hello world

neo/idlib/math/Ode.h

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+/*
+===========================================================================
+
+Doom 3 GPL Source Code
+Copyright (C) 1999-2011 id Software LLC, a ZeniMax Media company. 
+
+This file is part of the Doom 3 GPL Source Code (?Doom 3 Source Code?).  
+
+Doom 3 Source Code is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+Doom 3 Source Code 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 General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with Doom 3 Source Code.  If not, see <http://www.gnu.org/licenses/>.
+
+In addition, the Doom 3 Source Code is also subject to certain additional terms. You should have received a copy of these additional terms immediately following the terms and conditions of the GNU General Public License which accompanied the Doom 3 Source Code.  If not, please request a copy in writing from id Software at the address below.
+
+If you have questions concerning this license or the applicable additional terms, you may contact in writing id Software LLC, c/o ZeniMax Media Inc., Suite 120, Rockville, Maryland 20850 USA.
+
+===========================================================================
+*/
+
+#ifndef __MATH_ODE_H__
+#define __MATH_ODE_H__
+
+/*
+===============================================================================
+
+	Numerical solvers for ordinary differential equations.
+
+===============================================================================
+*/
+
+
+//===============================================================
+//
+//	idODE
+//
+//===============================================================
+
+typedef void (*deriveFunction_t)( const float t, const void *userData, const float *state, float *derivatives );
+
+class idODE {
+
+public:
+	virtual				~idODE( void ) {}
+
+	virtual float		Evaluate( const float *state, float *newState, float t0, float t1 ) = 0;
+
+protected:
+	int					dimension;		// dimension in floats allocated for
+	deriveFunction_t	derive;			// derive function
+	const void *		userData;		// client data
+};
+
+//===============================================================
+//
+//	idODE_Euler
+//
+//===============================================================
+
+class idODE_Euler : public idODE {
+
+public:
+						idODE_Euler( const int dim, const deriveFunction_t dr, const void *ud );
+	virtual				~idODE_Euler( void );
+
+	virtual float		Evaluate( const float *state, float *newState, float t0, float t1 );
+
+protected:
+	float *				derivatives;	// space to store derivatives
+};
+
+//===============================================================
+//
+//	idODE_Midpoint
+//
+//===============================================================
+
+class idODE_Midpoint : public idODE {
+
+public:
+						idODE_Midpoint( const int dim, const deriveFunction_t dr, const void *ud );
+	virtual				~idODE_Midpoint( void );
+
+	virtual float		Evaluate( const float *state, float *newState, float t0, float t1 );
+
+protected:
+	float *				tmpState;
+	float *				derivatives;	// space to store derivatives
+};
+
+//===============================================================
+//
+//	idODE_RK4
+//
+//===============================================================
+
+class idODE_RK4 : public idODE {
+
+public:
+						idODE_RK4( const int dim, const deriveFunction_t dr, const void *ud );
+	virtual				~idODE_RK4( void );
+
+	virtual float		Evaluate( const float *state, float *newState, float t0, float t1 );
+
+protected:
+	float *				tmpState;
+	float *				d1;				// derivatives
+	float *				d2;
+	float *				d3;
+	float *				d4;
+};
+
+//===============================================================
+//
+//	idODE_RK4Adaptive
+//
+//===============================================================
+
+class idODE_RK4Adaptive : public idODE {
+
+public:
+						idODE_RK4Adaptive( const int dim, const deriveFunction_t dr, const void *ud );
+	virtual				~idODE_RK4Adaptive( void );
+
+	virtual float		Evaluate( const float *state, float *newState, float t0, float t1 );
+	void				SetMaxError( const float err );
+
+protected:
+	float				maxError;		// maximum allowed error
+	float *				tmpState;
+	float *				d1;				// derivatives
+	float *				d1half;
+	float *				d2;
+	float *				d3;
+	float *				d4;
+};
+
+#endif /* !__MATH_ODE_H__ */