git-svn-id: https://reactphysics3d.googlecode.com/svn/trunk@210 92aac97c-a6ce-11dd-a772-7fcde58d38e6

sources/reactphysics3d/integration/SemiImplicitEuler.cpp

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+/****************************************************************************
+ * Copyright (C) 2009      Daniel Chappuis                                  *
+ ****************************************************************************
+ * This file is part of ReactPhysics3D.                                     *
+ *                                                                          *
+ * ReactPhysics3D is free software: you can redistribute it and/or modify   *
+ * it under the terms of the GNU Lesser General Public License as published *
+ * by the Free Software Foundation, either version 3 of the License, or     *
+ * (at your option) any later version.                                      *
+ *                                                                          *
+ * ReactPhysics3D is distributed in the hope that it will be useful,        *
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of           *
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the             *
+ * GNU Lesser General Public License for more details.                      *
+ *                                                                          *
+ * You should have received a copy of the GNU Lesser General Public License *
+ * along with ReactPhysics3D. If not, see <http://www.gnu.org/licenses/>.   *
+ ***************************************************************************/
+
+// Libraries
+#include "SemiImplicitEuler.h"
+
+// We want to use the ReactPhysics3D namespace
+using namespace reactphysics3d;
+
+// Constructor
+SemiImplicitEuler::SemiImplicitEuler() {
+
+}
+
+// Copy-constructor
+SemiImplicitEuler::SemiImplicitEuler(const SemiImplicitEuler& euler) {
+
+}
+
+// Destructor
+SemiImplicitEuler::~SemiImplicitEuler() {
+
+}
+
+// Integrate a body state over time. This method use the semi-implicit Euler integration algorithm
+void SemiImplicitEuler::integrate(BodyState& bodyState, const Time& time, const Time& timeStep) {
+    double dt = timeStep.getValue();    // Timestep
+
+    // Compute the integrated body state
+    bodyState.setLinearMomentum(bodyState.getLinearMomentum() + bodyState.getForce() * dt);
+    bodyState.setAngularMomentum(bodyState.getAngularMomentum() + bodyState.getTorque() * dt);
+
+    // Recalculate the secondary values of the body state
+    bodyState.recalculate();
+
+    // Compute the integrated position and orientation
+    bodyState.setPosition(bodyState.getPosition() + bodyState.getLinearVelocity() * dt);
+    bodyState.setOrientation(bodyState.getOrientation() + bodyState.getSpin() * dt);
+}
+

sources/reactphysics3d/integration/SemiImplicitEuler.h

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+/****************************************************************************
+* Copyright (C) 2009      Daniel Chappuis                                  *
+****************************************************************************
+* This file is part of ReactPhysics3D.                                     *
+*                                                                          *
+* ReactPhysics3D is free software: you can redistribute it and/or modify   *
+* it under the terms of the GNU Lesser General Public License as published *
+* by the Free Software Foundation, either version 3 of the License, or     *
+* (at your option) any later version.                                      *
+*                                                                          *
+* ReactPhysics3D is distributed in the hope that it will be useful,        *
+* but WITHOUT ANY WARRANTY; without even the implied warranty of           *
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the             *
+* GNU Lesser General Public License for more details.                      *
+*                                                                          *
+* You should have received a copy of the GNU Lesser General Public License *
+* along with ReactPhysics3D. If not, see <http://www.gnu.org/licenses/>.   *
+***************************************************************************/
+
+#ifndef SEMIIMPLICITEULER_H
+#define SEMIIMPLICITEULER_H
+
+// Libraries
+#include "IntegrationAlgorithm.h"
+#include "../body/BodyState.h"
+
+// Namespace ReactPhysics3D
+namespace reactphysics3d {
+
+// TODO : Test the semi-implicit Euler
+
+/*  -------------------------------------------------------------------
+    Class SemiImplicitEuler :
+        This class will be used to solve the differential equation of
+        movement by integrating a body state. This class implements
+        the semi-implicit Euler algorithm. It's a first order integrator
+        algorithm and it's always stable.
+    -------------------------------------------------------------------
+*/
+class SemiImplicitEuler : public IntegrationAlgorithm {
+    private :
+
+    public :
+        SemiImplicitEuler();                                       // Constructor
+        SemiImplicitEuler(const SemiImplicitEuler& euler);         // Copy-constructor
+        virtual ~SemiImplicitEuler();                              // Destructor
+
+        void integrate(BodyState& bodyState, const Time& t, const Time& dt);    // Integrate a body state over time
+};
+
+}
+
+#endif
+