softgym/PyFlex/bindings/demo/main.cpp

// This code contains NVIDIA Confidential Information and is disclosed to you
// under a form of NVIDIA software license agreement provided separately to you.
//
// Notice
// NVIDIA Corporation and its licensors retain all intellectual property and
// proprietary rights in and to this software and related documentation and
// any modifications thereto. Any use, reproduction, disclosure, or
// distribution of this software and related documentation without an express
// license agreement from NVIDIA Corporation is strictly prohibited.
//
// ALL NVIDIA DESIGN SPECIFICATIONS, CODE ARE PROVIDED "AS IS.". NVIDIA MAKES
// NO WARRANTIES, EXPRESSED, IMPLIED, STATUTORY, OR OTHERWISE WITH RESPECT TO
// THE MATERIALS, AND EXPRESSLY DISCLAIMS ALL IMPLIED WARRANTIES OF NONINFRINGEMENT,
// MERCHANTABILITY, AND FITNESS FOR A PARTICULAR PURPOSE.
//
// Information and code furnished is believed to be accurate and reliable.
// However, NVIDIA Corporation assumes no responsibility for the consequences of use of such
// information or for any infringement of patents or other rights of third parties that may
// result from its use. No license is granted by implication or otherwise under any patent
// or patent rights of NVIDIA Corporation. Details are subject to change without notice.
// This code supersedes and replaces all information previously supplied.
// NVIDIA Corporation products are not authorized for use as critical
// components in life support devices or systems without express written approval of
// NVIDIA Corporation.
//
// Copyright (c) 2013-2017 NVIDIA Corporation. All rights reserved.

#include "../core/types.h"
#include "../core/maths.h"
#include "../core/platform.h"
#include "../core/mesh.h"
#include "../core/voxelize.h"
#include "../core/sdf.h"
#include "../core/pfm.h"
#include "../core/tga.h"
#include "../core/perlin.h"
#include "../core/convex.h"
#include "../core/cloth.h"

#include "../external/SDL2-2.0.4/include/SDL.h"

#include "../include/NvFlex.h"
#include "../include/NvFlexExt.h"
#include "../include/NvFlexDevice.h"

#include <iostream>
#include <map>

#include "shaders.h"
#include "imgui.h"

#include "shadersDemoContext.h"

#if FLEX_DX
#include "d3d\appGraphCtx.h"
#endif

#if ENABLE_AFTERMATH_SUPPORT
#include <external/GFSDK_Aftermath_v1.21/include/GFSDK_Aftermath.h>
#endif

SDL_Window* g_window;			// window handle
unsigned int g_windowId;		// window id

#define SDL_CONTROLLER_BUTTON_LEFT_TRIGGER (SDL_CONTROLLER_BUTTON_MAX + 1)
#define SDL_CONTROLLER_BUTTON_RIGHT_TRIGGER (SDL_CONTROLLER_BUTTON_MAX + 2)

int GetKeyFromGameControllerButton(SDL_GameControllerButton button)
{
	switch (button)
	{
	case SDL_CONTROLLER_BUTTON_DPAD_UP:			{	return SDLK_q;		} // -- camera translate up
	case SDL_CONTROLLER_BUTTON_DPAD_DOWN:		{	return SDLK_z;		} // -- camera translate down
	case SDL_CONTROLLER_BUTTON_DPAD_LEFT:		{	return SDLK_h;		} // -- hide GUI
	case SDL_CONTROLLER_BUTTON_DPAD_RIGHT:		{	return -1;			} // -- unassigned
	case SDL_CONTROLLER_BUTTON_START:			{	return SDLK_RETURN;	} // -- start selected scene
	case SDL_CONTROLLER_BUTTON_BACK:			{	return SDLK_ESCAPE;	} // -- quit
	case SDL_CONTROLLER_BUTTON_LEFTSHOULDER:	{	return SDLK_UP;		} // -- select prev scene
	case SDL_CONTROLLER_BUTTON_RIGHTSHOULDER:	{	return SDLK_DOWN;	} // -- select next scene
	case SDL_CONTROLLER_BUTTON_A:				{	return SDLK_g;		} // -- toggle gravity
	case SDL_CONTROLLER_BUTTON_B:				{	return SDLK_p;		} // -- pause
	case SDL_CONTROLLER_BUTTON_X:				{	return SDLK_r;		} // -- reset
	case SDL_CONTROLLER_BUTTON_Y:				{	return SDLK_o;		} // -- step sim
	case SDL_CONTROLLER_BUTTON_RIGHT_TRIGGER:	{	return SDLK_SPACE;	} // -- emit particles
	default:									{	return -1;			} // -- nop
	};
};

//
// Gamepad thresholds taken from XINPUT API
//
#define XINPUT_GAMEPAD_LEFT_THUMB_DEADZONE  7849
#define XINPUT_GAMEPAD_RIGHT_THUMB_DEADZONE 8689
#define XINPUT_GAMEPAD_TRIGGER_THRESHOLD    30

int deadzones[3] = { XINPUT_GAMEPAD_LEFT_THUMB_DEADZONE, XINPUT_GAMEPAD_RIGHT_THUMB_DEADZONE, XINPUT_GAMEPAD_TRIGGER_THRESHOLD };

inline float joyAxisFilter(int value, int stick)
{
	//clamp values in deadzone to zero, and remap rest of range so that it linearly rises in value from edge of deadzone toward max value.
	if (value < -deadzones[stick])
		return (value + deadzones[stick]) / (32768.0f - deadzones[stick]);
	else if (value > deadzones[stick])
		return (value - deadzones[stick]) / (32768.0f - deadzones[stick]);
	else
		return 0.0f;
}

SDL_GameController* g_gamecontroller = NULL;

using namespace std;

int g_screenWidth = 1280;
int g_screenHeight = 720;
int g_msaaSamples = 8;

int g_numSubsteps;

// a setting of -1 means Flex will use the device specified in the NVIDIA control panel
int g_device = -1;
char g_deviceName[256];
bool g_vsync = true;

bool g_benchmark = false;
bool g_extensions = true;
bool g_teamCity = false;
bool g_interop = true;
bool g_d3d12 = false;
bool g_useAsyncCompute = true;		
bool g_increaseGfxLoadForAsyncComputeTesting = false;
int g_graphics = 0;	// 0=ogl, 1=DX11, 2=DX12

FluidRenderer* g_fluidRenderer;
FluidRenderBuffers* g_fluidRenderBuffers;
DiffuseRenderBuffers* g_diffuseRenderBuffers;

NvFlexSolver* g_solver;
NvFlexSolverDesc g_solverDesc;
NvFlexLibrary* g_flexLib;
NvFlexParams g_params;
NvFlexTimers g_timers;
int g_numDetailTimers;
NvFlexDetailTimer * g_detailTimers;

int g_maxDiffuseParticles;
int g_maxNeighborsPerParticle;
int g_numExtraParticles;
int g_numExtraMultiplier = 1;
int g_maxContactsPerParticle;

// mesh used for deformable object rendering
Mesh* g_mesh;
vector<int> g_meshSkinIndices;
vector<float> g_meshSkinWeights;
vector<Point3> g_meshRestPositions;
const int g_numSkinWeights = 4;

// mapping of collision mesh to render mesh
std::map<NvFlexConvexMeshId, GpuMesh*> g_convexes;
std::map<NvFlexTriangleMeshId, GpuMesh*> g_meshes;
std::map<NvFlexDistanceFieldId, GpuMesh*> g_fields;

// flag to request collision shapes be updated
bool g_shapesChanged = false;

/* Note that this array of colors is altered by demo code, and is also read from global by graphics API impls */
Colour g_colors[] =
{
	Colour(0.0f, 0.5f, 1.0f),
	Colour(0.797f, 0.354f, 0.000f),
	Colour(0.092f, 0.465f, 0.820f),
	Colour(0.000f, 0.349f, 0.173f),
	Colour(0.875f, 0.782f, 0.051f),
	Colour(0.000f, 0.170f, 0.453f),
	Colour(0.673f, 0.111f, 0.000f),
	Colour(0.612f, 0.194f, 0.394f)
};

struct SimBuffers
{
	NvFlexVector<Vec4> positions;
	NvFlexVector<Vec4> restPositions;
	NvFlexVector<Vec3> velocities;
	NvFlexVector<int> phases;
	NvFlexVector<float> densities;
	NvFlexVector<Vec4> anisotropy1;
	NvFlexVector<Vec4> anisotropy2;
	NvFlexVector<Vec4> anisotropy3;
	NvFlexVector<Vec4> normals;
	NvFlexVector<Vec4> smoothPositions;
	NvFlexVector<Vec4> diffusePositions;
	NvFlexVector<Vec4> diffuseVelocities;
	NvFlexVector<int> diffuseCount;

	NvFlexVector<int> activeIndices;

	// convexes
	NvFlexVector<NvFlexCollisionGeometry> shapeGeometry;
	NvFlexVector<Vec4> shapePositions;
	NvFlexVector<Quat> shapeRotations;
	NvFlexVector<Vec4> shapePrevPositions;
	NvFlexVector<Quat> shapePrevRotations;
	NvFlexVector<int> shapeFlags;

	// rigids
	NvFlexVector<int> rigidOffsets;
	NvFlexVector<int> rigidIndices;
	NvFlexVector<int> rigidMeshSize;
	NvFlexVector<float> rigidCoefficients;
	NvFlexVector<float> rigidPlasticThresholds;
	NvFlexVector<float> rigidPlasticCreeps;
	NvFlexVector<Quat> rigidRotations;
	NvFlexVector<Vec3> rigidTranslations;
	NvFlexVector<Vec3> rigidLocalPositions;
	NvFlexVector<Vec4> rigidLocalNormals;

	// inflatables
	NvFlexVector<int> inflatableTriOffsets;
	NvFlexVector<int> inflatableTriCounts;
	NvFlexVector<float> inflatableVolumes;
	NvFlexVector<float> inflatableCoefficients;
	NvFlexVector<float> inflatablePressures;

	// springs
	NvFlexVector<int> springIndices;
	NvFlexVector<float> springLengths;
	NvFlexVector<float> springStiffness;

	NvFlexVector<int> triangles;
	NvFlexVector<Vec3> triangleNormals;
	NvFlexVector<Vec3> uvs;

	SimBuffers(NvFlexLibrary* l) :
		positions(l), restPositions(l), velocities(l), phases(l), densities(l),
		anisotropy1(l), anisotropy2(l), anisotropy3(l), normals(l), smoothPositions(l),
		diffusePositions(l), diffuseVelocities(l), diffuseCount(l), activeIndices(l),
		shapeGeometry(l), shapePositions(l), shapeRotations(l), shapePrevPositions(l),
		shapePrevRotations(l),	shapeFlags(l), rigidOffsets(l), rigidIndices(l), rigidMeshSize(l),
		rigidCoefficients(l), rigidPlasticThresholds(l), rigidPlasticCreeps(l), rigidRotations(l), rigidTranslations(l),
		rigidLocalPositions(l), rigidLocalNormals(l), inflatableTriOffsets(l),
		inflatableTriCounts(l), inflatableVolumes(l), inflatableCoefficients(l),
		inflatablePressures(l), springIndices(l), springLengths(l),
		springStiffness(l), triangles(l), triangleNormals(l), uvs(l)
	{}
};

SimBuffers* g_buffers;

void MapBuffers(SimBuffers* buffers)
{
	buffers->positions.map();
	buffers->restPositions.map();
	buffers->velocities.map();
	buffers->phases.map();
	buffers->densities.map();
	buffers->anisotropy1.map();
	buffers->anisotropy2.map();
	buffers->anisotropy3.map();
	buffers->normals.map();
	buffers->diffusePositions.map();
	buffers->diffuseVelocities.map();
	buffers->diffuseCount.map();
	buffers->smoothPositions.map();
	buffers->activeIndices.map();

	// convexes
	buffers->shapeGeometry.map();
	buffers->shapePositions.map();
	buffers->shapeRotations.map();
	buffers->shapePrevPositions.map();
	buffers->shapePrevRotations.map();
	buffers->shapeFlags.map();

	buffers->rigidOffsets.map();
	buffers->rigidIndices.map();
	buffers->rigidMeshSize.map();
	buffers->rigidCoefficients.map();
	buffers->rigidPlasticThresholds.map();
	buffers->rigidPlasticCreeps.map();
	buffers->rigidRotations.map();
	buffers->rigidTranslations.map();
	buffers->rigidLocalPositions.map();
	buffers->rigidLocalNormals.map();

	buffers->springIndices.map();
	buffers->springLengths.map();
	buffers->springStiffness.map();

	// inflatables
	buffers->inflatableTriOffsets.map();
	buffers->inflatableTriCounts.map();
	buffers->inflatableVolumes.map();
	buffers->inflatableCoefficients.map();
	buffers->inflatablePressures.map();

	buffers->triangles.map();
	buffers->triangleNormals.map();
	buffers->uvs.map();
}

void UnmapBuffers(SimBuffers* buffers)
{
	// particles
	buffers->positions.unmap();
	buffers->restPositions.unmap();
	buffers->velocities.unmap();
	buffers->phases.unmap();
	buffers->densities.unmap();
	buffers->anisotropy1.unmap();
	buffers->anisotropy2.unmap();
	buffers->anisotropy3.unmap();
	buffers->normals.unmap();
	buffers->diffusePositions.unmap();
	buffers->diffuseVelocities.unmap();
	buffers->diffuseCount.unmap();
	buffers->smoothPositions.unmap();
	buffers->activeIndices.unmap();

	// convexes
	buffers->shapeGeometry.unmap();
	buffers->shapePositions.unmap();
	buffers->shapeRotations.unmap();
	buffers->shapePrevPositions.unmap();
	buffers->shapePrevRotations.unmap();
	buffers->shapeFlags.unmap();

	// rigids
	buffers->rigidOffsets.unmap();
	buffers->rigidIndices.unmap();
	buffers->rigidMeshSize.unmap();
	buffers->rigidCoefficients.unmap();
	buffers->rigidPlasticThresholds.unmap();
	buffers->rigidPlasticCreeps.unmap();
	buffers->rigidRotations.unmap();
	buffers->rigidTranslations.unmap();
	buffers->rigidLocalPositions.unmap();
	buffers->rigidLocalNormals.unmap();

	// springs
	buffers->springIndices.unmap();
	buffers->springLengths.unmap();
	buffers->springStiffness.unmap();

	// inflatables
	buffers->inflatableTriOffsets.unmap();
	buffers->inflatableTriCounts.unmap();
	buffers->inflatableVolumes.unmap();
	buffers->inflatableCoefficients.unmap();
	buffers->inflatablePressures.unmap();

	// triangles
	buffers->triangles.unmap();
	buffers->triangleNormals.unmap();
	buffers->uvs.unmap();

}

SimBuffers* AllocBuffers(NvFlexLibrary* lib)
{
	return new SimBuffers(lib);
}

void DestroyBuffers(SimBuffers* buffers)
{
	// particles
	buffers->positions.destroy();
	buffers->restPositions.destroy();
	buffers->velocities.destroy();
	buffers->phases.destroy();
	buffers->densities.destroy();
	buffers->anisotropy1.destroy();
	buffers->anisotropy2.destroy();
	buffers->anisotropy3.destroy();
	buffers->normals.destroy();
	buffers->diffusePositions.destroy();
	buffers->diffuseVelocities.destroy();
	buffers->diffuseCount.destroy();
	buffers->smoothPositions.destroy();
	buffers->activeIndices.destroy();

