94 lines
2.3 KiB
C++
94 lines
2.3 KiB
C++
/*
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* Copyright (c) 2016-2016 Irlan Robson http://www.irlan.net
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*
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* This software is provided 'as-is', without any express or implied
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* warranty. In no event will the authors be held liable for any damages
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* 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
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* freely, subject to the following restrictions:
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* 1. The origin of this software must not be misrepresented; you must not
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* claim that you wrote the original software. If you use this software
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* in a product, an acknowledgment in the product documentation would be
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* appreciated but is not required.
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* 2. Altered source versions must be plainly marked as such, and must not be
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* 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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#ifndef SHIFT_CENTER_H
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#define SHIFT_CENTER_H
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class ShiftCenter : public Test
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{
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public:
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ShiftCenter()
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{
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{
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b3BodyDef bd;
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b3Body* ground = m_world.CreateBody(bd);
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b3HullShape hs;
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hs.m_hull = &m_groundHull;
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b3ShapeDef sd;
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sd.shape = &hs;
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ground->CreateShape(sd);
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}
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{
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b3BodyDef bd;
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bd.type = e_dynamicBody;
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bd.position.Set(0.0f, 5.0f, 0.0f);
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b3Body* body = m_world.CreateBody(bd);
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b3SphereShape sphere;
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sphere.m_center.SetZero();
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sphere.m_radius = 1.0f;
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b3ShapeDef sd;
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sd.density = 0.1f;
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sd.friction = 0.3f;
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sd.shape = &sphere;
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body->CreateShape(sd);
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// Retrieve the local center of mass and inertia about the
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// local center of mass
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b3MassData massData;
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body->GetMassData(&massData);
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// Shift the inertia to the local origin
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massData.I += massData.mass * b3Steiner(massData.center);
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// Make a copy of the old local center of mass
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b3Vec3 oldCenter = massData.center;
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// Pick a center of mass of choice
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massData.center.z += 10.0f;
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// Measure the displacement from the old local center of mass
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// to the new local center of mass.
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b3Vec3 d = massData.center - oldCenter;
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// Move the inertia at the local origin to the new local origin
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massData.I += massData.mass * b3Steiner(d);
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// Update local center of mass and inertia
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body->SetMassData(&massData);
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}
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}
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~ShiftCenter()
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{
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}
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static Test* Create()
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{
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return new ShiftCenter();
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}
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};
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#endif |