#include <TiledGrid.h>

Classes
struct	Item
	One box with its id (slot), for With(). More...

Public Member Functions
	TiledGrid ()=default
	An empty grid with no extent; With() must not be called on it.

	TiledGrid (double xMin, double xMax, double yMin, double yMax, double cellSize)

bool	HasExtent () const
	True when the grid has an extent (was made with the extent constructor).

double	CellSize () const
	The cell edge in use [m].

std::size_t	CellCount () const
	The number of cells.

std::size_t	TileCount () const
	The number of tiles (with or without entries).

std::size_t	SharedTileCount (const TiledGrid &other) const
	Test hook: the number of tiles with entries that this grid shares (same object) with `other`.

std::size_t	FilledTileCount () const
	The number of tiles with entries.

std::size_t	OverflowCount () const
	The number of boxes in the overflow list.

bool	Inside (const Box &box) const
	True when the box is inside the extent (so it goes into the cells, not the overflow list).

TiledGrid	With (std::span< const Item > removed, std::span< const Item > added) const

TiledGrid	Cleared () const
	A grid with the same geometry and no boxes.

template<class Visitor >
void	ForEachCandidate (const Box &query, Visitor &&visit) const

void	Candidates (const Box &query, std::vector< std::uint32_t > &out) const
	Appends the ids of the boxes that overlap the query box to `out` (cleared first).

Static Public Attributes
static constexpr int	kTileSide = 8
	Cells per tile side.

static constexpr int	kTileCells = kTileSide * kTileSide
	Cells per tile.

Detailed Description

Index of boxes by horizontal cell for a field that changes by keyed steps (AggregationField::ApplyChanges).

The geometry (origin, cell size, cell counts) is fixed when the grid is made. The cells are grouped in square tiles of kTileSide x kTileSide cells. A copy of the grid shares every tile; With() makes a new grid in which only the tiles that a change touches are new. A box that is not inside the extent goes to an overflow list, which every query checks.

As in HashGrid, each box is listed in every cell its horizontal extent touches, with its own bounds, and a query reports a box once. The item id is a slot of the field's flat arrays. Immutable after construction: concurrent queries are safe, and a query on a copy is not affected by With() on another copy.

Constructor & Destructor Documentation

◆ TiledGrid()

environment::field::aggregation::TiledGrid::TiledGrid	(	double	xMin,
		double	xMax,
		double	yMin,
		double	yMax,
		double	cellSize
	)

An empty grid over a horizontal extent.

Parameters

[in]	xMin,xMax,yMin,yMax	The extent [m], relative to the field origin. Finite, minimum not above maximum.
[in]	cellSize	Cell edge [m]; positive. It is enlarged when the cell count would pass HashGrid::kMaxCells, and to at least 1e-3 of the longer side.

Member Function Documentation

◆ ForEachCandidate()

template<class Visitor >

void environment::field::aggregation::TiledGrid::ForEachCandidate	(	const Box &	query,
		Visitor &&	visit
	)		const

inline

Calls visit(id) once for each box that overlaps the query box: the cells first, then the overflow list.

The order is fixed by the grid's content (cells row by row, ids rising within a cell), so the same change sequence gives the same order.

◆ With()

TiledGrid environment::field::aggregation::TiledGrid::With	(	std::span< const Item >	removed,
		std::span< const Item >	added
	)		const

A new grid: this one without the removed items and with the added ones. Tiles that neither touches are shared.

Parameters

[in]	removed	Items to take out, with the box they were added with. An id may also be in `added` (an update).
[in]	added	Items to put in. Each id at most once.

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

webfhsim/reloadrepos/fhsim_environment/src/environment/aggregation/TiledGrid.h

Classes