Base class used to generate a grid of type GridType containing a narrow-band level set representation of a convex region. More...

#include <openvdb/tools/impl/ConvexVoxelizer.h>

Classes
class	XYRangeData
	Class that stores endpoints of a y range for each x value within a specified range and step size. More...

Public Member Functions
	ConvexVoxelizer (GridPtr &grid, const bool &threaded=false, InterruptType *interrupter=nullptr)
	Constructor. More...

virtual	~ConvexVoxelizer ()=default

ValueT	voxelSize () const
	Return the voxel size of the grid. More...

ValueT	halfWidth () const
	Return the half width of the narrow-band level set. More...

Protected Types
using	ValueT = typename GridType::ValueType

using	Vec3T = math::Vec3< ValueT >

using	Vec2T = math::Vec2< ValueT >

Protected Member Functions
void	iterate ()
	The function the derived class calls to create the level set, working in index space other than setting signed distance values. More...

void	setXYRangeData (const Index &)
	Determines the x bounds in index space of the convex region dilated by the half width. For each x value in index space, the y range in index space of the dilated region is computed. This function should store the data in `mXYData`. More...

bool	tileCanFit (const Index &) const
	Checks if the tile of a given dimension can possibly fit within the region. More...

ValueT	signedDistance (const Vec3T &) const
	Computes the signed distance from a point to the convex region in index space. More...

ValueT	tilePointSignedDistance (const Vec3T &p) const
	Computes the signed distance for tiles in index space, considering the center of the tile. This method is optional to override and defaults to `signedDistance`. More...

Static Protected Member Functions
static ValueT	tileCeil (const ValueT &x, const ValueT &step)
	Rounds an input scalar up to the nearest valid ordinate of tile of a specified size. More...

template<typename T >
static ValueT	tileCeil (const ValueT &x, const T &step)
	Rounds an input scalar up to the nearest valid ordinate of tile of a specified size. More...

static ValueT	tileFloor (const ValueT &x, const ValueT &step)
	Rounds an input scalar down to the nearest valid ordinate of tile of a specified size. More...

template<typename T >
static ValueT	tileFloor (const ValueT &x, const T &step)
	Rounds an input scalar down to the nearest valid ordinate of tile of a specified size. More...

static ValueT	circleBottom (const ValueT &x0, const ValueT &y0, const ValueT &r, const ValueT &x)
	Computes the bottom y-coordinate of a circle at a given x position. More...

static ValueT	circleTop (const ValueT &x0, const ValueT &y0, const ValueT &r, const ValueT &x)
	Computes the top y-coordinate of a circle at a given x position. More...

static ValueT	sphereBottom (const ValueT &x0, const ValueT &y0, const ValueT &z0, const ValueT &r, const ValueT &x, const ValueT &y)
	Computes the bottom z-coordinate of a sphere at a given (x, y) position. More...

static ValueT	sphereTop (const ValueT &x0, const ValueT &y0, const ValueT &z0, const ValueT &r, const ValueT &x, const ValueT &y)
	Computes the top z-coordinate of a sphere at a given (x, y) position. More...

Protected Attributes
std::function< bool(ValueT &, ValueT &, const ValueT &, const ValueT &)>	bottomTop
	Find where a vertical infinite line intersects a convex region dilated by the half width. More...

XYRangeData	mXYData

Detailed Description

template<typename GridType, typename Derived, typename InterruptType = util::NullInterrupter>
class openvdb::v12_1::tools::ConvexVoxelizer< GridType, Derived, InterruptType >

Base class used to generate a grid of type GridType containing a narrow-band level set representation of a convex region.

Note: GridType::ValueType must be a floating-point scalar.; Derived is the derived class that implements the base class (curiously recurring template pattern).

