in game snap to grid

hey everyone,

how can i go about making an object have a snap to grid feature while in game?

my current solution is to space apart empty game objects evenly around the level where snap is needed, but this can come out to be A LOT of points.

say i need the object to be able to be snapped every 1 unit, is there a more code efficient way to go about this?

thanks

 

Code (csharp):

1. var currentPos = transform.position;
2. transform.position = Vector3(Mathf.Round(currentPos.x),
3.                              Mathf.Round(currentPos.y),
4.                              Mathf.Round(currentPos.z));

--Eric

 

Impressive.

 

awesome! ill check it out thanks

 

Mathf... There we meet again...

Thanks for the code Eric.

 

Note to self: Don't over complicate simple things.

Thanks Eric.

 

Man.. Why is everything Eric posts so simple and profound?

 

how can you make it snap to a bigger, wider grid?

 

Try this (I haven't tested but it seemed logical to me).

Code (csharp):

1.  
2.     var currentPos = transform.position;
3.     transform.position = Vector3(Mathf.Round(currentPos.x * 10),
4.                                  Mathf.Round(currentPos.y * 10),
5.                                  Mathf.Round(currentPos.z * 10));
6.  

Or try multiply by 100 or 1000, whatever

 

Sorry, but that's incorrect. It's simply the other way around.

To get an object's position on a grid, you have to divide its position by the grid size.
So in case of a three dimensional grid, you'd calculate the position as follows:

Code (csharp):

1.  
2. Vector3 currentPos = transform.position;
3. transform.position = Vector3( Mathf.Round( currentPos.x / gridSize.x ),
4.                               Mathf.Round( currentPos.y / gridSize.y ),
5.                               Mathf.Round( currentPos.z / gridSize.z ) );
6.  

 

I guess that's how we learn thanks.

 

Another option: try

Mathf.Round(currentPos.x) * grid_scaling_size;

// multiplying AFTER rounding, which will "spread out" the otherwise unit-based grid if multiplying by values greater than 1, and will "squeeze" it if multiplying by values between 0 and 1.
// grid_scaling_size could also be a random value for craziness…

 

Of course, that's the great thing about coding. And I'm sorry, willemsenzo, I didn't want to sound too harsh, arrogant or even disrespectful.

 

If you want objects to keep as close to their original position as possible, but with a larger grid, you could use:

Code (csharp):

1. var currentPos = transform.position;
2. transform.position = Vector3(Mathf.Round(currentPos.x / grid_scale) * grid_scale,
3.                              Mathf.Round(currentPos.y / grid_scale) * grid_scale,
4.                              Mathf.Round(currentPos.z / grid_scale) * grid_scale);

 

Don't worry I don't feel offended in any way

 

Great thread, I plan to use some of the ideas on here. Could be very useful. Thanks everyone!

 

Just throwing in my two cents. I wrote a simple function that runs through an array of Vector2s (Or Vector3s) and returns the index of the position that is currently closest to yours.

Code (CSharp):

1.     int CompareSet( Vector2[] myArray, Vector2 pos ){
2.         int closestIndex = 0;
3.         float smallestDistance = 0.0f;
4.         for( int u = 0; u < myArray.Length; u++ ){
5.  
6.             if( u != 0 ){
7.  
8.                 float thisDistance = (pos - myArray[u]).sqrMagnitude;
9.  
10.                 closestIndex =  ( thisDistance < smallestDistance ) ? u : closestIndex;
11.                 smallestDistance = ( thisDistance < smallestDistance ) ? thisDistance : smallestDistance;
12.  
13.             }
14.  
15.             else smallestDistance = (pos - myArray[u]).sqrMagnitude;
16.  
17.         }
18.  
19.         return closestIndex;
20.  
21.     }

 

Still learning this. Could someone apply this in an example?

Code (CSharp):

1. Vector3 currentPos = transform.position;
2. transform.position = Vector3( Mathf.Round( currentPos.x / gridSize.x ),
3.                               Mathf.Round( currentPos.y / gridSize.y ),
4.                               Mathf.Round( currentPos.z / gridSize.z ) );

 

Yes I'd like to second that. I've tried to apply this to moving a cube around the terrain according to a grid but ended up with all kinds of errors.

 

Well, so far all we've talked about here is how to round numbers (note: only Errorsatz's post above does this correctly for a grid size other than one).

To actually apply this, we'd need to know more about what you're trying to accomplish... I mean, sure, you can snap an object to a grid, but how does it move? Does it move at all? Do you want it to slide smoothly from one grid position to another, and then snap? Or can it just jump from one grid position to the next? Are objects falling in from outer space, and you want them to only land on even grid positions? What?

Cheers,
- Joe

 

Hello JoeStrout. Thanks for the offer of help. Originally I wanted to move a building around the map according to a grid so it would be easier to place the buildings in perfectly straight lines. Since writing that comment I've found out that I do not need a grid to do this as I can just round to the nearest coordinate in unity. I will need to go back to grids soon though as I'm developing a turn-based combat system with tile-based movement (similar to fallout 1,2, wasteland 2 etc.).

So far I think I will need to instantiate a grid when combat begins and then limit movement to the tiles of that grid and to the number of points the player has to move (1 point = 1 grid square). I want the grid to be square and I want to allow diagonal movement and attack so it would have eight directions. The movement between grids should be smooth. I would also need to find a way to tie Aron Granberg's pathfinding into the grid so the units find the shortest route to the destination and avoid obstacles when they move.

