Added initial Smoothed Particle Hydrodynamics implementation (SPH), for CPU and CUDA.

This software is contributed under the ZLib license by Rama Hoetzlein, http://www.rchoetzlein.com
We plan to integrate the SPH into the core Bullet library, including interaction with rigid bodies and soft bodies.

Extras/sph/fluids/fluid_system.h

@@ -0,0 +1,106 @@
+/*
+  FLUIDS v.1 - SPH Fluid Simulator for CPU and GPU
+  Copyright (C) 2008. Rama Hoetzlein, http://www.rchoetzlein.com
+
+  ZLib license
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  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.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+
+
+#ifndef DEF_FLUID_SYS
+	#define DEF_FLUID_SYS
+
+	#include <iostream>
+	#include <vector>
+	#include <stdio.h>
+	#include <stdlib.h>
+	#include <math.h>
+
+	#include "point_set.h"
+	#include "fluid.h"
+	
+	// Scalar params
+	#define SPH_SIMSIZE			4
+	#define SPH_SIMSCALE		5
+	#define SPH_VISC			6
+	#define SPH_RESTDENSITY		7
+	#define SPH_PMASS			8
+	#define SPH_PRADIUS			9
+	#define SPH_PDIST			10
+	#define SPH_SMOOTHRADIUS	11
+	#define SPH_INTSTIFF		12
+	#define SPH_EXTSTIFF		13
+	#define SPH_EXTDAMP			14
+	#define SPH_LIMIT			15
+	#define BOUND_ZMIN_SLOPE	16
+	#define FORCE_XMAX_SIN		17
+	#define FORCE_XMIN_SIN		18
+	#define MAX_FRAC			19
+	#define CLR_MODE			20
+
+	// Vector params
+	#define SPH_VOLMIN			7
+	#define SPH_VOLMAX			8
+	#define SPH_INITMIN			9
+	#define SPH_INITMAX			10
+
+	// Toggles
+	#define	SPH_GRID			0
+	#define SPH_DEBUG			1
+	#define WRAP_X				2
+	#define WALL_BARRIER		3
+	#define LEVY_BARRIER		4
+	#define DRAIN_BARRIER		5
+	#define USE_CUDA			6
+	
+	#define MAX_PARAM			21
+	#define BFLUID				2
+
+	class FluidSystem : public PointSet {
+	public:
+		FluidSystem ();
+
+		// Basic Particle System
+		virtual void Initialize ( int mode, int nmax );
+		virtual void Reset ( int nmax );
+		virtual void Run ();
+		virtual void Advance ();
+		virtual int AddPoint ();		
+		virtual int AddPointReuse ();
+		Fluid* AddFluid ()			{ return (Fluid*) GetElem(0, AddPointReuse()); }
+		Fluid* GetFluid (int n)		{ return (Fluid*) GetElem(0, n); }
+		
+		// Smoothed Particle Hydrodynamics
+		void SPH_Setup ();
+		void SPH_CreateExample ( int n, int nmax );
+		void SPH_DrawDomain ();
+		void SPH_ComputeKernels ();
+
+		void SPH_ComputePressureSlow ();			// O(n^2)
+		void SPH_ComputePressureGrid ();			// O(kn) - spatial grid
+		
+		void SPH_ComputeForceSlow ();				// O(n^2)
+		void SPH_ComputeForceGrid ();				// O(kn) - spatial grid
+		void SPH_ComputeForceGridNC ();				// O(cn) - neighbor table		
+		
+	private:
+
+		// Smoothed Particle Hydrodynamics
+		double						m_R2, m_Poly6Kern, m_LapKern, m_SpikyKern;		// Kernel functions
+	};
+
+#endif