Hair Class Reference

#include <Hair.h>

Inheritance diagram for Hair:

Classes
struct	DrawSettings
struct	LeafShape
struct	UpdateContext

Public Types
enum class	ERenderStrandColor {   PerRenderStrand , PerSimulatedStrand , GravityFactor , WorldTransformInfluence ,   GridVelocityFactor , GlobalPose , SkinGlobalPose }
using	RenderPositionsToFloat3 = std::function<void(ComputeBuffer *, Float3 *, uint)>
	Function that converts the render positions buffer to Float3 vertices for debugging purposes. It maps an application defined format to Float3. Third parameter is the number of vertices.

Public Member Functions
	Hair (const HairSettings *inSettings, RVec3Arg inPosition, QuatArg inRotation, ObjectLayer inLayer)
	Constructor / destructor.
	~Hair ()
void	Init (ComputeSystem *inComputeSystem)
	Initialize.
void	SetPosition (RVec3Arg inPosition)
	Position and rotation of the hair in world space.
void	SetRotation (QuatArg inRotation)
RMat44	GetWorldTransform () const
void	OnTeleported ()
	The hair will be initialized in its default pose with zero velocity at the new position and rotation during the next update.
void	SetScalpVerticesCB (ComputeBuffer *inBuffer)
	Ability to externally provide the scalp vertices buffer. This allows skipping skinning the scalp during the simulation update. You may need to override JPH_SHADER_BIND_SCALP_VERTICES in HairSkinRootsBindings.h to match the format of the provided buffer.
void	SetScalpTrianglesCB (ComputeBuffer *inBuffer)
	Ability to externally provide the scalp triangle indices buffer. This allows skipping skinning the scalp in during the simulation update. You may need to override JPH_SHADER_BIND_SCALP_TRIANGLES in HairSkinRootsBindings.h to match the format of the provided buffer.
void	SetScalpToHead (Mat44Arg inMat)
	When skipping skinning, this allow specifying a transform that transforms the scalp mesh into head space.
void	OverrideRenderPositionsCB (const RenderPositionsToFloat3 &inRenderPositionsToFloat3)
	Enable externally set render vertices buffer (with potentially different vertex layout). Note that this also requires replacing the HairCalculateRenderPositions shader.
void	SetRenderPositionsCB (ComputeBuffer *inBuffer)
	Allow setting the render vertices buffer externally in case it has special requirements for the calling application. You may need to override JPH_SHADER_BIND_RENDER_POSITIONS in HairCalculateRenderPositionsBindings.h to match the format of the provided buffer.
void	Update (float inDeltaTime, Mat44Arg inJointToHair, const Mat44 *inJointMatrices, const PhysicsSystem &inSystem, const HairShaders &inShaders, ComputeSystem *inComputeSystem, ComputeQueue *inComputeQueue)
ComputeBuffer *	GetScalpVerticesCB () const
	Access to the resulting simulation data.
ComputeBuffer *	GetScalpTrianglesCB () const
	Skinned scalp triangle indices.
ComputeBuffer *	GetPositionsCB () const
	Note transposed for better memory access.
ComputeBuffer *	GetVelocitiesCB () const
	Note transposed for better memory access.
ComputeBuffer *	GetVelocityAndDensityCB () const
	Velocity grid.
ComputeBuffer *	GetRenderPositionsCB () const
	Render positions of the hair strands (see HairSettings::mRenderStrands to see where each strand starts and ends)
void	ReadBackGPUState (ComputeQueue *inComputeQueue)
	Read back the GPU state so that the functions below can be used. For debugging purposes only, this is slow!
void	LockReadBackBuffers ()
	Lock/unlock the data buffers so that the functions below return valid values.
void	UnlockReadBackBuffers ()
const Float3 *	GetScalpVertices () const
	Access to the resulting simulation data (only valid when ReadBackGPUState has been called and the buffers have been locked)
const Float3 *	GetPositions () const
const Quat *	GetRotations () const
StridedPtr< const Float3 >	GetVelocities () const
StridedPtr< const Float3 >	GetAngularVelocities () const
const Float4 *	GetGridVelocityAndDensity () const
const Float3 *	GetRenderPositions () const
void	Draw (const DrawSettings &inSettings, DebugRenderer *inRenderer)
	Debug functionality to draw the hair and its simulation properties.
Public Member Functions inherited from NonCopyable
	NonCopyable ()=default
	NonCopyable (const NonCopyable &)=delete
void	operator= (const NonCopyable &)=delete

