Trouble with Direction and Angle Updating in XNA

Question

I have been trying to make a tower defense game game where the mob is given a destination to move towards at a given velocity, and the way it is set up now something quirky is happening with the updateAngle() method that I am not sure about.

    // Destination is represented by Coordinates[index]

    public void Update(GameTime time)
    {
        Position.Y -= (float)(time.ElapsedGameTime.TotalSeconds * velocity * Math.Cos(angle));
        Position.X += (float)(time.ElapsedGameTime.TotalSeconds * velocity * Math.Sin(angle));

        float remainingX = Math.Abs(Destination.X - Position.Y);
        float remainingY = Math.Abs(Destination.Y - Position.Y);

        if (remainingX < 2 && remainingY < 2)
        {
            index++;

            if (index == Coordinates.Count - 1)
            {
                End = true;
            }
            else
            {
                updateAngle();
            }
        }

    }

    private void updateAngle()
    {
        angle = (float)Math.Atan((Position.Y - Destination.Y) / (Position.X - Destination.X));
    }

This didn't work. The output was the same as before using Math.Atan. — user2716722, Aug 26 '13 at 12:43
What's the output you are getting and what's the output you expect? — davidsbro, Aug 26 '13 at 13:48
Maybe your problem is here: `float remainingX = Math.Abs(Destination.X - Position.Y);` Shouldn't it be `Position.X`? — pinckerman, Aug 26 '13 at 14:10
The mob is supposed to move from the first red dot on the left moving to the other red dots preceding left to right (from coordinates I preset) but instead the mob appears to try to circle around the point. I have a poor quality video (about 10 secs) if you would care to watch it at http://youtu.be/RN6HgkCDMMo — user2716722, Aug 26 '13 at 14:24

score 0 · Answer 1 · answered Aug 26 '13 at 18:37

0

This gives the right angle if position and destination are right:

angle = Math.Atan2(Destination.Y-Position.Y, Destination.X-Position.X)

answered Aug 26 '13 at 18:37

Blau

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Trouble with Direction and Angle Updating in XNA

1 Answers1