//
// Cellgrid: stores sprites in a grid.
//
// To create a grid, just create an empty table.
// In actual usage, the cellgrid will be stored in the registry
// in the field "cellgrid_cells".  If you pass grid=nil to
// any of these routines, the system will automatically use
// the table in the registry.
//
// For purposes of this module, a "sprite" is any table
// having a metatable.  The (X,Y,Z,Plane) of the sprite are
// stored as hidden fields inside the metatable.
//
// We preserve the invariant that sprites whose plane is nil
// are not stored in the grid.  All sprites whose plane
// is a string are stored in the grid.
//
// When creating a new sprite, initialize plane to nil.  That
// fits the invariant that sprites whose plane is nil are
// not stored in the grid.  If you ever want to change the
// sprite's position, use cellgrid_setpos: that will
// preserve the invariant.
//

#ifndef CELLGRID_HPP
#define CELLGRID_HPP

#include "luastack.hpp"

int cellgrid_initgrid(lua_State *L);
int cellgrid_addplane(lua_State *L);
int cellgrid_setpos(lua_State *L);
int cellgrid_scanradius(lua_State *L);
int cellgrid_scanregion(lua_State *L);

#endif // CELLGRID_HPP