Protected Types
using	Gradient = HairSettings::Gradient
using	GradientSampler = HairSettings::GradientSampler

Protected Member Functions
void	InitializeContext (UpdateContext &outCtx, float inDeltaTime, const PhysicsSystem &inSystem)

Protected Attributes
RefConst< HairSettings >	mSettings
RVec3	mPrevPosition
RVec3	mPosition
Quat	mPrevRotation
Quat	mRotation
bool	mTeleported = true
ObjectLayer	mLayer
Mat44	mScalpToHead = Mat44::sIdentity()
bool	mRenderPositionsOverridden = false
RenderPositionsToFloat3	mRenderPositionsToFloat3
Ref< ComputeBuffer >	mScalpJointMatricesCB
Ref< ComputeBuffer >	mScalpVerticesCB
Ref< ComputeBuffer >	mScalpTrianglesCB
Ref< ComputeBuffer >	mTargetPositionsCB
Ref< ComputeBuffer >	mTargetGlobalPoseTransformsCB
Ref< ComputeBuffer >	mGlobalPoseTransformsCB
Ref< ComputeBuffer >	mShapePlanesCB
Ref< ComputeBuffer >	mShapeVerticesCB
Ref< ComputeBuffer >	mShapeIndicesCB
Ref< ComputeBuffer >	mCollisionPlanesCB
Ref< ComputeBuffer >	mCollisionShapesCB
Ref< ComputeBuffer >	mMaterialsCB
Ref< ComputeBuffer >	mPreviousPositionsCB
Ref< ComputeBuffer >	mPositionsCB
Ref< ComputeBuffer >	mVelocitiesCB
Ref< ComputeBuffer >	mVelocityAndDensityCB
Ref< ComputeBuffer >	mConstantsCB
Array< Ref< ComputeBuffer > >	mIterationConstantsCB
Ref< ComputeBuffer >	mRenderPositionsCB
Ref< ComputeBuffer >	mScalpVerticesReadBackCB
Ref< ComputeBuffer >	mPositionsReadBackCB
Ref< ComputeBuffer >	mVelocitiesReadBackCB
Ref< ComputeBuffer >	mVelocityAndDensityReadBackCB
Ref< ComputeBuffer >	mRenderPositionsReadBackCB
const Float3 *	mScalpVertices = nullptr
Float3 *	mPositions = nullptr
Quat *	mRotations = nullptr
JPH_HairVelocity *	mVelocities = nullptr
const Float4 *	mVelocityAndDensity = nullptr
const Float3 *	mRenderPositions = nullptr

Detailed Description

Hair simulation instance

Note that this system is currently still in development, it is missing important features like:

• Level of detail
• Wind forces
• Advection step for the grid velocity field
• Support for collision detection against shapes other than ConvexHullShape
• The Gradient class is very limited and will be replaced by a texture lookup
• Gravity preload factor is not fully functioning yet
• It is wasteful of memory (e.g. stores everything both on CPU and GPU)
• Only supports a single neutral pose to drive towards
• It could use further optimizations

Member Typedef Documentation

Gradient

using Hair::Gradient = HairSettings::Gradient

protected

GradientSampler

using Hair::GradientSampler = HairSettings::GradientSampler

protected

RenderPositionsToFloat3

using Hair::RenderPositionsToFloat3 = std::function<void(ComputeBuffer *, Float3 *, uint)>

Function that converts the render positions buffer to Float3 vertices for debugging purposes. It maps an application defined format to Float3. Third parameter is the number of vertices.

Member Enumeration Documentation

ERenderStrandColor

enum class Hair::ERenderStrandColor

strong

Enumerator
PerRenderStrand
PerSimulatedStrand
GravityFactor
WorldTransformInfluence
GridVelocityFactor
GlobalPose
SkinGlobalPose

Constructor & Destructor Documentation

Hair()

JPH_NAMESPACE_BEGIN Hair::Hair	(	const HairSettings *	inSettings,
		RVec3Arg	inPosition,
		QuatArg	inRotation,
		ObjectLayer	inLayer )

Constructor / destructor.

~Hair()

Hair::~Hair

(

)

Member Function Documentation

Draw()

void Hair::Draw	(	const DrawSettings &	inSettings,
		DebugRenderer *	inRenderer )

Debug functionality to draw the hair and its simulation properties.

GetAngularVelocities()

StridedPtr< const Float3 > Hair::GetAngularVelocities ( ) const

inline

GetGridVelocityAndDensity()

const Float4 * Hair::GetGridVelocityAndDensity ( ) const

inline

GetPositions()

const Float3 * Hair::GetPositions ( ) const

inline

GetPositionsCB()

ComputeBuffer * Hair::GetPositionsCB ( ) const

inline

Note transposed for better memory access.

