plGameGrid< CellData > Class Template Reference

plGameGrid is a general purpose 2D grid structure that has several convenience functions which are often required when working with a grid. More...

#include <GameGrid.h>

Public Types
enum	Orientation { InPlaneXY , InPlaneXZ , InPlaneXminusZ }

Public Member Functions
void	CreateGrid (plUInt16 uiSizeX, plUInt16 uiSizeY)
	Clears all data and reallocates the grid with the given dimensions.
void	SetWorldSpaceDimensions (const plVec3 &vLowerLeftCorner, const plVec3 &vCellSize, Orientation ori=InPlaneXZ)
	Sets the lower left position of the grid in world space coordinates and the cell size.
void	SetWorldSpaceDimensions (const plVec3 &vLowerLeftCorner, const plVec3 &vCellSize, const plMat3 &mRotation)
	Sets the lower left position of the grid in world space coordinates and the cell size.
plVec3	GetCellSize () const
	Returns the size of each cell.
plVec2I32	GetCellAtWorldPosition (const plVec3 &vWorldSpacePos) const
	Returns the coordinate of the cell at the given world-space position. The world space dimension must be set for this to work. The indices might be outside valid ranges (negative, larger than the maximum size).
plUInt16	GetGridSizeX () const
	Returns the number of cells along the X axis.
plUInt16	GetGridSizeY () const
	Returns the number of cells along the Y axis.
plBoundingBox	GetWorldBoundingBox () const
	Returns the world-space bounding box of the grid, as specified via SetWorldDimensions.
plUInt32	GetNumCells () const
	Returns the total number of cells.
CellData &	GetCell (plUInt32 uiIndex)
	Gives access to a cell by cell index.
const CellData &	GetCell (plUInt32 uiIndex) const
	Gives access to a cell by cell index.
CellData &	GetCell (const plVec2I32 &vCoord)
	Gives access to a cell by cell coordinates.
const CellData &	GetCell (const plVec2I32 &vCoord) const
	Gives access to a cell by cell coordinates.
plVec2I32	ConvertCellIndexToCoordinate (plUInt32 uiIndex) const
	Converts a cell index into a 2D cell coordinate.
plUInt32	ConvertCellCoordinateToIndex (const plVec2I32 &vCoord) const
	Converts a cell coordinate into a cell index.
plVec3	GetCellWorldSpaceOrigin (const plVec2I32 &vCoord) const
	Returns the lower left world space position of the cell with the given coordinates.
plVec3	GetCellLocalSpaceOrigin (const plVec2I32 &vCoord) const
plVec3	GetCellWorldSpaceCenter (const plVec2I32 &vCoord) const
	Returns the center world space position of the cell with the given coordinates.
plVec3	GetCellLocalSpaceCenter (const plVec2I32 &vCoord) const
bool	IsValidCellCoordinate (const plVec2I32 &vCoord) const
	Checks whether the given cell coordinate is inside valid ranges.
bool	PickCell (const plVec3 &vRayStartPos, const plVec3 &vRayDirNorm, plVec2I32 *out_pCellCoord, plVec3 *out_pIntersection=nullptr) const
	Casts a world space ray through the grid and determines which cell is hit (if any).
const plVec3 &	GetWorldSpaceOrigin () const
	Returns the lower left corner position in world space of the grid.
const plMat3 &	GetRotationToWorldSpace () const
	Returns the matrix used to rotate coordinates from grid space to world space.
const plMat3 &	GetRotationToGridSpace () const
	Returns the matrix used to rotate coordinates from world space to grid space.
bool	GetRayIntersection (const plVec3 &vRayStartWorldSpace, const plVec3 &vRayDirNormalizedWorldSpace, float fMaxLength, float &out_fIntersection, plVec2I32 &out_vCellCoord) const
	Tests where and at which cell the given world space ray intersects the grids bounding box.
bool	GetRayIntersectionExpandedBBox (const plVec3 &vRayStartWorldSpace, const plVec3 &vRayDirNormalizedWorldSpace, float fMaxLength, float &out_fIntersection, const plVec3 &vExpandBBoxByThis) const
	Tests whether a ray would hit the grid bounding box, if it were expanded by a constant.
void	ComputeWorldSpaceCorners (plVec3 *pCorners) const
plResult	Serialize (plStreamWriter &stream) const
plResult	Deserialize (plStreamReader &stream)

Detailed Description

template<class CellData>
class plGameGrid< CellData >

plGameGrid is a general purpose 2D grid structure that has several convenience functions which are often required when working with a grid.

Member Enumeration Documentation

Orientation

template<class CellData >

enum plGameGrid::Orientation

Enumerator
InPlaneXY	The grid is expected to lie in the XY plane in world-space (when Y is up, this is similar to a 2D side scroller)
InPlaneXZ	The grid is expected to lie in the XZ plane in world-space (when Y is up, this is similar to a top down RTS game)
InPlaneXminusZ	The grid is expected to lie in the XZ plane in world-space (when Y is up, this is similar to a top down RTS game)

Member Function Documentation

PickCell()

template<class CellData >

bool plGameGrid< CellData >::PickCell	(	const plVec3 &	vRayStartPos,
		const plVec3 &	vRayDirNorm,
		plVec2I32 *	out_pCellCoord,
		plVec3 *	out_pIntersection = nullptr ) const

Casts a world space ray through the grid and determines which cell is hit (if any).

Note

The picked cell is determined from where the ray hits the 'ground plane', ie. the plane that goes through the world space origin.

SetWorldSpaceDimensions() [1/2]

template<class CellData >

void plGameGrid< CellData >::SetWorldSpaceDimensions	(	const plVec3 &	vLowerLeftCorner,
		const plVec3 &	vCellSize,
		const plMat3 &	mRotation )

Sets the lower left position of the grid in world space coordinates and the cell size.

Together with the grid size, these values determine the final world space dimensions. The rotation defines how the grid is rotated in world space. An identity rotation means that grid cell coordinates (X, Y) map directly to world space coordinates (X, Y). So the grid is 'standing up' in world space (considering that Y is 'up'). Other rotations allow to rotate the grid into other planes, such as XZ, if that is more convenient.

SetWorldSpaceDimensions() [2/2]

template<class CellData >

void plGameGrid< CellData >::SetWorldSpaceDimensions	(	const plVec3 &	vLowerLeftCorner,
		const plVec3 &	vCellSize,
		Orientation	ori = InPlaneXZ )

Sets the lower left position of the grid in world space coordinates and the cell size.

Together with the grid size, these values determine the final world space dimensions. The rotation defines how the grid is rotated in world space. An identity rotation means that grid cell coordinates (X, Y) map directly to world space coordinates (X, Y). So the grid is 'standing up' in world space (considering that Y is 'up'). Other rotations allow to rotate the grid into other planes, such as XZ, if that is more convenient.

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

• Code/Engine/Utilities/DataStructures/GameGrid.h
• Code/Engine/Utilities/DataStructures/Implementation/GameGrid_inl.h