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added gyroscopic force option for btRigidBody, body->setFlags(BT_ENABLE_GYROPSCOPIC_FORCE);

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Note that it can easily introduce instability at regular (60Hertz) simulation steps so it is generally best to not use the option.
If needed, use a very small internal step, such as 1000 Hertz (world->stepSimulation(dt,100,1./1000.f); or stepSimulation(1./1000.,0);
This commit is contained in:
erwin.coumans
2012-09-14 21:39:48 +00:00
parent 3e9f35c0fd
commit 54744b6ab9
11 changed files with 464 additions and 7 deletions
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3
Demos/CMakeLists.txt
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@@ -12,7 +12,7 @@ IF (USE_GLUT)
SET(SharedDemoSubdirs
OpenGL AllBulletDemos ConvexDecompositionDemo
CcdPhysicsDemo ConstraintDemo SliderConstraintDemo GenericJointDemo Raytracer
RagdollDemo ForkLiftDemo BasicDemo RaytestDemo VoronoiFractureDemo FractureDemo Box2dDemo BspDemo MovingConcaveDemo VehicleDemo
RagdollDemo ForkLiftDemo BasicDemo RaytestDemo VoronoiFractureDemo GyroscopicDemo FractureDemo Box2dDemo BspDemo MovingConcaveDemo VehicleDemo
UserCollisionAlgorithm CharacterDemo SoftDemo
CollisionInterfaceDemo ConcaveConvexcastDemo SimplexDemo DynamicControlDemo
ConvexHullDistance
@@ -51,6 +51,7 @@ ELSE (USE_GLUT)
ConvexDecompositionDemo
InternalEdgeDemo
GimpactTestDemo
GyroscopicDemo
GenericJointDemo
SerializeDemo
SoftDemo

72
Demos/GyroscopicDemo/CMakeLists.txt Normal file
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@@ -0,0 +1,72 @@
# This is basically the overall name of the project in Visual Studio this is the name of the Solution File
# For every executable you have with a main method you should have an add_executable line below.
# For every add executable line you should list every .cpp and .h file you have associated with that executable.
# You shouldn't have to modify anything below this line
########################################################
INCLUDE_DIRECTORIES(
${BULLET_PHYSICS_SOURCE_DIR}/src
${BULLET_PHYSICS_SOURCE_DIR}/Demos/OpenGL
${BULLET_PHYSICS_SOURCE_DIR}/Extras/Serialize/BulletFileLoader
${BULLET_PHYSICS_SOURCE_DIR}/Extras/Serialize/BulletWorldImporter
)
IF (USE_GLUT)
LINK_LIBRARIES(
OpenGLSupport BulletWorldImporter BulletDynamics BulletCollision LinearMath BulletFileLoader ${GLUT_glut_LIBRARY} ${OPENGL_gl_LIBRARY} ${OPENGL_glu_LIBRARY}
)
ADD_EXECUTABLE(AppGyroscopicDemo
GyroscopicDemo.cpp
GyroscopicDemo.h
main.cpp
)
IF (WIN32)
IF (NOT INTERNAL_CREATE_DISTRIBUTABLE_MSVC_PROJECTFILES)
IF (CMAKE_CL_64)
ADD_CUSTOM_COMMAND(
TARGET AppGyroscopicDemo
POST_BUILD
COMMAND ${CMAKE_COMMAND} ARGS -E copy_if_different ${BULLET_PHYSICS_SOURCE_DIR}/glut64.dll ${CMAKE_CURRENT_BINARY_DIR}
)
ELSE(CMAKE_CL_64)
ADD_CUSTOM_COMMAND(
TARGET AppGyroscopicDemo
POST_BUILD
COMMAND ${CMAKE_COMMAND} ARGS -E copy_if_different ${BULLET_PHYSICS_SOURCE_DIR}/GLUT32.DLL ${CMAKE_CURRENT_BINARY_DIR}
COMMAND ${CMAKE_COMMAND} ARGS -E copy_if_different ${BULLET_PHYSICS_SOURCE_DIR}/GLUT32.DLL ${CMAKE_CURRENT_BINARY_DIR}/Debug
COMMAND ${CMAKE_COMMAND} ARGS -E copy_if_different ${BULLET_PHYSICS_SOURCE_DIR}/GLUT32.DLL ${CMAKE_CURRENT_BINARY_DIR}/Release
)
ENDIF(CMAKE_CL_64)
ENDIF (NOT INTERNAL_CREATE_DISTRIBUTABLE_MSVC_PROJECTFILES)
ENDIF(WIN32)
ELSE (USE_GLUT)
LINK_LIBRARIES(
OpenGLSupport BulletWorldImporter BulletDynamics BulletCollision LinearMath BulletFileLoader ${OPENGL_gl_LIBRARY} ${OPENGL_glu_LIBRARY}
)
ADD_EXECUTABLE(AppGyroscopicDemo
WIN32
../OpenGL/Win32AppMain.cpp
Win32GyroscopicDemo.cpp
GyroscopicDemo.cpp
GyroscopicDemo.h
)
ENDIF (USE_GLUT)
IF (INTERNAL_ADD_POSTFIX_EXECUTABLE_NAMES)
SET_TARGET_PROPERTIES(AppGyroscopicDemo PROPERTIES DEBUG_POSTFIX "_Debug")
SET_TARGET_PROPERTIES(AppGyroscopicDemo PROPERTIES MINSIZEREL_POSTFIX "_MinsizeRel")
SET_TARGET_PROPERTIES(AppGyroscopicDemo PROPERTIES RELWITHDEBINFO_POSTFIX "_RelWithDebugInfo")
ENDIF(INTERNAL_ADD_POSTFIX_EXECUTABLE_NAMES)

