CODEWITHSUNDEEP
c#unity-game-engineraycasting
MossTeMuerA
MossTeMuerA

Reputation: 165

Unity Raycast() and DrawRay() creates different Rays using same inputs

I'm trying to create a curved Ray and need to list the object that curved Ray hits. I am able to draw a curved Ray with Debug.DrawRay(). However, When I provide Raycast() the same parameters with DrawRay(), It's creating very different Ray (I guess because I can't see the Ray). The Raycast()'s Ray hits the object I highlighted in the image. But DrawRay()'s Ray is too far to hit the highlighted object. How can I make them create identical Rays? Here you can see the difference

//Here is the code:

public void CurveCast(Vector3 origin, Vector3 direction, Vector3 gravityDirection, int smoothness, float maxDistance, float direction_multiply, float radius)
{
    Vector3 currPos = origin, hypoPos = origin, hypoVel = (direction.normalized / smoothness) * direction_multiply;
    List<Vector3> v = new List<Vector3>();        
    float curveCastLength = 0;

    Ray ray;
    RaycastHit hit;
    hit_list = new List<RaycastHit>();
    while (curveCastLength < maxDistance)
    {
        ray = new Ray(currPos, hypoVel);

        Debug.DrawRay(currPos, hypoVel, Color.white);
        if (Physics.Raycast(currPos, hypoVel, out hit)) // if (Physics.SphereCast(ray, radius, out hit,maxDistance))
        {
            hit_list.Add(hit);
        }


        v.Add(hypoPos);
        currPos = hypoPos;
        hypoPos = currPos + hypoVel + (gravityDirection * Time.fixedDeltaTime / (smoothness * smoothness));
        hypoVel = hypoPos - currPos;
        curveCastLength += hypoVel.magnitude;
    }
}

Upvotes: 3

Views: 6683

Answers (1)

Basile Perrenoud
Basile Perrenoud

Reputation: 4112

It is because Debug.DrawRay and Physics.Raycast are not exactly the same.

In Debug.DrawRay, the length of the ray is defined by the vector magnitude. You can see it in the doc:

Draws a line from start to start + dir in world coordinates.

For Physics.Raycast, the length of the ray is independant from the direction and can be set as a parameter. Its default value is infinite, so if you don't define it, the raycast will go to infinity, even if the direction vector is short. See the doc:

Casts a ray, from point origin, in direction direction, of length maxDistance, against all colliders in the scene.

So the solution for you is to give the proper distance to the Raycast function:

Debug.DrawRay(currPos, hypoVel, Color.white);
if (Physics.Raycast(currPos, hypoVel, out hit, hypoVel.magnitude())) // if (Physics.SphereCast(ray, radius, out hit,maxDistance))
{
    hit_list.Add(hit);
}

Upvotes: 5

Related Questions