How to get the cell position in Tilemap by GridNode vice versa

General Grid graph
#1

Get gridNode by cellPosition of tilemap

float HeightOfTile = 2.56f;
Vector3Int indexOfCell = new Vector3Int(i, j);
Vector3 worldPosition = tilemap.GetCellCenterWorld(indexOfCell);
worldPosition.y += HeightOfTile / 2f; // GetCellCenterWorld always return the bottom-center of the tile so I have to add half of the height of tile before changing it to the GridNode in case the boundary problem
GraphNode gridNode = AstarPath.active.data.gridGraph.GetNearest(worldPosition).node;

Get the cellPosition of tilemap by gridNode

float HeightOfTile = 2.56f;
var worldPosition = (Vector3)gridNode.position;
worldPosition.y -= HeightOfTile / 2f; // have to add this line or the cellPosition is the wrong one
var cellPosition = tilemap.WorldToCell(worldPosition);

for now, my project seems working fine but not sure if the solution is correct when add/substract 1.28f to the worldPosition.y;
I have aligned the hexagonal grid to my tilemap., wonder if somewhere exists API for me to do transformation between cellPosition in tilemap and gridNode in Astar

#2

Hi

There’s no such conversion built-in at the moment. Though I think your conversion will be more stable if you base it on the grid coordinates, which can be accessed using gridNode.XCoordinateInGrid and gridNode.ZCoordinateInGrid.

#3

Yeah, that’s exactly what I want, I’m going to find the formula between cellPosition and gridNodePosition
but I’m not very familiar with the X(Z)CoordinateInGrid, can you give me some hits about it,
Given :

  1. Tilemap size is 25 * 20,
  2. A* size is 40 * 30,
  3. (0,0) in cellPosition == (X, Y) in gridNodePosition

The formula I need:

  1. (a, b) in cellPosition => (?, ?) in gridNodePosition
  2. (a, b) in gridNodePosition => (?, ?) in cellPosition
#4

I output some of the mapping between the two

截屏2023-08-28 下午11.18.36
截屏2023-08-28 下午11.18.36902×1118 133 KB

#5

finally I got the formula:
Given (0, 0) of cellPosition in tilemap == (_baseX, _baseY) of gridNodePosition in A* map
then

public static GridNode GetGridNodeByTileMapIndex(Vector3Int position)
        {
            int nx = position.x + _baseX + (position.y + 1) / 2;
            int ny = position.y + _baseY;
            return GridGraph.GetNode(nx, ny) as GridNode;
        }

public static Vector3Int GetTileMapIndexByGridNode(GridNode gridNode)
        {
            int y = gridNode.ZCoordinateInGrid - _baseY;
            int x = gridNode.XCoordinateInGrid - _baseX - (y + 1) / 2;
            return new Vector3Int(x, y);
        }
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