	// convexes
	buffers->shapeGeometry.destroy();
	buffers->shapePositions.destroy();
	buffers->shapeRotations.destroy();
	buffers->shapePrevPositions.destroy();
	buffers->shapePrevRotations.destroy();
	buffers->shapeFlags.destroy();

	// rigids
	buffers->rigidOffsets.destroy();
	buffers->rigidIndices.destroy();
	buffers->rigidMeshSize.destroy();
	buffers->rigidCoefficients.destroy();
	buffers->rigidPlasticThresholds.destroy();
	buffers->rigidPlasticCreeps.destroy();
	buffers->rigidRotations.destroy();
	buffers->rigidTranslations.destroy();
	buffers->rigidLocalPositions.destroy();
	buffers->rigidLocalNormals.destroy();

	// springs
	buffers->springIndices.destroy();
	buffers->springLengths.destroy();
	buffers->springStiffness.destroy();

	// inflatables
	buffers->inflatableTriOffsets.destroy();
	buffers->inflatableTriCounts.destroy();
	buffers->inflatableVolumes.destroy();
	buffers->inflatableCoefficients.destroy();
	buffers->inflatablePressures.destroy();

	// triangles
	buffers->triangles.destroy();
	buffers->triangleNormals.destroy();
	buffers->uvs.destroy();

	delete buffers;
}

Vec3 g_camPos(6.0f, 8.0f, 18.0f);
Vec3 g_camAngle(0.0f, -DegToRad(20.0f), 0.0f);
Vec3 g_camVel(0.0f);
Vec3 g_camSmoothVel(0.0f);

float g_camSpeed;
float g_camNear;
float g_camFar;

Vec3 g_lightPos;
Vec3 g_lightDir;
Vec3 g_lightTarget;

bool g_pause = false;
bool g_step = false;
bool g_capture = false;
bool g_showHelp = true;
bool g_tweakPanel = true;
bool g_fullscreen = false;
bool g_wireframe = false;
bool g_debug = false;

bool g_emit = false;
bool g_warmup = false;

float g_windTime = 0.0f;
float g_windFrequency = 0.1f;
float g_windStrength = 0.0f;

bool g_wavePool = false;
float g_waveTime = 0.0f;
float g_wavePlane;
float g_waveFrequency = 1.5f;
float g_waveAmplitude = 1.0f;
float g_waveFloorTilt = 0.0f;

Vec3 g_sceneLower;
Vec3 g_sceneUpper;

float g_blur;
float g_ior;
bool g_drawEllipsoids;
bool g_drawPoints;
bool g_drawMesh;
bool g_drawCloth;
float g_expandCloth;	// amount to expand cloth along normal (to account for particle radius)

bool g_drawOpaque;
int g_drawSprings;		// 0: no draw, 1: draw stretch 2: draw tether
bool g_drawBases = false;
bool g_drawContacts = false;
bool g_drawNormals = false;
bool g_drawDiffuse;
bool g_drawShapeGrid = false;
bool g_drawDensity = false;
bool g_drawRopes;
float g_pointScale;
float g_ropeScale;
float g_drawPlaneBias;	// move planes along their normal for rendering

float g_diffuseScale;
float g_diffuseMotionScale;
bool g_diffuseShadow;
float g_diffuseInscatter;
float g_diffuseOutscatter;

float g_dt = 1.0f / 60.0f;	// the time delta used for simulation
float g_realdt;				// the real world time delta between updates

float g_waitTime;		// the CPU time spent waiting for the GPU
float g_updateTime;     // the CPU time spent on Flex
float g_renderTime;		// the CPU time spent calling OpenGL to render the scene
                        // the above times don't include waiting for vsync
float g_simLatency;     // the time the GPU spent between the first and last NvFlexUpdateSolver() operation. Because some GPUs context switch, this can include graphics time.

int g_scene = 0;
int g_selectedScene = g_scene;
int g_levelScroll;			// offset for level selection scroll area
bool g_resetScene = false;  //if the user clicks the reset button or presses the reset key this is set to true;

int g_frame = 0;
int g_numSolidParticles = 0;

int g_mouseParticle = -1;
float g_mouseT = 0.0f;
Vec3 g_mousePos;
float g_mouseMass;
bool g_mousePicked = false;

// mouse
int g_lastx;
int g_lasty;
int g_lastb = -1;

bool g_profile = false;
bool g_outputAllFrameTimes = false;
bool g_asyncComputeBenchmark = false;

ShadowMap* g_shadowMap;

Vec4 g_fluidColor;
Vec4 g_diffuseColor;
Vec3 g_meshColor;
Vec3  g_clearColor;
float g_lightDistance;
float g_fogDistance;

FILE* g_ffmpeg;

void DrawShapes();

class Scene;
vector<Scene*> g_scenes;

struct Emitter
{
	Emitter() : mSpeed(0.0f), mEnabled(false), mLeftOver(0.0f), mWidth(8)   {}

	Vec3 mPos;
	Vec3 mDir;
	Vec3 mRight;
	float mSpeed;
	bool mEnabled;
	float mLeftOver;
	int mWidth;
};

vector<Emitter> g_emitters(1);	// first emitter is the camera 'gun'

struct Rope
{
	std::vector<int> mIndices;
};

vector<Rope> g_ropes;

inline float sqr(float x) { return x*x; }

#include "helpers.h"
#include "scenes.h"
#include "benchmark.h"

void Init(int scene, bool centerCamera = true)
{
	RandInit();

	if (g_solver)
	{
		if (g_buffers)
			DestroyBuffers(g_buffers);

		DestroyFluidRenderBuffers(g_fluidRenderBuffers);
		DestroyDiffuseRenderBuffers(g_diffuseRenderBuffers);

		for (auto& iter : g_meshes)
		{
			NvFlexDestroyTriangleMesh(g_flexLib, iter.first);
			DestroyGpuMesh(iter.second);
		}

		for (auto& iter : g_fields)
		{
			NvFlexDestroyDistanceField(g_flexLib, iter.first);
			DestroyGpuMesh(iter.second);
		}

		for (auto& iter : g_convexes)
		{
			NvFlexDestroyConvexMesh(g_flexLib, iter.first);
			DestroyGpuMesh(iter.second);
		}


		g_fields.clear();
		g_meshes.clear();
		g_convexes.clear();

		NvFlexDestroySolver(g_solver);
		g_solver = NULL;
	}

	// alloc buffers
	g_buffers = AllocBuffers(g_flexLib);

	// map during initialization
	MapBuffers(g_buffers);

	g_buffers->positions.resize(0);
	g_buffers->velocities.resize(0);
	g_buffers->phases.resize(0);

	g_buffers->rigidOffsets.resize(0);
	g_buffers->rigidIndices.resize(0);
	g_buffers->rigidMeshSize.resize(0);
	g_buffers->rigidRotations.resize(0);
	g_buffers->rigidTranslations.resize(0);
	g_buffers->rigidCoefficients.resize(0);
	g_buffers->rigidPlasticThresholds.resize(0);
	g_buffers->rigidPlasticCreeps.resize(0);
	g_buffers->rigidLocalPositions.resize(0);
	g_buffers->rigidLocalNormals.resize(0);

	g_buffers->springIndices.resize(0);
	g_buffers->springLengths.resize(0);
	g_buffers->springStiffness.resize(0);
	g_buffers->triangles.resize(0);
	g_buffers->triangleNormals.resize(0);
	g_buffers->uvs.resize(0);

	g_meshSkinIndices.resize(0);
	g_meshSkinWeights.resize(0);

	g_emitters.resize(1);
	g_emitters[0].mEnabled = false;
	g_emitters[0].mSpeed = 1.0f;
	g_emitters[0].mLeftOver = 0.0f;
	g_emitters[0].mWidth = 8;

	g_buffers->shapeGeometry.resize(0);
	g_buffers->shapePositions.resize(0);
	g_buffers->shapeRotations.resize(0);
	g_buffers->shapePrevPositions.resize(0);
	g_buffers->shapePrevRotations.resize(0);
	g_buffers->shapeFlags.resize(0);

	g_ropes.resize(0);

	// remove collision shapes
	delete g_mesh; g_mesh = NULL;

	g_frame = 0;
	g_pause = false;

	g_dt = 1.0f / 60.0f;
	g_waveTime = 0.0f;
	g_windTime = 0.0f;
	g_windStrength = 1.0f;

	g_blur = 1.0f;
	g_fluidColor = Vec4(0.1f, 0.4f, 0.8f, 1.0f);
	g_meshColor = Vec3(0.9f, 0.9f, 0.9f);
	g_drawEllipsoids = false;
	g_drawPoints = true;
	g_drawCloth = true;
	g_expandCloth = 0.0f;

	g_drawOpaque = false;
	g_drawSprings = false;
	g_drawDiffuse = false;
	g_drawMesh = true;
	g_drawRopes = true;
	g_drawDensity = false;
	g_ior = 1.0f;
	g_lightDistance = 2.0f;
	g_fogDistance = 0.005f;

	g_camSpeed = 0.075f;
	g_camNear = 0.01f;
	g_camFar = 1000.0f;

	g_pointScale = 1.0f;
	g_ropeScale = 1.0f;
	g_drawPlaneBias = 0.0f;

	// sim params
	g_params.gravity[0] = 0.0f;
	g_params.gravity[1] = -9.8f;
	g_params.gravity[2] = 0.0f;

	g_params.wind[0] = 0.0f;
	g_params.wind[1] = 0.0f;
	g_params.wind[2] = 0.0f;

	g_params.radius = 0.15f;
	g_params.viscosity = 0.0f;
	g_params.dynamicFriction = 0.0f;
	g_params.staticFriction = 0.0f;
	g_params.particleFriction = 0.0f; // scale friction between particles by default
	g_params.freeSurfaceDrag = 0.0f;
	g_params.drag = 0.0f;
	g_params.lift = 0.0f;
	g_params.numIterations = 3;
	g_params.fluidRestDistance = 0.0f;
	g_params.solidRestDistance = 0.0f;

	g_params.anisotropyScale = 1.0f;
	g_params.anisotropyMin = 0.1f;
	g_params.anisotropyMax = 2.0f;
	g_params.smoothing = 1.0f;

	g_params.dissipation = 0.0f;
	g_params.damping = 0.0f;
	g_params.particleCollisionMargin = 0.0f;
	g_params.shapeCollisionMargin = 0.0f;
	g_params.collisionDistance = 0.0f;
	g_params.sleepThreshold = 0.0f;
	g_params.shockPropagation = 0.0f;
	g_params.restitution = 0.0f;

	g_params.maxSpeed = FLT_MAX;
	g_params.maxAcceleration = 100.0f;	// approximately 10x gravity

	g_params.relaxationMode = eNvFlexRelaxationLocal;
	g_params.relaxationFactor = 1.0f;
	g_params.solidPressure = 1.0f;
	g_params.adhesion = 0.0f;
	g_params.cohesion = 0.025f;
	g_params.surfaceTension = 0.0f;
	g_params.vorticityConfinement = 0.0f;
	g_params.buoyancy = 1.0f;
	g_params.diffuseThreshold = 100.0f;
	g_params.diffuseBuoyancy = 1.0f;
	g_params.diffuseDrag = 0.8f;
	g_params.diffuseBallistic = 16;
	g_params.diffuseLifetime = 2.0f;

	g_numSubsteps = 2;

	// planes created after particles
	g_params.numPlanes = 1;

	g_diffuseScale = 0.5f;
	g_diffuseColor = 1.0f;
	g_diffuseMotionScale = 1.0f;
	g_diffuseShadow = false;
	g_diffuseInscatter = 0.8f;
	g_diffuseOutscatter = 0.53f;

	// reset phase 0 particle color to blue
	g_colors[0] = Colour(0.0f, 0.5f, 1.0f);

	g_numSolidParticles = 0;

	g_waveFrequency = 1.5f;
	g_waveAmplitude = 1.5f;
	g_waveFloorTilt = 0.0f;
	g_emit = false;
	g_warmup = false;

	g_mouseParticle = -1;

	g_maxDiffuseParticles = 0;	// number of diffuse particles
	g_maxNeighborsPerParticle = 96;
	g_numExtraParticles = 0;	// number of particles allocated but not made active	
	g_maxContactsPerParticle = 6;

	g_sceneLower = FLT_MAX;
	g_sceneUpper = -FLT_MAX;

	// initialize solver desc
	NvFlexSetSolverDescDefaults(&g_solverDesc);

	// create scene
	StartGpuWork();
	g_scenes[g_scene]->Initialize();
	EndGpuWork();

	uint32_t numParticles = g_buffers->positions.size();
	uint32_t maxParticles = numParticles + g_numExtraParticles*g_numExtraMultiplier;
	
	if (g_params.solidRestDistance == 0.0f)
		g_params.solidRestDistance = g_params.radius;

	// if fluid present then we assume solid particles have the same radius
	if (g_params.fluidRestDistance > 0.0f)
		g_params.solidRestDistance = g_params.fluidRestDistance;

	// set collision distance automatically based on rest distance if not alraedy set
	if (g_params.collisionDistance == 0.0f)
		g_params.collisionDistance = Max(g_params.solidRestDistance, g_params.fluidRestDistance)*0.5f;

	// default particle friction to 10% of shape friction
	if (g_params.particleFriction == 0.0f)
		g_params.particleFriction = g_params.dynamicFriction*0.1f;

	// add a margin for detecting contacts between particles and shapes
	if (g_params.shapeCollisionMargin == 0.0f)
		g_params.shapeCollisionMargin = g_params.collisionDistance*0.5f;

	// calculate particle bounds
	Vec3 particleLower, particleUpper;
	GetParticleBounds(particleLower, particleUpper);

	// accommodate shapes
	Vec3 shapeLower, shapeUpper;
	GetShapeBounds(shapeLower, shapeUpper);

	// update bounds
	g_sceneLower = Min(Min(g_sceneLower, particleLower), shapeLower);
	g_sceneUpper = Max(Max(g_sceneUpper, particleUpper), shapeUpper); 

	g_sceneLower -= g_params.collisionDistance;
	g_sceneUpper += g_params.collisionDistance;

	// update collision planes to match flexs
	Vec3 up = Normalize(Vec3(-g_waveFloorTilt, 1.0f, 0.0f));

	(Vec4&)g_params.planes[0] = Vec4(up.x, up.y, up.z, 0.0f);
	(Vec4&)g_params.planes[1] = Vec4(0.0f, 0.0f, 1.0f, -g_sceneLower.z);
	(Vec4&)g_params.planes[2] = Vec4(1.0f, 0.0f, 0.0f, -g_sceneLower.x);
	(Vec4&)g_params.planes[3] = Vec4(-1.0f, 0.0f, 0.0f, g_sceneUpper.x);
	(Vec4&)g_params.planes[4] = Vec4(0.0f, 0.0f, -1.0f, g_sceneUpper.z);
	(Vec4&)g_params.planes[5] = Vec4(0.0f, -1.0f, 0.0f, g_sceneUpper.y);

	g_wavePlane = g_params.planes[2][3];

	g_buffers->diffusePositions.resize(g_maxDiffuseParticles);
	g_buffers->diffuseVelocities.resize(g_maxDiffuseParticles);
	g_buffers->diffuseCount.resize(1, 0);

	// for fluid rendering these are the Laplacian smoothed positions
	g_buffers->smoothPositions.resize(maxParticles);

	g_buffers->normals.resize(0);
	g_buffers->normals.resize(maxParticles);

