Base class for volume primitives in mantra. More...

#include <VGEO_Volume.h>

Inheritance diagram for VGEO_Volume:

Classes
class	DiscreteRayMarcher
	Utility class to perform numerically safe ray marching. More...

class	HitList

Public Member Functions
	VGEO_Volume ()

virtual	~VGEO_Volume ()

virtual float	getNativeStepSize () const =0

virtual void	getBoxes (UT_Array< UT_BoundingBox > &boxes, float radius, float dbound, float zerothreshold) const =0

virtual void	getAttributeBinding (UT_StringArray &names, UT_IntArray &sizes) const =0

virtual void	evaluate (const UT_Vector3 &pos, const UT_Filter &filter, float radius, float time, int idx, float *data) const =0

virtual void	evaluateMulti (const UT_Vector3 pos, const UT_Filter &filter, float radius, const float time, int idx, float *data, int size, int stride) const

virtual bool	evaluateInterval (const UT_BoundingBox &box, const UT_Filter &filter, float radius, float time, int idx, float minval, float maxval) const

virtual void	intersectIsosurface (const VGEO_Ray &ray, const UT_Filter &filter, float radius, float time, int idx, float threshold, HitList &hits) const

virtual void	intersectVolume (const VGEO_Ray &ray, HitList &hits) const

virtual UT_Vector3	gradient (const UT_Vector3 &pos, const UT_Filter &filter, float radius, float time, int idx) const

virtual float	getGradientDelta () const
	Returns a local distance for use in default gradient calculations. More...

virtual int	getNormalAttribute () const

virtual float	getVoxelSize () const
	Returns the voxel size in the same space as 'pos' in evaluate. More...

virtual bool	isSDF () const
	Returns true when the volume data should be interpreted as an SDF. More...


virtual GA_Offset	getGeoPrimitive () const

virtual GA_Offset	getGeoVertex () const

Public Member Functions inherited from UT_IntrusiveRefCounter< VGEO_Volume >
SYS_FORCE_INLINE	UT_IntrusiveRefCounter () noexcept
	Default constructor: Sets counter to 0. More...

SYS_FORCE_INLINE	UT_IntrusiveRefCounter (const UT_IntrusiveRefCounter &) noexcept
	Copy constructor: Sets counter to 0. More...

UT_IntrusiveRefCounter &	operator= (const UT_IntrusiveRefCounter &) noexcept
	Assignment operator: Does not modify counter. More...

SYS_FORCE_INLINE uint32	use_count () const noexcept
	Return current counter. More...

SYS_FORCE_INLINE bool	conditionalAddRef () noexcept

Static Public Member Functions
static void	addVoxelBoxes (const UT_VoxelArrayF &voxels, UT_Array< UT_BoundingBox > &boxes, float radius, float dbound, float zerothreshold)

static GU_Detail *	getVoxelIsosurface (const UT_VoxelArrayF &voxels, float radius, float dbound, float zerothreshold)
	Utility method to create an isosurface from a voxel array. More...

Additional Inherited Members
Protected Member Functions inherited from UT_IntrusiveRefCounter< VGEO_Volume >
SYS_FORCE_INLINE	~UT_IntrusiveRefCounter ()
	Destructor: Only derived classes can destruct this. More...

Detailed Description

Base class for volume primitives in mantra.

Examples:: RAY/RAY_DemoVolumeSphere.C.

Definition at line 41 of file VGEO_Volume.h.

Constructor & Destructor Documentation

VGEO_Volume::VGEO_Volume ( )

virtual VGEO_Volume::~VGEO_Volume ( )

virtual

Member Function Documentation

static void VGEO_Volume::addVoxelBoxes	(	const UT_VoxelArrayF &	voxels,
		UT_Array< UT_BoundingBox > &	boxes,
		float	radius,
		float	dbound,
		float	zerothreshold
	)

static

Utility method to create bounding boxes for every nonzero voxel in the voxel array.

virtual void VGEO_Volume::evaluate	(	const UT_Vector3 &	pos,
		const UT_Filter &	filter,
		float	radius,
		float	time,
		int	idx,
		float *	data
	)		const

pure virtual

Evaluate a volume attribute at a given position.

Parameters

pos	Evaluation position
filter	Filter function
radius	Filter radius in voxels
time	Evaluation time (0-1)
idx	Attribute index (based on getAttributeBinding())
data	Storage for evaluation data

See Also: UT_Filter

Implemented in HDK_Sample::ray_VolumeSphere.

virtual bool VGEO_Volume::evaluateInterval	(	const UT_BoundingBox &	box,
		const UT_Filter &	filter,
		float	radius,
		float	time,
		int	idx,
		float *	minval,
		float *	maxval
	)		const

inlinevirtual

Evaluate the minimum and maximum values for an attribute within a given box. If this operation is not supported, the caller will assume that the interval is unbounded.

Parameters

box	Evaluation interval
filter	Filter function
radius	Filter radius in voxels
time	Evaluation time (0-1)
idx	Attribute index (based on getAttributeBinding())
minval	Storage for evaluation data (minimum over box)
maxval	Storage for evaluation data (maximum over box)

See Also: UT_Filter

Definition at line 133 of file VGEO_Volume.h.

virtual void VGEO_Volume::evaluateMulti	(	const UT_Vector3 *	pos,
		const UT_Filter &	filter,
		float	radius,
		const float *	time,
		int	idx,
		float *	data,
		int	size,
		int	stride
	)		const

virtual

Evaluate multiple volume attribute at given positions.

