Bullet Collision Detection & Physics Library
btTransformUtil.h
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1/*
2Copyright (c) 2003-2006 Gino van den Bergen / Erwin Coumans http://continuousphysics.com/Bullet/
3
4This software is provided 'as-is', without any express or implied warranty.
5In no event will the authors be held liable for any damages arising from the use of this software.
6Permission is granted to anyone to use this software for any purpose,
7including commercial applications, and to alter it and redistribute it freely,
8subject to the following restrictions:
9
101. 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.
112. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
123. This notice may not be removed or altered from any source distribution.
13*/
14
15
16#ifndef BT_TRANSFORM_UTIL_H
17#define BT_TRANSFORM_UTIL_H
18
19#include "btTransform.h"
20#define ANGULAR_MOTION_THRESHOLD btScalar(0.5)*SIMD_HALF_PI
21
22
23
24
25SIMD_FORCE_INLINE btVector3 btAabbSupport(const btVector3& halfExtents,const btVector3& supportDir)
26{
27 return btVector3(supportDir.x() < btScalar(0.0) ? -halfExtents.x() : halfExtents.x(),
28 supportDir.y() < btScalar(0.0) ? -halfExtents.y() : halfExtents.y(),
29 supportDir.z() < btScalar(0.0) ? -halfExtents.z() : halfExtents.z());
30}
31
32
33
34
35
36
39{
40
41public:
42
43 static void integrateTransform(const btTransform& curTrans,const btVector3& linvel,const btVector3& angvel,btScalar timeStep,btTransform& predictedTransform)
44 {
45 predictedTransform.setOrigin(curTrans.getOrigin() + linvel * timeStep);
46// #define QUATERNION_DERIVATIVE
47 #ifdef QUATERNION_DERIVATIVE
48 btQuaternion predictedOrn = curTrans.getRotation();
49 predictedOrn += (angvel * predictedOrn) * (timeStep * btScalar(0.5));
50 predictedOrn.safeNormalize();
51 #else
52 //Exponential map
53 //google for "Practical Parameterization of Rotations Using the Exponential Map", F. Sebastian Grassia
54
55 btVector3 axis;
56 btScalar fAngle2 = angvel.length2();
57 btScalar fAngle = 0;
58 if (fAngle2>SIMD_EPSILON)
59 {
60 fAngle = btSqrt(fAngle2);
61 }
62
63 //limit the angular motion
64 if (fAngle*timeStep > ANGULAR_MOTION_THRESHOLD)
65 {
66 fAngle = ANGULAR_MOTION_THRESHOLD / timeStep;
67 }
68
69 if ( fAngle < btScalar(0.001) )
70 {
71 // use Taylor's expansions of sync function
72 axis = angvel*( btScalar(0.5)*timeStep-(timeStep*timeStep*timeStep)*(btScalar(0.020833333333))*fAngle*fAngle );
73 }
74 else
75 {
76 // sync(fAngle) = sin(c*fAngle)/t
77 axis = angvel*( btSin(btScalar(0.5)*fAngle*timeStep)/fAngle );
78 }
79 btQuaternion dorn (axis.x(),axis.y(),axis.z(),btCos( fAngle*timeStep*btScalar(0.5) ));
80 btQuaternion orn0 = curTrans.getRotation();
81
82 btQuaternion predictedOrn = dorn * orn0;
83 predictedOrn.safeNormalize();
84 #endif
85 if (predictedOrn.length2()>SIMD_EPSILON)
86 {
87 predictedTransform.setRotation(predictedOrn);
88 }
89 else
90 {
91 predictedTransform.setBasis(curTrans.getBasis());
92 }
93 }
94
95 static void calculateVelocityQuaternion(const btVector3& pos0,const btVector3& pos1,const btQuaternion& orn0,const btQuaternion& orn1,btScalar timeStep,btVector3& linVel,btVector3& angVel)
96 {
97 linVel = (pos1 - pos0) / timeStep;
98 btVector3 axis;
99 btScalar angle;
100 if (orn0 != orn1)
101 {
102 calculateDiffAxisAngleQuaternion(orn0,orn1,axis,angle);
103 angVel = axis * angle / timeStep;
104 } else
105 {
106 angVel.setValue(0,0,0);
107 }
108 }
109
110 static void calculateDiffAxisAngleQuaternion(const btQuaternion& orn0,const btQuaternion& orn1a,btVector3& axis,btScalar& angle)
111 {
112 btQuaternion orn1 = orn0.nearest(orn1a);
113 btQuaternion dorn = orn1 * orn0.inverse();
114 angle = dorn.getAngle();
115 axis = btVector3(dorn.x(),dorn.y(),dorn.z());
116 axis[3] = btScalar(0.);
117 //check for axis length
118 btScalar len = axis.length2();
119 if (len < SIMD_EPSILON*SIMD_EPSILON)
120 axis = btVector3(btScalar(1.),btScalar(0.),btScalar(0.));
121 else
122 axis /= btSqrt(len);
123 }
124
125 static void calculateVelocity(const btTransform& transform0,const btTransform& transform1,btScalar timeStep,btVector3& linVel,btVector3& angVel)
126 {
127 linVel = (transform1.getOrigin() - transform0.getOrigin()) / timeStep;
128 btVector3 axis;
129 btScalar angle;
130 calculateDiffAxisAngle(transform0,transform1,axis,angle);
131 angVel = axis * angle / timeStep;
132 }
133
134 static void calculateDiffAxisAngle(const btTransform& transform0,const btTransform& transform1,btVector3& axis,btScalar& angle)
135 {
136 btMatrix3x3 dmat = transform1.getBasis() * transform0.getBasis().inverse();
137 btQuaternion dorn;
138 dmat.getRotation(dorn);
139
141 dorn.normalize();
142
143 angle = dorn.getAngle();
144 axis = btVector3(dorn.x(),dorn.y(),dorn.z());
145 axis[3] = btScalar(0.);
146 //check for axis length
147 btScalar len = axis.length2();
148 if (len < SIMD_EPSILON*SIMD_EPSILON)
149 axis = btVector3(btScalar(1.),btScalar(0.),btScalar(0.));
150 else
151 axis /= btSqrt(len);
152 }
153
154};
155
156
160{
165
167
171
172public:
173
174 btConvexSeparatingDistanceUtil(btScalar boundingRadiusA,btScalar boundingRadiusB)
175 :m_boundingRadiusA(boundingRadiusA),
176 m_boundingRadiusB(boundingRadiusB),
178 {
179 }
180
182 {
184 }
185
186 void updateSeparatingDistance(const btTransform& transA,const btTransform& transB)
187 {
188 const btVector3& toPosA = transA.getOrigin();
189 const btVector3& toPosB = transB.getOrigin();
190 btQuaternion toOrnA = transA.getRotation();
191 btQuaternion toOrnB = transB.getRotation();
192
193 if (m_separatingDistance>0.f)
194 {
195
196
197 btVector3 linVelA,angVelA,linVelB,angVelB;
198 btTransformUtil::calculateVelocityQuaternion(m_posA,toPosA,m_ornA,toOrnA,btScalar(1.),linVelA,angVelA);
199 btTransformUtil::calculateVelocityQuaternion(m_posB,toPosB,m_ornB,toOrnB,btScalar(1.),linVelB,angVelB);
200 btScalar maxAngularProjectedVelocity = angVelA.length() * m_boundingRadiusA + angVelB.length() * m_boundingRadiusB;
201 btVector3 relLinVel = (linVelB-linVelA);
202 btScalar relLinVelocLength = relLinVel.dot(m_separatingNormal);
203 if (relLinVelocLength<0.f)
204 {
205 relLinVelocLength = 0.f;
206 }
207
208 btScalar projectedMotion = maxAngularProjectedVelocity +relLinVelocLength;
209 m_separatingDistance -= projectedMotion;
210 }
211
212 m_posA = toPosA;
213 m_posB = toPosB;
214 m_ornA = toOrnA;
215 m_ornB = toOrnB;
216 }
217
218 void initSeparatingDistance(const btVector3& separatingVector,btScalar separatingDistance,const btTransform& transA,const btTransform& transB)
219 {
220 m_separatingDistance = separatingDistance;
221
222 if (m_separatingDistance>0.f)
223 {
224 m_separatingNormal = separatingVector;
225
226 const btVector3& toPosA = transA.getOrigin();
227 const btVector3& toPosB = transB.getOrigin();
228 btQuaternion toOrnA = transA.getRotation();
229 btQuaternion toOrnB = transB.getRotation();
230 m_posA = toPosA;
231 m_posB = toPosB;
232 m_ornA = toOrnA;
233 m_ornB = toOrnB;
234 }
235 }
236
237};
238
239
240#endif //BT_TRANSFORM_UTIL_H
241
float btScalar
The btScalar type abstracts floating point numbers, to easily switch between double and single floati...
Definition: btScalar.h:292
btScalar btSqrt(btScalar y)
Definition: btScalar.h:444
btScalar btSin(btScalar x)
Definition: btScalar.h:477
#define SIMD_FORCE_INLINE
Definition: btScalar.h:81
btScalar btCos(btScalar x)
Definition: btScalar.h:476
#define SIMD_EPSILON
Definition: btScalar.h:521
#define ANGULAR_MOTION_THRESHOLD
btVector3 btAabbSupport(const btVector3 &halfExtents, const btVector3 &supportDir)
The btConvexSeparatingDistanceUtil can help speed up convex collision detection by conservatively upd...
void initSeparatingDistance(const btVector3 &separatingVector, btScalar separatingDistance, const btTransform &transA, const btTransform &transB)
btConvexSeparatingDistanceUtil(btScalar boundingRadiusA, btScalar boundingRadiusB)
void updateSeparatingDistance(const btTransform &transA, const btTransform &transB)
The btMatrix3x3 class implements a 3x3 rotation matrix, to perform linear algebra in combination with...
Definition: btMatrix3x3.h:48
btMatrix3x3 inverse() const
Return the inverse of the matrix.
Definition: btMatrix3x3.h:1003
void getRotation(btQuaternion &q) const
Get the matrix represented as a quaternion.
Definition: btMatrix3x3.h:400
const btScalar & z() const
Return the z value.
Definition: btQuadWord.h:120
const btScalar & y() const
Return the y value.
Definition: btQuadWord.h:118
const btScalar & x() const
Return the x value.
Definition: btQuadWord.h:116
The btQuaternion implements quaternion to perform linear algebra rotations in combination with btMatr...
Definition: btQuaternion.h:55
btScalar getAngle() const
Return the angle [0, 2Pi] of rotation represented by this quaternion.
Definition: btQuaternion.h:452
btQuaternion nearest(const btQuaternion &qd) const
Definition: btQuaternion.h:548
btScalar length2() const
Return the length squared of the quaternion.
Definition: btQuaternion.h:348
btQuaternion & safeNormalize()
Definition: btQuaternion.h:358
btQuaternion inverse() const
Return the inverse of this quaternion.
Definition: btQuaternion.h:482
btQuaternion & normalize()
Normalize the quaternion Such that x^2 + y^2 + z^2 +w^2 = 1.
Definition: btQuaternion.h:369
Utils related to temporal transforms.
static void calculateDiffAxisAngleQuaternion(const btQuaternion &orn0, const btQuaternion &orn1a, btVector3 &axis, btScalar &angle)
static void calculateVelocityQuaternion(const btVector3 &pos0, const btVector3 &pos1, const btQuaternion &orn0, const btQuaternion &orn1, btScalar timeStep, btVector3 &linVel, btVector3 &angVel)
static void calculateDiffAxisAngle(const btTransform &transform0, const btTransform &transform1, btVector3 &axis, btScalar &angle)
static void integrateTransform(const btTransform &curTrans, const btVector3 &linvel, const btVector3 &angvel, btScalar timeStep, btTransform &predictedTransform)
static void calculateVelocity(const btTransform &transform0, const btTransform &transform1, btScalar timeStep, btVector3 &linVel, btVector3 &angVel)
The btTransform class supports rigid transforms with only translation and rotation and no scaling/she...
Definition: btTransform.h:34
btMatrix3x3 & getBasis()
Return the basis matrix for the rotation.
Definition: btTransform.h:112
void setRotation(const btQuaternion &q)
Set the rotational element by btQuaternion.
Definition: btTransform.h:165
btQuaternion getRotation() const
Return a quaternion representing the rotation.
Definition: btTransform.h:122
btVector3 & getOrigin()
Return the origin vector translation.
Definition: btTransform.h:117
void setOrigin(const btVector3 &origin)
Set the translational element.
Definition: btTransform.h:150
void setBasis(const btMatrix3x3 &basis)
Set the rotational element by btMatrix3x3.
Definition: btTransform.h:159
btVector3 can be used to represent 3D points and vectors.
Definition: btVector3.h:84
const btScalar & z() const
Return the z value.
Definition: btVector3.h:591
btScalar length() const
Return the length of the vector.
Definition: btVector3.h:263
btScalar dot(const btVector3 &v) const
Return the dot product.
Definition: btVector3.h:235
void setValue(const btScalar &_x, const btScalar &_y, const btScalar &_z)
Definition: btVector3.h:652
btScalar length2() const
Return the length of the vector squared.
Definition: btVector3.h:257
const btScalar & x() const
Return the x value.
Definition: btVector3.h:587
const btScalar & y() const
Return the y value.
Definition: btVector3.h:589