Unity: Touch Delay is too high - unity3d

Question

I want to make a game, where you can throw items in 2D via drag and drop. This works fine, but the tracking of grabbing them is very bad. If I touch them in the top half the tracking won't or barely work.
Are there other methods to prevent this?
public class DropsBehaviour : MonoBehaviour {
//Declaring Variables
public int force = 10;
float maxSpeedPreset = 5;
float maxSpeed = 5;
float MaxThrowSpeed = 8;
GameManager gm;
Rigidbody rig;
Camera cam;
bool selected = false;
bool once = false;
void Start() {
gm = GameManager.FindMe();
rig = GetComponent<Rigidbody>();
cam = Camera.main;
}
void Update() {
if (selected) {
rig.AddForce((cam.ScreenToWorldPoint(Input.mousePosition) - transform.position) * force);
rig.velocity = Vector3.zero;
} else {
if (!once) {
maxSpeed = maxSpeedPreset * gm.gameSpeed;
rig.velocity = new Vector3(Mathf.Clamp(rig.velocity.x, -maxSpeed, maxSpeed), Mathf.Clamp(rig.velocity.y, -maxSpeed, maxSpeed), Mathf.Clamp(rig.velocity.z, -maxSpeed, maxSpeed));
} else {
maxSpeed = maxSpeedPreset;
rig.velocity = new Vector3(Mathf.Clamp(rig.velocity.x, -MaxThrowSpeed, MaxThrowSpeed), Mathf.Clamp(rig.velocity.y, -MaxThrowSpeed, MaxThrowSpeed), Mathf.Clamp(rig.velocity.z, -MaxThrowSpeed, MaxThrowSpeed));
}
}
}
void OnMouseDown() {
if (tag != "NoInteract") {
selected = true;
once = true;
}
}
void OnMouseUp() {
selected = false;
}
}

Answer 1

I see quite a few issues in the code snippet you posted that could cause stuttering.
First, if you are making something in 2D, it's recommended to use Rigidbody2D and Collider2D.
Then, you shouldn't edit a rigidbody's velocity by hand, as stated in the doc. That's what add force is made for.
When updating anything related to physics, you should do it in FixedUpdate, not Update.
I assume you also forgot to put " once = false " on the first pass ? Really not sure about this one.
I edited your script following the points stated before, while keeping the rigidbody 3D. I dind't tested it, but hopefully it will correct the weird drag behavior you're experiencing! (note that I removed the GameManager part since i can't know what it does)
public class DropsBehaviour : MonoBehaviour
{
public int force = 10;
private const float MaxSpeedPreset = 5;
private float _maxSpeed = 5;
private const float MaxThrowSpeed = 8;
private Rigidbody _rig;
private Camera _cam;
private bool _selected;
private bool _once;
private Vector3 _targetVelocity;
private void Start()
{
_rig = GetComponent<Rigidbody>();
_cam = Camera.main;
}
private void Update()
{
if (_selected) return;
if (!_once)
{
_maxSpeed = MaxSpeedPreset * 10;
_targetVelocity = new Vector3(Mathf.Clamp(_rig.velocity.x, -_maxSpeed, _maxSpeed),
Mathf.Clamp(_rig.velocity.y, -_maxSpeed, _maxSpeed),
Mathf.Clamp(_rig.velocity.z, -_maxSpeed, _maxSpeed));
}
else
{
_maxSpeed = MaxSpeedPreset;
_targetVelocity = new Vector3(Mathf.Clamp(_rig.velocity.x, -MaxThrowSpeed, MaxThrowSpeed),
Mathf.Clamp(_rig.velocity.y, -MaxThrowSpeed, MaxThrowSpeed),
Mathf.Clamp(_rig.velocity.z, -MaxThrowSpeed, MaxThrowSpeed));
_once = false; //Dunno if it's intended or not ?
}
}
private void FixedUpdate()
{
if (_selected)
{
_rig.AddForce((_cam.ScreenToWorldPoint(Input.mousePosition) - transform.position) * force);
_rig.velocity = Vector3.zero;
return;
}
var velocity = _rig.velocity;
var velocityChange = _targetVelocity - velocity;
_rig.AddForce(velocityChange, ForceMode.VelocityChange);
}
private void OnMouseDown()
{
if (CompareTag("NoInteract")) return;
_selected = true;
_once = true;
}
private void OnMouseUp()
{
_selected = false;
}
}
On a side note, I personnaly don't like tags, I would use a LayerMask instead since it's somewhat related to physics. I'd probably replace the OnMouse events with a Raycast too, that way you would have a lot more control on what is happening on the physic side.