3 Replies Latest reply on May 17, 2006 3:04 PM by blemmo

    Finding the consistant slope

      I am trying to have a ball move from one side of the stage to the exact x and y points on the other side of the stage. For example, let's say the ball's x =25 and y=80, and the point I want it to move it to is at point x=350 and y=100. So if I want this ball to travel at a consistant speed (doesn't matter), how would I do this?

      Does this make sense? It's simliar to a movie clip following the mouse, sort of...help please.
        • 1. Re: Finding the consistant slope
          blemmo Level 1
          Is the speed fixed? If not, you just had to change the x and y position constantly, but I guess you wouldn't have asked then.
          So when it's fixed, you need to know the distance from start to end point. As you know both points, you can use
          distance = Math.sqrt( Math.pow(startPoint._x - endPoint._x, 2) + Math.pow(startPoint._y - endPoint._y, 2) );
          this gets the length of the line between those points in pixels.
          Then you can get the time it will take to go that distance in the given speed:
          time = distance / speed;

          Now if the speed is something like 50 pixels per second, the time is also in seconds, and you will get something like 5 seconds. Now take the animation speed (e.g. the framerate, if you animate with onEnterFrame), and get the number of animation steps it will take to reach the end:
          steps = time * animation_speed

          Finally get the total distances for x and y, which is endPoint.(x | y) - startPoint.(x | y), and divide those by the steps number to get the distance for each step:
          stepX = (endPoint._x - startPoint._x) / steps;
          stepY = (endPoint._y - startPoint._y) / steps;

          Now you have the distance for each animation step and can use them in the animation to move the ball with the given speed.

          • 2. Re: Finding the consistant slope
            gregmax17 Level 1
            THANK YOU!
            • 3. Re: Finding the consistant slope
              blemmo Level 1
              de nada.

              "information not shared is lost"
              don't know who said that, but it's a good statement... and true.