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// ****************************************************************************
// This snippet illustrates simple use of physx
//
// It creates a number of box stacks on a plane, and if rendering, allows the
// user to create new stacks and fire a ball from the camera position
// ****************************************************************************

#include <ctype.h>

#include "PxPhysicsAPI.h"

#include "../snippetcommon/SnippetPrint.h"
#include "../snippetcommon/SnippetPVD.h"
#include "../snippetutils/SnippetUtils.h"


using namespace physx;

PxDefaultAllocator		gAllocator;
PxDefaultErrorCallback	gErrorCallback;

PxFoundation*			gFoundation = NULL;
PxPhysics*				gPhysics	= NULL;

PxDefaultCpuDispatcher*	gDispatcher = NULL;
PxScene*				gScene		= NULL;

PxMaterial*				gMaterial	= NULL;

PxPvd*                  gPvd = NULL;

PxCudaContextManager* gCudaContextManager = NULL;

PxReal stackZ = 10.0f;

PxRigidDynamic* createDynamic(const PxTransform& t, const PxGeometry& geometry, const PxVec3& velocity=PxVec3(0))
{
	PxRigidDynamic* dynamic = PxCreateDynamic(*gPhysics, t, geometry, *gMaterial, 10.0f);
	dynamic->setAngularDamping(0.5f);
	dynamic->setLinearVelocity(velocity);
	gScene->addActor(*dynamic);
	return dynamic;
}

void createStack(const PxTransform& t, PxU32 size, PxReal halfExtent)
{
	PxShape* shape = gPhysics->createShape(PxBoxGeometry(halfExtent, halfExtent, halfExtent), *gMaterial);
	for(PxU32 i=0; i<size;i++)
	{
		for(PxU32 j=0;j<size-i;j++)
		{
			PxTransform localTm(PxVec3(PxReal(j*2) - PxReal(size-i), PxReal(i*2+1), 0) * halfExtent);
			PxRigidDynamic* body = gPhysics->createRigidDynamic(t.transform(localTm));
			body->attachShape(*shape);
			PxRigidBodyExt::updateMassAndInertia(*body, 10.0f);
			gScene->addActor(*body);
		}
	}
	shape->release();
}

void initPhysics(bool /*interactive*/)
{
	gFoundation = PxCreateFoundation(PX_PHYSICS_VERSION, gAllocator, gErrorCallback);
	gPvd = PxCreatePvd(*gFoundation);
	PxPvdTransport* transport = PxDefaultPvdSocketTransportCreate(PVD_HOST, 5425, 10);
	gPvd->connect(*transport, PxPvdInstrumentationFlag::ePROFILE);

	gPhysics = PxCreatePhysics(PX_PHYSICS_VERSION, *gFoundation, PxTolerancesScale(), true, gPvd);
	
	PxCudaContextManagerDesc cudaContextManagerDesc;

#ifdef RENDER_SNIPPET
	cudaContextManagerDesc.interopMode = PxCudaInteropMode::OGL_INTEROP;	//Choose interop mode. As the snippets use OGL, we select OGL_INTEROP
																			//when using D3D, cudaContextManagerDesc.graphicsDevice must be set as the graphics device pointer.
#else
	cudaContextManagerDesc.interopMode = PxCudaInteropMode::NO_INTEROP;
#endif
	

	gCudaContextManager = PxCreateCudaContextManager(*gFoundation, cudaContextManagerDesc, PxGetProfilerCallback());	//Create the CUDA context manager, required for GRB to dispatch CUDA kernels.
	if( gCudaContextManager )
	{
		if( !gCudaContextManager->contextIsValid() )
		{
			gCudaContextManager->release();
			gCudaContextManager = NULL;
		}
	}	

