Version: 2019.4
LanguageEnglish
  • C#

PhysicsScene2D.GetRayIntersection

Suggest a change

Success!

Thank you for helping us improve the quality of Unity Documentation. Although we cannot accept all submissions, we do read each suggested change from our users and will make updates where applicable.

Close

Submission failed

For some reason your suggested change could not be submitted. Please <a>try again</a> in a few minutes. And thank you for taking the time to help us improve the quality of Unity Documentation.

Close

Cancel

public RaycastHit2D GetRayIntersection(Ray ray, float distance, int layerMask = Physics2D.DefaultRaycastLayers);

Parameters

ray The 3D ray defining origin and direction to test.
distance Maximum distance over which to cast the ray.
layerMask Filter to detect colliders only on certain layers.

Returns

RaycastHit2D The cast results returned.

Description

Cast a 3D ray against the colliders in the PhysicsScene2D, returning the first intersection only.

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

Unlike Raycast which performs a 2D intersection test, this function performs a 3D intersection test on 2D colliders. It does this by projecting the 3D ray into 2D space then performs the 2D intersection test, ordering the results by the Z direction of the original 3D ray. In this case, only the first result is returned.

This function returns a RaycastHit2D object with a reference to the Collider2D 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.

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: PhysicsScene2D class, RaycastHit2D class, Physics2D.DefaultRaycastLayers, Physics2D.IgnoreRaycastLayer, Physics2D.queriesHitTriggers.


public int GetRayIntersection(Ray ray, float distance, RaycastHit2D[] results, int layerMask = Physics2D.DefaultRaycastLayers);

Parameters

ray The 3D ray defining origin and direction to test.
distance Maximum distance over which to cast the ray.
results The array to receive results. The size of the array determines the maximum number of results that can be returned.
layerMask Filter to detect colliders only on certain layers.

Returns

int The number of results returned.

Description

Cast a 3D ray against the colliders in the PhysicsScene2D, returning all intersections.

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

Unlike Raycast which performs a 2D intersection test, this function performs a 3D intersection test on 2D colliders. It does this by projecting the 3D ray into 2D space then performs the 2D intersection test, ordering the results by the Z direction of the original 3D ray.

This function returns any Collider2D that intersect the 3D ray with the results returned in the supplied array. The integer return value is the number of objects that intersect the line (possibly zero) but the results array will not be resized if it doesn't contain enough elements to report all the results. The significance of this is that no memory is allocated for the results and so garbage collection performance is improved. Note that you will always get zero results if you pass an empty array.

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.

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.

All results are sorted by ascending distance order.

See Also: PhysicsScene2D class, RaycastHit2D class, Physics2D.DefaultRaycastLayers, Physics2D.IgnoreRaycastLayer, Physics2D.queriesHitTriggers.