Unity SphereCast HitInfo Give me an interpolation of the normal surface?

Question

I'm doing a SphereCast for a GroundCheck of a player. I have my Raycast hitInfo, and here in the picture at the left, I Debug.drawRay in black the direction of the hitInfo.normal every frame

It seems like hitInfo.normal give me an interpolation of the normal, not the real normal of the surface...

I only want the real normal of the surface... (red normals I have draw on the right), and may be the green one (the perfect normal between 2 surface), but if I can have only the red one, it would be great

How can I do it ?

Thanks !

Answer 1

Ok, I found an temporary solution that give me the red normal IF I want to keep my SphereCast Test, I have to do a second Raycast for having this surface normal (C'mon Unity, why we haven't a hitInfo.surfaceNormal information ??)

//here my sphereCast in someFunction
RaycastHit hitInfo;
Vector3 position;     //origin of the sphereCast
float radiusRayCast;  //radius of the sphereCast
Vector3 dirCast;      //direction of the SphereCast
float magnitudeCast;  //magnitude of my sphereCast
int layerMask;        //layerMask used for both SphereCast & Raycast
float rayCastMargin;  //margin magnitude of the second raycast

if (Physics.SphereCast(position, radiusRayCast, dirCast, out hitInfo,
                               magnitudeCast, layerMask))
{
    //here my second raycast Test
    Vector3 surfaceNormal = GetSurfaceNormal(position,
                                             radiusRayCast,
                                             magnitudeCast,
                                             radiusRayCast,
                                             hitInfo.point,
                                             rayCastMargin,
                                             layerMask);
}

And here my static fonction, who calculate:

public static Vector3 GetCollisionCenterSphereCast(Vector3 castOrigin, Vector3 direction, float magnitude)
{
    Vector3 collisionCenter = castOrigin + (direction * magnitude);
    return (collisionCenter);
}

public static Vector3 CalculateRealNormal(Vector3 origin, Vector3 direction, float magnitude, float rayCastMargin, int layermask)
{
    //Ray ray = new Ray(origin, direction);
    RaycastHit hit;
    if (Physics.Raycast(origin, direction, out hit, magnitude + rayCastMargin, layermask))
    {
        //Debug.Log("Did Hit");
        return (hit.normal);
    }
    Debug.DrawRay(origin, direction.normalized * (magnitude + rayCastMargin));
    Debug.LogWarning("we are not suppose to miss that one...");
    return (Vector3.zero);
}

public static Vector3 SetSurfaceNormal(Vector3 castOrigin, Vector3 direction,
        float magnitude, float radius, Vector3 hitPoint,
        float rayCastMargin, int layerMask)
{
    Vector3 centerCollision = GetCollisionCenterSphereCast(castOrigin, direction, magnitude);
    Vector3 dirCenterToHit = hitPoint - castOrigin;
    float sizeRay = dirCenterToHit.magnitude;
    Vector3 surfaceNormal = CalculateRealNormal(centerCollision, dirCenterToHit, sizeRay, rayCastMargin, layerMask);

    Debug.DrawRay(centerCollision, surfaceNormal, Color.black, 5f);
    return (surfaceNormal);
}

As you see in this pictures below, black Ray are indeed the exacte normal of the surface, and the yellow Ray, the normal created by the SphereCast. It works !

Unfortunatly, it demand a second Raycast, and we can't have the perfect normal Intersection, but for now, it's good enought for me.