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      1 /*
      2 Bullet Continuous Collision Detection and Physics Library
      3 Copyright (c) 2003-2009 Erwin Coumans  http://bulletphysics.org
      4 
      5 This software is provided 'as-is', without any express or implied warranty.
      6 In no event will the authors be held liable for any damages arising from the use of this software.
      7 Permission is granted to anyone to use this software for any purpose,
      8 including commercial applications, and to alter it and redistribute it freely,
      9 subject to the following restrictions:
     10 
     11 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.
     12 2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
     13 3. This notice may not be removed or altered from any source distribution.
     14 */
     15 #include "BulletCollision/CollisionShapes/btCollisionShape.h"
     16 #include "LinearMath/btSerializer.h"
     17 
     18 /*
     19   Make sure this dummy function never changes so that it
     20   can be used by probes that are checking whether the
     21   library is actually installed.
     22 */
     23 extern "C"
     24 {
     25 void btBulletCollisionProbe ();
     26 
     27 void btBulletCollisionProbe () {}
     28 }
     29 
     30 
     31 
     32 void	btCollisionShape::getBoundingSphere(btVector3& center,btScalar& radius) const
     33 {
     34 	btTransform tr;
     35 	tr.setIdentity();
     36 	btVector3 aabbMin,aabbMax;
     37 
     38 	getAabb(tr,aabbMin,aabbMax);
     39 
     40 	radius = (aabbMax-aabbMin).length()*btScalar(0.5);
     41 	center = (aabbMin+aabbMax)*btScalar(0.5);
     42 }
     43 
     44 
     45 btScalar	btCollisionShape::getContactBreakingThreshold(btScalar defaultContactThreshold) const
     46 {
     47 	return getAngularMotionDisc() * defaultContactThreshold;
     48 }
     49 
     50 btScalar	btCollisionShape::getAngularMotionDisc() const
     51 {
     52 	///@todo cache this value, to improve performance
     53 	btVector3	center;
     54 	btScalar disc;
     55 	getBoundingSphere(center,disc);
     56 	disc += (center).length();
     57 	return disc;
     58 }
     59 
     60 void btCollisionShape::calculateTemporalAabb(const btTransform& curTrans,const btVector3& linvel,const btVector3& angvel,btScalar timeStep, btVector3& temporalAabbMin,btVector3& temporalAabbMax) const
     61 {
     62 	//start with static aabb
     63 	getAabb(curTrans,temporalAabbMin,temporalAabbMax);
     64 
     65 	btScalar temporalAabbMaxx = temporalAabbMax.getX();
     66 	btScalar temporalAabbMaxy = temporalAabbMax.getY();
     67 	btScalar temporalAabbMaxz = temporalAabbMax.getZ();
     68 	btScalar temporalAabbMinx = temporalAabbMin.getX();
     69 	btScalar temporalAabbMiny = temporalAabbMin.getY();
     70 	btScalar temporalAabbMinz = temporalAabbMin.getZ();
     71 
     72 	// add linear motion
     73 	btVector3 linMotion = linvel*timeStep;
     74 	///@todo: simd would have a vector max/min operation, instead of per-element access
     75 	if (linMotion.x() > btScalar(0.))
     76 		temporalAabbMaxx += linMotion.x();
     77 	else
     78 		temporalAabbMinx += linMotion.x();
     79 	if (linMotion.y() > btScalar(0.))
     80 		temporalAabbMaxy += linMotion.y();
     81 	else
     82 		temporalAabbMiny += linMotion.y();
     83 	if (linMotion.z() > btScalar(0.))
     84 		temporalAabbMaxz += linMotion.z();
     85 	else
     86 		temporalAabbMinz += linMotion.z();
     87 
     88 	//add conservative angular motion
     89 	btScalar angularMotion = angvel.length() * getAngularMotionDisc() * timeStep;
     90 	btVector3 angularMotion3d(angularMotion,angularMotion,angularMotion);
     91 	temporalAabbMin = btVector3(temporalAabbMinx,temporalAabbMiny,temporalAabbMinz);
     92 	temporalAabbMax = btVector3(temporalAabbMaxx,temporalAabbMaxy,temporalAabbMaxz);
     93 
     94 	temporalAabbMin -= angularMotion3d;
     95 	temporalAabbMax += angularMotion3d;
     96 }
     97 
     98 ///fills the dataBuffer and returns the struct name (and 0 on failure)
     99 const char*	btCollisionShape::serialize(void* dataBuffer, btSerializer* serializer) const
    100 {
    101 	btCollisionShapeData* shapeData = (btCollisionShapeData*) dataBuffer;
    102 	char* name = (char*) serializer->findNameForPointer(this);
    103 	shapeData->m_name = (char*)serializer->getUniquePointer(name);
    104 	if (shapeData->m_name)
    105 	{
    106 		serializer->serializeName(name);
    107 	}
    108 	shapeData->m_shapeType = m_shapeType;
    109 	//shapeData->m_padding//??
    110 	return "btCollisionShapeData";
    111 }
    112 
    113 void	btCollisionShape::serializeSingleShape(btSerializer* serializer) const
    114 {
    115 	int len = calculateSerializeBufferSize();
    116 	btChunk* chunk = serializer->allocate(len,1);
    117 	const char* structType = serialize(chunk->m_oldPtr, serializer);
    118 	serializer->finalizeChunk(chunk,structType,BT_SHAPE_CODE,(void*)this);
    119 }