253 lines
7.4 KiB
C++
253 lines
7.4 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 "btCylinderShape.h"
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btCylinderShape::btCylinderShape(const btVector3& halfExtents)
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: btConvexInternalShape(),
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m_upAxis(1)
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{
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btVector3 margin(getMargin(), getMargin(), getMargin());
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m_implicitShapeDimensions = (halfExtents * m_localScaling) - margin;
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setSafeMargin(halfExtents);
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m_shapeType = CYLINDER_SHAPE_PROXYTYPE;
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}
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btCylinderShapeX::btCylinderShapeX(const btVector3& halfExtents)
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: btCylinderShape(halfExtents)
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{
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m_upAxis = 0;
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}
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btCylinderShapeZ::btCylinderShapeZ(const btVector3& halfExtents)
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: btCylinderShape(halfExtents)
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{
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m_upAxis = 2;
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}
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void btCylinderShape::getAabb(const btTransform& t, btVector3& aabbMin, btVector3& aabbMax) const
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{
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btTransformAabb(getHalfExtentsWithoutMargin(), getMargin(), t, aabbMin, aabbMax);
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}
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void btCylinderShape::calculateLocalInertia(btScalar mass, btVector3& inertia) const
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{
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//Until Bullet 2.77 a box approximation was used, so uncomment this if you need backwards compatibility
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//#define USE_BOX_INERTIA_APPROXIMATION 1
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#ifndef USE_BOX_INERTIA_APPROXIMATION
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/*
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cylinder is defined as following:
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*
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* - principle axis aligned along y by default, radius in x, z-value not used
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* - for btCylinderShapeX: principle axis aligned along x, radius in y direction, z-value not used
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* - for btCylinderShapeZ: principle axis aligned along z, radius in x direction, y-value not used
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*
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*/
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btScalar radius2; // square of cylinder radius
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btScalar height2; // square of cylinder height
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btVector3 halfExtents = getHalfExtentsWithMargin(); // get cylinder dimension
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btScalar div12 = mass / 12.f;
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btScalar div4 = mass / 4.f;
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btScalar div2 = mass / 2.f;
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int idxRadius, idxHeight;
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switch (m_upAxis) // get indices of radius and height of cylinder
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{
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case 0: // cylinder is aligned along x
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idxRadius = 1;
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idxHeight = 0;
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break;
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case 2: // cylinder is aligned along z
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idxRadius = 0;
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idxHeight = 2;
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break;
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default: // cylinder is aligned along y
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idxRadius = 0;
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idxHeight = 1;
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}
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// calculate squares
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radius2 = halfExtents[idxRadius] * halfExtents[idxRadius];
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height2 = btScalar(4.) * halfExtents[idxHeight] * halfExtents[idxHeight];
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// calculate tensor terms
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btScalar t1 = div12 * height2 + div4 * radius2;
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btScalar t2 = div2 * radius2;
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switch (m_upAxis) // set diagonal elements of inertia tensor
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{
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case 0: // cylinder is aligned along x
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inertia.setValue(t2, t1, t1);
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break;
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case 2: // cylinder is aligned along z
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inertia.setValue(t1, t1, t2);
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break;
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default: // cylinder is aligned along y
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inertia.setValue(t1, t2, t1);
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}
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#else //USE_BOX_INERTIA_APPROXIMATION
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//approximation of box shape
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btVector3 halfExtents = getHalfExtentsWithMargin();
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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.setValue(mass / (btScalar(12.0)) * (ly * ly + lz * lz),
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mass / (btScalar(12.0)) * (lx * lx + lz * lz),
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mass / (btScalar(12.0)) * (lx * lx + ly * ly));
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#endif //USE_BOX_INERTIA_APPROXIMATION
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}
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SIMD_FORCE_INLINE btVector3 CylinderLocalSupportX(const btVector3& halfExtents, const btVector3& v)
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{
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const int cylinderUpAxis = 0;
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const int XX = 1;
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const int YY = 0;
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const int ZZ = 2;
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//mapping depends on how cylinder local orientation is
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// extents of the cylinder is: X,Y is for radius, and Z for height
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btScalar radius = halfExtents[XX];
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btScalar halfHeight = halfExtents[cylinderUpAxis];
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btVector3 tmp;
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btScalar d;
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btScalar s = btSqrt(v[XX] * v[XX] + v[ZZ] * v[ZZ]);
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if (s != btScalar(0.0))