GetRenderPositions()

const Float3 * Hair::GetRenderPositions ( ) const

inline

GetRenderPositionsCB()

ComputeBuffer * Hair::GetRenderPositionsCB ( ) const

inline

Render positions of the hair strands (see HairSettings::mRenderStrands to see where each strand starts and ends)

GetRotations()

const Quat * Hair::GetRotations ( ) const

inline

GetScalpTrianglesCB()

ComputeBuffer * Hair::GetScalpTrianglesCB ( ) const

inline

Skinned scalp triangle indices.

GetScalpVertices()

const Float3 * Hair::GetScalpVertices ( ) const

inline

Access to the resulting simulation data (only valid when ReadBackGPUState has been called and the buffers have been locked)

GetScalpVerticesCB()

ComputeBuffer * Hair::GetScalpVerticesCB ( ) const

inline

Access to the resulting simulation data.

Skinned scalp vertices

GetVelocities()

StridedPtr< const Float3 > Hair::GetVelocities ( ) const

inline

GetVelocitiesCB()

ComputeBuffer * Hair::GetVelocitiesCB ( ) const

inline

Note transposed for better memory access.

GetVelocityAndDensityCB()

ComputeBuffer * Hair::GetVelocityAndDensityCB ( ) const

inline

Velocity grid.

GetWorldTransform()

RMat44 Hair::GetWorldTransform ( ) const

inline

Init()

void Hair::Init

(

ComputeSystem *

inComputeSystem

)

Initialize.

InitializeContext()

void Hair::InitializeContext ( UpdateContext & outCtx, float inDeltaTime, const PhysicsSystem & inSystem )

protected

LockReadBackBuffers()

void Hair::LockReadBackBuffers

(

)

Lock/unlock the data buffers so that the functions below return valid values.

OnTeleported()

void Hair::OnTeleported ( )

inline

The hair will be initialized in its default pose with zero velocity at the new position and rotation during the next update.

OverrideRenderPositionsCB()

void Hair::OverrideRenderPositionsCB ( const RenderPositionsToFloat3 & inRenderPositionsToFloat3 )

inline

Enable externally set render vertices buffer (with potentially different vertex layout). Note that this also requires replacing the HairCalculateRenderPositions shader.

ReadBackGPUState()

void Hair::ReadBackGPUState

(

ComputeQueue *

inComputeQueue

)

Read back the GPU state so that the functions below can be used. For debugging purposes only, this is slow!

SetPosition()

void Hair::SetPosition ( RVec3Arg inPosition )

inline

Position and rotation of the hair in world space.

SetRenderPositionsCB()

void Hair::SetRenderPositionsCB ( ComputeBuffer * inBuffer )

inline

Allow setting the render vertices buffer externally in case it has special requirements for the calling application. You may need to override JPH_SHADER_BIND_RENDER_POSITIONS in HairCalculateRenderPositionsBindings.h to match the format of the provided buffer.

SetRotation()

void Hair::SetRotation ( QuatArg inRotation )

inline

SetScalpToHead()

void Hair::SetScalpToHead ( Mat44Arg inMat )

inline

When skipping skinning, this allow specifying a transform that transforms the scalp mesh into head space.

SetScalpTrianglesCB()

void Hair::SetScalpTrianglesCB ( ComputeBuffer * inBuffer )

inline

Ability to externally provide the scalp triangle indices buffer. This allows skipping skinning the scalp in during the simulation update. You may need to override JPH_SHADER_BIND_SCALP_TRIANGLES in HairSkinRootsBindings.h to match the format of the provided buffer.

SetScalpVerticesCB()

void Hair::SetScalpVerticesCB ( ComputeBuffer * inBuffer )

inline

Ability to externally provide the scalp vertices buffer. This allows skipping skinning the scalp during the simulation update. You may need to override JPH_SHADER_BIND_SCALP_VERTICES in HairSkinRootsBindings.h to match the format of the provided buffer.

