LargeIslandSplitter Class Reference

#include <LargeIslandSplitter.h>

Inheritance diagram for LargeIslandSplitter:

Classes
struct	Split
	Describes a split of constraints and contacts. More...
class	Splits
	Structure that describes the resulting splits from the large island splitter. More...

Public Types
enum class	EStatus { WaitingForBatch , BatchRetrieved , AllBatchesDone }
	Status code for retrieving a batch. More...

Public Member Functions
	~LargeIslandSplitter ()
	Destructor.
void	Prepare (const IslandBuilder &inIslandBuilder, uint32 inNumActiveBodies, TempAllocator *inTempAllocator)
	Prepare the island splitter by allocating memory.
uint	AssignSplit (const Body *inBody1, const Body *inBody2)
	Assign two bodies to a split. Returns the split index.
uint	AssignToNonParallelSplit (const Body *inBody)
	Force a body to be in a non parallel split. Returns the split index.
bool	SplitIsland (uint32 inIslandIndex, const IslandBuilder &inIslandBuilder, const BodyManager &inBodyManager, const ContactConstraintManager &inContactManager, Constraint **inActiveConstraints, int inNumVelocitySteps, int inNumPositionSteps)
	Splits up an island, the created splits will be added to the list of batches and can be fetched with FetchNextBatch. Returns false if the island did not need splitting.
EStatus	FetchNextBatch (uint &outSplitIslandIndex, uint32 *&outConstraintsBegin, uint32 *&outConstraintsEnd, uint32 *&outContactsBegin, uint32 *&outContactsEnd, bool &outFirstIteration)
	Fetch the next batch to process, returns a handle in outSplitIslandIndex that must be provided to MarkBatchProcessed when complete.
void	MarkBatchProcessed (uint inSplitIslandIndex, const uint32 *inConstraintsBegin, const uint32 *inConstraintsEnd, const uint32 *inContactsBegin, const uint32 *inContactsEnd, bool &outLastIteration, bool &outFinalBatch)
	Mark a batch as processed.
uint32	GetIslandIndex (uint inSplitIslandIndex) const
	Get the island index of the island that was split for a particular split island index.
void	PrepareForSolvePositions ()
	Prepare the island splitter for iterating over the split islands again for position solving. Marks all batches as startable.
void	Reset (TempAllocator *inTempAllocator)
	Reset the island splitter.
Public Member Functions inherited from NonCopyable
	NonCopyable ()=default
	NonCopyable (const NonCopyable &)=delete
void	operator= (const NonCopyable &)=delete

Static Public Attributes
static constexpr uint	cNumSplits = sizeof(SplitMask) * 8
static constexpr uint	cNonParallelSplitIdx = cNumSplits - 1
static constexpr uint	cLargeIslandTreshold = 128
	If the number of constraints + contacts in an island is larger than this, we will try to split the island.

Detailed Description

Assigns bodies in large islands to multiple groups that can run in parallel

This basically implements what is described in: High-Performance Physical Simulations on Next-Generation Architecture with Many Cores by Chen et al. See: http://web.eecs.umich.edu/~msmelyan/papers/physsim_onmanycore_itj.pdf section "PARALLELIZATION METHODOLOGY"

Member Enumeration Documentation

EStatus

enum class LargeIslandSplitter::EStatus

strong

Status code for retrieving a batch.

Enumerator
WaitingForBatch	Work is expected to be available later.
BatchRetrieved	Work is being returned.
AllBatchesDone	No further work is expected from this.

Constructor & Destructor Documentation

~LargeIslandSplitter()

LargeIslandSplitter::~LargeIslandSplitter

(

)

Destructor.

Member Function Documentation

AssignSplit()

uint LargeIslandSplitter::AssignSplit	(	const Body *	inBody1,
		const Body *	inBody2 )

Assign two bodies to a split. Returns the split index.

AssignToNonParallelSplit()

uint LargeIslandSplitter::AssignToNonParallelSplit

(

const Body *

inBody

)

Force a body to be in a non parallel split. Returns the split index.

FetchNextBatch()

LargeIslandSplitter::EStatus LargeIslandSplitter::FetchNextBatch	(	uint &	outSplitIslandIndex,
		uint32 *&	outConstraintsBegin,
		uint32 *&	outConstraintsEnd,
		uint32 *&	outContactsBegin,
		uint32 *&	outContactsEnd,
		bool &	outFirstIteration )

Fetch the next batch to process, returns a handle in outSplitIslandIndex that must be provided to MarkBatchProcessed when complete.

GetIslandIndex()

uint32 LargeIslandSplitter::GetIslandIndex ( uint inSplitIslandIndex ) const

inline

Get the island index of the island that was split for a particular split island index.

MarkBatchProcessed()

void LargeIslandSplitter::MarkBatchProcessed	(	uint	inSplitIslandIndex,
		const uint32 *	inConstraintsBegin,
		const uint32 *	inConstraintsEnd,
		const uint32 *	inContactsBegin,
		const uint32 *	inContactsEnd,
		bool &	outLastIteration,
		bool &	outFinalBatch )

Mark a batch as processed.

Prepare()

void LargeIslandSplitter::Prepare	(	const IslandBuilder &	inIslandBuilder,
		uint32	inNumActiveBodies,
		TempAllocator *	inTempAllocator )

Prepare the island splitter by allocating memory.

PrepareForSolvePositions()

void LargeIslandSplitter::PrepareForSolvePositions

(

)

Prepare the island splitter for iterating over the split islands again for position solving. Marks all batches as startable.

Reset()

void LargeIslandSplitter::Reset

(

TempAllocator *

inTempAllocator

)

Reset the island splitter.

SplitIsland()

bool LargeIslandSplitter::SplitIsland	(	uint32	inIslandIndex,
		const IslandBuilder &	inIslandBuilder,
		const BodyManager &	inBodyManager,
		const ContactConstraintManager &	inContactManager,
		Constraint **	inActiveConstraints,
		int	inNumVelocitySteps,
		int	inNumPositionSteps )

Splits up an island, the created splits will be added to the list of batches and can be fetched with FetchNextBatch. Returns false if the island did not need splitting.

Member Data Documentation

cLargeIslandTreshold

constexpr uint LargeIslandSplitter::cLargeIslandTreshold = 128

staticconstexpr

If the number of constraints + contacts in an island is larger than this, we will try to split the island.

cNonParallelSplitIdx

constexpr uint LargeIslandSplitter::cNonParallelSplitIdx = cNumSplits - 1

staticconstexpr

cNumSplits

constexpr uint LargeIslandSplitter::cNumSplits = sizeof(SplitMask) * 8

staticconstexpr

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The documentation for this class was generated from the following files:

• Jolt/Physics/LargeIslandSplitter.h
• Jolt/Physics/LargeIslandSplitter.cpp