Meshes created from code don't have a position unity-CodePudding

So, I tried to create a grid so that I can instantiate objects on it. I check for the position of said hit object (one of the squares I created) and then set the instantiated object to that position. Problem is, the squares I created with code don't have a position and are all set to 0, 0, 0.

    {
        GameObject tileObject = new GameObject(string.Format("{0}, {1}", x, y));
        tileObject.transform.parent = transform;

        Mesh mesh = new Mesh();
        tileObject.AddComponent<MeshFilter>().mesh = mesh;
        tileObject.AddComponent<MeshRenderer>().material = tileMaterial;

        Vector3[] vertices = new Vector3[4];
        vertices[0] = new Vector3(x * tileSize, 0, y * tileSize);
        vertices[1] = new Vector3(x * tileSize, 0, (y  1) * tileSize);
        vertices[2] = new Vector3((x  1) * tileSize, 0, y * tileSize);
        vertices[3] = new Vector3((x  1) * tileSize, 0, (y  1) * tileSize);

        int[] tris = new int[] { 0, 1, 2, 1, 3, 2 };

        mesh.vertices = vertices;
        mesh.triangles = tris;
        mesh.RecalculateNormals();

        tileObject.layer = LayerMask.NameToLayer("Tile");
        tileObject.AddComponent<BoxCollider>();

        //var xPos = Mathf.Round(x);
        //var yPos = Mathf.Round(y);

        //tileObject.gameObject.transform.position = new Vector3(xPos , 0f, yPos);

        return tileObject;
    }```

CodePudding user response：

As said your issue is that you leave all tiles on the position 0,0,0 and only set their vertices to the desired world space positions.

You would rather want to keep your vertices local like e.g.

// I would use the offset of -0.5f so the mesh is centered at the transform pivot
// Also no need to recreate the arrays everytime, you can simply reference the same ones
private readonly Vector3[] vertices = new Vector3[4]
{
    new Vector3(-0.5f, 0, -0.5f);
    new Vector3(-0.5f, 0, 0.5f);
    new Vector3(0.5f, 0, -0.5f);
    new Vector3(0.5f, 0, 0.5f);
};

private readonly int[] tris = new int[] { 0, 1, 2, 1, 3, 2 };

and then in your method do

GameObject tileObject = new GameObject($"{x},{y}");
tileObject.transform.parent = transform;
tileObject.localScale = new Vector3 (tileSize, 1, tileSize);
tileObject.localPosition = new Vector3(x * tileSize, 0, y * tileSize);

The latter depends of course on your needs. Actually I would prefer to have the tiles also centered around the grid object so something like e.g.

// The "-0.5f" is for centering the tile itself correctly 
// The "-gridWith/2f" makes the entire grid centered around the parent
tileObject.localPosition = new Vector3((x - 0.5f - gridWidth/2f) * tileSize, 0, (y - 0.5f - gridHeight/2f) * tileSize);

In order to later find out which tile you are standing on (e.g. via raycasts, collisions, etc) I would then rather use a dedicated component and simply tell it it's coordinates like e.g.

// Note that Tile is a built-in type so you would want to avoid confusion
public class MyTile : MonoBehaviour
{
    public Vector2Int GridPosition;
}

and then while generating your grid you would simply add

var tile = tileObject.AddComponent<MyTile>();
tile.GridPosition = new Vector2Int(x,y);

while you can still also access its transform.position to get the actual world space center of the tiles