UnlockReadBackBuffers()

void Hair::UnlockReadBackBuffers

(

)

Update()

void Hair::Update	(	float	inDeltaTime,
		Mat44Arg	inJointToHair,
		const Mat44 *	inJointMatrices,
		const PhysicsSystem &	inSystem,
		const HairShaders &	inShaders,
		ComputeSystem *	inComputeSystem,
		ComputeQueue *	inComputeQueue )

Step the hair simulation forward in time

Parameters

inDeltaTime	Time step
inJointToHair	Transform that transforms from joint space to hair local space (as defined by GetWorldTransform)
inJointMatrices	Array of joint matrices in world space, length needs to match HairSettings::mScalpInverseBindPose.size()
inSystem	Physics system used for collision detection
inShaders	Preloaded hair compute shaders
inComputeSystem	Compute system to use
inComputeQueue	Compute queue to use

Member Data Documentation

mCollisionPlanesCB

Ref<ComputeBuffer> Hair::mCollisionPlanesCB

protected

mCollisionShapesCB

Ref<ComputeBuffer> Hair::mCollisionShapesCB

protected

mConstantsCB

Ref<ComputeBuffer> Hair::mConstantsCB

protected

mGlobalPoseTransformsCB

Ref<ComputeBuffer> Hair::mGlobalPoseTransformsCB

protected

mIterationConstantsCB

Array<Ref<ComputeBuffer> > Hair::mIterationConstantsCB

protected

mLayer

ObjectLayer Hair::mLayer

protected

mMaterialsCB

Ref<ComputeBuffer> Hair::mMaterialsCB

protected

mPosition

RVec3 Hair::mPosition

protected

mPositions

Float3* Hair::mPositions = nullptr

protected

mPositionsCB

Ref<ComputeBuffer> Hair::mPositionsCB

protected

mPositionsReadBackCB

Ref<ComputeBuffer> Hair::mPositionsReadBackCB

protected

mPreviousPositionsCB

Ref<ComputeBuffer> Hair::mPreviousPositionsCB

protected

mPrevPosition

RVec3 Hair::mPrevPosition

protected

mPrevRotation

Quat Hair::mPrevRotation

protected

mRenderPositions

const Float3* Hair::mRenderPositions = nullptr

protected

mRenderPositionsCB

Ref<ComputeBuffer> Hair::mRenderPositionsCB

protected

mRenderPositionsOverridden

bool Hair::mRenderPositionsOverridden = false

protected

mRenderPositionsReadBackCB

Ref<ComputeBuffer> Hair::mRenderPositionsReadBackCB

protected

mRenderPositionsToFloat3

RenderPositionsToFloat3 Hair::mRenderPositionsToFloat3

protected

mRotation

Quat Hair::mRotation

protected

mRotations

Quat* Hair::mRotations = nullptr

protected

mScalpJointMatricesCB

Ref<ComputeBuffer> Hair::mScalpJointMatricesCB

protected

mScalpToHead

Mat44 Hair::mScalpToHead = Mat44::sIdentity()

protected

mScalpTrianglesCB

Ref<ComputeBuffer> Hair::mScalpTrianglesCB

protected

mScalpVertices

const Float3* Hair::mScalpVertices = nullptr

protected

mScalpVerticesCB

Ref<ComputeBuffer> Hair::mScalpVerticesCB

protected

mScalpVerticesReadBackCB

Ref<ComputeBuffer> Hair::mScalpVerticesReadBackCB

protected

mSettings

RefConst<HairSettings> Hair::mSettings

protected

mShapeIndicesCB

Ref<ComputeBuffer> Hair::mShapeIndicesCB

protected

mShapePlanesCB

Ref<ComputeBuffer> Hair::mShapePlanesCB

protected

mShapeVerticesCB

Ref<ComputeBuffer> Hair::mShapeVerticesCB

protected

mTargetGlobalPoseTransformsCB

Ref<ComputeBuffer> Hair::mTargetGlobalPoseTransformsCB

protected

mTargetPositionsCB

Ref<ComputeBuffer> Hair::mTargetPositionsCB

protected

mTeleported

bool Hair::mTeleported = true

protected

mVelocities

JPH_HairVelocity* Hair::mVelocities = nullptr

protected

mVelocitiesCB

Ref<ComputeBuffer> Hair::mVelocitiesCB

protected

mVelocitiesReadBackCB

Ref<ComputeBuffer> Hair::mVelocitiesReadBackCB

protected

mVelocityAndDensity

const Float4* Hair::mVelocityAndDensity = nullptr

protected

mVelocityAndDensityCB

Ref<ComputeBuffer> Hair::mVelocityAndDensityCB

protected

mVelocityAndDensityReadBackCB

Ref<ComputeBuffer> Hair::mVelocityAndDensityReadBackCB

protected

---

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

• Jolt/Physics/Hair/Hair.h
• Jolt/Physics/Hair/Hair.cpp