Frame rate when moving input.MousePosition

Question

Why is it that when the Input.MousePosition of frames is accelerated, it drops quickly and the actions performed at this moment are performed several times less often, let's say we spawn the object, when the mouse is moved slowly, the detours will spawn perfectly, and if we move the mesh to another point faster, then we will spawn these detours less often by 3-4 times, depending on the speed of the jerk?

public GameObject prefab;

void FixedUpdate()
{
    if(Input.GetMouseButton(0))
    {
        SpawnPoint();
    }
}
public void SpawnPoint()
{
    Transform inst = Instantiate(prefab).transform;

    inst.position = (Vector2)Camera.main.ScreenToWorldPoint(Input.mousePosition);
}

Here's what happens in the game itself 1 when moving slowly 2 with a quick jerk of movement enter image description here

Answer 1

You should check for user input in Update() instead of FixedUpdate()

The reason you typically get user input in Update is because it runs once per frame, where FixedUpdate does not - it runs per physics tick, and more or less than one of those may occur each frame.

So a general rule is to get user input in Update and handle the physics related stuff in FixedUpdate.

Then in your SpawnPoint you are instantiating an object and Instantiate() is little bit expensive plus Camera.main will try to find camera every physics frame by doing FindGameObjectsWithTag() so you should also cache Camera into a variable instead.