mirror of https://github.com/axmolengine/axmol.git
336 lines
11 KiB
C++
336 lines
11 KiB
C++
/*
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Bullet Continuous Collision Detection and Physics Library
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Copyright (c) 2003-2009 Erwin Coumans http://bulletphysics.org
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This software is provided 'as-is', without any express or implied warranty.
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In no event will the authors be held liable for any damages arising from the use of this software.
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Permission is granted to anyone to use this software for any purpose,
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including commercial applications, and to alter it and redistribute it freely,
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subject to the following restrictions:
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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.
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2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
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3. This notice may not be removed or altered from any source distribution.
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*/
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#include "btCompoundShape.h"
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#include "btCollisionShape.h"
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#include "BulletCollision/BroadphaseCollision/btDbvt.h"
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#include "LinearMath/btSerializer.h"
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btCompoundShape::btCompoundShape(bool enableDynamicAabbTree, const int initialChildCapacity)
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: m_localAabbMin(btScalar(BT_LARGE_FLOAT), btScalar(BT_LARGE_FLOAT), btScalar(BT_LARGE_FLOAT)),
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m_localAabbMax(btScalar(-BT_LARGE_FLOAT), btScalar(-BT_LARGE_FLOAT), btScalar(-BT_LARGE_FLOAT)),
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m_dynamicAabbTree(0),
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m_updateRevision(1),
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m_collisionMargin(btScalar(0.)),
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m_localScaling(btScalar(1.), btScalar(1.), btScalar(1.))
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{
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m_shapeType = COMPOUND_SHAPE_PROXYTYPE;
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if (enableDynamicAabbTree)
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{
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void* mem = btAlignedAlloc(sizeof(btDbvt), 16);
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m_dynamicAabbTree = new (mem) btDbvt();
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btAssert(mem == m_dynamicAabbTree);
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}
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m_children.reserve(initialChildCapacity);
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}
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btCompoundShape::~btCompoundShape()
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{
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if (m_dynamicAabbTree)
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{
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m_dynamicAabbTree->~btDbvt();
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btAlignedFree(m_dynamicAabbTree);
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}
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}
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void btCompoundShape::addChildShape(const btTransform& localTransform, btCollisionShape* shape)
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{
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m_updateRevision++;
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//m_childTransforms.push_back(localTransform);
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//m_childShapes.push_back(shape);
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btCompoundShapeChild child;
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child.m_node = 0;
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child.m_transform = localTransform;
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child.m_childShape = shape;
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child.m_childShapeType = shape->getShapeType();
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child.m_childMargin = shape->getMargin();
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//extend the local aabbMin/aabbMax
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btVector3 localAabbMin, localAabbMax;
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shape->getAabb(localTransform, localAabbMin, localAabbMax);
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for (int i = 0; i < 3; i++)
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{
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if (m_localAabbMin[i] > localAabbMin[i])
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{
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m_localAabbMin[i] = localAabbMin[i];
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}
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if (m_localAabbMax[i] < localAabbMax[i])
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{
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m_localAabbMax[i] = localAabbMax[i];
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}
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}
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if (m_dynamicAabbTree)
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{
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const btDbvtVolume bounds = btDbvtVolume::FromMM(localAabbMin, localAabbMax);
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size_t index = m_children.size();
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child.m_node = m_dynamicAabbTree->insert(bounds, reinterpret_cast<void*>(index));
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}
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m_children.push_back(child);
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}
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void btCompoundShape::updateChildTransform(int childIndex, const btTransform& newChildTransform, bool shouldRecalculateLocalAabb)
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{
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m_children[childIndex].m_transform = newChildTransform;
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if (m_dynamicAabbTree)
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{
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///update the dynamic aabb tree
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btVector3 localAabbMin, localAabbMax;
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m_children[childIndex].m_childShape->getAabb(newChildTransform, localAabbMin, localAabbMax);
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ATTRIBUTE_ALIGNED16(btDbvtVolume)
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bounds = btDbvtVolume::FromMM(localAabbMin, localAabbMax);
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//int index = m_children.size()-1;
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m_dynamicAabbTree->update(m_children[childIndex].m_node, bounds);
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}
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if (shouldRecalculateLocalAabb)
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{
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recalculateLocalAabb();
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}
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}
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void btCompoundShape::removeChildShapeByIndex(int childShapeIndex)
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{
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m_updateRevision++;
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btAssert(childShapeIndex >= 0 && childShapeIndex < m_children.size());
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if (m_dynamicAabbTree)
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{
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m_dynamicAabbTree->remove(m_children[childShapeIndex].m_node);
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}
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m_children.swap(childShapeIndex, m_children.size() - 1);
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if (m_dynamicAabbTree)
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m_children[childShapeIndex].m_node->dataAsInt = childShapeIndex;
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m_children.pop_back();
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}
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void btCompoundShape::removeChildShape(btCollisionShape* shape)
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{
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m_updateRevision++;
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// Find the children containing the shape specified, and remove those children.
