RaycastSphere.hlsl

float3 RaycastSphere(float3 origin, float3 direction, out float hit)
{   
    float radius = _HoleRadius;
    float3 holeOrigin = _HoleOffset;
    float3 toCenter = holeOrigin - origin;

    if (SqrLength(toCenter) <= pow(radius, 2))
    {
        hit = 1;
        return origin;
    }
    else
    {
        if (dot(direction, toCenter) <= 0)
        {
            hit = -1;
            return origin;
        }
        
        float a = SqrLength(direction);
        float b = dot(holeOrigin - origin, direction);
        float c = SqrLength(holeOrigin - origin) - pow(radius, 2);

        float ddt = pow(b, 2) - a * c;
        if (ddt < 0)
        {
            hit = -1;
            return origin;
        }

        float dt = sqrt(ddt);

        float t = (b - dt) / a;

        hit = 1;
        float3 hitPosition = origin + direction * t;
        return hitPosition;
    }
}