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How to detect when a cube is directly above another cube?

I am using the Unity Engine with C#.
I have a 1x1 cube which moves forward on a grid of 49, 1x1 cubes (screenshot below) - when I press the start button on the controller.
The movement code for the cube is below.
void MovePlayerCube()
{
transform.Translate(direction * moveSpeed * Time.deltaTime);
}
When this cube passes over a cube with an arrow on it, the cube will change direction to where the arrow is pointing (staying on the same Y axis).
I need to detect the exact point at which the cube is directly over the cube with the arrow on it, and run the 'change direction' code at that point.
I'm currently using Vector3.Distance to check if the X and Z coordinates of the 2 cubes are close enough together (if they are less than 0.03f in distance), I can't check if they are equal due to floating point imprecision.
However this is really ineffective as half the time this code doesn't register for probably the same reason, and if I increase the 0.03f to a point where it never misses it becomes really noticeable that the cube isn't aligned with the grid anymore.
There has to be a proper solution to this and hopefully I've clarified the situation enough?
Any advice is appreciated.

You are moving your cube via
transform.Translate(direction * moveSpeed * Time.deltaTime);
which will never be exact an might overshoot your positions.
=> I would rather implement a coroutine for moving the cube exactly one field at a time, ensuring that after each iteration it fully aligns with the grid and run your checks once in that moment.
It doesn't even have to match exactly then, you only need to check if you are somewhere hitting a cube below you.
So something like e.g.
private Vector3Int direction = Vector3Int.left;
private IEnumerator MoveRoutine()
{
// depends on your needs if this runs just forever or certain steps
// or has some exit condition
while(true)
{
// calculate the next position
// optional round it to int => 1x1 grid ensured on arrival
// again depends a bit on your needs
var nextPosition = Vector3Int.RoundToInt(transform.position) + direction;
// move until reaching the target position
// Vector3 == Vector3 uses a precision of 1e-5
while(transform.position != nextPosition)
{
transform.position = Vector3.MoveTowards(transform.position, nextPosition, moveSpeed * Time.deltaTime);
yield return null;
}
// set target position in one frame just to be sure
transform.position = nextPosition;
// run your check here ONCE and adjust direction
}
}
start this routine only ONCE via
StartCoroutine(MoveRoutine());
or if you have certain exit conditions at least only run one routine at a time.
A Corouine is basically just a temporary Update routine with a little bit different writing => of course you could implement the same in Update as well if you prefer that
private Vector3Int direction = Vector3Int.left;
private Vector3 nextPosition;
private void Start()
{
nextPosition = transform.position;
}
private void Update()
{
if(transform.position != nextPosition)
{
transform.position = Vector3.MoveTowards(transform.position, nextPosition, moveSpeed * Time.deltaTime);
}
else
{
transform.position = nextPosition;
// run your check here ONCE and adjust direction
// then set next position
nextPosition = Vector3Int.RoundToInt(transform.position) + direction;
}
}
Then regarding the check you can have a simple raycast since you only run it in a specific moment:
if(Physics.Raycast(transform.position, Vector3.down, out var hit))
{
direction = Vector3Int.RountToInt(hit.transform.forward);
}
assuming of course your targets have colliders attached, your moved cube position (pivot) is above those colliders (assumed it from your image) and your targets forward actually points int the desired new diretcion

I would do it this way. First I would split the ability of certain objects to be "moving with certain speed" and "moving in a certain direction", this can be done with C# interfaces. Why? Because then your "arrow" cube could affect not only your current moving cube, but anything that implements the interfaces (maybe in the future you'll have some enemy cube, and it will also be affected by the arrow modifier).
IMovingSpeed.cs
public interface IMovementSpeed
{
float MovementSpeed{ get; set; }
}
IMovementDirection3D.cs
public interface IMovementDirection3D
{
Vector3 MovementDirection { get; set; }
}
Then you implement the logic of your cube that moves automatically in a certain direction. Put this component on your player cube.
public class MovingStraight: MonoBehaviour, IMovementSpeed, IMovementDirection3D
{
private float _movementSpeed;
Vector3 MovementSpeed
{
get { return _movementSpeed; }
set { _movementSpeed = value; }
}
private Vector3 _movementDirection;
Vector3 MovementDirection
{
get { return _movementDirection; }
set { _movementDirection= value; }
}
void Update()
{
// use MovementSpeed and MovementDirection to advance the object position
}
}
Now to implement how the arrow cube modifies other objects, I would attach a collision (trigger) component for both moving cube and the arrow cube.
In the component of the arrow cube, you can implement an action when something enters this trigger zone, in our case we check if this object "has direction that we can change", and if so, we change the direction, and make sure that the object will be aligned, by forcing the arrow cube's position and the other object's position to be the same on the grid.
public class DirectionModifier: MonoBehaviour
{
private Vector3 _newDirection;
private void OnTriggerEnter(Collider collider)
{
IMovementDirection3D objectWithDirection = collider as IMovementDirection3D ;
if (objectWithDirection !=null)
{
objectWithDirection.MovementDirection = _newDirection;
// to make sure the object will continue moving exactly
// from where the arrow cube is
collider.transform.position.x = transform.position.x;
collider.transform.position.y = transform.position.y;
}
}
}
If you made your trigger zones too large, however, then the moving cube will "jump" abruptly when it enters the arrow cube's trigger zone. You can fix it by either starting a coroutine as other answers suggested, or you could make the trigger zones pretty small, so that the jump is not noticeable (just make sure not to make them too small, or they may not intersect each other)
You could then similarly create many other modifying blocks, that would change speed or something

