converted FractureDemo

2015-05-03 10:01:30 -07:00
parent 59b511a14e
commit 7288313970
8 changed files with 1387 additions and 0 deletions
--- a/examples/FractureDemo/btFractureBody.cpp
+++ b/examples/FractureDemo/btFractureBody.cpp
@@ -0,0 +1,139 @@
+
+#include "btFractureBody.h"
+#include "BulletCollision/CollisionDispatch/btCollisionWorld.h"
+#include "BulletCollision/CollisionShapes/btCompoundShape.h"
+#include "BulletDynamics/Dynamics/btDynamicsWorld.h"
+
+
+
+void	btFractureBody::recomputeConnectivity(btCollisionWorld* world)
+{
+	m_connections.clear();
+	//@todo use the AABB tree to avoid N^2 checks
+
+	if (getCollisionShape()->isCompound())
+	{
+		btCompoundShape* compound = (btCompoundShape*)getCollisionShape();
+		for (int i=0;i<compound->getNumChildShapes();i++)
+		{
+			for (int j=i+1;j<compound->getNumChildShapes();j++)
+			{
+
+				struct   MyContactResultCallback : public btCollisionWorld::ContactResultCallback
+				{
+					bool m_connected;
+					btScalar m_margin;
+					MyContactResultCallback() :m_connected(false),m_margin(0.05)
+					{
+					}
+					virtual   btScalar   addSingleResult(btManifoldPoint& cp,   const btCollisionObjectWrapper* colObj0Wrap,int partId0,int index0,const btCollisionObjectWrapper* colObj1Wrap,int partId1,int index1)
+					{
+						if (cp.getDistance()<=m_margin)
+							m_connected = true;
+						return 1.f;
+					}
+			   };
+
+				MyContactResultCallback result;
+
+				btCollisionObject obA;
+				obA.setWorldTransform(compound->getChildTransform(i));
+				obA.setCollisionShape(compound->getChildShape(i));
+				btCollisionObject obB;
+				obB.setWorldTransform(compound->getChildTransform(j));
+				obB.setCollisionShape(compound->getChildShape(j));
+				world->contactPairTest(&obA,&obB,result);
+				if (result.m_connected)
+				{
+					btConnection tmp;
+					tmp.m_childIndex0 = i;
+					tmp.m_childIndex1 = j;
+					tmp.m_childShape0 = compound->getChildShape(i);
+					tmp.m_childShape1 = compound->getChildShape(j);
+					tmp.m_strength = 1.f;//??
+					m_connections.push_back(tmp);
+				}
+			}
+		}
+	}
+	
+
+}
+
+btCompoundShape* btFractureBody::shiftTransformDistributeMass(btCompoundShape* boxCompound,btScalar mass,btTransform& shift)
+{
+
+	btVector3 principalInertia;
+
+	btScalar* masses = new btScalar[boxCompound->getNumChildShapes()];
+	for (int j=0;j<boxCompound->getNumChildShapes();j++)
+	{
+		//evenly distribute mass
+		masses[j]=mass/boxCompound->getNumChildShapes();
+	}
+
+	return shiftTransform(boxCompound,masses,shift,principalInertia);
+
+}
+
+
+btCompoundShape* btFractureBody::shiftTransform(btCompoundShape* boxCompound,btScalar* masses,btTransform& shift, btVector3& principalInertia)
+{
+	btTransform principal;
+
+	boxCompound->calculatePrincipalAxisTransform(masses,principal,principalInertia);
+
+
+	///create a new compound with world transform/center of mass properly aligned with the principal axis
+
+	///non-recursive compound shapes perform better
+	
+#ifdef USE_RECURSIVE_COMPOUND
+
+	btCompoundShape* newCompound = new btCompoundShape();
+	newCompound->addChildShape(principal.inverse(),boxCompound);
+	newBoxCompound = newCompound;
+	//m_collisionShapes.push_back(newCompound);
+
+	//btDefaultMotionState* myMotionState = new btDefaultMotionState(startTransform);
+	//btRigidBody::btRigidBodyConstructionInfo rbInfo(mass,myMotionState,newCompound,principalInertia);
+
+#else
+#ifdef CHANGE_COMPOUND_INPLACE
+	newBoxCompound = boxCompound;
+	for (int i=0;i<boxCompound->getNumChildShapes();i++)
+	{
+		btTransform newChildTransform = principal.inverse()*boxCompound->getChildTransform(i);
+		///updateChildTransform is really slow, because it re-calculates the AABB each time. todo: add option to disable this update
+		boxCompound->updateChildTransform(i,newChildTransform);
+	}
+	bool isDynamic = (mass != 0.f);
+	btVector3 localInertia(0,0,0);
+	if (isDynamic)
+		boxCompound->calculateLocalInertia(mass,localInertia);
+	
+#else
+	///creation is faster using a new compound to store the shifted children
+	btCompoundShape* newBoxCompound = new btCompoundShape();
+	for (int i=0;i<boxCompound->getNumChildShapes();i++)
+	{
+		btTransform newChildTransform = principal.inverse()*boxCompound->getChildTransform(i);
+		///updateChildTransform is really slow, because it re-calculates the AABB each time. todo: add option to disable this update
+		newBoxCompound->addChildShape(newChildTransform,boxCompound->getChildShape(i));
+	}
+
+
+
+#endif
+
+#endif//USE_RECURSIVE_COMPOUND
+
+	shift = principal;
+	return newBoxCompound;
+}
+
+
+
+
+
+