	// initialize normals (just for rendering before simulation starts)
	int numTris = g_buffers->triangles.size() / 3;
	for (int i = 0; i < numTris; ++i)
	{
		Vec3 v0 = Vec3(g_buffers->positions[g_buffers->triangles[i * 3 + 0]]);
		Vec3 v1 = Vec3(g_buffers->positions[g_buffers->triangles[i * 3 + 1]]);
		Vec3 v2 = Vec3(g_buffers->positions[g_buffers->triangles[i * 3 + 2]]);

		Vec3 n = Cross(v1 - v0, v2 - v0);

		g_buffers->normals[g_buffers->triangles[i * 3 + 0]] += Vec4(n, 0.0f);
		g_buffers->normals[g_buffers->triangles[i * 3 + 1]] += Vec4(n, 0.0f);
		g_buffers->normals[g_buffers->triangles[i * 3 + 2]] += Vec4(n, 0.0f);
	}

	for (int i = 0; i < int(maxParticles); ++i)
		g_buffers->normals[i] = Vec4(SafeNormalize(Vec3(g_buffers->normals[i]), Vec3(0.0f, 1.0f, 0.0f)), 0.0f);


	// save mesh positions for skinning
	if (g_mesh)
	{
		g_meshRestPositions = g_mesh->m_positions;
	}
	else
	{
		g_meshRestPositions.resize(0);
	}

	g_solverDesc.maxParticles = maxParticles;
	g_solverDesc.maxDiffuseParticles = g_maxDiffuseParticles;
	g_solverDesc.maxNeighborsPerParticle = g_maxNeighborsPerParticle;
	g_solverDesc.maxContactsPerParticle = g_maxContactsPerParticle;

	// main create method for the Flex solver
	g_solver = NvFlexCreateSolver(g_flexLib, &g_solverDesc);

	// give scene a chance to do some post solver initialization
	g_scenes[g_scene]->PostInitialize();

	// center camera on particles
	if (centerCamera)
	{
		g_camPos = Vec3((g_sceneLower.x + g_sceneUpper.x)*0.5f, min(g_sceneUpper.y*1.25f, 6.0f), g_sceneUpper.z + min(g_sceneUpper.y, 6.0f)*2.0f);
		g_camAngle = Vec3(0.0f, -DegToRad(15.0f), 0.0f);

		// give scene a chance to modify camera position
		g_scenes[g_scene]->CenterCamera();
	}

	// create active indices (just a contiguous block for the demo)
	g_buffers->activeIndices.resize(g_buffers->positions.size());
	for (int i = 0; i < g_buffers->activeIndices.size(); ++i)
		g_buffers->activeIndices[i] = i;

	// resize particle buffers to fit
	g_buffers->positions.resize(maxParticles);
	g_buffers->velocities.resize(maxParticles);
	g_buffers->phases.resize(maxParticles);

	g_buffers->densities.resize(maxParticles);
	g_buffers->anisotropy1.resize(maxParticles);
	g_buffers->anisotropy2.resize(maxParticles);
	g_buffers->anisotropy3.resize(maxParticles);

	// save rest positions
	g_buffers->restPositions.resize(g_buffers->positions.size());
	for (int i = 0; i < g_buffers->positions.size(); ++i)
		g_buffers->restPositions[i] = g_buffers->positions[i];

	// builds rigids constraints
	if (g_buffers->rigidOffsets.size())
	{
		assert(g_buffers->rigidOffsets.size() > 1);

		const int numRigids = g_buffers->rigidOffsets.size() - 1;

		// If the centers of mass for the rigids are not yet computed, this is done here
		// (If the CreateParticleShape method is used instead of the NvFlexExt methods, the centers of mass will be calculated here)
		if (g_buffers->rigidTranslations.size() == 0) 
		{
			g_buffers->rigidTranslations.resize(g_buffers->rigidOffsets.size() - 1, Vec3());
			CalculateRigidCentersOfMass(&g_buffers->positions[0], g_buffers->positions.size(), &g_buffers->rigidOffsets[0], &g_buffers->rigidTranslations[0], &g_buffers->rigidIndices[0], numRigids);
		}

		// calculate local rest space positions
		g_buffers->rigidLocalPositions.resize(g_buffers->rigidOffsets.back());
		CalculateRigidLocalPositions(&g_buffers->positions[0], &g_buffers->rigidOffsets[0], &g_buffers->rigidTranslations[0], &g_buffers->rigidIndices[0], numRigids, &g_buffers->rigidLocalPositions[0]);

		// set rigidRotations to correct length, probably NULL up until here
		g_buffers->rigidRotations.resize(g_buffers->rigidOffsets.size() - 1, Quat());
	}

	// unmap so we can start transferring data to GPU
	UnmapBuffers(g_buffers);

	//-----------------------------
	// Send data to Flex

	NvFlexCopyDesc copyDesc;
	copyDesc.dstOffset = 0;
	copyDesc.srcOffset = 0;
	copyDesc.elementCount = numParticles;

	NvFlexSetParams(g_solver, &g_params);
	NvFlexSetParticles(g_solver, g_buffers->positions.buffer, &copyDesc);
	NvFlexSetVelocities(g_solver, g_buffers->velocities.buffer, &copyDesc);
	NvFlexSetNormals(g_solver, g_buffers->normals.buffer, &copyDesc);
	NvFlexSetPhases(g_solver, g_buffers->phases.buffer, &copyDesc);
	NvFlexSetRestParticles(g_solver, g_buffers->restPositions.buffer, &copyDesc);

	NvFlexSetActive(g_solver, g_buffers->activeIndices.buffer, &copyDesc);
	NvFlexSetActiveCount(g_solver, numParticles);
	
	// springs
	if (g_buffers->springIndices.size())
	{
		assert((g_buffers->springIndices.size() & 1) == 0);
		assert((g_buffers->springIndices.size() / 2) == g_buffers->springLengths.size());

		NvFlexSetSprings(g_solver, g_buffers->springIndices.buffer, g_buffers->springLengths.buffer, g_buffers->springStiffness.buffer, g_buffers->springLengths.size());
	}

	// rigids
	if (g_buffers->rigidOffsets.size())
	{
		NvFlexSetRigids(g_solver, g_buffers->rigidOffsets.buffer, g_buffers->rigidIndices.buffer, g_buffers->rigidLocalPositions.buffer, g_buffers->rigidLocalNormals.buffer, g_buffers->rigidCoefficients.buffer, g_buffers->rigidPlasticThresholds.buffer, g_buffers->rigidPlasticCreeps.buffer, g_buffers->rigidRotations.buffer, g_buffers->rigidTranslations.buffer, g_buffers->rigidOffsets.size() - 1, g_buffers->rigidIndices.size());
	}

	// inflatables
	if (g_buffers->inflatableTriOffsets.size())
	{
		NvFlexSetInflatables(g_solver, g_buffers->inflatableTriOffsets.buffer, g_buffers->inflatableTriCounts.buffer, g_buffers->inflatableVolumes.buffer, g_buffers->inflatablePressures.buffer, g_buffers->inflatableCoefficients.buffer, g_buffers->inflatableTriOffsets.size());
	}

	// dynamic triangles
	if (g_buffers->triangles.size())
	{
		NvFlexSetDynamicTriangles(g_solver, g_buffers->triangles.buffer, g_buffers->triangleNormals.buffer, g_buffers->triangles.size() / 3);
	}

	// collision shapes
	if (g_buffers->shapeFlags.size())
	{
		NvFlexSetShapes(
			g_solver,
			g_buffers->shapeGeometry.buffer,
			g_buffers->shapePositions.buffer,
			g_buffers->shapeRotations.buffer,
			g_buffers->shapePrevPositions.buffer,
			g_buffers->shapePrevRotations.buffer,
			g_buffers->shapeFlags.buffer,
			int(g_buffers->shapeFlags.size()));
	}

	// create render buffers
	g_fluidRenderBuffers = CreateFluidRenderBuffers(maxParticles, g_interop);
	g_diffuseRenderBuffers = CreateDiffuseRenderBuffers(g_maxDiffuseParticles, g_interop);

	// perform initial sim warm up
	if (g_warmup)
	{
		printf("Warming up sim..\n");

		// warm it up (relax positions to reach rest density without affecting velocity)
		NvFlexParams copy = g_params;
		copy.numIterations = 4;

		NvFlexSetParams(g_solver, &copy);

		const int kWarmupIterations = 100;

		for (int i = 0; i < kWarmupIterations; ++i)
		{
			NvFlexUpdateSolver(g_solver, 0.0001f, 1, false);
			NvFlexSetVelocities(g_solver, g_buffers->velocities.buffer, NULL);
		}

		// udpate host copy
		NvFlexGetParticles(g_solver, g_buffers->positions.buffer, NULL);
		NvFlexGetSmoothParticles(g_solver, g_buffers->smoothPositions.buffer, NULL);
		NvFlexGetAnisotropy(g_solver, g_buffers->anisotropy1.buffer, g_buffers->anisotropy2.buffer, g_buffers->anisotropy3.buffer, NULL);

		printf("Finished warm up.\n");
	}
}

void Reset()
{
	Init(g_scene, false);
}

void Shutdown()
{
	// free buffers
	DestroyBuffers(g_buffers);

	for (auto& iter : g_meshes)
	{
		NvFlexDestroyTriangleMesh(g_flexLib, iter.first);
		DestroyGpuMesh(iter.second);
	}

	for (auto& iter : g_fields)
	{
		NvFlexDestroyDistanceField(g_flexLib, iter.first);
		DestroyGpuMesh(iter.second);
	}

	for (auto& iter : g_convexes)
	{
		NvFlexDestroyConvexMesh(g_flexLib, iter.first);
		DestroyGpuMesh(iter.second);
	}

	g_fields.clear();
	g_meshes.clear();

	NvFlexDestroySolver(g_solver);
	NvFlexShutdown(g_flexLib);

#if _WIN32
	if (g_ffmpeg)
		_pclose(g_ffmpeg);
#endif
}

void UpdateEmitters()
{
	float spin = DegToRad(15.0f);

	const Vec3 forward(-sinf(g_camAngle.x + spin)*cosf(g_camAngle.y), sinf(g_camAngle.y), -cosf(g_camAngle.x + spin)*cosf(g_camAngle.y));
	const Vec3 right(Normalize(Cross(forward, Vec3(0.0f, 1.0f, 0.0f))));

	g_emitters[0].mDir = Normalize(forward + Vec3(0.0, 0.4f, 0.0f));
	g_emitters[0].mRight = right;
	g_emitters[0].mPos = g_camPos + forward*1.f + Vec3(0.0f, 0.2f, 0.0f) + right*0.65f;

	// process emitters
	if (g_emit)
	{
		int activeCount = NvFlexGetActiveCount(g_solver);

		size_t e = 0;

		// skip camera emitter when moving forward or things get messy
		if (g_camSmoothVel.z >= 0.025f)
			e = 1;

		for (; e < g_emitters.size(); ++e)
		{
			if (!g_emitters[e].mEnabled)
				continue;

			Vec3 emitterDir = g_emitters[e].mDir;
			Vec3 emitterRight = g_emitters[e].mRight;
			Vec3 emitterPos = g_emitters[e].mPos;


			float r = g_params.fluidRestDistance;
			int phase = NvFlexMakePhase(0, eNvFlexPhaseSelfCollide | eNvFlexPhaseFluid);

			float numParticles = (g_emitters[e].mSpeed / r)*g_dt;

			// whole number to emit
			int n = int(numParticles + g_emitters[e].mLeftOver);

			if (n)
				g_emitters[e].mLeftOver = (numParticles + g_emitters[e].mLeftOver) - n;
			else
				g_emitters[e].mLeftOver += numParticles;

			// create a grid of particles (n particles thick)
			for (int k = 0; k < n; ++k)
			{
				int emitterWidth = g_emitters[e].mWidth;
				int numParticles = emitterWidth*emitterWidth;
				for (int i = 0; i < numParticles; ++i)
				{
					float x = float(i%emitterWidth) - float(emitterWidth/2);
					float y = float((i / emitterWidth) % emitterWidth) - float(emitterWidth/2);

					if ((sqr(x) + sqr(y)) <= (emitterWidth / 2)*(emitterWidth / 2))
					{
						Vec3 up = Normalize(Cross(emitterDir, emitterRight));
						Vec3 offset = r*(emitterRight*x + up*y) + float(k)*emitterDir*r;

						if (activeCount < g_buffers->positions.size())
						{
							g_buffers->positions[activeCount] = Vec4(emitterPos + offset, 1.0f);
							g_buffers->velocities[activeCount] = emitterDir*g_emitters[e].mSpeed;
							g_buffers->phases[activeCount] = phase;

							g_buffers->activeIndices.push_back(activeCount);

							activeCount++;
						}
					}
				}
			}
		}
	}
}

void UpdateCamera()
{
	Vec3 forward(-sinf(g_camAngle.x)*cosf(g_camAngle.y), sinf(g_camAngle.y), -cosf(g_camAngle.x)*cosf(g_camAngle.y));
	Vec3 right(Normalize(Cross(forward, Vec3(0.0f, 1.0f, 0.0f))));

	g_camSmoothVel = Lerp(g_camSmoothVel, g_camVel, 0.1f);
	g_camPos += (forward*g_camSmoothVel.z + right*g_camSmoothVel.x + Cross(right, forward)*g_camSmoothVel.y);
}

void UpdateMouse()
{
	// mouse button is up release particle
	if (g_lastb == -1)
	{
		if (g_mouseParticle != -1)
		{
			// restore particle mass
			g_buffers->positions[g_mouseParticle].w = g_mouseMass;

			// deselect
			g_mouseParticle = -1;
		}
	}

	// mouse went down, pick new particle
	if (g_mousePicked)
	{
		assert(g_mouseParticle == -1);

		Vec3 origin, dir;
		GetViewRay(g_lastx, g_screenHeight - g_lasty, origin, dir);

		const int numActive = NvFlexGetActiveCount(g_solver);

		g_mouseParticle = PickParticle(origin, dir, &g_buffers->positions[0], &g_buffers->phases[0], numActive, g_params.radius*0.8f, g_mouseT);

		if (g_mouseParticle != -1)
		{
			printf("picked: %d, mass: %f v: %f %f %f\n", g_mouseParticle, g_buffers->positions[g_mouseParticle].w, g_buffers->velocities[g_mouseParticle].x, g_buffers->velocities[g_mouseParticle].y, g_buffers->velocities[g_mouseParticle].z);

			g_mousePos = origin + dir*g_mouseT;
			g_mouseMass = g_buffers->positions[g_mouseParticle].w;
			g_buffers->positions[g_mouseParticle].w = 0.0f;		// increase picked particle's mass to force it towards the point
		}

		g_mousePicked = false;
	}

	// update picked particle position
	if (g_mouseParticle != -1)
	{
		Vec3 p = Lerp(Vec3(g_buffers->positions[g_mouseParticle]), g_mousePos, 0.8f);
		Vec3 delta = p - Vec3(g_buffers->positions[g_mouseParticle]);

		g_buffers->positions[g_mouseParticle].x = p.x;
		g_buffers->positions[g_mouseParticle].y = p.y;
		g_buffers->positions[g_mouseParticle].z = p.z;

		g_buffers->velocities[g_mouseParticle].x = delta.x / g_dt;
		g_buffers->velocities[g_mouseParticle].y = delta.y / g_dt;
		g_buffers->velocities[g_mouseParticle].z = delta.z / g_dt;
	}
}

void UpdateWind()
{
	g_windTime += g_dt;

	const Vec3 kWindDir = Vec3(3.0f, 15.0f, 0.0f);
	const float kNoise = Perlin1D(g_windTime*g_windFrequency, 10, 0.25f);
	Vec3 wind = g_windStrength*kWindDir*Vec3(kNoise, fabsf(kNoise), 0.0f);

	g_params.wind[0] = wind.x;
	g_params.wind[1] = wind.y;
	g_params.wind[2] = wind.z;

	if (g_wavePool)
	{
		g_waveTime += g_dt;

		g_params.planes[2][3] = g_wavePlane + (sinf(float(g_waveTime)*g_waveFrequency - kPi*0.5f)*0.5f + 0.5f)*g_waveAmplitude;
	}
}

void SyncScene()
{
	// let the scene send updates to flex directly
	g_scenes[g_scene]->Sync();
}

void UpdateScene()
{
	// give scene a chance to make changes to particle buffers
	g_scenes[g_scene]->Update();
}

void RenderScene()
{
	const int numParticles = NvFlexGetActiveCount(g_solver);
	const int numDiffuse = g_buffers->diffuseCount[0];

