/// <summary>
/// Inserts an object into the grid, expanding the cell to fit the element
/// </summary>
/// <param name="obj">The object to insert</param>
public void Insert(IGridElt obj)
{
int xIdx = GridLocalToCellCol(obj.Xf);
int yIdx = GridLocalToCellRow(obj.Yf);
InsertToCell(obj, xIdx, yIdx);
}
/// <summary>
/// Removes an element from the grid. The <see cref="IUGridElt"/> of the object must give
/// the same position where the element is currently in the grid
/// </summary>
/// <param name="obj">The object to remove</param>
public void Remove(IGridElt obj)
{
int xIdx = GridLocalToCellCol(obj.Xf);
int yIdx = GridLocalToCellRow(obj.Yf);
RemoveFromCell(obj, xIdx, yIdx);
}
/// <summary>
/// Moves an element in the grid from the former position to the new one.
/// </summary>
/// <param name="obj">The object to move</param>
/// <param name="fromX">The current position of the object in the grid</param>
/// <param name="fromY">The current position of the object in the grid</param>
/// <param name="toX">The new position of the object in the grid</param>
/// <param name="toY">The new position of the object in the grid</param>
public void Move(IGridElt obj, float fromX, float fromY, float toX, float toY)
{
int oldCol = GridLocalToCellCol(fromX);
int oldRow = GridLocalToCellRow(fromY);
int newCol = GridLocalToCellCol(toX);
int newRow = GridLocalToCellRow(toY);
ref LooseGridRow row = ref rows[oldRow];
/// <summary>
/// Inserts an object into a grid cell at the given index
/// </summary>
/// <param name="elt">The object to insert</param>
/// <param name="xIdx">The column index of the cell</param>
/// <param name="yIdx">The row index of the cell</param>
private void InsertToCell(IGridElt elt, int xIdx, int yIdx)
{
LooseCell cell = rows[yIdx].cells[xIdx];
//if the cell is empty, initialize the bounds to match the element
if (cell.FirstElt == null)
{
cell.Push(elt);
cell.lft = (int)elt.Xf;
cell.btm = (int)elt.Yf;
cell.rgt = cell.lft + elt.Width;
cell.top = cell.btm + elt.Height;
//insert into the tight cells it overlaps
InsertToCoarseGrid(cell);
}
else //otherwise, see if the bounds need to change to fit the element
{
cell.Push(elt);
ExpandCell(cell, elt);
}
}
private void RemoveFromCell(IGridElt obj, int xIdx, int yIdx)
{
LooseCell cell = rows[yIdx].cells[xIdx];
IGridElt elt = cell.FirstElt;
IGridElt prevElt = null;
while (elt.ID != obj.ID)
{
prevElt = elt;
elt = elt.NextElt;
}
if (prevElt == null)
{
cell.Pop();
}
else
{
prevElt.NextElt = elt.NextElt;
}
}
public void LooseCell(IGridElt firstElt, AABB bounds)
{
GizmoHelp.DrawAABB(Color.yellow, bounds);
}
