private PlayerSprite LoadPlayer(IPlayerInput playerInput, int playerNumber)
        {
            //TODO: this should be done via different sprites
            Color playerColor = Color.White;

            switch (playerNumber)
            {
            case 1:
                playerColor = Color.White;
                break;

            case 2:
                playerColor = Color.Black;
                break;

            case 3:
                playerColor = Color.Green;
                break;

            case 4:
                playerColor = Color.Yellow;
                break;
            }
            PlayerSprite player = new PlayerSprite(playerInput, playerColor, playerNumber, 1, 0, "crosshair", 1.0f);

            return(player);
        }
        private void UpdatePlayer(PlayerSprite player)
        {
            player.UpdatePlayerIsActive();
            if (player.IsActive)
            {
                player.UpdatePauseState();
                if (player.IsPaused)
                {
                    this.Exit();
                }

                player.UpdateFiringState();
                if (player.IsFiring)
                {
                    Vector2 shotLocation = player.GetShotLocation();
                    foreach (Target target in levels[0].Waves[levels[0].CurrentWaveIndex].Targets)
                    {
                        if (target.IsActive)
                        {
                            //TODO: factor this out so pixel based hit detection can be used elsewhere
                            //TODO: pixel based hit detection does not work when target is rotated...

                            //only do pixel detection if mouse in area
                            if (target.BoundingBox.Contains(new Rectangle((int)shotLocation.X, (int)shotLocation.Y, 1, 1)))
                            {
                                //do we hit alpha pixel or 'body' pixel?

                                Vector2 relativeShotLocation = new Vector2(shotLocation.X - target.BoundingBox.X, shotLocation.Y - target.BoundingBox.Y);
                                relativeShotLocation = Vector2.Divide(relativeShotLocation, target.Scale);

                                Rectangle targetTexturePixels   = Textures.Instance.SpriteSheet.SourceRectangle(target.GetSpriteSheetIndex());
                                Vector2   hitPointOnSpriteSheet = new Vector2(targetTexturePixels.X + relativeShotLocation.X, targetTexturePixels.Y + relativeShotLocation.Y);

                                int   hitPointOnSpriteSheetIndex = (int)hitPointOnSpriteSheet.Y * Textures.Instance.SpriteSheet.Texture.Width + (int)hitPointOnSpriteSheet.X;
                                Color pixelColor = Textures.Instance.SpriteSheetColors[hitPointOnSpriteSheetIndex];

                                //hit!
                                if (pixelColor.A != 0)
                                {
                                    target.IsActive = false;
                                    player.Score   += target.PointValue;

                                    //Explosion particle
                                    explosionEmitterParticleSystem.AddParticles(new Vector2(target.BoundingBox.Center.X, target.BoundingBox.Center.Y));
                                }
                            }
                        }
                    }
                }

                player.UpdatePlayerPosition();
                player.MoveTo(new Vector2(player.Position.X, player.Position.Y));
            }
        }