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{
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d = radius / s;
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tmp[XX] = v[XX] * d;
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tmp[YY] = v[YY] < 0.0 ? -halfHeight : halfHeight;
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tmp[ZZ] = v[ZZ] * d;
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return tmp;
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}
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else
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{
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tmp[XX] = radius;
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tmp[YY] = v[YY] < 0.0 ? -halfHeight : halfHeight;
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tmp[ZZ] = btScalar(0.0);
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return tmp;
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}
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}
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inline btVector3 CylinderLocalSupportY(const btVector3& halfExtents, const btVector3& v)
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{
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const int cylinderUpAxis = 1;
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const int XX = 0;
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const int YY = 1;
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const int ZZ = 2;
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btScalar radius = halfExtents[XX];
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btScalar halfHeight = halfExtents[cylinderUpAxis];
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btVector3 tmp;
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btScalar d;
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btScalar s = btSqrt(v[XX] * v[XX] + v[ZZ] * v[ZZ]);
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if (s != btScalar(0.0))
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{
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d = radius / s;
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tmp[XX] = v[XX] * d;
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tmp[YY] = v[YY] < 0.0 ? -halfHeight : halfHeight;
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tmp[ZZ] = v[ZZ] * d;
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return tmp;
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}
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else
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{
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tmp[XX] = radius;
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tmp[YY] = v[YY] < 0.0 ? -halfHeight : halfHeight;
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tmp[ZZ] = btScalar(0.0);
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return tmp;
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}
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}
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inline btVector3 CylinderLocalSupportZ(const btVector3& halfExtents, const btVector3& v)
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{
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const int cylinderUpAxis = 2;
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const int XX = 0;
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const int YY = 2;
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const int ZZ = 1;
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//mapping depends on how cylinder local orientation is
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// extents of the cylinder is: X,Y is for radius, and Z for height
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btScalar radius = halfExtents[XX];
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btScalar halfHeight = halfExtents[cylinderUpAxis];
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btVector3 tmp;
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btScalar d;
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btScalar s = btSqrt(v[XX] * v[XX] + v[ZZ] * v[ZZ]);
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if (s != btScalar(0.0))
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{
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d = radius / s;
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tmp[XX] = v[XX] * d;
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tmp[YY] = v[YY] < 0.0 ? -halfHeight : halfHeight;
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tmp[ZZ] = v[ZZ] * d;
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return tmp;
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}
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else
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{
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tmp[XX] = radius;
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tmp[YY] = v[YY] < 0.0 ? -halfHeight : halfHeight;
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tmp[ZZ] = btScalar(0.0);
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return tmp;
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}
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}
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btVector3 btCylinderShapeX::localGetSupportingVertexWithoutMargin(const btVector3& vec) const
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{
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return CylinderLocalSupportX(getHalfExtentsWithoutMargin(), vec);
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}
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btVector3 btCylinderShapeZ::localGetSupportingVertexWithoutMargin(const btVector3& vec) const
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{
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return CylinderLocalSupportZ(getHalfExtentsWithoutMargin(), vec);
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}
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btVector3 btCylinderShape::localGetSupportingVertexWithoutMargin(const btVector3& vec) const
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{
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return CylinderLocalSupportY(getHalfExtentsWithoutMargin(), vec);
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}
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void btCylinderShape::batchedUnitVectorGetSupportingVertexWithoutMargin(const btVector3* vectors, btVector3* supportVerticesOut, int numVectors) const
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{
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for (int i = 0; i < numVectors; i++)
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{
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supportVerticesOut[i] = CylinderLocalSupportY(getHalfExtentsWithoutMargin(), vectors[i]);
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}
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}
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void btCylinderShapeZ::batchedUnitVectorGetSupportingVertexWithoutMargin(const btVector3* vectors, btVector3* supportVerticesOut, int numVectors) const
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{
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for (int i = 0; i < numVectors; i++)
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{
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supportVerticesOut[i] = CylinderLocalSupportZ(getHalfExtentsWithoutMargin(), vectors[i]);
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}
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}
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void btCylinderShapeX::batchedUnitVectorGetSupportingVertexWithoutMargin(const btVector3* vectors, btVector3* supportVerticesOut, int numVectors) const
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{
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for (int i = 0; i < numVectors; i++)
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{
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supportVerticesOut[i] = CylinderLocalSupportX(getHalfExtentsWithoutMargin(), vectors[i]);
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}
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}
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