Example of derived level set sphere class: template <typename GridType>
class SphereVoxelizer : public ConvexVoxelizer<GridType, SphereVoxelizer<GridType>>
{
using GridPtr = typename GridType::Ptr;
using BaseT = ConvexVoxelizer<GridType, SphereVoxelizer<GridType>>;
using BaseT::mXYData;
using BaseT::tileCeil;
using ValueT = typename BaseT::ValueT;
using Vec3T = typename BaseT::Vec3T;
public:
friend class ConvexVoxelizer<GridType, SphereVoxelizer<GridType>>;
SphereVoxelizer(GridPtr& grid, const bool& threaded = true)
: BaseT(grid, threaded)
{
}
template <typename ScalarT>
void
operator()(const math::Vec3<ScalarT>& pt, const ScalarT& r)
{
static_assert(std::is_floating_point<ScalarT>::value);
if (r <= 0)
return;
initialize<ScalarT>(pt, r);
BaseT::iterate();
}
private:
inline ValueT
signedDistance(const Vec3T& p) const
{
return (p - mPt).length() - mRad;
}
inline void
setXYRangeData(const Index& step = 1)
{
mXYData.reset(mX - mORad, mX + mORad, step);
for (ValueT x = tileCeil(mX - mORad, step); x <= mX + mORad; x += step)
mXYData.expandYRange(x, BaseT::circleBottom(mX, mY, mORad, x),
BaseT::circleTop(mX, mY, mORad, x));
}
std::function<bool(ValueT&, ValueT&, const ValueT&, const ValueT&)> sphereBottomTop =
[this](ValueT& zb, ValueT& zt, const ValueT& x, const ValueT& y)
{
zb = BaseT::sphereBottom(mX, mY, mZ, mORad, x, y);
zt = BaseT::sphereTop(mX, mY, mZ, mORad, x, y);
return std::isfinite(zb) && std::isfinite(zt);
};
template <typename ScalarT>
inline void
initialize(const math::Vec3<ScalarT>& pt, const ScalarT& r)
{
const ValueT vx = BaseT::voxelSize(),
hw = BaseT::halfWidth();
// sphere data in index space
mPt = Vec3T(pt)/vx;
mRad = ValueT(r)/vx;
mX = mPt.x(); mY = mPt.y(); mZ = mPt.z();
// padded radius used to populate the outer halfwidth of the sdf
mORad = mRad + hw;
BaseT::bottomTop = sphereBottomTop;
}
Vec3T mPt;
ValueT mRad, mORad, mX, mY, mZ;
};
// usage:
// initialize level set grid with voxel size 0.1 and half width 3.0
FloatGrid::Ptr grid = createLevelSet<GridT>(0.1f, 3.0f);
// populate grid with a sphere centered at (0, 1, 2) and radius 5
SphereVoxelizer<FloatGrid> op(grid);
op(Vec3s(0.0f, 1.0f, 2.0f), 5.0f);

Member Typedef Documentation

using ValueT = typename GridType::ValueType

protected

using Vec2T = math::Vec2<ValueT>

protected

using Vec3T = math::Vec3<ValueT>

protected

Constructor & Destructor Documentation

ConvexVoxelizer	(	GridPtr &	grid,
		const bool &	threaded = `false`,
		InterruptType *	interrupter = `nullptr`
	)

inline

Constructor.

Parameters

grid	scalar grid to populate the level set in
threaded	center of the sphere in world units
interrupter	pointer to optional interrupter. Use template argument util::NullInterrupter if no interruption is desired.

Note: The voxel size and half width are determined from the input grid, meaning the voxel size and background value need to be set prior to voxelization

virtual ~ConvexVoxelizer ( )

virtualdefault

Member Function Documentation

static ValueT circleBottom	(	const ValueT &	x0,
		const ValueT &	y0,
		const ValueT &	r,
		const ValueT &	x
	)

inlinestaticprotected

Computes the bottom y-coordinate of a circle at a given x position.

Parameters

x0	X-coordinate of the circle's center.
y0	Y-coordinate of the circle's center.
r	Radius of the circle.
x	X-coordinate for which to compute the bottom y-coordinate.

Returns: The y-coordinate at the bottom of the circle for the given x position.

static ValueT circleTop	(	const ValueT &	x0,
		const ValueT &	y0,
		const ValueT &	r,
		const ValueT &	x
	)

inlinestaticprotected

Computes the top y-coordinate of a circle at a given x position.

Parameters

x0	X-coordinate of the circle's center.
y0	Y-coordinate of the circle's center.
r	Radius of the circle.
x	X-coordinate for which to compute the top y-coordinate.

Returns: The y-coordinate at the top of the circle for the given x position.

ValueT halfWidth ( ) const

inline

Return the half width of the narrow-band level set.

void iterate ( )

inlineprotected

The function the derived class calls to create the level set, working in index space other than setting signed distance values.

Note: This function handles both parallel and serial iterations. If running in serial mode, it flood fills the tile topology immediately; otherwise, it avoids duplicating nontrivial tree topology over multiple threads. This method also checks for background tiles that are too thin to fit and delegates accordingly.

void setXYRangeData ( const Index & )

inlineprotected

Determines the x bounds in index space of the convex region dilated by the half width. For each x value in index space, the y range in index space of the dilated region is computed. This function should store the data in mXYData.

Parameters

step	The step size for setting the XY range data, defaults to 1.

Note: Function to be implemented by derived classes to set XY range data. This function is called at most 4 times within iterate().

ValueT signedDistance ( const Vec3T & ) const

inlineprotected

Computes the signed distance from a point to the convex region in index space.

Parameters

p	The point in 3D space for which to compute the signed distance.

static ValueT sphereBottom	(	const ValueT &	x0,
		const ValueT &	y0,
		const ValueT &	z0,
		const ValueT &	r,
		const ValueT &	x,
		const ValueT &	y
	)

inlinestaticprotected

Computes the bottom z-coordinate of a sphere at a given (x, y) position.

Parameters

x0	X-coordinate of the sphere's center.
y0	Y-coordinate of the sphere's center.
z0	Z-coordinate of the sphere's center.
r	Radius of the sphere.
x	X-coordinate for which to compute the bottom z-coordinate.
y	Y-coordinate for which to compute the bottom z-coordinate.

Returns: The z-coordinate at the bottom of the sphere for the given (x, y) position.

static ValueT sphereTop	(	const ValueT &	x0,
		const ValueT &	y0,
		const ValueT &	z0,
		const ValueT &	r,
		const ValueT &	x,
		const ValueT &	y
	)

inlinestaticprotected

Computes the top z-coordinate of a sphere at a given (x, y) position.

Parameters

x0	X-coordinate of the sphere's center.
y0	Y-coordinate of the sphere's center.
z0	Z-coordinate of the sphere's center.
r	Radius of the sphere.
x	X-coordinate for which to compute the top z-coordinate.
y	Y-coordinate for which to compute the top z-coordinate.

Returns: The z-coordinate at the top of the sphere for the given (x, y) position.

bool tileCanFit ( const Index & ) const

inlineprotected

Checks if the tile of a given dimension can possibly fit within the region.

The derived class does not need to implement it if the default behavior is acceptable, which assumes a tile can always possibly fit.

Parameters

dim	The dimension of the tile in which to check if the tile fits.

Note: This is meant as a short-circuting method: if a tile of a given dimension can't fit then iterate will not try to populate the level set with background tiles of this dimension.

Returns: true if the tile can possibly fit; otherwise false.

static ValueT tileCeil	(	const ValueT &	x,
		const ValueT &	step
	)

inlinestaticprotected

Rounds an input scalar up to the nearest valid ordinate of tile of a specified size.

Parameters

x	Input value.
step	Tile step size.

Returns: The ceiling of the value based on the tile size.

static ValueT tileCeil	(	const ValueT &	x,
		const T &	step
	)

inlinestaticprotected

Rounds an input scalar up to the nearest valid ordinate of tile of a specified size.

Template Parameters

T	Any integral type (int, unsigned int, size_t, etc.)

Parameters

x	Input value.
step	Tile step size.

Returns: The ceiling of the value based on the tile size.

static ValueT tileFloor	(	const ValueT &	x,
		const ValueT &	step
	)

inlinestaticprotected

Rounds an input scalar down to the nearest valid ordinate of tile of a specified size.

Parameters

x	Input value.
step	Tile step size.

Returns: The ceiling of the value based on the tile size.

static ValueT tileFloor	(	const ValueT &	x,
		const T &	step
	)

inlinestaticprotected

Rounds an input scalar down to the nearest valid ordinate of tile of a specified size.

Template Parameters

T	Any integral type (int, unsigned int, size_t, etc.)

Parameters

x	Input value.
step	Tile step size.

Returns: The ceiling of the value based on the tile size.

ValueT tilePointSignedDistance ( const Vec3T & p ) const

inlineprotected

Computes the signed distance for tiles in index space, considering the center of the tile. This method is optional to override and defaults to signedDistance.

Parameters

p	The point at the center of the tile in 3D space.

Note: This can be useful for cases that build objects from multiple primitives, e.g. dilated mesh is built by constructing and unioning open prisms and open tube wedges. A tile might not fully fit in an open prism but might fit in the union of a prism and wedge, and so in this case it might make sense to use the sdf for an offset triangle on tiles during the open prism scan.

ValueT voxelSize ( ) const

inline

Return the voxel size of the grid.

Member Data Documentation

std::function<bool(ValueT&, ValueT&, const ValueT&, const ValueT&)> bottomTop

protected

Initial value:

=

[](ValueT&, ValueT&, const ValueT&, const ValueT&) { return false; }

Find where a vertical infinite line intersects a convex region dilated by the half width.

Parameters

[out]	zb	Reference to the z ordinate where the bottom intersection occurs.
[out]	zt	Reference to the z ordinate where the top intersection occurs.
[in]	x	The x ordinate of the infinte line.
[in]	y	The y ordinate of the infinte line.

Returns: true if an intersection occurs; otherwise false.

Note: The derived class can override this lambda to implement different behavior for degenerate cases.

XYRangeData mXYData

protected

Classes

Public Member Functions

Protected Types

Protected Member Functions

Static Protected Member Functions

Protected Attributes

Detailed Description

template<typename GridType, typename Derived, typename InterruptType = util::NullInterrupter> class openvdb::v12_1::tools::ConvexVoxelizer< GridType, Derived, InterruptType >

Member Typedef Documentation

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation

template<typename GridType, typename Derived, typename InterruptType = util::NullInterrupter>
class openvdb::v12_1::tools::ConvexVoxelizer< GridType, Derived, InterruptType >