I think bullets come out now.

[rbdr/super-polarity] / Super Polarity / Actors / Actor.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Content;
using Microsoft.Xna.Framework.Graphics;

namespace SuperPolarity
{
    class Actor
    {
        protected Game game;

        public List<Actor> Children;

        // Graphics / In-Game
        protected Texture2D Texture;
        protected Vector2 Origin;
        public bool Active;

        // Physical Properties
        public Vector2 Position;
        protected Vector2 Velocity;
        protected Vector2 Acceleration;
        public float Angle;

        // Constraints / Behavior
        protected float MaxVelocity;
        protected float AccelerationRate;

        public int Width
        {
            get { return Texture.Width; }
        }

        public int Height
        {
            get { return Texture.Height; }
        }

        public Actor(Game newGame)
        {
            game = newGame;
        }

        public virtual void Initialize(Texture2D texture, Vector2 position)
        {
            Texture = texture;
            Position = position;
            Active = true;

            Children = new List<Actor>();

            Origin = new Vector2(Texture.Width / 2, Texture.Height / 2);
            Velocity = new Vector2(0, 0);
            Acceleration = new Vector2(0, 0);

            MaxVelocity = 5;
            AccelerationRate = 10;
        }

        public void AutoDeccelerate(GameTime gameTime)
        {
            if (Acceleration.X == 0 && Velocity.X > 0)
            {
                if (AccelerationRate * gameTime.ElapsedGameTime.TotalSeconds > Velocity.X)
                {
                    Velocity.X = 0;
                    Acceleration.X = 0;
                }
                else
                {
                    Acceleration.X = -AccelerationRate;
                }
            }

            if (Acceleration.X == 0 && Velocity.X < 0)
            {
                if (-AccelerationRate * gameTime.ElapsedGameTime.TotalSeconds < Velocity.X)
                {
                    Velocity.X = 0;
                    Acceleration.X = 0;
                }
                else
                {
                    Acceleration.X = AccelerationRate;
                }
            }

            if (Acceleration.Y == 0 && Velocity.Y > 0)
            {
                if (AccelerationRate * gameTime.ElapsedGameTime.TotalSeconds > Velocity.Y)
                {
                    Velocity.Y = 0;
                    Acceleration.Y = 0;
                }
                else
                {
                    Acceleration.Y = -AccelerationRate;
                }
            }

            if (Acceleration.Y == 0 && Velocity.Y < 0)
            {
                if (-AccelerationRate * gameTime.ElapsedGameTime.TotalSeconds < Velocity.Y)
                {
                    Velocity.Y = 0;
                    Acceleration.Y = 0;
                }
                else
                {
                    Acceleration.Y = AccelerationRate;
                }
            }
        }

        public virtual void Update(GameTime gameTime)
        {
            Move(gameTime);
            ChangeAngle();
            CheckOutliers();
        }

        public virtual void Move(GameTime gameTime)
        {
            AutoDeccelerate(gameTime);

            var maxVelocity = MaxVelocity;

            Velocity.X = Velocity.X + Acceleration.X * (float)gameTime.ElapsedGameTime.TotalSeconds;
            Velocity.Y = Velocity.Y + Acceleration.Y * (float)gameTime.ElapsedGameTime.TotalSeconds;

            if (Velocity.X > MaxVelocity)
            {
                Velocity.X = MaxVelocity;
            }

            if (Velocity.X < -MaxVelocity)
            {
                Velocity.X = -MaxVelocity;
            }

            if (Velocity.Y > MaxVelocity)
            {
                Velocity.Y = MaxVelocity;
            }

            if (Velocity.Y < -MaxVelocity)
            {
                Velocity.Y = -MaxVelocity;
            }

            Position.X = Position.X + Velocity.X;
            Position.Y = Position.Y + Velocity.Y;
        }

        public void ChangeAngle()
        {
            Angle = (float)Math.Atan2(Velocity.Y, Velocity.X);
        }

        public virtual void Draw(SpriteBatch spriteBatch)
        {
            foreach (Actor child in Children)
            {
                child.Draw(spriteBatch);
            }

            spriteBatch.Draw(Texture, Position, null, Color.White, Angle, Origin, 1f, SpriteEffects.None, 0f);
        }

        void CheckOutliers()
        {
            for (var i = Children.Count; i > 0; i--)
            {
                var actor = Children[i - 1];
                if (actor.Position.X < -SuperPolarity.OutlierBounds || actor.Position.Y < -SuperPolarity.OutlierBounds ||
                    actor.Position.X > game.GraphicsDevice.Viewport.Width + SuperPolarity.OutlierBounds ||
                    actor.Position.Y > game.GraphicsDevice.Viewport.Height + SuperPolarity.OutlierBounds)
                {
                    Children.Remove(actor);
                }
            }
        }
    }
}