Physics2D.Raycast

Parámetros

Valor de retorno

RaycastHit2D The cast results returned.

Descripción

Casts a ray against colliders in the Scene.

A raycast is conceptually like a laser beam that is fired from a point in space along a particular direction. Any object making contact with the beam can be detected and reported.

This function returns a RaycastHit object with a reference to the collider that is hit by the ray (the collider property of the result will be NULL if nothing was hit). The layerMask can be used to detect objects selectively only on certain layers (this allows you to apply the detection only to enemy characters, for example).

Overloads of this method that use contactFilter can filter the results by the options available in ContactFilter2D.

Raycasts are useful for determining lines of sight, targets hit by gunfire and for many other purposes in gameplay.

Additionally, this will also detect Collider(s) at the start of the ray. In this case, the ray starts inside the Collider and doesn't intersect the Collider surface. This means that the collision normal cannot be calculated, in which case the returned collision normal is set to the inverse of the ray vector being tested. This can easily be detected because such results are always at a RaycastHit2D fraction of zero.

See Also: LayerMask class, RaycastHit2D class, RaycastAll, Linecast, DefaultRaycastLayers, IgnoreRaycastLayer, raycastsHitTriggers.

using UnityEngine;

public class Example : MonoBehaviour
{
    // Float a rigidbody object a set distance above a surface.

    public float floatHeight;     // Desired floating height.
    public float liftForce;       // Force to apply when lifting the rigidbody.
    public float damping;         // Force reduction proportional to speed (reduces bouncing).

    Rigidbody2D rb2D;


    void Start()
    {
        rb2D = GetComponent<Rigidbody2D>();
    }

    void FixedUpdate()
    {
        // Cast a ray straight down.
        RaycastHit2D hit = Physics2D.Raycast(transform.position, -Vector2.up);

        // If it hits something...
        if (hit.collider != null)
        {
            // Calculate the distance from the surface and the "error" relative
            // to the floating height.
            float distance = Mathf.Abs(hit.point.y - transform.position.y);
            float heightError = floatHeight - distance;

            // The force is proportional to the height error, but we remove a part of it
            // according to the object's speed.
            float force = liftForce * heightError - rb2D.velocity.y * damping;

            // Apply the force to the rigidbody.
            rb2D.AddForce(Vector3.up * force);
        }
    }
}

Parámetros

Valor de retorno

int Returns the number of results placed in the results array.

Descripción

Casts a ray against colliders in the Scene.

A raycast is conceptually like a laser beam that is fired from a point in space along a particular direction. Any object making contact with the beam can be detected and reported.

This function returns the number of contacts found and places those contacts in the results array. The results can also be filtered by the contactFilter.

See Also: ContactFilter2D and RaycastHit2D.