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  A* pathfinding in slick  (Read 601 times)
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Offline superhigh

Senior Newbie





« Posted 2013-05-03 22:20:34 »

So I figured out my A* pathfinding, and I want to figure out how to move my entity there! Here is a movement code for the player which happens when you press "up"
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trans.y = -speed * delta;
            sprite = up;
            sprite.update(delta);

and when you press down
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trans.y = speed * delta;
            sprite = down;
            sprite.update(delta);

Because I want my player/ another entity to just walk there, not instantly show up there, and these are the codes I use for arrows keys.
And here is my pathfinding which I want the player to move through, nice and smooth like.
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public static void PathFind(int startx, int starty, int endx, int endy) {
if (SimpleMap.MAP[endx][endy] == 1) {
AStarPathFinder pathFinder = new AStarPathFinder(mapd, 100, false);
        Path path = pathFinder.findPath(null, startx, starty, endx, endy);

        int length = path.getLength();
        System.out.println("Found path of length: " + length + ".");

        for(int i = 0; i < length; i++) {
            System.out.println("Move to: " + path.getX(i) + "," + path.getY(i) + ".");
        }
      } else {
      System.out.println("You can not move here!");
      }
}
Offline alaslipknot
« Reply #1 - Posted 2013-05-04 03:17:37 »

you can make an object move from a current location (x,y) to target location (tx,ty) by doing something like this :

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   //distance between current and target location
  float dx = tx - x ;
   float dy = ty - y ;
   
      //normalize it
     int len = (int)Math.sqrt(dx * dx + dy * dy);
      if (len!=0) {
         dx /= len;
         dy /= len;
      }

      //scale the vector based on our movement speed
     float speed = 2f;
      dx *= speed;
      dy *= speed;

      //move the entity with our new direction vector
     x += dx;
      y += dy;


Am trying ...
hoping that it works
Offline Jimmt
« League of Dukes »

JGO Kernel


Medals: 114
Projects: 4
Exp: 3 years



« Reply #2 - Posted 2013-05-04 05:47:54 »

you can make an object move from a current location (x,y) to target location (tx,ty) by doing something like this :
...
Did you even read the question? He's not asking for linear movement, he's asking for A* pathfinding, completely different from what you posted. Not to mention that he's not even using vectors like in your example (minus/negative sign doesn't operate on vector objects).

@OP
I don't use Slick, but here's some explanation and example code by kevglass (you've probably seen it already, oh well).
Games published by our own members! Check 'em out!
Legends of Yore - The Casual Retro Roguelike
Offline HeroesGraveDev

JGO Kernel


Medals: 212
Projects: 11
Exp: 2 years


If it wasn't Awesome, it wasn't me.


« Reply #3 - Posted 2013-05-04 10:00:48 »

@alaslipknot: The variable len should be a float.

Also, pathfinding, while still moving an object from point A to point B, is a bit more complicated than calculating velocity.

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