240
Demos/GyroscopicDemo/GyroscopicDemo.cpp Normal file
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@@ -0,0 +1,240 @@
/*
Bullet Continuous Collision Detection and Physics Library
Copyright (c) 2003-2006 Erwin Coumans http://continuousphysics.com/Bullet/
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 "btBulletDynamicsCommon.h"
#include "LinearMath/btIDebugDraw.h"
#include "GLDebugDrawer.h"
#include "GLDebugFont.h"
#include <stdio.h> //printf debugging
#include "GyroscopicDemo.h"
#include "GL_ShapeDrawer.h"
#include "GlutStuff.h"
#include "GLDebugDrawer.h"
static GLDebugDrawer gDebugDrawer;
void GyroscopicDemo::setupEmptyDynamicsWorld()
{
m_collisionConfiguration = new btDefaultCollisionConfiguration();
m_dispatcher = new btCollisionDispatcher(m_collisionConfiguration);
m_overlappingPairCache = new btDbvtBroadphase();
m_constraintSolver = new btSequentialImpulseConstraintSolver();
m_dynamicsWorld = new btDiscreteDynamicsWorld(m_dispatcher,m_overlappingPairCache,m_constraintSolver,m_collisionConfiguration);
}
void GyroscopicDemo::clientResetScene()
{
exitPhysics();
initPhysics();
}
void GyroscopicDemo::initPhysics()
{
m_azi=90;
m_ele = 20;
setTexturing(true);
setShadows(true);
setCameraUp(btVector3(0,0,1));
setCameraForwardAxis(1);
m_sundirection.setValue(0,-1,-1);
setCameraDistance(7.f);
setupEmptyDynamicsWorld();
m_dynamicsWorld->setGravity(btVector3(0,0,-9.8));
m_dynamicsWorld->setDebugDrawer(&gDebugDrawer);
//btCollisionShape* groundShape = new btBoxShape(btVector3(btScalar(50.),btScalar(50.),btScalar(0.5)));
btCollisionShape* groundShape = new btStaticPlaneShape(btVector3(0,0,1),0);
m_collisionShapes.push_back(groundShape);
btTransform groundTransform;
groundTransform.setIdentity();
groundTransform.setOrigin(btVector3(0,0,0));
btRigidBody* groundBody;
groundBody= localCreateRigidBody(0, groundTransform, groundShape);
groundBody->setFriction(btSqrt(2));
btVector3 positions[2] = {
btVector3(0.8,-2,2),
btVector3(0.8,2,2)
};
bool gyro[2] = {
true,
false
};
for (int i=0;i<2;i++)
{
btCylinderShapeZ* top = new btCylinderShapeZ(btVector3(1,1,0.125));
btCapsuleShapeZ* pin = new btCapsuleShapeZ(0.05,1.5);
top->setMargin(0.01);
pin->setMargin(0.01);
btCompoundShape* compound = new btCompoundShape();
compound->addChildShape(btTransform::getIdentity(),top);
compound->addChildShape(btTransform::getIdentity(),pin);
btVector3 localInertia;
top->calculateLocalInertia(1,localInertia);
btRigidBody* body = new btRigidBody(1,0,compound,localInertia);
btTransform tr;
tr.setIdentity();
tr.setOrigin(positions[i]);
body->setCenterOfMassTransform(tr);
body->setAngularVelocity(btVector3(0,0,1000));
body->setLinearVelocity(btVector3(0,.2,0));
body->setFriction(btSqrt(1));
m_dynamicsWorld->addRigidBody(body);
if (gyro[i])
{
body->setFlags(BT_ENABLE_GYROPSCOPIC_FORCE);
} else
{
body->setFlags(0);
}
body->setDamping(0.00001f,0.0001f);
}
}
void GyroscopicDemo::exitPhysics()
{
int i;
//removed/delete constraints
for (i=m_dynamicsWorld->getNumConstraints()-1; i>=0 ;i--)
{
btTypedConstraint* constraint = m_dynamicsWorld->getConstraint(i);
m_dynamicsWorld->removeConstraint(constraint);
delete constraint;
}
//remove the rigidbodies from the dynamics world and delete them
for (i=m_dynamicsWorld->getNumCollisionObjects()-1; i>=0 ;i--)
{
btCollisionObject* obj = m_dynamicsWorld->getCollisionObjectArray()[i];
btRigidBody* body = btRigidBody::upcast(obj);
if (body && body->getMotionState())
{
delete body->getMotionState();
}
m_dynamicsWorld->removeCollisionObject( obj );
delete obj;
}
//delete collision shapes
for (int j=0;j<m_collisionShapes.size();j++)
{
btCollisionShape* shape = m_collisionShapes[j];
delete shape;
}
m_collisionShapes.clear();
//delete dynamics world
delete m_dynamicsWorld;
//delete solver
delete m_constraintSolver;
//delete broadphase
delete m_overlappingPairCache;
//delete dispatcher
delete m_dispatcher;
delete m_collisionConfiguration;
}
GyroscopicDemo::GyroscopicDemo()
{
}
GyroscopicDemo::~GyroscopicDemo()
{
//cleanup in the reverse order of creation/initialization
exitPhysics();
}
void GyroscopicDemo::clientMoveAndDisplay()
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
float dt = float(getDeltaTimeMicroseconds()) * 0.000001f;
//printf("dt = %f: ",dt);
{
static bool once = true;
if ( m_dynamicsWorld->getDebugDrawer() && once)
{
m_dynamicsWorld->getDebugDrawer()->setDebugMode(btIDebugDraw::DBG_DrawConstraints+btIDebugDraw::DBG_DrawConstraintLimits);
once=false;
}
}
{
//during idle mode, just run 1 simulation step maximum
int numSimSteps = m_dynamicsWorld->stepSimulation(dt,100,1./1000.f);
//optional but useful: debug drawing
m_dynamicsWorld->debugDrawWorld();
}
renderme();
glFlush();
swapBuffers();
}
void GyroscopicDemo::displayCallback(void) {
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
if (m_dynamicsWorld)
m_dynamicsWorld->debugDrawWorld();
renderme();
glFlush();
swapBuffers();
}