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//note: there might be multiple children using the same shape!
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for (int i = m_children.size() - 1; i >= 0; i--)
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{
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if (m_children[i].m_childShape == shape)
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{
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removeChildShapeByIndex(i);
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}
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}
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recalculateLocalAabb();
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}
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void btCompoundShape::recalculateLocalAabb()
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{
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// Recalculate the local aabb
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// Brute force, it iterates over all the shapes left.
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m_localAabbMin = btVector3(btScalar(BT_LARGE_FLOAT), btScalar(BT_LARGE_FLOAT), btScalar(BT_LARGE_FLOAT));
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m_localAabbMax = btVector3(btScalar(-BT_LARGE_FLOAT), btScalar(-BT_LARGE_FLOAT), btScalar(-BT_LARGE_FLOAT));
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//extend the local aabbMin/aabbMax
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for (int j = 0; j < m_children.size(); j++)
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{
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btVector3 localAabbMin, localAabbMax;
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m_children[j].m_childShape->getAabb(m_children[j].m_transform, localAabbMin, localAabbMax);
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for (int i = 0; i < 3; i++)
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{
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if (m_localAabbMin[i] > localAabbMin[i])
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m_localAabbMin[i] = localAabbMin[i];
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if (m_localAabbMax[i] < localAabbMax[i])
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m_localAabbMax[i] = localAabbMax[i];
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}
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}
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}
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///getAabb's default implementation is brute force, expected derived classes to implement a fast dedicated version
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void btCompoundShape::getAabb(const btTransform& trans, btVector3& aabbMin, btVector3& aabbMax) const
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{
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btVector3 localHalfExtents = btScalar(0.5) * (m_localAabbMax - m_localAabbMin);
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btVector3 localCenter = btScalar(0.5) * (m_localAabbMax + m_localAabbMin);
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//avoid an illegal AABB when there are no children
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if (!m_children.size())
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{
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localHalfExtents.setValue(0, 0, 0);
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localCenter.setValue(0, 0, 0);
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}
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localHalfExtents += btVector3(getMargin(), getMargin(), getMargin());
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btMatrix3x3 abs_b = trans.getBasis().absolute();
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btVector3 center = trans(localCenter);
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btVector3 extent = localHalfExtents.dot3(abs_b[0], abs_b[1], abs_b[2]);
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aabbMin = center - extent;
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aabbMax = center + extent;
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}
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void btCompoundShape::calculateLocalInertia(btScalar mass, btVector3& inertia) const
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{
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//approximation: take the inertia from the aabb for now
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btTransform ident;
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ident.setIdentity();
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btVector3 aabbMin, aabbMax;
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getAabb(ident, aabbMin, aabbMax);
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btVector3 halfExtents = (aabbMax - aabbMin) * btScalar(0.5);
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btScalar lx = btScalar(2.) * (halfExtents.x());
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btScalar ly = btScalar(2.) * (halfExtents.y());
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btScalar lz = btScalar(2.) * (halfExtents.z());
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inertia[0] = mass / (btScalar(12.0)) * (ly * ly + lz * lz);
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inertia[1] = mass / (btScalar(12.0)) * (lx * lx + lz * lz);
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inertia[2] = mass / (btScalar(12.0)) * (lx * lx + ly * ly);
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}
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void btCompoundShape::calculatePrincipalAxisTransform(const btScalar* masses, btTransform& principal, btVector3& inertia) const
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{
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int n = m_children.size();
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btScalar totalMass = 0;
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btVector3 center(0, 0, 0);
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int k;
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for (k = 0; k < n; k++)
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{
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btAssert(masses[k] > 0);
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center += m_children[k].m_transform.getOrigin() * masses[k];
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totalMass += masses[k];
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}
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btAssert(totalMass > 0);
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center /= totalMass;
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principal.setOrigin(center);
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btMatrix3x3 tensor(0, 0, 0, 0, 0, 0, 0, 0, 0);
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for (k = 0; k < n; k++)
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{
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btVector3 i;
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m_children[k].m_childShape->calculateLocalInertia(masses[k], i);
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const btTransform& t = m_children[k].m_transform;
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btVector3 o = t.getOrigin() - center;
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//compute inertia tensor in coordinate system of compound shape
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btMatrix3x3 j = t.getBasis().transpose();
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j[0] *= i[0];
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j[1] *= i[1];
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j[2] *= i[2];