I think that it is enough for you to check if the X and Z coordinates are equal, since the movement occurs only along them
Example
if(_player.transfom.position.x == _gameSquare.transfom.position.x && _player.transfom.position.z == _gameSquare.transfom.position.z)
{
Debag.Log("Rotate!")
}

how to rotate object according to the rotation of the camera?

i want to rotate player body according to the rotation of the camera. like FPS game.
STEPS >>
When the camera is facing down, i can see my body under the camera.
My body has to follow the location of the camera.
My body has to also follow the rotation of the camera.
So i can see my body anywhere when i facing down camera.
here is my code. It is attached to body(the object i have to rotate).
private void Update()
{
transform.position = arCamera.transform.position;
transform.rotation = arCamera.transform.rotation;
}
I want to see my body when the camera facing down but body rotates according with camera so i never see the body. How can i see it? ;(
Please help!

Sounds like you want your body only copy the rotation around the Y axis.
It is way easier to calculate with vectors than with quaternion rotations ;)
private void Update()
{
transform.position = arCamera.transform.position;
// Take your camera forward vector
var camForward = arCamera.transform.forward;
// erase the Y component
camForward.y = 0;
// and now make your body look into this flattened direction
transform.rotation = Quaternion.LookDirection(camForward, Vector3.up);
}
See also Quaternion.LookDirection.
This has of course one little flaw: The moment the camera looks up or down more than 90° the body is flipping to the opposite direction. So you either want to limit the camera rotation or come up with a different approach.
E.g. assuming that it is way harder for a human being to rotate (tilt) the head more then 90° on the Z axis, you could instead also do
private void Update()
{
transform.position = arCamera.transform.position;
// Take your camera forward vector
var camRight = arCamera.transform.right;
// erase the Y component
camRight.y = 0;
// and now align the body's right axis with this flattened direction
// Since we never touch the object's up vector this works without problems
transform.right = camRight;
}

Getting distance between point of an object and another object

First, I'd like to apologize because this is a very basic and repetitive question, but I am completely new to game development.
I understand that I can find a distance between two objects using:
float dist = Vector3.Distance(other.position, transform.position);
However, how can I find the distance between a point of one object to other object?
For instance let's say my object is this sphere
Now, how can I return an array that says that there are no objects to the left (null), in the front there is an object at 1, and to the right there is an object at 0.5?
Thank you for your patience and understanding

I'm not exactly sure what you wan't to achieve...
If you wan't to get potential objects at 0.5, 1, 1.5, etc. on lets say the Z Axis you probably would want to do this with raycasting.
If you wish to check for any objects returning the direction dependant to the Z Axis (0.5, 0.856, 1.45, etc) in contrast, you probably would either
use a scaled sphere collider and add the colliding object with the OnCollisionEnter Callback to the array/List
iterate through every object of the scene and check it's relative pos
Use Raycast Probes procedurally (using a density float and Raycasting every density offset on the Z Axis and checking if the ray hit anything ...)
...
Totally dependant on your case of use, and whether you use 2D or 3D.
Seneral
EDIT: Here's what you would want in 2D to get a wall withing range maxRange on the layer optionalWallLayer in direction y 1 (up in unity 2D)
float maxRange = 10.0f;
RaycastHit hit;
Vector3 dir = transform.TransformDirection(new Vector3 (0, 1, 0));
if (Physics.Raycast(transform.position, dir, maxRange, out hit, LayerMask optionalWallLayer))
{
Debug.Log ("Wall infront of this object in Range" + hit.distance);
// hit contains every information you need about the hit
// Look into the docs for more information on these
}
This would likely go into the Update Function of your Sphere's MonoBehaviour.
The option with the Sphere collider is useful if you are not sure if you are going to hit your obstacles. If these are small, you would likely want to add the said Sphere Collider as a component to your sphere, scale it up to your maximum distance, and add a MonoBehaviour script to the sphere, which would contain something like this:
public List<Transform> allObjectsInRange; // GameObjects to enclose into calculations, basically all which ever entered the sphere collider.
public List<float> relatedDistances;
void Update () {
// basic loop to iterate through each object in range to update it's distance in the Lists IF YOU NEED...
for (int cnt = 0; cnt < allObjectsInRange.Count; cnt++) {
relatedDistances[cnt] = Vector2.Distance (transform.position, allObjectsInRange[cnt].position);
}
}
// Add new entered Colliders (Walls, entities, .. all Objects with a collider on the same layer) to the watched ones
void OnCollisionEnter (Collision col) {
allObjectsInRange.Add (col.collider.transform);
relatedDistances.Add (Vector2.Distance (transform.position, col.collider.transform));
}
// And remove them if they are no longer in reasonable range
void OnCollisionExit (Collision col) {
if (allObjectsInRange.Contains (col.collider.transform)) {
relatedDistances.RemoveAt (allObjectsInRange.IndexOf (col.collider.transform));
allObjectsInRange.Remove (col.collider.transform);
}
}
That should do it, either of the options, based on your exact case, again:) Note both are pseudo-codes... Hope it helps!