	//---------------------------------------------------
	// use VBO buffer wrappers to allow Flex to write directly to the OpenGL buffers
	// Flex will take care of any CUDA interop mapping/unmapping during the get() operations

	if (numParticles)
	{

		if (g_interop)
		{
			// copy data directly from solver to the renderer buffers
			UpdateFluidRenderBuffers(g_fluidRenderBuffers, g_solver, g_drawEllipsoids, g_drawDensity);
		}
		else
		{
			// copy particle data to GPU render device

			if (g_drawEllipsoids)
			{
				// if fluid surface rendering then update with smooth positions and anisotropy
				UpdateFluidRenderBuffers(g_fluidRenderBuffers,
					&g_buffers->smoothPositions[0],
					(g_drawDensity) ? &g_buffers->densities[0] : (float*)&g_buffers->phases[0],
					&g_buffers->anisotropy1[0],
					&g_buffers->anisotropy2[0],
					&g_buffers->anisotropy3[0],
					g_buffers->positions.size(),
					&g_buffers->activeIndices[0],
					numParticles);
			}
			else
			{
				// otherwise just send regular positions and no anisotropy
				UpdateFluidRenderBuffers(g_fluidRenderBuffers,
					&g_buffers->positions[0],
					(float*)&g_buffers->phases[0],
					NULL, NULL, NULL,
					g_buffers->positions.size(),
					&g_buffers->activeIndices[0],
					numParticles);
			}
		}
	}

	// GPU Render time doesn't include CPU->GPU copy time
	GraphicsTimerBegin();
	
	if (numDiffuse)
	{
		if (g_interop)
		{
			// copy data directly from solver to the renderer buffers
			UpdateDiffuseRenderBuffers(g_diffuseRenderBuffers, g_solver);
		}
		else
		{
			// copy diffuse particle data from host to GPU render device 
			UpdateDiffuseRenderBuffers(g_diffuseRenderBuffers,
				&g_buffers->diffusePositions[0],
				&g_buffers->diffuseVelocities[0],
				numDiffuse);
		}
	}
	
	//---------------------------------------
	// setup view and state

	float fov = kPi / 4.0f;
	float aspect = float(g_screenWidth) / g_screenHeight;

	Matrix44 proj = ProjectionMatrix(RadToDeg(fov), aspect, g_camNear, g_camFar);
	Matrix44 view = RotationMatrix(-g_camAngle.x, Vec3(0.0f, 1.0f, 0.0f))*RotationMatrix(-g_camAngle.y, Vec3(cosf(-g_camAngle.x), 0.0f, sinf(-g_camAngle.x)))*TranslationMatrix(-Point3(g_camPos));

	//------------------------------------
	// lighting pass

	// expand scene bounds to fit most scenes
	g_sceneLower = Min(g_sceneLower, Vec3(-2.0f, 0.0f, -2.0f));
	g_sceneUpper = Max(g_sceneUpper, Vec3(2.0f, 2.0f, 2.0f));

	Vec3 sceneExtents = g_sceneUpper - g_sceneLower;
	Vec3 sceneCenter = 0.5f*(g_sceneUpper + g_sceneLower);

	g_lightDir = Normalize(Vec3(5.0f, 15.0f, 7.5f));
	g_lightPos = sceneCenter + g_lightDir*Length(sceneExtents)*g_lightDistance;
	g_lightTarget = sceneCenter;

	// calculate tight bounds for shadow frustum
	float lightFov = 2.0f*atanf(Length(g_sceneUpper - sceneCenter) / Length(g_lightPos - sceneCenter));

	// scale and clamp fov for aesthetics
	lightFov = Clamp(lightFov, DegToRad(25.0f), DegToRad(65.0f));

	Matrix44 lightPerspective = ProjectionMatrix(RadToDeg(lightFov), 1.0f, 1.0f, 1000.0f);
	Matrix44 lightView = LookAtMatrix(Point3(g_lightPos), Point3(g_lightTarget));
	Matrix44 lightTransform = lightPerspective*lightView;

	// radius used for drawing
	float radius = Max(g_params.solidRestDistance, g_params.fluidRestDistance)*0.5f*g_pointScale;

	//-------------------------------------
	// shadowing pass 

	if (g_meshSkinIndices.size())
		SkinMesh();

	// create shadow maps
	ShadowBegin(g_shadowMap);

	SetView(lightView, lightPerspective);
	SetCullMode(false);

	// give scene a chance to do custom drawing
	g_scenes[g_scene]->Draw(1);

	if (g_drawMesh)
		DrawMesh(g_mesh, g_meshColor);

	DrawShapes();

	if (g_drawCloth && g_buffers->triangles.size())
	{
		DrawCloth(&g_buffers->positions[0], &g_buffers->normals[0], g_buffers->uvs.size() ? &g_buffers->uvs[0].x : NULL, &g_buffers->triangles[0], g_buffers->triangles.size() / 3, g_buffers->positions.size(), 3, g_expandCloth);
	}

	if (g_drawRopes)
	{
		for (size_t i = 0; i < g_ropes.size(); ++i)
			DrawRope(&g_buffers->positions[0], &g_ropes[i].mIndices[0], g_ropes[i].mIndices.size(), radius*g_ropeScale, i);
	}

	int shadowParticles = numParticles;
	int shadowParticlesOffset = 0;

	if (!g_drawPoints)
	{
		shadowParticles = 0;

		if (g_drawEllipsoids)
		{
			shadowParticles = numParticles - g_numSolidParticles;
			shadowParticlesOffset = g_numSolidParticles;
		}
	}
	else
	{
		int offset = g_drawMesh ? g_numSolidParticles : 0;

		shadowParticles = numParticles - offset;
		shadowParticlesOffset = offset;
	}

	if (g_buffers->activeIndices.size())
		DrawPoints(g_fluidRenderBuffers, shadowParticles, shadowParticlesOffset, radius, 2048, 1.0f, lightFov, g_lightPos, g_lightTarget, lightTransform, g_shadowMap, g_drawDensity);

	ShadowEnd();

	//----------------
	// lighting pass

	BindSolidShader(g_lightPos, g_lightTarget, lightTransform, g_shadowMap, 0.0f, Vec4(g_clearColor, g_fogDistance));

	SetView(view, proj);
	SetCullMode(true);

	// When the benchmark measures async compute, we need a graphics workload that runs for a whole frame.
	// We do this by rerendering our simple graphics many times.
	int passes = g_increaseGfxLoadForAsyncComputeTesting ? 50 : 1;

	for (int i = 0; i != passes; i++)
	{

		DrawPlanes((Vec4*)g_params.planes, g_params.numPlanes, g_drawPlaneBias);

		if (g_drawMesh)
			DrawMesh(g_mesh, g_meshColor);


		DrawShapes();

		if (g_drawCloth && g_buffers->triangles.size())
			DrawCloth(&g_buffers->positions[0], &g_buffers->normals[0], g_buffers->uvs.size() ? &g_buffers->uvs[0].x : NULL, &g_buffers->triangles[0], g_buffers->triangles.size() / 3, g_buffers->positions.size(), 3, g_expandCloth);

		if (g_drawRopes)
		{
			for (size_t i = 0; i < g_ropes.size(); ++i)
				DrawRope(&g_buffers->positions[0], &g_ropes[i].mIndices[0], g_ropes[i].mIndices.size(), g_params.radius*0.5f*g_ropeScale, i);
		}

		// give scene a chance to do custom drawing
		g_scenes[g_scene]->Draw(0);
	}
	UnbindSolidShader();


	// first pass of diffuse particles (behind fluid surface)
	if (g_drawDiffuse)
		RenderDiffuse(g_fluidRenderer, g_diffuseRenderBuffers, numDiffuse, radius*g_diffuseScale, float(g_screenWidth), aspect, fov, g_diffuseColor, g_lightPos, g_lightTarget, lightTransform, g_shadowMap, g_diffuseMotionScale, g_diffuseInscatter, g_diffuseOutscatter, g_diffuseShadow, false);

	if (g_drawEllipsoids)
	{
		// draw solid particles separately
		if (g_numSolidParticles && g_drawPoints)
			DrawPoints(g_fluidRenderBuffers, g_numSolidParticles, 0, radius, float(g_screenWidth), aspect, fov, g_lightPos, g_lightTarget, lightTransform, g_shadowMap, g_drawDensity);

		// render fluid surface
		RenderEllipsoids(g_fluidRenderer, g_fluidRenderBuffers, numParticles - g_numSolidParticles, g_numSolidParticles, radius, float(g_screenWidth), aspect, fov, g_lightPos, g_lightTarget, lightTransform, g_shadowMap, g_fluidColor, g_blur, g_ior, g_drawOpaque);

		// second pass of diffuse particles for particles in front of fluid surface
		if (g_drawDiffuse)
			RenderDiffuse(g_fluidRenderer, g_diffuseRenderBuffers, numDiffuse, radius*g_diffuseScale, float(g_screenWidth), aspect, fov, g_diffuseColor, g_lightPos, g_lightTarget, lightTransform, g_shadowMap, g_diffuseMotionScale, g_diffuseInscatter, g_diffuseOutscatter, g_diffuseShadow, true);
	}
	else
	{
		// draw all particles as spheres
		if (g_drawPoints)
		{
			int offset = g_drawMesh ? g_numSolidParticles : 0;

			if (g_buffers->activeIndices.size())
				DrawPoints(g_fluidRenderBuffers, numParticles - offset, offset, radius, float(g_screenWidth), aspect, fov, g_lightPos, g_lightTarget, lightTransform, g_shadowMap, g_drawDensity);
		}
	}

	GraphicsTimerEnd();
}

void RenderDebug()
{
	if (g_mouseParticle != -1)
	{
		// draw mouse spring
		BeginLines();
		DrawLine(g_mousePos, Vec3(g_buffers->positions[g_mouseParticle]), Vec4(1.0f));
		EndLines();
	}

	// springs
	if (g_drawSprings)
	{
		Vec4 color;

		if (g_drawSprings == 1)
		{
			// stretch 
			color = Vec4(0.0f, 0.0f, 1.0f, 0.8f);
		}
		if (g_drawSprings == 2)
		{
			// tether
			color = Vec4(0.0f, 1.0f, 0.0f, 0.8f);
		}

		BeginLines();

		int start = 0;

		for (int i = start; i < g_buffers->springLengths.size(); ++i)
		{
			if (g_drawSprings == 1 && g_buffers->springStiffness[i] < 0.0f)
				continue;
			if (g_drawSprings == 2 && g_buffers->springStiffness[i] > 0.0f)
				continue;

			int a = g_buffers->springIndices[i * 2];
			int b = g_buffers->springIndices[i * 2 + 1];

			DrawLine(Vec3(g_buffers->positions[a]), Vec3(g_buffers->positions[b]), color);
		}

		EndLines();
	}

	// visualize contacts against the environment
	if (g_drawContacts)
	{
		const int maxContactsPerParticle = 6;

		NvFlexVector<Vec4> contactPlanes(g_flexLib, g_buffers->positions.size()*maxContactsPerParticle);
		NvFlexVector<Vec4> contactVelocities(g_flexLib, g_buffers->positions.size()*maxContactsPerParticle);
		NvFlexVector<int> contactIndices(g_flexLib, g_buffers->positions.size());
		NvFlexVector<unsigned int> contactCounts(g_flexLib, g_buffers->positions.size());

		NvFlexGetContacts(g_solver, contactPlanes.buffer, contactVelocities.buffer, contactIndices.buffer, contactCounts.buffer);

		// ensure transfers have finished
		contactPlanes.map();
		contactVelocities.map();
		contactIndices.map();
		contactCounts.map();

		BeginLines();

		for (int i = 0; i < int(g_buffers->activeIndices.size()); ++i)
		{
			const int contactIndex = contactIndices[g_buffers->activeIndices[i]];
			const unsigned int count = contactCounts[contactIndex];

			const float scale = 0.1f;

			for (unsigned int c = 0; c < count; ++c)
			{
				Vec4 plane = contactPlanes[contactIndex*maxContactsPerParticle + c];

				DrawLine(Vec3(g_buffers->positions[g_buffers->activeIndices[i]]), 
						 Vec3(g_buffers->positions[g_buffers->activeIndices[i]]) + Vec3(plane)*scale,
						 Vec4(0.0f, 1.0f, 0.0f, 0.0f));
			}
		}

		EndLines();
	}
	
	if (g_drawBases)
	{
		for (int i = 0; i < int(g_buffers->rigidRotations.size()); ++i)
		{
			BeginLines();

			float size = 0.1f;

			for (int b = 0; b < 3; ++b)
			{
				Vec3 color;
				color[b] = 1.0f;
			
				Matrix33 frame(g_buffers->rigidRotations[i]);

				DrawLine(Vec3(g_buffers->rigidTranslations[i]),
						 Vec3(g_buffers->rigidTranslations[i] + frame.cols[b] * size),
						 Vec4(color, 0.0f));
			}

			EndLines();
		}
	}

	if (g_drawNormals)
	{
		NvFlexGetNormals(g_solver, g_buffers->normals.buffer, NULL);

		BeginLines();

		for (int i = 0; i < g_buffers->normals.size(); ++i)
		{
			DrawLine(Vec3(g_buffers->positions[i]),
					 Vec3(g_buffers->positions[i] - g_buffers->normals[i] * g_buffers->normals[i].w),
					 Vec4(0.0f, 1.0f, 0.0f, 0.0f));
		}

		EndLines();
	}
}

void DrawShapes()
{
	for (int i = 0; i < g_buffers->shapeFlags.size(); ++i)
	{
		const int flags = g_buffers->shapeFlags[i];

		// unpack flags
		int type = int(flags&eNvFlexShapeFlagTypeMask);
		//bool dynamic = int(flags&eNvFlexShapeFlagDynamic) > 0;

		Vec3 color = Vec3(0.9f);

		if (flags & eNvFlexShapeFlagTrigger)
		{
			color = Vec3(0.6f, 1.0, 0.6f);

			SetFillMode(true);		
		}

		// render with prev positions to match particle update order
		// can also think of this as current/next
		const Quat rotation = g_buffers->shapePrevRotations[i];
		const Vec3 position = Vec3(g_buffers->shapePrevPositions[i]);

		NvFlexCollisionGeometry geo = g_buffers->shapeGeometry[i];

		if (type == eNvFlexShapeSphere)
		{
			Mesh* sphere = CreateSphere(20, 20, geo.sphere.radius);

			Matrix44 xform = TranslationMatrix(Point3(position))*RotationMatrix(Quat(rotation));
			sphere->Transform(xform);

			DrawMesh(sphere, Vec3(color));

			delete sphere;
		}
		else if (type == eNvFlexShapeCapsule)
		{
			Mesh* capsule = CreateCapsule(10, 20, geo.capsule.radius, geo.capsule.halfHeight);

