Platformer.Player.ApplyPhysics C# (CSharp) Method

        public void ApplyPhysics(GameTime gameTime)
        {
            float elapsed = (float)gameTime.ElapsedGameTime.TotalSeconds;

            Vector2 previousPosition = Position;

            // Base velocity is a combination of horizontal movement control and
            // acceleration downward due to gravity.

            //velocity.X += movement * MoveAcceleration * elapsed;
            //velocity.Y = MathHelper.Clamp(velocity.Y + GravityAcceleration * elapsed, -MaxFallSpeed, MaxFallSpeed);

            // If not climbing ladder, handle Y movement as before
            if (!isClimbing)
            {
                if (wasClimbing)
                {
                    velocity.Y = 0;
                }
                else
                {
                    velocity.Y = MathHelper.Clamp(velocity.Y + GravityAcceleration * elapsed, -MaxFallSpeed, MaxFallSpeed);
                }
            }
            else
            {
                velocity.Y = movement.Y * MoveAcceleration * elapsed;
            }

            velocity.X += movement.X * MoveAcceleration * elapsed;
            velocity.Y = DoJump(velocity.Y, gameTime);

            // Apply pseudo-drag horizontally.
            if (IsOnGround)
                velocity.X *= GroundDragFactor;
            else
                velocity.X *= AirDragFactor;

            // Prevent the player from running faster than his top speed.
            velocity.X = MathHelper.Clamp(velocity.X, -MaxMoveSpeed, MaxMoveSpeed);

            // Apply velocity.
            Position += velocity * elapsed;
            //position = new Vector2((float)Math.Round(Position.X), (float)Math.Round(Position.Y));

            // If the player is now colliding with the level, separate them.
            HandleCollisions();

            // If the collision stopped us from moving, reset the velocity to zero.
            if (Position.X == previousPosition.X)
                velocity.X = 0;

            if (Position.Y == previousPosition.Y)
                velocity.Y = 0;
        }

        /// <summary>
        /// Updates all objects in the world, performs collision between them,
        /// and handles the time limit with scoring.
        /// </summary>
        public void Update(
            GameTime gameTime,
            KeyboardState keyboardState,
            GamePadState gamePadState,
            TouchCollection touchState,
            AccelerometerState accelState,
            DisplayOrientation orientation)
        {
            // Pause while the player is dead or time is expired.
            // Pause while the player is dead or time is expired.

            if (!Player.IsAlive || TimeRemaining == TimeSpan.Zero)
            {
                // Still want to perform physics on the player.
                Player.ApplyPhysics(gameTime);
            }
            else if (ReachedExit)
            {
                // Animate the time being converted into points.
                int seconds = (int)Math.Round(gameTime.ElapsedGameTime.TotalSeconds * 100.0f);
                seconds        = Math.Min(seconds, (int)Math.Ceiling(TimeRemaining.TotalSeconds));
                timeRemaining -= TimeSpan.FromSeconds(seconds);
                score         += seconds * PointsPerSecond;
            }
            else
            {
                timeRemaining -= gameTime.ElapsedGameTime;

                Player.Update(gameTime, keyboardState, gamePadState, touchState, accelState, orientation);
                UpdateMovableTiles(gameTime);

                UpdateGems(gameTime);

                // Falling off the bottom of the level kills the player.
                if (Player.BoundingRectangle.Top >= Height * Tile.Height)
                {
                    OnPlayerKilled(null);
                }

                UpdateEnemies(gameTime);

                // The player has reached the exit if they are standing on the ground and
                // his bounding rectangle contains the center of the exit tile. They can only
                // exit when they have collected all of the gems.
                if (Player.IsAlive &&
                    Player.IsOnGround &&
                    Player.BoundingRectangle.Contains(exit))
                {
                    OnExitReached();
                }
            }

            // Clamp the time remaining at zero.
            if (timeRemaining < TimeSpan.Zero)
            {
                timeRemaining = TimeSpan.Zero;
            }
        }