	PxSceneDesc sceneDesc(gPhysics->getTolerancesScale());
	sceneDesc.gravity = PxVec3(0.0f, -9.81f, 0.0f);
	gDispatcher = PxDefaultCpuDispatcherCreate(4);			//Create a CPU dispatcher using 4 worther threads
	sceneDesc.cpuDispatcher	= gDispatcher;
	sceneDesc.filterShader	= PxDefaultSimulationFilterShader;

	sceneDesc.cudaContextManager = gCudaContextManager;		//Set the CUDA context manager, used by GRB.

	sceneDesc.flags |= PxSceneFlag::eENABLE_GPU_DYNAMICS;	//Enable GPU dynamics - without this enabled, simulation (contact gen and solver) will run on the CPU.
	sceneDesc.flags |= PxSceneFlag::eENABLE_PCM;			//Enable PCM. PCM NP is supported on GPU. Legacy contact gen will fall back to CPU
	sceneDesc.flags |= PxSceneFlag::eENABLE_STABILIZATION;	//Improve solver stability by enabling post-stabilization.
	sceneDesc.broadPhaseType = PxBroadPhaseType::eGPU;		//Enable GPU broad phase. Without this set, broad phase will run on the CPU.
	sceneDesc.gpuMaxNumPartitions = 8;						//Defines the maximum number of partitions used by the solver. Only power-of-2 values are valid. 
															//A value of 8 generally gives best balance between performance and stability.

	gScene = gPhysics->createScene(sceneDesc);


	PxPvdSceneClient* pvdClient = gScene->getScenePvdClient();
	if (pvdClient)
	{
		pvdClient->setScenePvdFlag(PxPvdSceneFlag::eTRANSMIT_CONSTRAINTS, false);
		pvdClient->setScenePvdFlag(PxPvdSceneFlag::eTRANSMIT_CONTACTS, false);
		pvdClient->setScenePvdFlag(PxPvdSceneFlag::eTRANSMIT_SCENEQUERIES, false);
	}



	gMaterial = gPhysics->createMaterial(0.5f, 0.5f, 0.6f);

	PxRigidStatic* groundPlane = PxCreatePlane(*gPhysics, PxPlane(0,1,0,0), *gMaterial);
	gScene->addActor(*groundPlane);

	for(PxU32 i=0;i<40;i++)
		createStack(PxTransform(PxVec3(0,0,stackZ-=10.0f)), 20, 1.0f);

	PxRigidDynamic* ball = createDynamic(PxTransform(PxVec3(0,20,100)), PxSphereGeometry(5), PxVec3(0,-25,-100));
	PxRigidBodyExt::updateMassAndInertia(*ball, 1000.f);
}

void stepPhysics(bool /*interactive*/)
{
	gScene->simulate(1.0f/60.0f);
	gScene->fetchResults(true);
}
	
void cleanupPhysics(bool /*interactive*/)
{
	PX_RELEASE(gScene);
	PX_RELEASE(gDispatcher);
	PX_RELEASE(gPhysics);

	if(gPvd)
	{
		PxPvdTransport* transport = gPvd->getTransport();
		gPvd->release();	gPvd = NULL;
		PX_RELEASE(transport);
	}

	PX_RELEASE(gCudaContextManager);
	PX_RELEASE(gFoundation);
	
	printf("SnippetHelloWorld done.\n");
}

void keyPress(const char key, const PxTransform& camera)
{
	switch(toupper(key))
	{
	case 'B':	createStack(PxTransform(PxVec3(0,0,stackZ-=10.0f)), 10, 2.0f);						break;
	case ' ':	createDynamic(camera, PxSphereGeometry(3.0f), camera.rotate(PxVec3(0,0,-1))*200);	break;
	}
}

int snippetMain(int, const char*const*)
{
#ifdef RENDER_SNIPPET
	extern void renderLoop();
	renderLoop();
#else
	static const PxU32 frameCount = 100;
	initPhysics(false);
	for(PxU32 i=0; i<frameCount; i++)
		stepPhysics(false);
	cleanupPhysics(false);
#endif

	return 0;
}