public void Update(GameTime gameTime, KeyboardState keyboardState)
        {
            // Calculate strafe
            if (keyboardState.IsKeyDown(Keys.Left) || keyboardState.IsKeyDown(Keys.Right))
            {
                if (keyboardState.IsKeyDown(Keys.Left))
                    velocity.X = -strafe_mutator;
                else
                    velocity.X = strafe_mutator;
            } else
                velocity.X = 0;

            // Determine the state of the player
            if (position.Bottom >= 600)
            {
                // player is not in the air
                velocity.Y = 0;
                position.Y = 600 - position.Height;
                // check for jumping
                if (keyboardState.IsKeyDown(Keys.Space))
                    velocity.Y = -jump_mutator;
            } else
                // player is in the air
                velocity.Y += (gravity_mutator) * gameTime.ElapsedGameTime.Milliseconds;

            position.X += (int)velocity.X;
            position.Y += (int)velocity.Y;
        }