Physics2D. Raycast() - How to use the ContactFilter2D Overload?

Unity Engine
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1

Concept: I’m using this to create a 2D “laser” hazard of sorts for a 2D puzzle game. Laser can be blocked by certain objects to allow passage and it will cause damage to the player if they touch the laser.

I am basically trying to use Raycast to shoot a ray and detect collisions in the game space, however I only want the ray to detect collisions with particular layers in my scene and not others (i.e. the tilemap, the player, a platform, etc.)

I declare a public variable for ContactFilter2D and call if “cf”. I configure the layers I want to be detected in the unity inspector and check the “use Layer Mask” checkbox.

However, when I try to use “cf” as an ContactFilter2D overload in Physics2D.Raycast, it is expecting the ContactFilter2D to return an int value.

Might I need to convert the layers I specified in my contact filter into an array of some sort that will give them an int value?

2

Hey,

I’ve never actually used this before, but it looks like you need to access the .layerMask property of the contact filter.

    ContactFilter2D filter;

    void Update()
    {
        Physics2D.Raycast(transform.position, Vector2.up, 1f, filter.layerMask);
    }

Hopefully that works, I haven’t tested it.

3

Physics2D.Raycast has a bunch of overloads, so you might be getting the wrong one by accident. I do it like this:

int hitCount = Physics2D.Raycast(origin, dir, filter, output, length);

In this case, output is a RaycastHit2D[ ], and filter is the ContactFilter2D. If you don’t include the RaycastHit2D array output, I think you’ll get a different overload.

4

That seems to have done the trick. Thanks!

5

this is exactly what I was looking for. I appreciate the help

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