mirror of
https://github.com/bulletphysics/bullet3
synced 2024-12-14 05:40:05 +00:00
140 lines
4.1 KiB
C++
140 lines
4.1 KiB
C++
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#include "btFractureBody.h"
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#include "BulletCollision/CollisionDispatch/btCollisionWorld.h"
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#include "BulletCollision/CollisionShapes/btCompoundShape.h"
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#include "BulletDynamics/Dynamics/btDynamicsWorld.h"
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void btFractureBody::recomputeConnectivity(btCollisionWorld* world)
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{
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m_connections.clear();
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//@todo use the AABB tree to avoid N^2 checks
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if (getCollisionShape()->isCompound())
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{
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btCompoundShape* compound = (btCompoundShape*)getCollisionShape();
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for (int i=0;i<compound->getNumChildShapes();i++)
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{
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for (int j=i+1;j<compound->getNumChildShapes();j++)
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{
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struct MyContactResultCallback : public btCollisionWorld::ContactResultCallback
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{
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bool m_connected;
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btScalar m_margin;
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MyContactResultCallback() :m_connected(false),m_margin(0.05)
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{
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}
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virtual btScalar addSingleResult(btManifoldPoint& cp, const btCollisionObjectWrapper* colObj0Wrap,int partId0,int index0,const btCollisionObjectWrapper* colObj1Wrap,int partId1,int index1)
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{
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if (cp.getDistance()<=m_margin)
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m_connected = true;
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return 1.f;
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}
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};
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MyContactResultCallback result;
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btCollisionObject obA;
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obA.setWorldTransform(compound->getChildTransform(i));
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obA.setCollisionShape(compound->getChildShape(i));
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btCollisionObject obB;
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obB.setWorldTransform(compound->getChildTransform(j));
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obB.setCollisionShape(compound->getChildShape(j));
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world->contactPairTest(&obA,&obB,result);
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if (result.m_connected)
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{
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btConnection tmp;
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tmp.m_childIndex0 = i;
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tmp.m_childIndex1 = j;
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tmp.m_childShape0 = compound->getChildShape(i);
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tmp.m_childShape1 = compound->getChildShape(j);
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tmp.m_strength = 1.f;//??
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m_connections.push_back(tmp);
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}
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}
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}
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}
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}
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btCompoundShape* btFractureBody::shiftTransformDistributeMass(btCompoundShape* boxCompound,btScalar mass,btTransform& shift)
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{
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btVector3 principalInertia;
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btScalar* masses = new btScalar[boxCompound->getNumChildShapes()];
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for (int j=0;j<boxCompound->getNumChildShapes();j++)
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{
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//evenly distribute mass
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masses[j]=mass/boxCompound->getNumChildShapes();
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}
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return shiftTransform(boxCompound,masses,shift,principalInertia);
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}
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btCompoundShape* btFractureBody::shiftTransform(btCompoundShape* boxCompound,btScalar* masses,btTransform& shift, btVector3& principalInertia)
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{
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btTransform principal;
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boxCompound->calculatePrincipalAxisTransform(masses,principal,principalInertia);
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///create a new compound with world transform/center of mass properly aligned with the principal axis
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///non-recursive compound shapes perform better
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#ifdef USE_RECURSIVE_COMPOUND
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btCompoundShape* newCompound = new btCompoundShape();
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newCompound->addChildShape(principal.inverse(),boxCompound);
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newBoxCompound = newCompound;
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//m_collisionShapes.push_back(newCompound);
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//btDefaultMotionState* myMotionState = new btDefaultMotionState(startTransform);
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//btRigidBody::btRigidBodyConstructionInfo rbInfo(mass,myMotionState,newCompound,principalInertia);
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#else
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#ifdef CHANGE_COMPOUND_INPLACE
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newBoxCompound = boxCompound;
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for (int i=0;i<boxCompound->getNumChildShapes();i++)
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{
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btTransform newChildTransform = principal.inverse()*boxCompound->getChildTransform(i);
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///updateChildTransform is really slow, because it re-calculates the AABB each time. todo: add option to disable this update
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boxCompound->updateChildTransform(i,newChildTransform);
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}
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bool isDynamic = (mass != 0.f);
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btVector3 localInertia(0,0,0);
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if (isDynamic)
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boxCompound->calculateLocalInertia(mass,localInertia);
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#else
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///creation is faster using a new compound to store the shifted children
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btCompoundShape* newBoxCompound = new btCompoundShape();
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for (int i=0;i<boxCompound->getNumChildShapes();i++)
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{
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btTransform newChildTransform = principal.inverse()*boxCompound->getChildTransform(i);
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///updateChildTransform is really slow, because it re-calculates the AABB each time. todo: add option to disable this update
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newBoxCompound->addChildShape(newChildTransform,boxCompound->getChildShape(i));
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}
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#endif
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#endif//USE_RECURSIVE_COMPOUND
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shift = principal;
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return newBoxCompound;
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}
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