How can I rotate a vector (centripetal force)?

I'm trying to implement centripetal force in a programming language.
I saw some videos teaching the theory. But I dont know how to apply that in a programming language.
If I understand I have to apply centripetal force ac = v²/r to the velocity vector. But I dont know exactly how to proceed.
I have two game objects, one depicting Earth, other depicting Moon. What I wanted is to translate the moon around earth and using a button to "cut/cancel" the centripetal force in order to the moon get out to the earth's orbit.
I have no clue how to start that.
All I know is to rotate like this:
velocity.x = Mathf.Cos(Time.time) * earth_moon_radius;
velocity.z = Mathf.Sin(Time.time) * earth_moon_radius;
moon.transform.position = velocity;
But how to apply centripetal force as described above?

If you just want to have the moon rotating around earth and some trigger to release the moon, it's easier to use rotation around a center instead of forces. Given the following GameObject hierarchy:
Center (MoonRotator attached)
-- Moon
-- Earth
public class MoonRotator : MonoBehaviour
{
public bool cancelCentripetalForce = false;
public Vector3 angularVelocity = new Vector3 (0f, 0f, 100f);
public GameObject moon;
void Update () {
if (cancelCentripetalForce) {
Vector3 radius = moon.transform.position - transform.position;
Vector3 angularVelocityRadians = Mathf.Deg2Rad * angularVelocity;
moon.rigidbody.velocity = Vector3.Cross (angularVelocityRadians, radius);
moon.transform.parent = null;
Destroy (this);
} else {
Vector3 rot = transform.rotation.eulerAngles + angularVelocity * Time.deltaTime;
transform.rotation = Quaternion.Euler (rot);
}
}
}
If cancelCentripetalForce is set true Moon stops travelling around earth but proceeds with its current tangential velocity. This is given as:
v = ω × r
Earth has localPosition (0, 0, 0) and Moon is in this example located in the x-y plane rotating around the z axis.

If you want to cancel the force, add an opposing force vector that is based on your object's linear velocity and current direction.
So I have an object pointing straight along the Z axis. The object's 'forward' vector is 0, 0, 1. Do 1 - Math.abs(forward.x), same for y and z to get 1, 1, 0 when you're pointing forward along the Z axis. You want the direction you're pointing in to be 0'd so that the inertia from that direction is not damped in any way. Now you can apply a cancellation force in any direction that you are NOT pointed in.
This means that if your object is moving in any direction in world space that it's not facing in you can easily apply a cancellation force that is multiplied by the object's linear velocity to get circular motion that uses forces instead of directly setting velocity.
Another way you can do it is solve for V by manually setting it, then find radius using V=RW. You should know V and R or W. Now you can find the force necessary to keep the orbit stable around a point, rather than adding inertia from every frame.

Rotating a vector

I want to do a simple vector rotation.
The goal is to head my first-person camera which is currently pointing to to target t with direction d to a new target t1 with a new direction d1.
The transition between d and d1 should be a smooth movement.
With
public void FlyLookTo(Vector3 target) {
_flyTargetDirection = target - _cameraPosition;
_flyTargetDirection.Normalize();
_rotation = new Matrix();
_rotationAxis = Vector3.Cross(Direction, _flyTargetDirection);
// This bool tells the Update()-method to trigger the changeDirection() method.
_isLooking = true;
}
I am initiating the direction change with its new parameter and with
// this method gets executed by the Update()-method if the isLooking flag is up.
private void _changeDirection() {
dist = Vector3.Distance(Direction, _flyTargetDirection);
// check whether we have reached the desired direction
if (dist >= 0.00001f) {
_rotationAxis = Vector3.Cross(Direction, _flyTargetDirection);
_rotation = Matrix.CreateFromAxisAngle(_rotationAxis, MathHelper.ToRadians(_flyViewingSpeed - Math.ToRadians(rotationSpeed)));
// update the cameras direction.
Direction = Vector3.TransformNormal(Direction, _rotation);
} else {
_onDirectionReached();
_isLooking = false;
}
}
I am performing the actual movement.
My Problem: The actual movement works fine but the speed of the movement slows down the more the current direction gets closer to the desired direction which makes it a very unpleasant movement if executes several times in a row.
How can I make the camera move from direction d to direction d1 with an equal speed over its movement ?

your code looks pretty solid. does _flyViewingSpeed or rotationSpeed change at all?
Another approach would be to use Vector3.Lerp() which will do exactly what you're trying to do. note however, you need to use the initial start and goal directions - not the current directions - or you'll get varying speed changes.
Also, instead of using distance (which is usually used for points), i would use Vector3.Dot() which is kind of like distance for directions. it should also be faster than Distance().
hope this helps.