on poles;
|
|
// new position of X, allowed limits are (-PI,PI);
|
|
// So to simulate ODE Universal joint we should use parent axis as Z, child axis as Y and limit all other DOFs
|
|
// Build the frame in world coordinate system first
|
|
btVector3 zAxis = m_axis1.normalize();
|
|
btVector3 yAxis = m_axis2.normalize();
|
|
btVector3 xAxis = yAxis.cross(zAxis); // we want right coordinate system
|
|
btTransform frameInW;
|
|
frameInW.setIdentity();
|
|
frameInW.getBasis().setValue(xAxis[0], yAxis[0], zAxis[0],
|
|
xAxis[1], yAxis[1], zAxis[1],
|
|
xAxis[2], yAxis[2], zAxis[2]);
|
|
frameInW.setOrigin(anchor);
|
|
// now get constraint frame in local coordinate systems
|
|
m_frameInA = rbA.getCenterOfMassTransform().inverse() * frameInW;
|
|
m_frameInB = rbB.getCenterOfMassTransform().inverse() * frameInW;
|
|
// sei limits
|
|
setLinearLowerLimit(btVector3(0., 0., 0.));
|
|
setLinearUpperLimit(btVector3(0., 0., 0.));
|
|
setAngularLowerLimit(btVector3(0.f, -SIMD_HALF_PI + UNIV_EPS, -SIMD_PI + UNIV_EPS));
|
|
setAngularUpperLimit(btVector3(0.f, SIMD_HALF_PI - UNIV_EPS, SIMD_PI - UNIV_EPS));
|
|
}
|
|
|
|
void btUniversalConstraint::setAxis(const btVector3& axis1, const btVector3& axis2)
|
|
{
|
|
m_axis1 = axis1;
|
|
m_axis2 = axis2;
|
|
|
|
btVector3 zAxis = axis1.normalized();
|
|
btVector3 yAxis = axis2.normalized();
|
|
btVector3 xAxis = yAxis.cross(zAxis); // we want right coordinate system
|
|
|
|
btTransform frameInW;
|
|
frameInW.setIdentity();
|
|
frameInW.getBasis().setValue(xAxis[0], yAxis[0], zAxis[0],
|
|
xAxis[1], yAxis[1], zAxis[1],
|
|
xAxis[2], yAxis[2], zAxis[2]);
|
|
frameInW.setOrigin(m_anchor);
|
|
|
|
// now get constraint frame in local coordinate systems
|
|
m_frameInA = m_rbA.getCenterOfMassTransform().inverse() * frameInW;
|
|
m_frameInB = m_rbB.getCenterOfMassTransform().inverse() * frameInW;
|
|
|
|
calculateTransforms();
|
|
}
|