Ray3.cs

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namespace Engine {
    public struct Ray3 : IEquatable<Ray3> {
        public Vector3 Position;
 
        public Vector3 Direction;
 
        public Ray3(Vector3 position, Vector3 direction) {
            Position = position;
            Direction = direction;
        }
 
        public override bool Equals(object obj) => obj is Ray3 && Equals((Ray3)obj);
 
        public override int GetHashCode() => Position.GetHashCode() + Direction.GetHashCode();
 
        public override string ToString() => $"{Position.ToString()},{Direction.ToString()}";
 
        public bool Equals(Ray3 other) => Position == other.Position && Direction == other.Direction;
 
        public float? Intersection(BoundingBox box) {
            if (Position.X >= box.Min.X
                && Position.X <= box.Max.X
                && Position.Y >= box.Min.Y
                && Position.Y <= box.Max.Y
                && Position.Z >= box.Min.Z
                && Position.Z <= box.Max.Z) {
                return 0f;
            }
            Vector3 vector = new(-1f);
            if (Direction.X != 0f) {
                if (Position.X < box.Min.X) {
                    vector.X = (box.Min.X - Position.X) / Direction.X;
                }
                else if (Position.X > box.Max.X) {
                    vector.X = (box.Max.X - Position.X) / Direction.X;
                }
            }
            if (Direction.Y != 0f) {
                if (Position.Y < box.Min.Y) {
                    vector.Y = (box.Min.Y - Position.Y) / Direction.Y;
                }
                else if (Position.Y > box.Max.Y) {
                    vector.Y = (box.Max.Y - Position.Y) / Direction.Y;
                }
            }
            if (Direction.Z != 0f) {
                if (Position.Z < box.Min.Z) {
                    vector.Z = (box.Min.Z - Position.Z) / Direction.Z;
                }
                else if (Position.Z > box.Max.Z) {
                    vector.Z = (box.Max.Z - Position.Z) / Direction.Z;
                }
            }
            if (vector.X > vector.Y
                && vector.X > vector.Z) {
                if (vector.X < 0f) {
                    return null;
                }
                float num = Position.Z + vector.X * Direction.Z;
                if (num < box.Min.Z
                    || num > box.Max.Z) {
                    return null;
                }
                num = Position.Y + vector.X * Direction.Y;
                return num < box.Min.Y || num > box.Max.Y ? null : vector.X;
            }
            if (vector.Y > vector.X
                && vector.Y > vector.Z) {
                if (vector.Y < 0f) {
                    return null;
                }
                float num2 = Position.Z + vector.Y * Direction.Z;
                if (num2 < box.Min.Z
                    || num2 > box.Max.Z) {
                    return null;
                }
                num2 = Position.X + vector.Y * Direction.X;
                return num2 < box.Min.X || num2 > box.Max.X ? null : vector.Y;
            }
            if (vector.Z < 0f) {
                return null;
            }
            float num3 = Position.X + vector.Z * Direction.X;
            if (num3 < box.Min.X
                || num3 > box.Max.X) {
                return null;
            }
            num3 = Position.Y + vector.Z * Direction.Y;
            return num3 < box.Min.Y || num3 > box.Max.Y ? null : vector.Z;
        }
 
        public float? Intersection(BoundingSphere sphere) {
            Vector3 v = sphere.Center - Position;
            float num = v.LengthSquared();
            float num2 = sphere.Radius * sphere.Radius;
            if (num < num2) {
                return 0f;
            }
            float num3 = Vector3.Dot(Direction, v);
            if (num3 < 0f) {
                return null;
            }
            float num4 = num2 + num3 * num3 - num;
            return !(num4 < 0f) ? num3 - MathF.Sqrt(num4) : null;
        }
 
        public float? Intersection(Plane plane) {
            float num = Vector3.Dot(Direction, plane.Normal);
            return num == 0f ? null : (0f - (Vector3.Dot(Position, plane.Normal) + plane.D)) / num;
        }
 
        public Vector3 Sample(float distance) => Position + Direction * distance;
 
        public static Ray3 Transform(Ray3 r, Matrix m) {
            Transform(ref r, ref m, out Ray3 result);
            return result;
        }
 
        public static void Transform(ref Ray3 r, ref Matrix m, out Ray3 result) {
            Vector3.Transform(ref r.Position, ref m, out result.Position);
            Vector3.TransformNormal(ref r.Direction, ref m, out result.Direction);
        }
 
        public static bool operator ==(Ray3 a, Ray3 b) => a.Equals(b);
 
        public static bool operator !=(Ray3 a, Ray3 b) => !a.Equals(b);
    }
}