			// transform to world space
			Matrix44 xform = TranslationMatrix(Point3(position))*RotationMatrix(Quat(rotation))*RotationMatrix(DegToRad(-90.0f), Vec3(0.0f, 0.0f, 1.0f));
			capsule->Transform(xform);

			DrawMesh(capsule, Vec3(color));

			delete capsule;
		}
		else if (type == eNvFlexShapeBox)
		{
			Mesh* box = CreateCubeMesh();

			Matrix44 xform = TranslationMatrix(Point3(position))*RotationMatrix(Quat(rotation))*ScaleMatrix(Vec3(geo.box.halfExtents)*2.0f);
			box->Transform(xform);

			DrawMesh(box, Vec3(color));
			delete box;			
		}
		else if (type == eNvFlexShapeConvexMesh)
		{
			if (g_convexes.find(geo.convexMesh.mesh) != g_convexes.end())
			{
				GpuMesh* m = g_convexes[geo.convexMesh.mesh];

				if (m)
				{
					Matrix44 xform = TranslationMatrix(Point3(g_buffers->shapePositions[i]))*RotationMatrix(Quat(g_buffers->shapeRotations[i]))*ScaleMatrix(geo.convexMesh.scale);
					DrawGpuMesh(m, xform, Vec3(color));
				}
			}
		}
		else if (type == eNvFlexShapeTriangleMesh)
		{
			if (g_meshes.find(geo.triMesh.mesh) != g_meshes.end())
			{
				GpuMesh* m = g_meshes[geo.triMesh.mesh];

				if (m)
				{
					Matrix44 xform = TranslationMatrix(Point3(position))*RotationMatrix(Quat(rotation))*ScaleMatrix(geo.triMesh.scale);
					DrawGpuMesh(m, xform, Vec3(color));
				}
			}
		}
		else if (type == eNvFlexShapeSDF)
		{
			if (g_fields.find(geo.sdf.field) != g_fields.end())
			{
				GpuMesh* m = g_fields[geo.sdf.field];

				if (m)
				{
					Matrix44 xform = TranslationMatrix(Point3(position))*RotationMatrix(Quat(rotation))*ScaleMatrix(geo.sdf.scale);
					DrawGpuMesh(m, xform, Vec3(color));
				}
			}
		}
	}

	SetFillMode(g_wireframe);
}


// returns the new scene if one is selected
int DoUI()
{
	// gui may set a new scene
	int newScene = -1;

	if (g_showHelp)
	{
		const int numParticles = NvFlexGetActiveCount(g_solver);		
		const int numDiffuse = g_buffers->diffuseCount[0];

		int x = g_screenWidth - 200;
		int y = g_screenHeight - 23;

		// imgui
		unsigned char button = 0;
		if (g_lastb == SDL_BUTTON_LEFT)
			button = IMGUI_MBUT_LEFT;
		else if (g_lastb == SDL_BUTTON_RIGHT)
			button = IMGUI_MBUT_RIGHT;

		imguiBeginFrame(g_lastx, g_screenHeight - g_lasty, button, 0);

		x += 180;

		int fontHeight = 13;

		if (1)
		{
			DrawImguiString(x, y, Vec3(1.0f), IMGUI_ALIGN_RIGHT, "Frame: %d", g_frame); y -= fontHeight * 2;

			if (!g_ffmpeg)
			{
				DrawImguiString(x, y, Vec3(1.0f), IMGUI_ALIGN_RIGHT, "Frame Time: %.2fms", g_realdt*1000.0f); y -= fontHeight * 2;

				// If detailed profiling is enabled, then these timers will contain the overhead of the detail timers, so we won't display them.
				if (!g_profile)
				{
					DrawImguiString(x, y, Vec3(1.0f), IMGUI_ALIGN_RIGHT, "Sim Time (CPU): %.2fms", g_updateTime*1000.0f); y -= fontHeight;
					DrawImguiString(x, y, Vec3(0.97f, 0.59f, 0.27f), IMGUI_ALIGN_RIGHT, "Sim Latency (GPU): %.2fms", g_simLatency); y -= fontHeight * 2;

					BenchmarkUpdateGraph();
				}
				else
				{
					y -= fontHeight * 3;
				}
			}

			DrawImguiString(x, y, Vec3(1.0f), IMGUI_ALIGN_RIGHT, "Particle Count: %d", numParticles); y -= fontHeight;
			DrawImguiString(x, y, Vec3(1.0f), IMGUI_ALIGN_RIGHT, "Diffuse Count: %d", numDiffuse); y -= fontHeight;
			DrawImguiString(x, y, Vec3(1.0f), IMGUI_ALIGN_RIGHT, "Rigid Count: %d", g_buffers->rigidOffsets.size() > 0 ? g_buffers->rigidOffsets.size() - 1 : 0); y -= fontHeight;
			DrawImguiString(x, y, Vec3(1.0f), IMGUI_ALIGN_RIGHT, "Spring Count: %d", g_buffers->springLengths.size()); y -= fontHeight;
			DrawImguiString(x, y, Vec3(1.0f), IMGUI_ALIGN_RIGHT, "Num Substeps: %d", g_numSubsteps); y -= fontHeight;
			DrawImguiString(x, y, Vec3(1.0f), IMGUI_ALIGN_RIGHT, "Num Iterations: %d", g_params.numIterations); y -= fontHeight * 2;

			DrawImguiString(x, y, Vec3(1.0f), IMGUI_ALIGN_RIGHT, "Device: %s", g_deviceName); y -= fontHeight * 2;
		}

		if (g_profile)
		{
			DrawImguiString(x, y, Vec3(0.97f, 0.59f, 0.27f), IMGUI_ALIGN_RIGHT, "Total GPU Sim Latency: %.2fms", g_timers.total); y -= fontHeight * 2;

			DrawImguiString(x, y, Vec3(0.0f, 1.0f, 0.0f), IMGUI_ALIGN_RIGHT, "GPU Latencies"); y -= fontHeight;

			DrawImguiString(x, y, Vec3(1.0f), IMGUI_ALIGN_RIGHT, "Predict: %.2fms", g_timers.predict); y -= fontHeight;
			DrawImguiString(x, y, Vec3(1.0f), IMGUI_ALIGN_RIGHT, "Create Cell Indices: %.2fms", g_timers.createCellIndices); y -= fontHeight;
			DrawImguiString(x, y, Vec3(1.0f), IMGUI_ALIGN_RIGHT, "Sort Cell Indices: %.2fms", g_timers.sortCellIndices); y -= fontHeight;
			DrawImguiString(x, y, Vec3(1.0f), IMGUI_ALIGN_RIGHT, "Reorder: %.2fms", g_timers.reorder); y -= fontHeight;
			DrawImguiString(x, y, Vec3(1.0f), IMGUI_ALIGN_RIGHT, "CreateGrid: %.2fms", g_timers.createGrid); y -= fontHeight;
			DrawImguiString(x, y, Vec3(1.0f), IMGUI_ALIGN_RIGHT, "Collide Particles: %.2fms", g_timers.collideParticles); y -= fontHeight;
			DrawImguiString(x, y, Vec3(1.0f), IMGUI_ALIGN_RIGHT, "Collide Shapes: %.2fms", g_timers.collideShapes); y -= fontHeight;
			DrawImguiString(x, y, Vec3(1.0f), IMGUI_ALIGN_RIGHT, "Collide Triangles: %.2fms", g_timers.collideTriangles); y -= fontHeight;
			DrawImguiString(x, y, Vec3(1.0f), IMGUI_ALIGN_RIGHT, "Calculate Density: %.2fms", g_timers.calculateDensity); y -= fontHeight;
			DrawImguiString(x, y, Vec3(1.0f), IMGUI_ALIGN_RIGHT, "Solve Densities: %.2fms", g_timers.solveDensities); y -= fontHeight;
			DrawImguiString(x, y, Vec3(1.0f), IMGUI_ALIGN_RIGHT, "Solve Velocities: %.2fms", g_timers.solveVelocities); y -= fontHeight;
			DrawImguiString(x, y, Vec3(1.0f), IMGUI_ALIGN_RIGHT, "Solve Rigids: %.2fms", g_timers.solveShapes); y -= fontHeight;
			DrawImguiString(x, y, Vec3(1.0f), IMGUI_ALIGN_RIGHT, "Solve Springs: %.2fms", g_timers.solveSprings); y -= fontHeight;
			DrawImguiString(x, y, Vec3(1.0f), IMGUI_ALIGN_RIGHT, "Solve Inflatables: %.2fms", g_timers.solveInflatables); y -= fontHeight;
			DrawImguiString(x, y, Vec3(1.0f), IMGUI_ALIGN_RIGHT, "Solve Contacts: %.2fms", g_timers.solveContacts); y -= fontHeight;
			DrawImguiString(x, y, Vec3(1.0f), IMGUI_ALIGN_RIGHT, "Apply Deltas: %.2fms", g_timers.applyDeltas); y -= fontHeight;
			DrawImguiString(x, y, Vec3(1.0f), IMGUI_ALIGN_RIGHT, "Finalize: %.2fms", g_timers.finalize); y -= fontHeight;
			DrawImguiString(x, y, Vec3(1.0f), IMGUI_ALIGN_RIGHT, "Update Triangles: %.2fms", g_timers.updateTriangles); y -= fontHeight;
			DrawImguiString(x, y, Vec3(1.0f), IMGUI_ALIGN_RIGHT, "Update Normals: %.2fms", g_timers.updateNormals); y -= fontHeight;
			DrawImguiString(x, y, Vec3(1.0f), IMGUI_ALIGN_RIGHT, "Update Bounds: %.2fms", g_timers.updateBounds); y -= fontHeight;
			DrawImguiString(x, y, Vec3(1.0f), IMGUI_ALIGN_RIGHT, "Calculate Anisotropy: %.2fms", g_timers.calculateAnisotropy); y -= fontHeight;
			DrawImguiString(x, y, Vec3(1.0f), IMGUI_ALIGN_RIGHT, "Update Diffuse: %.2fms", g_timers.updateDiffuse); y -= fontHeight * 2;
		}

		x -= 180;

		int uiOffset = 250;
		int uiBorder = 20;
		int uiWidth = 200;
		int uiHeight = g_screenHeight - uiOffset - uiBorder * 3;
		int uiLeft = uiBorder;

		if (g_tweakPanel)
			imguiBeginScrollArea("Scene", uiLeft, g_screenHeight - uiBorder - uiOffset, uiWidth, uiOffset, &g_levelScroll);
		else
			imguiBeginScrollArea("Scene", uiLeft, uiBorder, uiWidth, g_screenHeight - uiBorder - uiBorder, &g_levelScroll);

		for (int i = 0; i < int(g_scenes.size()); ++i)
		{
			unsigned int color = g_scene == i ? imguiRGBA(255, 151, 61, 255) : imguiRGBA(255, 255, 255, 200);
			if (imguiItem(g_scenes[i]->GetName(), true, color)) // , i == g_selectedScene))
			{
				newScene = i;
			}
		}

		imguiEndScrollArea();

		if (g_tweakPanel)
		{
			static int scroll = 0;

			imguiBeginScrollArea("Options", uiLeft, g_screenHeight - uiBorder - uiHeight - uiOffset - uiBorder, uiWidth, uiHeight, &scroll);
			imguiSeparatorLine();

			// global options
			imguiLabel("Global");
			if (imguiCheck("Emit particles", g_emit))
				g_emit = !g_emit;

			if (imguiCheck("Pause", g_pause))
				g_pause = !g_pause;

			imguiSeparatorLine();

			if (imguiCheck("Wireframe", g_wireframe))
				g_wireframe = !g_wireframe;

			if (imguiCheck("Draw Points", g_drawPoints))
				g_drawPoints = !g_drawPoints;

			if (imguiCheck("Draw Fluid", g_drawEllipsoids))
				g_drawEllipsoids = !g_drawEllipsoids;

			if (imguiCheck("Draw Mesh", g_drawMesh))
			{
				g_drawMesh = !g_drawMesh;
				g_drawRopes = !g_drawRopes;
			}

			if (imguiCheck("Draw Basis", g_drawBases))
				g_drawBases = !g_drawBases;

			if (imguiCheck("Draw Springs", bool(g_drawSprings != 0)))
				g_drawSprings = (g_drawSprings) ? 0 : 1;

			if (imguiCheck("Draw Contacts", g_drawContacts))
				g_drawContacts = !g_drawContacts;

			imguiSeparatorLine();

			// scene options
			g_scenes[g_scene]->DoGui();

		if (imguiButton("Reset Scene"))
			g_resetScene = true;

			imguiSeparatorLine();

			float n = float(g_numSubsteps);
			if (imguiSlider("Num Substeps", &n, 1, 10, 1))
				g_numSubsteps = int(n);

			n = float(g_params.numIterations);
			if (imguiSlider("Num Iterations", &n, 1, 20, 1))
				g_params.numIterations = int(n);

			imguiSeparatorLine();
			imguiSlider("Gravity X", &g_params.gravity[0], -50.0f, 50.0f, 1.0f);
			imguiSlider("Gravity Y", &g_params.gravity[1], -50.0f, 50.0f, 1.0f);
			imguiSlider("Gravity Z", &g_params.gravity[2], -50.0f, 50.0f, 1.0f);

			imguiSeparatorLine();
			imguiSlider("Radius", &g_params.radius, 0.01f, 0.5f, 0.01f);
			imguiSlider("Solid Radius", &g_params.solidRestDistance, 0.0f, 0.5f, 0.001f);
			imguiSlider("Fluid Radius", &g_params.fluidRestDistance, 0.0f, 0.5f, 0.001f);

			// common params
			imguiSeparatorLine();
			imguiSlider("Dynamic Friction", &g_params.dynamicFriction, 0.0f, 1.0f, 0.01f);
			imguiSlider("Static Friction", &g_params.staticFriction, 0.0f, 1.0f, 0.01f);
			imguiSlider("Particle Friction", &g_params.particleFriction, 0.0f, 1.0f, 0.01f);
			imguiSlider("Restitution", &g_params.restitution, 0.0f, 1.0f, 0.01f);
			imguiSlider("SleepThreshold", &g_params.sleepThreshold, 0.0f, 1.0f, 0.01f);
			imguiSlider("Shock Propagation", &g_params.shockPropagation, 0.0f, 10.0f, 0.01f);
			imguiSlider("Damping", &g_params.damping, 0.0f, 10.0f, 0.01f);
			imguiSlider("Dissipation", &g_params.dissipation, 0.0f, 0.01f, 0.0001f);
			imguiSlider("SOR", &g_params.relaxationFactor, 0.0f, 5.0f, 0.01f);

			imguiSlider("Collision Distance", &g_params.collisionDistance, 0.0f, 0.5f, 0.001f);
			imguiSlider("Collision Margin", &g_params.shapeCollisionMargin, 0.0f, 5.0f, 0.01f);

			// cloth params
			imguiSeparatorLine();
			imguiSlider("Wind", &g_windStrength, -1.0f, 1.0f, 0.01f);
			imguiSlider("Drag", &g_params.drag, 0.0f, 1.0f, 0.01f);
			imguiSlider("Lift", &g_params.lift, 0.0f, 1.0f, 0.01f);
			imguiSeparatorLine();