I definitely don't expect anyone to have any ready made solutions to this. However any pointers in the right direction in regards any of the points raised would be appreciated.

 

You might look through the Asset Store... something like this or this might help.

Good luck,
- Joe

 

Thank you. If purchased assets allow you to look at the original code then this would be a great way to learn how to do some of these things.

 

Make sure you use a new Vector3 in C#

Code (CSharp):

1. Vector3 currentPos = transform.position;
2.         gameObject.transform.position = new Vector3(Mathf.Round(currentPos.x), Mathf.Round(currentPos.y), Mathf.Round(currentPos.z));

 

Old thread I know but I read it after searching as to why my function wasn't working and have some code that gives you an example.(FYI, MY problem was actually that I'm tired and used getkeydown instead of getkey and didn't notice, lol)

Code (CSharp):

1.             Vector3 MouseWorld = GetComponent<Camera>().ScreenToWorldPoint(new Vector3(Input.mousePosition.x, Input.mousePosition.y, -GetComponent<Camera>().transform.position.z - 5.0f));
2.  
3.             if (Input.GetKey(KeyCode.LeftControl))
4.             {
5.                 EditorPrefab.transform.position = new Vector3(((int)(MouseWorld.x / GridSize.x)) * GridSize.x, ((int)(MouseWorld.y / GridSize.y)) * GridSize.y, -5.0f);
6.             }
7.             else
8.             {
9.                 EditorPrefab.transform.position = MouseWorld;
10.             }

 

I made a forum account just to say that you are brilliant.

 

Well, thank you. Welcome to the forums!

--Eric

 

If I want to have differents prefab with diferen grid size of ocuppation for example house 4*4 bank 2*2 how can attack this problem with this piece of script:

1. Vector3 currentPos = transform.position;
2. transform.position = Vector3( Mathf.Round( currentPos.x / gridSize.x ),
3. Mathf.Round( currentPos.y / gridSize.y ),
4. Mathf.Round( currentPos.z / gridSize.z ) );

 

I followed this amazing tutorial :

how do i get that grid in there..can't figure it out...it uses a transform to instantiate a gameobject..but how do i link this to the grid can't get it done..

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4.  
5. public class StructurePlacement : MonoBehaviour {
6.  
7.  
8.     private Transform currentStructure;
9.     private PlaceableStructure placeableStructure;
10.     private Camera cam;
11.     private bool hasPlaced;
12.    
13.  
14.     public LayerMask structureMask;
15.  
16.     // Use this for initialization
17.     void Start() {
18.         cam = Camera.main;
19.     }
20.  
21.     // Update is called once per frame
22.     void Update()
23.     {
24.         Vector3 m = Input.mousePosition;
25.         m = new Vector3(m.x, m.y, transform.position.y);
26.         Vector3 p = cam.ScreenToWorldPoint(m);
27.  
28.         if (currentStructure != null && !hasPlaced)
29.         {
30.  
31.             currentStructure.position = new Vector3(p.x, 0, p.z);
32.  
33.             if (Input.GetMouseButtonDown(0))
34.             {
35.                 if (IsLegalPosition())
36.                 {
37.                     hasPlaced = true;
38.                 }
39.             }
40.         }
41.         else
42.         {
43.             if (Input.GetMouseButtonDown(0))
44.             {
45.                 RaycastHit hit = new RaycastHit();
46.                 Ray ray = new Ray(new Vector3(p.x, 8, p.z), Vector3.down);
47.                 if (Physics.Raycast(ray, out hit, Mathf.Infinity, structureMask))
48.                 {
49.                     Debug.Log(hit.collider.name);
50.                     //destroy the object that is clicked
51.                     Destroy(hit.collider.gameObject);
52.                 }
53.             }
54.         }
55.     }
56.  
57.  
58.     bool IsLegalPosition()
59.     {
60.         if(placeableStructure.colliders.Count>0)
61.         {
62.             return false;
63.         }
64.         return true;
65.     }
66.  
67.     public void SetItem(GameObject b)
68.     {
69.         hasPlaced = false;
70.         currentStructure = ((GameObject)Instantiate(b)).transform;
71.         placeableStructure = currentStructure.GetComponent<PlaceableStructure>();
72.     }
73. }

 

Okay say that you wanted your object to snap to a 0.5 grid, you can't use a math.Round on that because to it will just move it by moving it to an int, how do you get around this?

 

You divide by 0.5, round, and then multiply by 0.5.

 

Which is more performant:

Code (CSharp):

1. var p = new Vector3(Mathf.Round(r.x/g.x) * g.x, Mathf.Round(r.y/g.y) * g.y, Mathf.Round(r.z/g.z) * g.z);

or

Code (CSharp):

1. vvar p = new Vector3((int)(r.x / g.x) * g.x, (int)(r.y / g.y) * g.y, (int)(r.z / g.z) * g.z);

I suspect the latter as Math.Round has more processing

*I know one is to the nearest, the other is to the lower..

 

Spock, there is only ever one answer to this:

On the specific hardware you care about (NOT in the editor!), attach the Profiler (Window -> Profiler) and see.

Any other answer is simply not logical.

Kirk, er Kurt

 

I don't have test case to profile. That's why I'm asking.