71
Demos/GyroscopicDemo/GyroscopicDemo.h Normal file
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@@ -0,0 +1,71 @@
/*
Bullet Continuous Collision Detection and Physics Library
Copyright (c) 2003-2006 Erwin Coumans http://continuousphysics.com/Bullet/
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.
*/
#ifndef BT_GYROSCOPIC_DEMO_H
#define BT_GYROSCOPIC_DEMO_H
#ifdef _WINDOWS
#include "Win32DemoApplication.h"
#define PlatformDemoApplication Win32DemoApplication
#else
#include "GlutDemoApplication.h"
#define PlatformDemoApplication GlutDemoApplication
#endif
///GyroscopicDemo shows how to create a constraint, like Hinge or btGenericD6constraint
class GyroscopicDemo : public PlatformDemoApplication
{
//keep track of variables to delete memory at the end
btAlignedObjectArray<btCollisionShape*> m_collisionShapes;
class btBroadphaseInterface* m_overlappingPairCache;
class btCollisionDispatcher* m_dispatcher;
class btConstraintSolver* m_constraintSolver;
class btDefaultCollisionConfiguration* m_collisionConfiguration;
void setupEmptyDynamicsWorld();
void clientResetScene();
public:
GyroscopicDemo();
virtual ~GyroscopicDemo();
void initPhysics();
void exitPhysics();
virtual void clientMoveAndDisplay();
virtual void displayCallback();
static DemoApplication* Create()
{
GyroscopicDemo* demo = new GyroscopicDemo();
demo->myinit();
demo->initPhysics();
return demo;
}
};
#endif //BT_GYROSCOPIC_DEMO_H

25
Demos/GyroscopicDemo/Win32GyroscopicDemo.cpp Normal file
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@@ -0,0 +1,25 @@
#ifdef _WINDOWS
/*
Bullet Continuous Collision Detection and Physics Library
Copyright (c) 2003-2009 Erwin Coumans http://bulletphysics.org
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 "GyroscopicDemo.h"
///The 'createDemo' function is called from Bullet/Demos/OpenGL/Win32AppMain.cpp to instantiate this particular demo
DemoApplication* createDemo()
{
return new GyroscopicDemo();
}
#endif

20
Demos/GyroscopicDemo/main.cpp Normal file
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@@ -0,0 +1,20 @@
#include "GyroscopicDemo.h"
#include "GlutStuff.h"
#include "GLDebugDrawer.h"
#include "btBulletDynamicsCommon.h"
int main(int argc,char** argv)
{
GyroscopicDemo* constraintDemo = new GyroscopicDemo();
constraintDemo->initPhysics();
constraintDemo->setDebugMode(btIDebugDraw::DBG_DrawConstraints+btIDebugDraw::DBG_DrawConstraintLimits);
return glutmain(argc, argv,640,480,"Constraint Demo. http://www.continuousphysics.com/Bullet/phpBB2/",constraintDemo);
}

1
Demos/premake4.lua
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@@ -65,6 +65,7 @@ end
"GenericJointDemo",
"GimpactTestDemo",
"GjkConvexCastDemo",
"GyroscopicDemo",
"InternalEdgeDemo",
"MovingConcaveDemo",
"MultiMaterialDemo",

2
src/BulletDynamics/ConstraintSolver/btContactSolverInfo.h
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@@ -56,6 +56,7 @@ struct btContactSolverInfoData
int m_solverMode;
int m_restingContactRestitutionThreshold;
int m_minimumSolverBatchSize;
btScalar m_maxGyroscopicForce;
};
@@ -86,6 +87,7 @@ struct btContactSolverInfo : public btContactSolverInfoData
//m_solverMode = SOLVER_USE_WARMSTARTING | SOLVER_SIMD | SOLVER_DISABLE_VELOCITY_DEPENDENT_FRICTION_DIRECTION|SOLVER_USE_2_FRICTION_DIRECTIONS|SOLVER_ENABLE_FRICTION_DIRECTION_CACHING;// | SOLVER_RANDMIZE_ORDER;
m_solverMode = SOLVER_USE_WARMSTARTING | SOLVER_SIMD;// | SOLVER_RANDMIZE_ORDER;
m_minimumSolverBatchSize = 128; //try to combine islands until the amount of constraints reaches this limit
m_maxGyroscopicForce = 100.f; ///only used to clamp forces for bodies that have their BT_ENABLE_GYROPSCOPIC_FORCE flag set (using btRigidBody::setFlag)
}
};

7
src/BulletDynamics/ConstraintSolver/btSequentialImpulseConstraintSolver.cpp
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@@ -837,8 +837,13 @@ btScalar btSequentialImpulseConstraintSolver::solveGroupCacheFriendlySetup(btCol
if (body && body->getInvMass())
{
btSolverBody& solverBody = m_tmpSolverBodyPool[bodyId];
btVector3 gyroForce (0,0,0);
if (body->getFlags()&BT_ENABLE_GYROPSCOPIC_FORCE)
{
gyroForce = body->computeGyroscopicForce(infoGlobal.m_maxGyroscopicForce);
}
solverBody.m_linearVelocity += body->getTotalForce()*body->getInvMass()*infoGlobal.m_timeStep;
solverBody.m_angularVelocity += body->getTotalTorque()*body->getInvInertiaTensorWorld()*infoGlobal.m_timeStep;
solverBody.m_angularVelocity += (body->getTotalTorque()-gyroForce)*body->getInvInertiaTensorWorld()*infoGlobal.m_timeStep;
}
}

17
src/BulletDynamics/Dynamics/btRigidBody.cpp
View File

@@ -256,6 +256,23 @@ void btRigidBody::updateInertiaTensor()
}
btVector3 btRigidBody::computeGyroscopicForce(btScalar maxGyroscopicForce) const
{
btVector3 inertiaLocal;
inertiaLocal[0] = 1.f/getInvInertiaDiagLocal()[0];
inertiaLocal[1] = 1.f/getInvInertiaDiagLocal()[1];
inertiaLocal[2] = 1.f/getInvInertiaDiagLocal()[2];
btMatrix3x3 inertiaTensorWorld = getWorldTransform().getBasis().scaled(inertiaLocal) * getWorldTransform().getBasis().transpose();
btVector3 tmp = inertiaTensorWorld*getAngularVelocity();
btVector3 gf = getAngularVelocity().cross(tmp);
btScalar l2 = gf.length2();
if (l2>maxGyroscopicForce*maxGyroscopicForce)
{
gf *= btScalar(1.)/btSqrt(l2)*maxGyroscopicForce;
}
return gf;
}
void btRigidBody::integrateVelocities(btScalar step)
{
if (isStaticOrKinematicObject())

9
src/BulletDynamics/Dynamics/btRigidBody.h
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@@ -40,7 +40,11 @@ extern bool gDisableDeactivation;
enum btRigidBodyFlags
{
BT_DISABLE_WORLD_GRAVITY = 1
BT_DISABLE_WORLD_GRAVITY = 1,
///The BT_ENABLE_GYROPSCOPIC_FORCE can easily introduce instability
///So generally it is best to not enable it.
///If really needed, run at a high frequency like 1000 Hertz: ///See Demos/GyroscopicDemo for an example use
BT_ENABLE_GYROPSCOPIC_FORCE = 2
};
@@ -519,8 +523,7 @@ public:
return m_rigidbodyFlags;
}
btVector3 computeGyroscopicForce(btScalar maxGyroscopicForce) const;
///////////////////////////////////////////////