Parameters

pos	Evaluation positions
filter	Filter function
radius	Filter radius in voxels
time	Evaluation times (0-1)
idx	Attribute index (based on getAttributeBinding())
data	Storage for evaluation data
size	Number of positions to evaluate
stride	Data size for an individual evaluation, this should match the size returned by getAttributeBinding() for the given index.

See Also: UT_Filter

virtual void VGEO_Volume::getAttributeBinding	(	UT_StringArray &	names,
		UT_IntArray &	sizes
	)		const

pure virtual

Return a list of attributes present in this volume. These attributes will be bound to surface shader variables when the volume is rendered. The "idx" passed into evaluation routines will be the array index returned by this operation.

sizes: number of floats in each attribute

Implemented in HDK_Sample::ray_VolumeSphere.

virtual void VGEO_Volume::getBoxes	(	UT_Array< UT_BoundingBox > &	boxes,
		float	radius,
		float	dbound,
		float	zerothreshold
	)		const

pure virtual

Return a set of bounding boxes that define the structure of the volumetric data. The boxes are used to accelerate ray intersection testing with the volume and to cull empty space for micropolygon rendering. They need not be an exact representation of the volume, though more accurate boxes will lead to more efficient renders. Specifically, the union of the boxes returned by this method should fully enclose the region of the volume to be rendered. If there is volumetric data outside all boxes, the render may contain artifacts.

Boxes should be defined locally, and need to incorporate the displacement bound.

Parameters

radius	Filter radius in voxels
dbound	Displacement bound in local space
zerothreshold	Threshold value under which the volume is considered empty.

Implemented in HDK_Sample::ray_VolumeSphere.

virtual GA_Offset VGEO_Volume::getGeoPrimitive ( ) const

inlinevirtual

Return the geometric primitive or vertex associated with the volume. These can be used to fill in primitive and detail attributes associated with the volume.

Definition at line 52 of file VGEO_Volume.h.

virtual GA_Offset VGEO_Volume::getGeoVertex ( ) const

inlinevirtual

Return the geometric primitive or vertex associated with the volume. These can be used to fill in primitive and detail attributes associated with the volume.

Definition at line 54 of file VGEO_Volume.h.

virtual float VGEO_Volume::getGradientDelta ( ) const

inlinevirtual

Returns a local distance for use in default gradient calculations.

Definition at line 239 of file VGEO_Volume.h.

virtual float VGEO_Volume::getNativeStepSize ( ) const

pure virtual

Return the object space step size to use when the volume quality is 1 and there is no object-level scale. For primitives based on voxel grids, this method is usually implemented by returning the voxel size.

Implemented in HDK_Sample::ray_VolumeSphere.

virtual int VGEO_Volume::getNormalAttribute ( ) const

inlinevirtual

Returns the volume attribute index to be used for normal vector calculations.

Definition at line 243 of file VGEO_Volume.h.

static GU_Detail* VGEO_Volume::getVoxelIsosurface	(	const UT_VoxelArrayF &	voxels,
		float	radius,
		float	dbound,
		float	zerothreshold
	)

static

Utility method to create an isosurface from a voxel array.

virtual float VGEO_Volume::getVoxelSize ( ) const

inlinevirtual

Returns the voxel size in the same space as 'pos' in evaluate.

Definition at line 246 of file VGEO_Volume.h.

virtual UT_Vector3 VGEO_Volume::gradient	(	const UT_Vector3 &	pos,
		const UT_Filter &	filter,
		float	radius,
		float	time,
		int	idx
	)		const

virtual

Evaluate the gradient of a volume attribute at a given position.

Parameters

pos	Evaluation position
filter	Filter function
radius	Filter radius in voxels
time	Evaluation time (0-1)
idx	Attribute index (based on getAttributeBinding())

See Also: UT_Filter

Reimplemented in HDK_Sample::ray_VolumeSphere.

virtual void VGEO_Volume::intersectIsosurface	(	const VGEO_Ray &	ray,
		const UT_Filter &	filter,
		float	radius,
		float	time,
		int	idx,
		float	threshold,
		HitList &	hits
	)		const

virtual

Find the intersection of a ray against the isosurface defined by a scalar field. The default implementation uses ray marching and the evaluateMulti() method to find a zero-crossing via sampling.

Parameters

ray	Ray for intersection testing
filter	Filter function
radius	Filter radius in voxels
time	Evaluation time (0-1)
idx	Attribute index (based on getAttributeBinding())
threshold	Isosurface threshold value
hits	Callback object for insertion of ray intersection results

virtual void VGEO_Volume::intersectVolume	(	const VGEO_Ray &	ray,
		HitList &	hits
	)		const

virtual

Perform ray marching through a volume. The default implementation finds occupied intervals of the volume based on the boxes returned by getBoxes(), and inserts evenly spaced samples within these intervals.

Parameters

ray	Ray for intersection testing
hits	Callback object for insertion of ray intersection results

virtual bool VGEO_Volume::isSDF ( ) const

inlinevirtual

Returns true when the volume data should be interpreted as an SDF.

Definition at line 249 of file VGEO_Volume.h.

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

VGEO/VGEO_Volume.h

Classes

Public Member Functions

Static Public Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation