OpenVDB: ValueAccessor< _TreeType, IsSafe, CacheLevels, MutexType > Class Template Reference

OpenVDB 9.0.0

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ValueAccessor< _TreeType, IsSafe, CacheLevels, MutexType > Class Template Reference

`#include <openvdb/tree/ValueAccessor.h>`

Inherits ValueAccessorBase< _TreeType, true >.

## Public Types
using | TreeType = _TreeType
using | RootNodeT = typename TreeType::RootNodeType
using | LeafNodeT = typename TreeType::LeafNodeType
using | ValueType = typename RootNodeT::ValueType
using | BaseT = ValueAccessorBase< TreeType, IsSafe >
using | LockT = typename MutexType::scoped_lock

## Public Member Functions
| ValueAccessor (TreeType &tree)
| ValueAccessor (const ValueAccessor &other)
ValueAccessor & | operator= (const ValueAccessor &other)
| ~ValueAccessor () override=default
bool | isCached (const Coord &xyz) const
| Return `true` if nodes along the path to the given voxel have been cached. More...
const ValueType & | getValue (const Coord &xyz) const
| Return the value of the voxel at the given coordinates. More...
bool | isValueOn (const Coord &xyz) const
| Return the active state of the voxel at the given coordinates. More...
bool | probeValue (const Coord &xyz, ValueType &value) const
| Return the active state of the voxel as well as its value. More...
int | getValueDepth (const Coord &xyz) const
bool | isVoxel (const Coord &xyz) const
void | setValue (const Coord &xyz, const ValueType &value)
| Set the value of the voxel at the given coordinates and mark the voxel as active. More...
void | setValueOn (const Coord &xyz, const ValueType &value)
void | setValueOnly (const Coord &xyz, const ValueType &value)
| Set the value of the voxel at the given coordinate but don't change its active state. More...
void | setValueOff (const Coord &xyz, const ValueType &value)
| Set the value of the voxel at the given coordinates and mark the voxel as inactive. More...
template<typename ModifyOp >
void | modifyValue (const Coord &xyz, const ModifyOp &op)
| Apply a functor to the value of the voxel at the given coordinates and mark the voxel as active. More...
template<typename ModifyOp >
void | modifyValueAndActiveState (const Coord &xyz, const ModifyOp &op)
| Apply a functor to the voxel at the given coordinates. More...
void | setActiveState (const Coord &xyz, bool on=true)
| Set the active state of the voxel at the given coordinates but don't change its value. More...
void | setValueOn (const Coord &xyz)
| Mark the voxel at the given coordinates as active but don't change its value. More...
void | setValueOff (const Coord &xyz)
| Mark the voxel at the given coordinates as inactive but don't change its value. More...
template<typename NodeType >
NodeType * | getNode ()
| Return the cached node of type NodeType. [Mainly for internal use]. More...
template<typename NodeType >
void | insertNode (const Coord &xyz, NodeType &node)
template<typename NodeType >
void | eraseNode ()
void | addLeaf (LeafNodeT *leaf)
| Add the specified leaf to this tree, possibly creating a child branch in the process. If the leaf node already exists, replace it. More...
void | addTile (Index level, const Coord &xyz, const ValueType &value, bool state)
| Add a tile at the specified tree level that contains voxel (x, y, z), possibly deleting existing nodes or creating new nodes in the process. More...
LeafNodeT * | touchLeaf (const Coord &xyz)
| Return a pointer to the leaf node that contains voxel (x, y, z). If no such node exists, create one, but preserve the values and active states of all voxels. More...
template<typename NodeT >
NodeT * | probeNode (const Coord &xyz)
| Return a pointer to the node of the specified type that contains voxel (x, y, z), or `nullptr` if no such node exists. More...
template<typename NodeT >
const NodeT * | probeConstNode (const Coord &xyz) const
template<typename NodeT >
const NodeT * | probeNode (const Coord &xyz) const
LeafNodeT * | probeLeaf (const Coord &xyz)
| Return a pointer to the leaf node that contains voxel (x, y, z), or `nullptr` if no such node exists. More...
const LeafNodeT * | probeConstLeaf (const Coord &xyz) const
const LeafNodeT * | probeLeaf (const Coord &xyz) const
void | clear () override
| Remove all nodes from this cache, then reinsert the root node. More...
_TreeType * | getTree () const
| Return a pointer to the tree associated with this accessor. More...
_TreeType & | tree () const
| Return a reference to the tree associated with this accessor. More...

## Static Public Member Functions
static Index | numCacheLevels ()
| Return the number of cache levels employed by this accessor. More...
static bool | isSafe ()
| Return true if this accessor is safe, i.e. registered by the tree from which it is constructed. Un-registered accessors can in rare cases be faster because it avoids the (small) overhead of registration, but they are unsafe if the tree is modified. So unless you're an expert it is highly recommended to set IsSafe = true (which is the default). More...

## Static Public Attributes
static const bool | IsConstTree

## Protected Attributes
_TreeType * | mTree

## Friends
template<typename >
class | RootNode
template<typename , Index >
class | InternalNode
template<typename , Index >
class | LeafNode
template<typename >
class | Tree

## Detailed Description

template<typename _TreeType, bool IsSafe = true, Index CacheLevels = _TreeType::DEPTH-1, typename MutexType = tbb::null_mutex>
class openvdb::v9_0::tree::ValueAccessor< _TreeType, IsSafe, CacheLevels, MutexType >

When traversing a grid in a spatially coherent pattern (e.g., iterating over neighboring voxels), request a `ValueAccessor` from the grid (with Grid::getAccessor()) and use the accessor's `getValue()` and `setValue()` methods. These will typically be significantly faster than accessing voxels directly in the grid's tree.

A ValueAccessor caches pointers to tree nodes along the path to a voxel (x, y, z). A subsequent access to voxel (x', y', z') starts from the cached leaf node and moves up until a cached node that encloses (x', y', z') is found, then traverses down the tree from that node to a leaf, updating the cache with the new path. This leads to significant acceleration of spatially-coherent accesses.

Parameters

  _TreeType | the type of the tree to be accessed [required]
  IsSafe | if IsSafe = false then the ValueAccessor will not register itself with the tree from which it is constructed (see warning).
  CacheLevels | the number of nodes to be cached, starting from the leaf level and not including the root (i.e., CacheLevels < DEPTH), and defaulting to all non-root nodes
  MutexType | the type of mutex to use (see note)

Warning
  If IsSafe = false then the ValueAccessor will not register itself with the tree from which it is constructed. While in some rare cases this can lead to better performance (since it avoids the small overhead of insertion on creation and deletion on destruction) it is also unsafe if the tree is modified. So unless you're an expert it is highly recommended to set IsSafe = true, which is the default. However if you know that the tree is no being modifed for the lifespan of the ValueAccessor AND the work performed per ValueAccessor is small relative to overhead of registering it you should consider setting IsSafe = false. If this improves performance you should really rewrite your code so as to better amortize the construction of the ValueAccessor, i.e. reuse it as much as possible!

Note
  If `MutexType` is a TBB-compatible mutex, then multiple threads may safely access a single, shared accessor. However, it is highly recommended that, instead, each thread be assigned its own, non-mutex-protected accessor.

## Member Typedef Documentation

## ◆ BaseT

using BaseT = ValueAccessorBase<TreeType, IsSafe>

## ◆ LeafNodeT

using LeafNodeT = typename TreeType::LeafNodeType

## ◆ LockT

using LockT = typename MutexType::scoped_lock

## ◆ RootNodeT

using RootNodeT = typename TreeType::RootNodeType

## ◆ TreeType

using TreeType = _TreeType

## ◆ ValueType

using ValueType = typename RootNodeT::ValueType

## Constructor & Destructor Documentation

## ◆ ValueAccessor() [1/2]

ValueAccessor | ( | TreeType & | tree | ) |
| inline

## ◆ ValueAccessor() [2/2]

ValueAccessor | ( | const ValueAccessor< _TreeType, IsSafe, CacheLevels, MutexType > & | other | ) |
| inline

## ◆ ~ValueAccessor()

~ValueAccessor | ( |  | ) |
| overridedefault

## Member Function Documentation

## ◆ addLeaf()

void addLeaf | ( | LeafNodeT * | leaf | ) |
| inline

Add the specified leaf to this tree, possibly creating a child branch in the process. If the leaf node already exists, replace it.

## ◆ addTile()

void addTile | ( | Index | level,
|  | const Coord & | xyz,
|  | const ValueType & | value,
|  | bool | state
| ) |  |
| inline

Add a tile at the specified tree level that contains voxel (x, y, z), possibly deleting existing nodes or creating new nodes in the process.

## ◆ clear()

void clear | ( |  | ) |
| inlineoverridevirtual

Remove all nodes from this cache, then reinsert the root node.

Implements ValueAccessorBase< _TreeType, true >.

## ◆ eraseNode()

void eraseNode | ( |  | ) |
| inline

If a node of the given type exists in the cache, remove it, so that isCached(xyz) returns `false` for any voxel (x, y, z) contained in that node. [Mainly for internal use]

## ◆ getNode()

NodeType * getNode | ( |  | ) |
| inline

Return the cached node of type NodeType. [Mainly for internal use].

## ◆ getTree()

_TreeType * getTree | ( |  | ) | const
| inlineinherited

Return a pointer to the tree associated with this accessor.

The pointer will be null only if the tree from which this accessor was constructed was subsequently deleted (which generally leaves the accessor in an unsafe state).

## ◆ getValue()

const ValueType & getValue | ( | const Coord & | xyz | ) | const
| inline

Return the value of the voxel at the given coordinates.

## ◆ getValueDepth()

int getValueDepth | ( | const Coord & | xyz | ) | const
| inline

Return the tree depth (0 = root) at which the value of voxel (x, y, z) resides, or -1 if (x, y, z) isn't explicitly represented in the tree (i.e., if it is implicitly a background voxel).

## ◆ insertNode()

void insertNode | ( | const Coord & | xyz,
|  | NodeType & | node
| ) |  |
| inline

Cache the given node, which should lie along the path from the root node to the node containing voxel (x, y, z). [Mainly for internal use]

## ◆ isCached()

bool isCached | ( | const Coord & | xyz | ) | const
| inline

Return `true` if nodes along the path to the given voxel have been cached.

## ◆ isSafe()

static bool isSafe | ( |  | ) |
| inlinestaticinherited

Return true if this accessor is safe, i.e. registered by the tree from which it is constructed. Un-registered accessors can in rare cases be faster because it avoids the (small) overhead of registration, but they are unsafe if the tree is modified. So unless you're an expert it is highly recommended to set IsSafe = true (which is the default).

## ◆ isValueOn()

bool isValueOn | ( | const Coord & | xyz | ) | const
| inline

Return the active state of the voxel at the given coordinates.

## ◆ isVoxel()

bool isVoxel | ( | const Coord & | xyz | ) | const
| inline

Return `true` if the value of voxel (x, y, z) resides at the leaf level of the tree, i.e., if it is not a tile value.

## ◆ modifyValue()

void modifyValue | ( | const Coord & | xyz,
|  | const ModifyOp & | op
| ) |  |
| inline

Apply a functor to the value of the voxel at the given coordinates and mark the voxel as active.

See Tree::modifyValue() for details.

## ◆ modifyValueAndActiveState()

void modifyValueAndActiveState | ( | const Coord & | xyz,
|  | const ModifyOp & | op
| ) |  |
| inline

Apply a functor to the voxel at the given coordinates.

See Tree::modifyValueAndActiveState() for details.

## ◆ numCacheLevels()

static Index numCacheLevels | ( |  | ) |
| inlinestatic

Return the number of cache levels employed by this accessor.

## ◆ operator=()

ValueAccessor & operator= | ( | const ValueAccessor< _TreeType, IsSafe, CacheLevels, MutexType > & | other | ) |
| inline

## ◆ probeConstLeaf()

const LeafNodeT * probeConstLeaf | ( | const Coord & | xyz | ) | const
| inline

## ◆ probeConstNode()

const NodeT * probeConstNode | ( | const Coord & | xyz | ) | const
| inline

## ◆ probeLeaf() [1/2]

LeafNodeT * probeLeaf | ( | const Coord & | xyz | ) |
| inline

Return a pointer to the leaf node that contains voxel (x, y, z), or `nullptr` if no such node exists.

## ◆ probeLeaf() [2/2]

const LeafNodeT * probeLeaf | ( | const Coord & | xyz | ) | const
| inline

## ◆ probeNode() [1/2]

NodeT * probeNode | ( | const Coord & | xyz | ) |
| inline

Return a pointer to the node of the specified type that contains voxel (x, y, z), or `nullptr` if no such node exists.

## ◆ probeNode() [2/2]

const NodeT * probeNode | ( | const Coord & | xyz | ) | const
| inline

## ◆ probeValue()

bool probeValue | ( | const Coord & | xyz,
|  | ValueType & | value
| ) |  | const
| inline

Return the active state of the voxel as well as its value.

## ◆ setActiveState()

void setActiveState | ( | const Coord & | xyz,
|  | bool | on = `true`
| ) |  |
| inline

Set the active state of the voxel at the given coordinates but don't change its value.

## ◆ setValue()

void setValue | ( | const Coord & | xyz,
|  | const ValueType & | value
| ) |  |
| inline

Set the value of the voxel at the given coordinates and mark the voxel as active.

## ◆ setValueOff() [1/2]

void setValueOff | ( | const Coord & | xyz | ) |
| inline

Mark the voxel at the given coordinates as inactive but don't change its value.

## ◆ setValueOff() [2/2]

void setValueOff | ( | const Coord & | xyz,
|  | const ValueType & | value
| ) |  |
| inline

Set the value of the voxel at the given coordinates and mark the voxel as inactive.

## ◆ setValueOn() [1/2]

void setValueOn | ( | const Coord & | xyz | ) |
| inline

Mark the voxel at the given coordinates as active but don't change its value.

## ◆ setValueOn() [2/2]

void setValueOn | ( | const Coord & | xyz,
|  | const ValueType & | value
| ) |  |
| inline

## ◆ setValueOnly()

void setValueOnly | ( | const Coord & | xyz,
|  | const ValueType & | value
| ) |  |
| inline

Set the value of the voxel at the given coordinate but don't change its active state.

## ◆ touchLeaf()

LeafNodeT * touchLeaf | ( | const Coord & | xyz | ) |
| inline

Return a pointer to the leaf node that contains voxel (x, y, z). If no such node exists, create one, but preserve the values and active states of all voxels.

Use this method to preallocate a static tree topology over which to safely perform multithreaded processing.

## ◆ tree()

_TreeType & tree | ( |  | ) | const
| inlineinherited

Return a reference to the tree associated with this accessor.

## Friends And Related Function Documentation

## ◆ InternalNode

friend class InternalNode
| friend

## ◆ LeafNode

friend class LeafNode
| friend

## ◆ RootNode

friend class RootNode
| friend

## ◆ Tree

friend class Tree
| friend

## Member Data Documentation

## ◆ IsConstTree

const bool IsConstTree
| static

## ◆ mTree

_TreeType * mTree
| protectedinherited