			// fluid params
			imguiSlider("Adhesion", &g_params.adhesion, 0.0f, 10.0f, 0.01f);
			imguiSlider("Cohesion", &g_params.cohesion, 0.0f, 0.2f, 0.0001f);
			imguiSlider("Surface Tension", &g_params.surfaceTension, 0.0f, 50.0f, 0.01f);
			imguiSlider("Viscosity", &g_params.viscosity, 0.0f, 120.0f, 0.01f);
			imguiSlider("Vorticicty Confinement", &g_params.vorticityConfinement, 0.0f, 120.0f, 0.1f);
			imguiSlider("Solid Pressure", &g_params.solidPressure, 0.0f, 1.0f, 0.01f);
			imguiSlider("Surface Drag", &g_params.freeSurfaceDrag, 0.0f, 1.0f, 0.01f);
			imguiSlider("Buoyancy", &g_params.buoyancy, -1.0f, 1.0f, 0.01f);

			imguiSeparatorLine();
			imguiSlider("Anisotropy Scale", &g_params.anisotropyScale, 0.0f, 30.0f, 0.01f);
			imguiSlider("Smoothing", &g_params.smoothing, 0.0f, 1.0f, 0.01f);

			// diffuse params
			imguiSeparatorLine();
			imguiSlider("Diffuse Threshold", &g_params.diffuseThreshold, 0.0f, 1000.0f, 1.0f);
			imguiSlider("Diffuse Buoyancy", &g_params.diffuseBuoyancy, 0.0f, 2.0f, 0.01f);
			imguiSlider("Diffuse Drag", &g_params.diffuseDrag, 0.0f, 2.0f, 0.01f);
			imguiSlider("Diffuse Scale", &g_diffuseScale, 0.0f, 1.5f, 0.01f);
			imguiSlider("Diffuse Alpha", &g_diffuseColor.w, 0.0f, 3.0f, 0.01f);
			imguiSlider("Diffuse Inscatter", &g_diffuseInscatter, 0.0f, 2.0f, 0.01f);
			imguiSlider("Diffuse Outscatter", &g_diffuseOutscatter, 0.0f, 2.0f, 0.01f);
			imguiSlider("Diffuse Motion Blur", &g_diffuseMotionScale, 0.0f, 5.0f, 0.1f);

			n = float(g_params.diffuseBallistic);
			if (imguiSlider("Diffuse Ballistic", &n, 1, 40, 1))
				g_params.diffuseBallistic = int(n);

			imguiEndScrollArea();
		}
		imguiEndFrame();

		// kick render commands
		DrawImguiGraph();
	}

	return newScene;
}

void UpdateFrame()
{
	static double lastTime;

	// real elapsed frame time
	double frameBeginTime = GetSeconds();

	g_realdt = float(frameBeginTime - lastTime);
	lastTime = frameBeginTime;

	// do gamepad input polling
	double currentTime = frameBeginTime;
	static double lastJoyTime = currentTime;

	if (g_gamecontroller && currentTime - lastJoyTime > g_dt)
	{
		lastJoyTime = currentTime;

		int leftStickX = SDL_GameControllerGetAxis(g_gamecontroller, SDL_CONTROLLER_AXIS_LEFTX);
		int leftStickY = SDL_GameControllerGetAxis(g_gamecontroller, SDL_CONTROLLER_AXIS_LEFTY);
		int rightStickX = SDL_GameControllerGetAxis(g_gamecontroller, SDL_CONTROLLER_AXIS_RIGHTX);
		int rightStickY = SDL_GameControllerGetAxis(g_gamecontroller, SDL_CONTROLLER_AXIS_RIGHTY);
		int leftTrigger = SDL_GameControllerGetAxis(g_gamecontroller, SDL_CONTROLLER_AXIS_TRIGGERLEFT);
		int rightTrigger = SDL_GameControllerGetAxis(g_gamecontroller, SDL_CONTROLLER_AXIS_TRIGGERRIGHT);

		Vec2 leftStick(joyAxisFilter(leftStickX, 0), joyAxisFilter(leftStickY, 0));
		Vec2 rightStick(joyAxisFilter(rightStickX, 1), joyAxisFilter(rightStickY, 1));
		Vec2 trigger(leftTrigger / 32768.0f, rightTrigger / 32768.0f);

		if (leftStick.x != 0.0f || leftStick.y != 0.0f ||
			rightStick.x != 0.0f || rightStick.y != 0.0f)
		{
			// note constant factor to speed up analog control compared to digital because it is more controllable.
			g_camVel.z = -4 * g_camSpeed * leftStick.y;
			g_camVel.x = 4 * g_camSpeed * leftStick.x;

			// cam orientation
			g_camAngle.x -= rightStick.x * 0.05f;
			g_camAngle.y -= rightStick.y * 0.05f;
		}

		// Handle left stick motion
		static bool bLeftStick = false;

		if ((leftStick.x != 0.0f || leftStick.y != 0.0f) && !bLeftStick)
		{
			bLeftStick = true;
		}
		else if ((leftStick.x == 0.0f && leftStick.y == 0.0f) && bLeftStick)
		{
			bLeftStick = false;
			g_camVel.z = -4 * g_camSpeed * leftStick.y;
			g_camVel.x = 4 * g_camSpeed * leftStick.x;
		}

		// Handle triggers as controller button events
		void ControllerButtonEvent(SDL_ControllerButtonEvent event);

		static bool bLeftTrigger = false;
		static bool bRightTrigger = false;
		SDL_ControllerButtonEvent e;

		if (!bLeftTrigger && trigger.x > 0.0f)
		{
			e.type = SDL_CONTROLLERBUTTONDOWN;
			e.button = SDL_CONTROLLER_BUTTON_LEFT_TRIGGER;
			ControllerButtonEvent(e);
			bLeftTrigger = true;
		}
		else if (bLeftTrigger && trigger.x == 0.0f)
		{
			e.type = SDL_CONTROLLERBUTTONUP;
			e.button = SDL_CONTROLLER_BUTTON_LEFT_TRIGGER;
			ControllerButtonEvent(e);
			bLeftTrigger = false;
		}

		if (!bRightTrigger && trigger.y > 0.0f)
		{
			e.type = SDL_CONTROLLERBUTTONDOWN;
			e.button = SDL_CONTROLLER_BUTTON_RIGHT_TRIGGER;
			ControllerButtonEvent(e);
			bRightTrigger = true;
		}
		else if (bRightTrigger && trigger.y == 0.0f)
		{
			e.type = SDL_CONTROLLERBUTTONDOWN;
			e.button = SDL_CONTROLLER_BUTTON_RIGHT_TRIGGER;
			ControllerButtonEvent(e);
			bRightTrigger = false;
		}
	}

	//-------------------------------------------------------------------
	// Scene Update

	double waitBeginTime = GetSeconds();

	MapBuffers(g_buffers);

	double waitEndTime = GetSeconds();

	// Getting timers causes CPU/GPU sync, so we do it after a map
	float newSimLatency = NvFlexGetDeviceLatency(g_solver, &g_GpuTimers.computeBegin, &g_GpuTimers.computeEnd, &g_GpuTimers.computeFreq);
	float newGfxLatency = RendererGetDeviceTimestamps(&g_GpuTimers.renderBegin, &g_GpuTimers.renderEnd, &g_GpuTimers.renderFreq);
	(void)newGfxLatency;

	UpdateCamera();

	if (!g_pause || g_step)
	{
		UpdateEmitters();
		UpdateMouse();
		UpdateWind();
		UpdateScene();
	}

	//-------------------------------------------------------------------
	// Render

	double renderBeginTime = GetSeconds();

	if (g_profile && (!g_pause || g_step))
	{
		if (g_benchmark)
		{
			g_numDetailTimers = NvFlexGetDetailTimers(g_solver, &g_detailTimers);
		}
		else
		{
			memset(&g_timers, 0, sizeof(g_timers));
			NvFlexGetTimers(g_solver, &g_timers);
		}
	}

	StartFrame(Vec4(g_clearColor, 1.0f));

	// main scene render
	RenderScene();
	RenderDebug();

	int newScene = DoUI();

	EndFrame();

	// If user has disabled async compute, ensure that no compute can overlap 
	// graphics by placing a sync between them	
	if (!g_useAsyncCompute)
		NvFlexComputeWaitForGraphics(g_flexLib);

	UnmapBuffers(g_buffers);

	// move mouse particle (must be done here as GetViewRay() uses the GL projection state)
	if (g_mouseParticle != -1)
	{
		Vec3 origin, dir;
		GetViewRay(g_lastx, g_screenHeight - g_lasty, origin, dir);

		g_mousePos = origin + dir*g_mouseT;
	}

	if (g_capture)
	{
		TgaImage img;
		img.m_width = g_screenWidth;
		img.m_height = g_screenHeight;
		img.m_data = new uint32_t[g_screenWidth*g_screenHeight];

		ReadFrame((int*)img.m_data, g_screenWidth, g_screenHeight);

		fwrite(img.m_data, sizeof(uint32_t)*g_screenWidth*g_screenHeight, 1, g_ffmpeg);

		delete[] img.m_data;
	}

	double renderEndTime = GetSeconds();

	// if user requested a scene reset process it now
	if (g_resetScene)
	{
		Reset();
		g_resetScene = false;
	}

	//-------------------------------------------------------------------
	// Flex Update

	double updateBeginTime = GetSeconds();

	// send any particle updates to the solver
	NvFlexSetParticles(g_solver, g_buffers->positions.buffer, NULL);
	NvFlexSetVelocities(g_solver, g_buffers->velocities.buffer, NULL);
	NvFlexSetPhases(g_solver, g_buffers->phases.buffer, NULL);
	NvFlexSetActive(g_solver, g_buffers->activeIndices.buffer, NULL);

	NvFlexSetActiveCount(g_solver, g_buffers->activeIndices.size());

	// allow scene to update constraints etc
	SyncScene();

	if (g_shapesChanged)
	{
		NvFlexSetShapes(
			g_solver,
			g_buffers->shapeGeometry.buffer,
			g_buffers->shapePositions.buffer,
			g_buffers->shapeRotations.buffer,
			g_buffers->shapePrevPositions.buffer,
			g_buffers->shapePrevRotations.buffer,
			g_buffers->shapeFlags.buffer,
			int(g_buffers->shapeFlags.size()));

		g_shapesChanged = false;
	}

	if (!g_pause || g_step)
	{
		// tick solver
		NvFlexSetParams(g_solver, &g_params);
		NvFlexUpdateSolver(g_solver, g_dt, g_numSubsteps, g_profile);

		g_frame++;
		g_step = false;
	}

	// read back base particle data
	// Note that flexGet calls don't wait for the GPU, they just queue a GPU copy 
	// to be executed later.
	// When we're ready to read the fetched buffers we'll Map them, and that's when
	// the CPU will wait for the GPU flex update and GPU copy to finish.
	NvFlexGetParticles(g_solver, g_buffers->positions.buffer, NULL);
	NvFlexGetVelocities(g_solver, g_buffers->velocities.buffer, NULL);
	NvFlexGetNormals(g_solver, g_buffers->normals.buffer, NULL);

	// readback triangle normals
	if (g_buffers->triangles.size())
		NvFlexGetDynamicTriangles(g_solver, g_buffers->triangles.buffer, g_buffers->triangleNormals.buffer, g_buffers->triangles.size() / 3);

	// readback rigid transforms
	if (g_buffers->rigidOffsets.size())
		NvFlexGetRigids(g_solver, NULL, NULL, NULL, NULL, NULL, NULL, NULL, g_buffers->rigidRotations.buffer, g_buffers->rigidTranslations.buffer);

	if (!g_interop)
	{
		// if not using interop then we read back fluid data to host
		if (g_drawEllipsoids)
		{
			NvFlexGetSmoothParticles(g_solver, g_buffers->smoothPositions.buffer, NULL);
			NvFlexGetAnisotropy(g_solver, g_buffers->anisotropy1.buffer, g_buffers->anisotropy2.buffer, g_buffers->anisotropy3.buffer, NULL);
		}

		// read back diffuse data to host
		if (g_drawDensity)
			NvFlexGetDensities(g_solver, g_buffers->densities.buffer, NULL);

		if (GetNumDiffuseRenderParticles(g_diffuseRenderBuffers))
		{
			NvFlexGetDiffuseParticles(g_solver, g_buffers->diffusePositions.buffer, g_buffers->diffuseVelocities.buffer, g_buffers->diffuseCount.buffer);
		}
	}
	else
	{
		// read back just the new diffuse particle count, render buffers will be updated during rendering
		NvFlexGetDiffuseParticles(g_solver, NULL, NULL, g_buffers->diffuseCount.buffer);
	}

	double updateEndTime = GetSeconds();

	//-------------------------------------------------------
	// Update the on-screen timers

	float newUpdateTime = float(updateEndTime - updateBeginTime);
	float newRenderTime = float(renderEndTime - renderBeginTime);
	float newWaitTime = float(waitBeginTime - waitEndTime);

	// Exponential filter to make the display easier to read
	const float timerSmoothing = 0.05f;

	g_updateTime = (g_updateTime == 0.0f) ? newUpdateTime : Lerp(g_updateTime, newUpdateTime, timerSmoothing);
	g_renderTime = (g_renderTime == 0.0f) ? newRenderTime : Lerp(g_renderTime, newRenderTime, timerSmoothing);
	g_waitTime = (g_waitTime == 0.0f) ? newWaitTime : Lerp(g_waitTime, newWaitTime, timerSmoothing);
	g_simLatency = (g_simLatency == 0.0f) ? newSimLatency : Lerp(g_simLatency, newSimLatency, timerSmoothing);

	if (g_benchmark) newScene = BenchmarkUpdate();

	// flush out the last frame before freeing up resources in the event of a scene change
	// this is necessary for d3d12
	PresentFrame(g_vsync);

	// if gui or benchmark requested a scene change process it now
	if (newScene != -1)
	{
		g_scene = newScene;
		Init(g_scene);
	}
}

#if ENABLE_AFTERMATH_SUPPORT
void DumpAftermathData()
{
	GFSDK_Aftermath_ContextData dataOut;
	GFSDK_Aftermath_Status statusOut;

	NvFlexGetDataAftermath(g_flexLib, &dataOut, &statusOut);
	wprintf(L"Last Aftermath event: %s\n", (wchar_t *)dataOut.markerData);
}
#endif

void ReshapeWindow(int width, int height)
{
	if (!g_benchmark)
		printf("Reshaping\n");

	ReshapeRender(g_window);

	if (!g_fluidRenderer || (width != g_screenWidth || height != g_screenHeight))
	{
		if (g_fluidRenderer)
			DestroyFluidRenderer(g_fluidRenderer);
		g_fluidRenderer = CreateFluidRenderer(width, height);
	}

	g_screenWidth = width;
	g_screenHeight = height;
}

void InputArrowKeysDown(int key, int x, int y)
{
	switch (key)
	{
	case SDLK_DOWN:
	{
		if (g_selectedScene < int(g_scenes.size()) - 1)
			g_selectedScene++;

		// update scroll UI to center on selected scene
		g_levelScroll = max((g_selectedScene - 4) * 24, 0);
		break;
	}
	case SDLK_UP:
	{
		if (g_selectedScene > 0)
			g_selectedScene--;

		// update scroll UI to center on selected scene
		g_levelScroll = max((g_selectedScene - 4) * 24, 0);
		break;
	}
	case SDLK_LEFT:
	{
		if (g_scene > 0)
			--g_scene;
		Init(g_scene);

		// update scroll UI to center on selected scene
		g_levelScroll = max((g_scene - 4) * 24, 0);
		break;
	}
	case SDLK_RIGHT:
	{
		if (g_scene < int(g_scenes.size()) - 1)
			++g_scene;
		Init(g_scene);