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j = t.getBasis() * j;
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//add inertia tensor
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tensor[0] += j[0];
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tensor[1] += j[1];
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tensor[2] += j[2];
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//compute inertia tensor of pointmass at o
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btScalar o2 = o.length2();
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j[0].setValue(o2, 0, 0);
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j[1].setValue(0, o2, 0);
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j[2].setValue(0, 0, o2);
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j[0] += o * -o.x();
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j[1] += o * -o.y();
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j[2] += o * -o.z();
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//add inertia tensor of pointmass
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tensor[0] += masses[k] * j[0];
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tensor[1] += masses[k] * j[1];
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tensor[2] += masses[k] * j[2];
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}
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tensor.diagonalize(principal.getBasis(), btScalar(0.00001), 20);
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inertia.setValue(tensor[0][0], tensor[1][1], tensor[2][2]);
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}
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void btCompoundShape::setLocalScaling(const btVector3& scaling)
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{
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for (int i = 0; i < m_children.size(); i++)
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{
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btTransform childTrans = getChildTransform(i);
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btVector3 childScale = m_children[i].m_childShape->getLocalScaling();
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// childScale = childScale * (childTrans.getBasis() * scaling);
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childScale = childScale * scaling / m_localScaling;
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m_children[i].m_childShape->setLocalScaling(childScale);
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childTrans.setOrigin((childTrans.getOrigin()) * scaling / m_localScaling);
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updateChildTransform(i, childTrans, false);
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}
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m_localScaling = scaling;
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recalculateLocalAabb();
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}
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void btCompoundShape::createAabbTreeFromChildren()
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{
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if (!m_dynamicAabbTree)
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{
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void* mem = btAlignedAlloc(sizeof(btDbvt), 16);
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m_dynamicAabbTree = new (mem) btDbvt();
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btAssert(mem == m_dynamicAabbTree);
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for (int index = 0; index < m_children.size(); index++)
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{
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btCompoundShapeChild& child = m_children[index];
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//extend the local aabbMin/aabbMax
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btVector3 localAabbMin, localAabbMax;
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child.m_childShape->getAabb(child.m_transform, localAabbMin, localAabbMax);
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const btDbvtVolume bounds = btDbvtVolume::FromMM(localAabbMin, localAabbMax);
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size_t index2 = index;
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child.m_node = m_dynamicAabbTree->insert(bounds, reinterpret_cast<void*>(index2));
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}
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}
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}
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///fills the dataBuffer and returns the struct name (and 0 on failure)
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const char* btCompoundShape::serialize(void* dataBuffer, btSerializer* serializer) const
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{
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btCompoundShapeData* shapeData = (btCompoundShapeData*)dataBuffer;
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btCollisionShape::serialize(&shapeData->m_collisionShapeData, serializer);
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shapeData->m_collisionMargin = float(m_collisionMargin);
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shapeData->m_numChildShapes = m_children.size();
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shapeData->m_childShapePtr = 0;
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if (shapeData->m_numChildShapes)
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{
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btChunk* chunk = serializer->allocate(sizeof(btCompoundShapeChildData), shapeData->m_numChildShapes);
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btCompoundShapeChildData* memPtr = (btCompoundShapeChildData*)chunk->m_oldPtr;
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shapeData->m_childShapePtr = (btCompoundShapeChildData*)serializer->getUniquePointer(memPtr);
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for (int i = 0; i < shapeData->m_numChildShapes; i++, memPtr++)
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{
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memPtr->m_childMargin = float(m_children[i].m_childMargin);
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memPtr->m_childShape = (btCollisionShapeData*)serializer->getUniquePointer(m_children[i].m_childShape);
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//don't serialize shapes that already have been serialized
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if (!serializer->findPointer(m_children[i].m_childShape))
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{
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btChunk* chunk = serializer->allocate(m_children[i].m_childShape->calculateSerializeBufferSize(), 1);
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const char* structType = m_children[i].m_childShape->serialize(chunk->m_oldPtr, serializer);
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serializer->finalizeChunk(chunk, structType, BT_SHAPE_CODE, m_children[i].m_childShape);
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}
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memPtr->m_childShapeType = m_children[i].m_childShapeType;
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m_children[i].m_transform.serializeFloat(memPtr->m_transform);
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}
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serializer->finalizeChunk(chunk, "btCompoundShapeChildData", BT_ARRAY_CODE, chunk->m_oldPtr);
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}
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return "btCompoundShapeData";
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}
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