Can't snap to isometric grid properly (with screenshot)

Hello all !
I'm working on a 2D isometric city building game. I made a script that rounds the position of the spawned building to make it snap to my isometric grid. It works fine but I would like to avoid "half values" : at the moment the player can spawn a building between two cells as shown on the image.


The following is the code I use (BuildingData is a ScriptableObject). The magic mostly happens between line 60 and 70 :

Code (CSharp):

1. using System;
2. using System.Collections;
3. using System.Collections.Generic;
4. using UnityEngine;
5. using UnityEngine.UI;
6.  
7. public class BuildItems : MonoBehaviour
8. {
9.     [HideInInspector] public float buildingCount;
10.  
11.     [Header("UI Elements")]
12.     public Text natureDisplay;
13.     public Text foodDisplay;
14.  
15.     [Header("Forge")]
16.     public BuildingData forgeData;
17.     [SerializeField] private GameObject forgePrefab;
18.  
19.     private float naturePoints, foodPoints;
20.     private Vector3 mousePosition, worldPosition;
21.     private bool isPlacing, isOverlapping;
22.     private GameObject lastBuilt;
23.     private GameObject canva;
24.     //This code is responsible for triggering the building of an item when a button is pressed in the UI.
25.  
26.     private void Start()
27.     {
28.         naturePoints = GameObject.Find("ResourceController").GetComponent<NatureController>().naturePoints;
29.         foodPoints = GameObject.Find("ResourceController").GetComponent<FoodController>().foodPoints;
30.         natureDisplay = GameObject.Find("NaturePointsDisplay").GetComponent<Text>();
31.         foodDisplay = GameObject.Find("FoodPointsDisplay").GetComponent<Text>();
32.         canva = GameObject.Find("Canvas");
33.         natureDisplay.text = naturePoints.ToString();
34.  
35.         buildingCount = 0;
36.     }
37.  
38.     private void Update()
39.     {
40.         //We store the world location of the mouse at each frame.
41.         CheckMouseInput();
42.  
43.         //Opens Build Menu if player presses tab.
44.         if (Input.GetKeyDown(KeyCode.Tab))
45.         {
46.             canva.SetActive(true);
47.         }
48.  
49.         //If the player pressed a build button and had enought Points, he is placing the future building in the world.
50.         if (isPlacing == true)
51.         {
52.             //We assign the building blueprint's position to the mouse position.
53.             lastBuilt.transform.position = worldPosition;
54.  
55.             //We assign the collision checking method to the instantiated gameobject.
56.             isOverlapping = lastBuilt.GetComponent<ItemManager>().isOverlapping;
57.  
58.             //If the player presses his mouse button, we check for collision. If any, the player can't build. Otherwise, the building is placed.
59.             if (Input.GetMouseButtonDown(0))
60.             {
61.                 if (isOverlapping == false)
62.                 {
63.                     isPlacing = false;
64.                     Debug.Log("You built an item.");
65.  
66.                     //We assign the object's position to mouse position rounded to isometric proportions.
67.                     lastBuilt.transform.position = new Vector3(Mathf.Round(worldPosition.x * 2) / 2, Mathf.Round(worldPosition.y * 4) / 4, worldPosition.z);
68.  
69.                     //Nature cost is paid and nature points are displayed.
70.                     naturePoints = naturePoints - lastBuilt.GetComponent<ItemManager>().natureCost;
71.                     natureDisplay.text = naturePoints.ToString();
72.  
73.                     lastBuilt.GetComponent<ItemManager>().StartBuilding();
74.                 }
75.                 else
76.                 {
77.                     Debug.Log("You can't build here.");
78.                 }
79.             }
80.         }
81.     }
82.  
83.     public void BuildForge()
84.     {
85.         if (naturePoints >= forgeData.natureCost)
86.         {
87.             canva.SetActive(false);
88.             //If the player has enough Nature Points, the item is created as "forge
89.             lastBuilt = Instantiate(forgePrefab);
90.             lastBuilt.name = forgeData.buildingName + buildingCount++;
91.             isPlacing = true;
92.         }
93.     }
94.  
95.     private void CheckMouseInput()
96.     {
97.         mousePosition = Input.mousePosition;
98.         mousePosition.z = Camera.main.nearClipPlane;
99.         worldPosition = Camera.main.ScreenToWorldPoint(mousePosition);
100.     }
101. }
102.  

How could I avoid that ?
Thank you for reading me.
Best regards;

 

Probably should just be using the worldtocell/celltoworld function from the grid for this sort of thing instead of manually computing it.

 

Thank you for your answer.
I am a bit confused, as the Unity Scripting API describes worldtocell as to be used with a GridLayout and not a Grid. Isn't a Grid Layout an UI component ?
Thank you

 

Figured it out, thank you so much ! I'm pasting the code in here. I have taken off many things to leave the minimum, so some things might not fit with the //description.
Void BuildForge is triggered by a button.

Code (CSharp):

1. using System;
2. using System.Collections;
3. using System.Collections.Generic;
4. using UnityEngine;
5. using UnityEngine.UI;
6. using UnityEngine.Tilemaps;
7.  
8. public class BuildItems : MonoBehaviour
9. {
10.     [Header("Forge")]
11.     [SerializeField] private GameObject forgePrefab;
12.  
13.     private Vector3 mousePosition, worldPosition;
14.     private Vector3Int cellPosition;
15.     private GameObject lastBuilt;
16.     private Tilemap tilemap;
17.     //This code is responsible for triggering the building of an item when a button is pressed in the UI.
18.  
19.     private void Start()
20.     {
21.         tilemap = GameObject.Find("Tilemap").GetComponent<Tilemap>();
22.     }
23.  
24.     private void Update()
25.     {
26.         //We store the world location of the mouse at each frame.
27.         CheckMouseInput();
28.  
29.         //If the player pressed a build button and had enought Points, he is placing the future building in the world.
30.         if (isPlacing == true)
31.         {
32.             //We assign the building blueprint's position to the mouse position.
33.             lastBuilt.transform.position = worldPosition;
34.  
35.             //If the player presses his mouse button, we check for collision. If any, the player can't build. Otherwise, the building is placed.
36.             if (Input.GetMouseButtonDown(0))
37.             {
38.                 if (isOverlapping == false)
39.                 {
40.                     isPlacing = false;
41.                     Debug.Log("You built an item.");
42.  
43.                     //We assign the object's position to mouse position rounded to isometric proportions.
44.                     lastBuilt.transform.position = new Vector3 (tilemap.GetCellCenterLocal(cellPosition).x, tilemap.GetCellCenterLocal(cellPosition).y, -1);
45.  
46.                     lastBuilt.GetComponent<ItemManager>().StartBuilding();
47.                 }
48.                 else
49.                 {
50.                     Debug.Log("You can't build here.");
51.                 }
52.             }
53.         }
54.     }
55.  
56.     public void BuildForge()
57.     {
58.         if (naturePoints >= forgeData.natureCost)
59.         {
60.             canva.SetActive(false);
61.             //If the player has enough Nature Points, the item is created as "forge
62.             lastBuilt = Instantiate(forgePrefab);
63.             lastBuilt.name = forgeData.buildingName + buildingCount++;
64.             isPlacing = true;
65.         }
66.     }
67.  
68.     private void CheckMouseInput()
69.     {
70.         mousePosition = Input.mousePosition;
71.         mousePosition.z = Camera.main.nearClipPlane;
72.         worldPosition = Camera.main.ScreenToWorldPoint(mousePosition);
73.         cellPosition = tilemap.WorldToCell(worldPosition);
74.     }
75. }