		// update scroll UI to center on selected scene
		g_levelScroll = max((g_scene - 4) * 24, 0);
		break;
	}
	}
}

void InputArrowKeysUp(int key, int x, int y)
{
}

bool InputKeyboardDown(unsigned char key, int x, int y)
{
	if (key > '0' && key <= '9')
	{
		g_scene = key - '0' - 1;
		Init(g_scene);
		return false;
	}

	float kSpeed = g_camSpeed;

	switch (key)
	{
	case 'w':
	{
		g_camVel.z = kSpeed;
		break;
	}
	case 's':
	{
		g_camVel.z = -kSpeed;
		break;
	}
	case 'a':
	{
		g_camVel.x = -kSpeed;
		break;
	}
	case 'd':
	{
		g_camVel.x = kSpeed;
		break;
	}
	case 'q':
	{
		g_camVel.y = kSpeed;
		break;
	}
	case 'z':
	{
		//g_drawCloth = !g_drawCloth;
		g_camVel.y = -kSpeed;
		break;
	}

	case 'u':
	{
#ifndef ANDROID
		if (g_fullscreen)
		{
			SDL_SetWindowFullscreen(g_window, 0);
			ReshapeWindow(1280, 720);
			g_fullscreen = false;
		}
		else
		{
			SDL_SetWindowFullscreen(g_window, SDL_WINDOW_FULLSCREEN_DESKTOP);
			g_fullscreen = true;
		}
#endif
		break;
	}
	case 'r':
	{
		g_resetScene = true;
		break;
	}
	case 'y':
	{
		g_wavePool = !g_wavePool;
		break;
	}
	case 'c':
	{
#if _WIN32
		if (!g_ffmpeg)
		{
			// open ffmpeg stream

			int i = 0;
			char buf[255];
			FILE* f = NULL;

			do
			{
				sprintf(buf, "../../movies/output%d.mp4", i);
				f = fopen(buf, "rb");
				if (f)
					fclose(f);

				++i;
			} while (f);

			const char* str = "ffmpeg -r 60 -f rawvideo -pix_fmt rgba -s 1280x720 -i - "
				"-threads 0 -preset fast -y -crf 19 -pix_fmt yuv420p -tune animation -vf vflip %s";

			char cmd[1024];
			sprintf(cmd, str, buf);

			g_ffmpeg = _popen(cmd, "wb");
			assert(g_ffmpeg);
		}
		else
		{
			_pclose(g_ffmpeg);
			g_ffmpeg = NULL;
		}

		g_capture = !g_capture;
		g_frame = 0;
#endif
		break;
	}
	case 'p':
	{
		g_pause = !g_pause;
		break;
	}
	case 'o':
	{
		g_step = true;
		break;
	}
	case 'h':
	{
		g_showHelp = !g_showHelp;
		break;
	}
	case 'e':
	{
		g_drawEllipsoids = !g_drawEllipsoids;
		break;
	}
	case 't':
	{
		g_drawOpaque = !g_drawOpaque;
		break;
	}
	case 'v':
	{
		g_drawPoints = !g_drawPoints;
		break;
	}
	case 'f':
	{
		g_drawSprings = (g_drawSprings + 1) % 3;
		break;
	}
	case 'i':
	{
		g_drawDiffuse = !g_drawDiffuse;
		break;
	}
	case 'm':
	{
		g_drawMesh = !g_drawMesh;
		break;
	}
	case 'n':
	{
		g_drawRopes = !g_drawRopes;
		break;
	}
	case 'j':
	{
		g_windTime = 0.0f;
		g_windStrength = 1.5f;
		g_windFrequency = 0.2f;
		break;
	}
	case '.':
	{
		g_profile = !g_profile;
		break;
	}
	case 'g':
	{
		if (g_params.gravity[1] != 0.0f)
			g_params.gravity[1] = 0.0f;
		else
			g_params.gravity[1] = -9.8f;

		break;
	}
	case '-':
	{
		if (g_params.numPlanes)
			g_params.numPlanes--;

		break;
	}
	case ' ':
	{
		g_emit = !g_emit;
		break;
	}
	case ';':
	{
		g_debug = !g_debug;
		break;
	}
	case 13:
	{
		g_scene = g_selectedScene;
		Init(g_scene);
		break;
	}
	case 27:
	{
		// return quit = true
		return true;
	}
#if ENABLE_AFTERMATH_SUPPORT
	case 'l':
		DumpAftermathData();
		break;
#endif
	};

	g_scenes[g_scene]->KeyDown(key);

	return false;
}

void InputKeyboardUp(unsigned char key, int x, int y)
{
	switch (key)
	{
	case 'w':
	case 's':
	{
		g_camVel.z = 0.0f;
		break;
	}
	case 'a':
	case 'd':
	{
		g_camVel.x = 0.0f;
		break;
	}
	case 'q':
	case 'z':
	{
		g_camVel.y = 0.0f;
		break;
	}
	};
}

void MouseFunc(int b, int state, int x, int y)
{
	switch (state)
	{
	case SDL_RELEASED:
	{
		g_lastx = x;
		g_lasty = y;
		g_lastb = -1;

		break;
	}
	case SDL_PRESSED:
	{
		g_lastx = x;
		g_lasty = y;
		g_lastb = b;
#ifdef ANDROID
		extern void setStateLeft(bool bLeftDown);
		setStateLeft(false);
#else
		if ((SDL_GetModState() & KMOD_LSHIFT) && g_lastb == SDL_BUTTON_LEFT)
		{
			// record that we need to update the picked particle
			g_mousePicked = true;
		}
#endif
		break;
	}
	};
}

void MousePassiveMotionFunc(int x, int y)
{
	g_lastx = x;
	g_lasty = y;
}

void MouseMotionFunc(unsigned state, int x, int y)
{
	float dx = float(x - g_lastx);
	float dy = float(y - g_lasty);

	g_lastx = x;
	g_lasty = y;

	if (state & SDL_BUTTON_RMASK)
	{
		const float kSensitivity = DegToRad(0.1f);
		const float kMaxDelta = FLT_MAX;

		g_camAngle.x -= Clamp(dx*kSensitivity, -kMaxDelta, kMaxDelta);
		g_camAngle.y -= Clamp(dy*kSensitivity, -kMaxDelta, kMaxDelta);
	}
}

bool g_Error = false;

void ErrorCallback(NvFlexErrorSeverity severity, const char* msg, const char* file, int line)
{
	printf("Flex: %s - %s:%d\n", msg, file, line);
	g_Error = (severity == eNvFlexLogError);
	//assert(0); asserts are bad for TeamCity
}

void ControllerButtonEvent(SDL_ControllerButtonEvent event)
{
	// map controller buttons to keyboard keys
	if (event.type == SDL_CONTROLLERBUTTONDOWN)
	{
		InputKeyboardDown(GetKeyFromGameControllerButton(SDL_GameControllerButton(event.button)), 0, 0);
		InputArrowKeysDown(GetKeyFromGameControllerButton(SDL_GameControllerButton(event.button)), 0, 0);

		if (event.button == SDL_CONTROLLER_BUTTON_LEFT_TRIGGER)
		{
			// Handle picking events using the game controller
			g_lastx = g_screenWidth / 2;
			g_lasty = g_screenHeight / 2;
			g_lastb = 1;

			// record that we need to update the picked particle
			g_mousePicked = true;
		}
	}
	else
	{
		InputKeyboardUp(GetKeyFromGameControllerButton(SDL_GameControllerButton(event.button)), 0, 0);
		InputArrowKeysUp(GetKeyFromGameControllerButton(SDL_GameControllerButton(event.button)), 0, 0);

		if (event.button == SDL_CONTROLLER_BUTTON_LEFT_TRIGGER)
		{
			// Handle picking events using the game controller
			g_lastx = g_screenWidth / 2;
			g_lasty = g_screenHeight / 2;
			g_lastb = -1;
		}
	}
}

void ControllerDeviceUpdate()
{
	if (SDL_NumJoysticks() > 0)
	{
		SDL_JoystickEventState(SDL_ENABLE);
		if (SDL_IsGameController(0))
		{
			g_gamecontroller = SDL_GameControllerOpen(0);
		}
	}
}

void SDLInit(const char* title)
{
	if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_GAMECONTROLLER) < 0)	// Initialize SDL's Video subsystem and game controllers
		printf("Unable to initialize SDL");

	unsigned int flags = SDL_WINDOW_RESIZABLE;
#if !FLEX_DX
	if (g_graphics == 0)
	{
		SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
		flags = SDL_WINDOW_RESIZABLE | SDL_WINDOW_OPENGL;
	}
#endif

	g_window = SDL_CreateWindow(title, SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED,
		g_screenWidth, g_screenHeight, flags);

	g_windowId = SDL_GetWindowID(g_window);
}

void SDLMainLoop()
{
#if ENABLE_AFTERMATH_SUPPORT
	__try
#endif
	{
		bool quit = false;
		SDL_Event e;
		while (!quit)
		{
			UpdateFrame();

			while (SDL_PollEvent(&e))
			{
				switch (e.type)
				{
				case SDL_QUIT:
					quit = true;
					break;

				case SDL_KEYDOWN:
					if (e.key.keysym.sym < 256 && (e.key.keysym.mod == KMOD_NONE || (e.key.keysym.mod & KMOD_NUM)))
						quit = InputKeyboardDown(e.key.keysym.sym, 0, 0);
					InputArrowKeysDown(e.key.keysym.sym, 0, 0);
					break;

				case SDL_KEYUP:
					if (e.key.keysym.sym < 256 && (e.key.keysym.mod == 0 || (e.key.keysym.mod & KMOD_NUM)))
						InputKeyboardUp(e.key.keysym.sym, 0, 0);
					InputArrowKeysUp(e.key.keysym.sym, 0, 0);
					break;

				case SDL_MOUSEMOTION:
					if (e.motion.state)
						MouseMotionFunc(e.motion.state, e.motion.x, e.motion.y);
					else
						MousePassiveMotionFunc(e.motion.x, e.motion.y);
					break;

				case SDL_MOUSEBUTTONDOWN:
				case SDL_MOUSEBUTTONUP:
					MouseFunc(e.button.button, e.button.state, e.motion.x, e.motion.y);
					break;

				case SDL_WINDOWEVENT:
					if (e.window.windowID == g_windowId)
					{
						if (e.window.event == SDL_WINDOWEVENT_SIZE_CHANGED)
							ReshapeWindow(e.window.data1, e.window.data2);
					}
					break;

				case SDL_WINDOWEVENT_LEAVE:
					g_camVel = Vec3(0.0f, 0.0f, 0.0f);
					break;

				case SDL_CONTROLLERBUTTONUP:
				case SDL_CONTROLLERBUTTONDOWN:
					ControllerButtonEvent(e.cbutton);
					break;

				case SDL_JOYDEVICEADDED:
				case SDL_JOYDEVICEREMOVED:
					ControllerDeviceUpdate();
					break;
				}
			}
		}
	}
#if ENABLE_AFTERMATH_SUPPORT
	__except (true)
	{
		DumpAftermathData();
	}
#endif
}

int main(int argc, char* argv[])
{
	// process command line args
	for (int i = 1; i < argc; ++i)
	{
		int d;
		if (sscanf(argv[i], "-device=%d", &d))
			g_device = d;

		if (sscanf(argv[i], "-extensions=%d", &d))
			g_extensions = d != 0;

		if (strcmp(argv[i], "-benchmark") == 0)
		{
			g_benchmark = true;
			g_profile = true;
			g_outputAllFrameTimes = false;
			g_vsync = false;
			g_fullscreen = true;
		}

		if (strcmp(argv[i], "-d3d12") == 0)
		{
			g_d3d12 = true;
			// Currently interop doesn't work on d3d12
			g_interop = false;
		}

		if (strcmp(argv[i], "-benchmarkAllFrameTimes") == 0)
		{
			g_benchmark = true;
			g_outputAllFrameTimes = true;
		}

		if (strcmp(argv[i], "-tc") == 0)
		{
			g_teamCity = true;
		}

		if (sscanf(argv[i], "-msaa=%d", &d))
			g_msaaSamples = d;

		int w = 1280;
		int h = 720;
		if (sscanf(argv[i], "-fullscreen=%dx%d", &w, &h) == 2)
		{
			g_screenWidth = w;
			g_screenHeight = h;
			g_fullscreen = true;
		}
		else if (strcmp(argv[i], "-fullscreen") == 0)
		{
			g_screenWidth = w;
			g_screenHeight = h;
			g_fullscreen = true;
		}

		if (sscanf(argv[i], "-windowed=%dx%d", &w, &h) == 2)
		{
			g_screenWidth = w;
			g_screenHeight = h;
			g_fullscreen = false;
		}
		else if (strstr(argv[i], "-windowed"))
		{
			g_screenWidth = w;
			g_screenHeight = h;
			g_fullscreen = false;
		}

		if (sscanf(argv[i], "-vsync=%d", &d))
			g_vsync = d != 0;

		if (sscanf(argv[i], "-multiplier=%d", &d) == 1)
		{
			g_numExtraMultiplier = d;
		}

		if (strcmp(argv[i], "-disabletweak") == 0)
		{
			g_tweakPanel = false;
		}

		if (strcmp(argv[i], "-disableinterop") == 0)
		{
			g_interop = false;
		}

		if (sscanf(argv[i], "-asynccompute=%d", &d) == 1)
		{
			g_useAsyncCompute = (d != 0);
		}

		if (sscanf(argv[i], "-graphics=%d", &d) == 1)
		{
			if (d >= 0 && d <= 2)
				g_graphics = d;
		}
	}

	// opening scene
	g_scenes.push_back(new PotPourri("Pot Pourri"));

	// soft body scenes
	SoftBody::Instance octopus("../../data/softs/octopus.obj");
	octopus.mScale = Vec3(32.0f);
	octopus.mClusterSpacing = 2.75f;
	octopus.mClusterRadius = 3.0f;
	octopus.mClusterStiffness = 0.15f;
	octopus.mSurfaceSampling = 1.0f;
	SoftBody* softOctopusSceneNew = new SoftBody("Soft Octopus");
	softOctopusSceneNew->AddStack(octopus, 1, 3, 1);

	SoftBody::Instance rope("../../data/rope.obj");
	rope.mScale = Vec3(50.0f);
	rope.mClusterSpacing = 1.5f;
	rope.mClusterRadius = 0.0f;
	rope.mClusterStiffness = 0.55f;
	SoftBody* softRopeSceneNew = new SoftBody("Soft Rope");
	softRopeSceneNew->AddInstance(rope);

	SoftBody::Instance bowl("../../data/bowl_high.ply");
	bowl.mScale = Vec3(10.0f);
	bowl.mClusterSpacing = 2.0f;
	bowl.mClusterRadius = 2.0f;
	bowl.mClusterStiffness = 0.55f;
	SoftBody* softBowlSceneNew = new SoftBody("Soft Bowl");
	softBowlSceneNew->AddInstance(bowl);

	SoftBody::Instance cloth("../../data/box_ultra_high.ply");
	cloth.mScale = Vec3(20.0f, 0.2f, 20.0f);
	cloth.mClusterSpacing = 1.0f;
	cloth.mClusterRadius = 2.0f;
	cloth.mClusterStiffness = 0.2f;
	cloth.mLinkRadius = 2.0f;
	cloth.mLinkStiffness = 1.0f;
	cloth.mSkinningFalloff = 1.0f;
	cloth.mSkinningMaxDistance = 100.f;
	SoftBody* softClothSceneNew = new SoftBody("Soft Cloth");
	softClothSceneNew->mRadius = 0.05f;
	softClothSceneNew->AddInstance(cloth);

	SoftBody::Instance rod("../../data/box_very_high.ply");
	rod.mScale = Vec3(20.0f, 2.0f, 2.0f);
	rod.mTranslation = Vec3(-0.3f, 1.0f, 0.0f);
	rod.mClusterSpacing = 2.0f;
	rod.mClusterRadius = 2.0f;
	rod.mClusterStiffness = 0.225f;
	SoftBodyFixed* softRodSceneNew = new SoftBodyFixed("Soft Rod");
	softRodSceneNew->AddStack(rod, 3);

	SoftBody::Instance teapot("../../data/teapot.ply");
	teapot.mScale = Vec3(25.0f);
	teapot.mClusterSpacing = 3.0f;
	teapot.mClusterRadius = 0.0f;
	teapot.mClusterStiffness = 0.1f;
	SoftBody* softTeapotSceneNew = new SoftBody("Soft Teapot");
	softTeapotSceneNew->AddInstance(teapot);

	SoftBody::Instance armadillo("../../data/armadillo.ply");
	armadillo.mScale = Vec3(25.0f);
	armadillo.mClusterSpacing = 3.0f;
	armadillo.mClusterRadius = 0.0f;
	SoftBody* softArmadilloSceneNew = new SoftBody("Soft Armadillo");
	softArmadilloSceneNew->AddInstance(armadillo);

	SoftBody::Instance softbunny("../../data/bunny.ply");
	softbunny.mScale = Vec3(20.0f);
	softbunny.mClusterSpacing = 3.5f;
	softbunny.mClusterRadius = 0.0f;
	softbunny.mClusterStiffness = 0.2f;
	SoftBody* softBunnySceneNew = new SoftBody("Soft Bunny");
	softBunnySceneNew->AddInstance(softbunny);

	// plastic scenes
	SoftBody::Instance plasticbunny("../../data/bunny.ply");
	plasticbunny.mScale = Vec3(10.0f);
	plasticbunny.mClusterSpacing = 1.0f;
	plasticbunny.mClusterRadius = 0.0f;
	plasticbunny.mClusterStiffness = 0.0f;
	plasticbunny.mGlobalStiffness = 1.0f;
	plasticbunny.mClusterPlasticThreshold = 0.0015f;
	plasticbunny.mClusterPlasticCreep = 0.15f;
	plasticbunny.mTranslation[1] = 5.0f;
	SoftBody* plasticBunniesSceneNew = new SoftBody("Plastic Bunnies");
	plasticBunniesSceneNew->mPlinth = true;
	plasticBunniesSceneNew->AddStack(plasticbunny, 1, 10, 1, true);

	SoftBody::Instance bunny1("../../data/bunny.ply");
	bunny1.mScale = Vec3(10.0f);
	bunny1.mClusterSpacing = 1.0f;
	bunny1.mClusterRadius = 0.0f;
	bunny1.mClusterStiffness = 0.0f;
	bunny1.mGlobalStiffness = 1.0f;
	bunny1.mClusterPlasticThreshold = 0.0015f;
	bunny1.mClusterPlasticCreep = 0.15f;
	bunny1.mTranslation[1] = 5.0f;
	SoftBody::Instance bunny2("../../data/bunny.ply");
	bunny2.mScale = Vec3(10.0f);
	bunny2.mClusterSpacing = 1.0f;
	bunny2.mClusterRadius = 0.0f;
	bunny2.mClusterStiffness = 0.0f;
	bunny2.mGlobalStiffness = 1.0f;
	bunny2.mClusterPlasticThreshold = 0.0015f;
	bunny2.mClusterPlasticCreep = 0.30f;
	bunny2.mTranslation[1] = 5.0f;
	bunny2.mTranslation[0] = 2.0f;
	SoftBody* plasticComparisonScene = new SoftBody("Plastic Comparison");
	plasticComparisonScene->AddInstance(bunny1);
	plasticComparisonScene->AddInstance(bunny2);
	plasticComparisonScene->mPlinth = true;

	SoftBody::Instance stackBox("../../data/box_high.ply");
	stackBox.mScale = Vec3(10.0f);
	stackBox.mClusterSpacing = 1.5f;
	stackBox.mClusterRadius = 0.0f;
	stackBox.mClusterStiffness = 0.0f;
	stackBox.mGlobalStiffness = 1.0f;
	stackBox.mClusterPlasticThreshold = 0.0015f;
	stackBox.mClusterPlasticCreep = 0.25f;
	stackBox.mTranslation[1] = 1.0f;
	SoftBody::Instance stackSphere("../../data/sphere.ply");
	stackSphere.mScale = Vec3(10.0f);
	stackSphere.mClusterSpacing = 1.5f;
	stackSphere.mClusterRadius = 0.0f;
	stackSphere.mClusterStiffness = 0.0f;
	stackSphere.mGlobalStiffness = 1.0f;
	stackSphere.mClusterPlasticThreshold = 0.0015f;
	stackSphere.mClusterPlasticCreep = 0.25f;
	stackSphere.mTranslation[1] = 2.0f;
	SoftBody* plasticStackScene = new SoftBody("Plastic Stack");
	plasticStackScene->AddInstance(stackBox);
	plasticStackScene->AddInstance(stackSphere);
	for (int i = 0; i < 3; i++)
	{
		stackBox.mTranslation[1] += 2.0f;
		stackSphere.mTranslation[1] += 2.0f;
		plasticStackScene->AddInstance(stackBox);
		plasticStackScene->AddInstance(stackSphere);
	}

	g_scenes.push_back(softOctopusSceneNew);
	g_scenes.push_back(softTeapotSceneNew);
	g_scenes.push_back(softRopeSceneNew);
	g_scenes.push_back(softClothSceneNew);
	g_scenes.push_back(softBowlSceneNew);
	g_scenes.push_back(softRodSceneNew);
	g_scenes.push_back(softArmadilloSceneNew);
	g_scenes.push_back(softBunnySceneNew);

	g_scenes.push_back(plasticBunniesSceneNew);
	g_scenes.push_back(plasticComparisonScene);
	g_scenes.push_back(plasticStackScene);

	// collision scenes
	g_scenes.push_back(new FrictionRamp("Friction Ramp"));
	g_scenes.push_back(new FrictionMovingShape("Friction Moving Box", 0));
	g_scenes.push_back(new FrictionMovingShape("Friction Moving Sphere", 1));
	g_scenes.push_back(new FrictionMovingShape("Friction Moving Capsule", 2));
	g_scenes.push_back(new FrictionMovingShape("Friction Moving Mesh", 3));
	g_scenes.push_back(new ShapeCollision("Shape Collision"));
	g_scenes.push_back(new ShapeChannels("Shape Channels"));
	g_scenes.push_back(new TriangleCollision("Triangle Collision"));
	g_scenes.push_back(new LocalSpaceFluid("Local Space Fluid"));
	g_scenes.push_back(new LocalSpaceCloth("Local Space Cloth"));
	g_scenes.push_back(new CCDFluid("World Space Fluid"));

	// cloth scenes
	g_scenes.push_back(new EnvironmentalCloth("Env Cloth Small", 6, 6, 40, 16));
	g_scenes.push_back(new EnvironmentalCloth("Env Cloth Large", 16, 32, 10, 3));
	g_scenes.push_back(new FlagCloth("Flag Cloth"));
	g_scenes.push_back(new Inflatable("Inflatables"));
	g_scenes.push_back(new ClothLayers("Cloth Layers"));
	g_scenes.push_back(new SphereCloth("Sphere Cloth"));
	g_scenes.push_back(new Tearing("Tearing"));
	g_scenes.push_back(new Pasta("Pasta"));

	// game mesh scenes
	g_scenes.push_back(new GameMesh("Game Mesh Rigid", 0));
	g_scenes.push_back(new GameMesh("Game Mesh Particles", 1));
	g_scenes.push_back(new GameMesh("Game Mesh Fluid", 2));
	g_scenes.push_back(new GameMesh("Game Mesh Cloth", 3));
	g_scenes.push_back(new RigidDebris("Rigid Debris"));

	// viscous fluids
	g_scenes.push_back(new Viscosity("Viscosity Low", 0.5f));
	g_scenes.push_back(new Viscosity("Viscosity Med", 3.0f));
	g_scenes.push_back(new Viscosity("Viscosity High", 5.0f, 0.12f));
	g_scenes.push_back(new Adhesion("Adhesion"));
	g_scenes.push_back(new GooGun("Goo Gun", true));

	// regular fluids
	g_scenes.push_back(new Buoyancy("Buoyancy"));
	g_scenes.push_back(new Melting("Melting"));
	g_scenes.push_back(new SurfaceTension("Surface Tension Low", 0.0f));
	g_scenes.push_back(new SurfaceTension("Surface Tension Med", 10.0f));
	g_scenes.push_back(new SurfaceTension("Surface Tension High", 20.0f));
	g_scenes.push_back(new DamBreak("DamBreak  5cm", 0.05f));
	g_scenes.push_back(new DamBreak("DamBreak 10cm", 0.1f));
	g_scenes.push_back(new DamBreak("DamBreak 15cm", 0.15f));
	g_scenes.push_back(new RockPool("Rock Pool"));
	g_scenes.push_back(new RayleighTaylor2D("Rayleigh Taylor 2D"));

	// misc feature scenes
	g_scenes.push_back(new TriggerVolume("Trigger Volume"));
	g_scenes.push_back(new ForceField("Force Field"));
	g_scenes.push_back(new InitialOverlap("Initial Overlap"));

	// rigid body scenes
	g_scenes.push_back(new RigidPile("Rigid2", 2));
	g_scenes.push_back(new RigidPile("Rigid4", 4));
	g_scenes.push_back(new RigidPile("Rigid8", 12));
	g_scenes.push_back(new BananaPile("Bananas"));
	g_scenes.push_back(new LowDimensionalShapes("Low Dimensional Shapes"));

	// granular scenes
	g_scenes.push_back(new GranularPile("Granular Pile"));

	// coupling scenes
	g_scenes.push_back(new ParachutingBunnies("Parachuting Bunnies"));
	g_scenes.push_back(new WaterBalloon("Water Balloons"));
	g_scenes.push_back(new RigidFluidCoupling("Rigid Fluid Coupling"));
	g_scenes.push_back(new FluidBlock("Fluid Block"));
	g_scenes.push_back(new FluidClothCoupling("Fluid Cloth Coupling Water", false));
	g_scenes.push_back(new FluidClothCoupling("Fluid Cloth Coupling Goo", true));
	g_scenes.push_back(new BunnyBath("Bunny Bath Dam", true));

	// init graphics
	RenderInitOptions options;

#ifndef ANDROID
	DemoContext* demoContext = nullptr;
#if FLEX_DX
	// Flex DX demo will always create the renderer using the same DX api as the flex lib
	if (g_d3d12)
	{
		// workaround for a driver issue with D3D12 with msaa, force it to off
		// options.numMsaaSamples = 1;
		g_graphics = 2;
	}
	else
	{
		g_graphics = 1;
	}
#else
	switch (g_graphics)
	{
	case 0: break;
	case 1: break;
	case 2:
		// workaround for a driver issue with D3D12 with msaa, force it to off
		// options.numMsaaSamples = 1;
		// Currently interop doesn't work on d3d12
		g_interop = false;
		break;
	default: assert(0);
	}
#endif
	// Create the demo context
	CreateDemoContext(g_graphics);

	std::string str;
#if FLEX_DX
	if (g_d3d12)
		str = "Flex Demo (Compute: DX12) ";
	else
		str = "Flex Demo (Compute: DX11) ";
#else
	str = "Flex Demo (Compute: CUDA) ";
#endif
	switch (g_graphics)
	{
	case 0:
		str += "(Graphics: OpenGL)";
		break;
	case 1:
		str += "(Graphics: DX11)";
		break;
	case 2:
		str += "(Graphics: DX12)";
		break;
	}
	const char* title = str.c_str();

	SDLInit(title);

	options.window = g_window;
	options.numMsaaSamples = g_msaaSamples;
	options.asyncComputeBenchmark = g_asyncComputeBenchmark;
	options.defaultFontHeight = -1;
	options.fullscreen = g_fullscreen;

	InitRender(options);

	if (g_fullscreen)
		SDL_SetWindowFullscreen(g_window, SDL_WINDOW_FULLSCREEN_DESKTOP);

	ReshapeWindow(g_screenWidth, g_screenHeight);

#endif // ifndef ANDROID

#if _WIN32 && !FLEX_DX
	// use the PhysX GPU selected from the NVIDIA control panel	
	if (g_device == -1)
		g_device = NvFlexDeviceGetSuggestedOrdinal();

	// Create an optimized CUDA context for Flex and set it on the 
	// calling thread. This is an optional call, it is fine to use 
	// a regular CUDA context, although creating one through this API
	// is recommended for best performance.
	bool success = NvFlexDeviceCreateCudaContext(g_device);

	if (!success)
	{
		printf("Error creating CUDA context.\n");
		exit(-1);
	}
#endif

	NvFlexInitDesc desc;
	desc.deviceIndex = g_device;
	desc.enableExtensions = g_extensions;
	desc.renderDevice = 0;
	desc.renderContext = 0;
	desc.computeContext = 0;
	desc.computeType = eNvFlexCUDA;

#if FLEX_DX
	if (g_d3d12)
		desc.computeType = eNvFlexD3D12;
	else
		desc.computeType = eNvFlexD3D11;

	bool userSpecifiedGpuToUseForFlex = (g_device != -1);

	if (userSpecifiedGpuToUseForFlex)
	{
		// Flex doesn't currently support interop between different D3DDevices.
		// If the user specifies which physical device to use, then Flex always 
		// creates its own D3DDevice, even if graphics is on the same physical device.
		// So specified physical device always means no interop.
		g_interop = false;
	}
	else
	{
		// Ask Flex to run on the same GPU as rendering
		GetRenderDevice(&desc.renderDevice,
			&desc.renderContext);
	}

	// Shared resources are unimplemented on D3D12,
	// so disable it for now.
	if (g_d3d12)
		g_interop = false;

	// Setting runOnRenderContext = true doesn't prevent async compute, it just 
	// makes Flex send compute and graphics to the GPU on the same queue.
	//
	// So to allow the user to toggle async compute, we set runOnRenderContext = false
	// and provide a toggleable sync between compute and graphics in the app.
	//
	// Search for g_useAsyncCompute for details
	desc.runOnRenderContext = false;
#else
	// Shared resources are unimplemented on D3D12,
	// so disable it for now.
	if (g_d3d12)
		g_interop = false;
#endif

	// Init Flex library, note that no CUDA methods should be called before this 
	// point to ensure we get the device context we want
	g_flexLib = NvFlexInit(NV_FLEX_VERSION, ErrorCallback, &desc);

	if (g_Error || g_flexLib == NULL)
	{
		printf("Could not initialize Flex, exiting.\n");
		exit(-1);
	}

	// store device name
	strcpy(g_deviceName, NvFlexGetDeviceName(g_flexLib));
	printf("Compute Device: %s\n\n", g_deviceName);

	if (g_benchmark)
		g_scene = BenchmarkInit();

	// create shadow maps
	g_shadowMap = ShadowCreate();

	// init default scene
	StartGpuWork();
	Init(g_scene);
	EndGpuWork();

	SDLMainLoop();

	if (g_fluidRenderer)
		DestroyFluidRenderer(g_fluidRenderer);

	DestroyFluidRenderBuffers(g_fluidRenderBuffers);
	DestroyDiffuseRenderBuffers(g_diffuseRenderBuffers);

	ShadowDestroy(g_shadowMap);

	Shutdown();
	DestroyRender();

	SDL_DestroyWindow(g_window);
	SDL_Quit();

	return 0;
}