Do you mean like this?

Adapted Code

1. PVector begin, end, distance, current;
2. float pct;
3. float exponent = 4;
4. float step = 0.01;
5. boolean automatic = true;
6.  
7. void setup() {
8.   size(640, 360);
9.   noStroke();
10.   smooth();
11.   begin = new PVector(20, 10);
12.   end = new PVector(570, 320);
13.   distance = PVector.sub(end, begin);
14.   current = new PVector();
15. }
16.  
17. void draw() {
18.   pct += step;
19.   if (pct < 1.0) {
20.     current.x = begin.x + (pct * distance.x);
21.     current.y = begin.y + (pow(pct, exponent) * distance.y);
22.   } else if (automatic) {
23.     setTarget(random(width), random(height));
24.   }
25.   fill(0, 2);
26.   rect(0, 0, width, height);
27.   fill(255);
28.   ellipse(current.x, current.y, 20, 20);
29. }
30.  
31. void keyPressed() {
32.   automatic = !automatic;
33. }
34.  
35. void mousePressed() {
36.   setTarget(mouseX, mouseY);
37. }
38.  
39. void setTarget(float tx, float ty) {
40.   begin.set(current.x, current.y, 0);
41.   end.set(tx, ty, 0);
42.   distance = PVector.sub(end, begin);
43.   pct = 0;
44. }

Thank you for replay,

I was thinking more like take PVector begin get from main code's PVector pointP. each begin find the point(i), each end find the point(i+1). and the train is a PVector class.

>< something like this train make movement on the ArrayList<PVector> Points

 

1. class Trains {
    
   PVector begin, end, distance, current;
   float pct;
   float exponent = 4;
   float step = 0.01;
   boolean automatic = true;
2.   Train(PVector _s,PVector _e,PVector _d,PVector _c) { //this looks strange, right? because I don't know how to construct them//////
3. 
     begin=_s ;
     end =_e;
     distance=_d ;
     current=_c ;
   }
4. void update(){
     pct += step;
     if (pct < 1.0) {
       current.x = begin.x + (pct * distance.x);
       current.y = begin.y + (pow(pct, exponent) * distance.y);
     } else if (automatic) {
       setTarget(random(width), random(height));
     }
5. 
     fill(0, 2);
     rect(0, 0, width, height);
     fill(255);
     ellipse(current.x, current.y, 20, 20);
   }
6. 
   void keyPressed() {
     automatic = !automatic;
   }
    
   void mousePressed() {
     setTarget(mouseX, mouseY);
   }
    
   void setTarget(float tx, float ty) {
     begin.set(current.x, current.y, 0);
     end.set(tx, ty, 0);
     distance = PVector.sub(end, begin);
     pct = 0;
   }
   }

 

main code

1. float pX[]= {
     57.74, 79.07, 83.95, 107.40, 146.86, 186.85, 229.05, 270.10, 308.35, 391.8
   };
   float pY[]= {
     119.04, 153.9, 196.17, 230.47, 246.30, 257.21, 252.62, 261.94, 246.10, 241.08
   };
   ArrayList<PVector> Points;
2. void setup() {
     size(400, 300);
     noStroke();
     smooth();
     Points = new ArrayList<PVector>();
     for (int i =0; i<pX.length;i++)
     {
       float pointPX=pX[i] ;
       float pointPY=pY[i] ;
       PVector pointP = new PVector(pointPX, pointPY);
       Points.add(pointP);
       fill(255, 0, 0);
       noStroke();
       ellipse(pointPX, pointPY, 5, 5);
     }
   }
3. void draw() {
    
   }

 

 

Your English is hard to understand. Do you mean like this?

If you want to move a point over a curve, also check out curvePoint.

If you want to learn about classes and objects, check out: http://processing.org/learning/objects/

Code Example

1. Train t;
2. PVector [] track  = {
3.   new PVector(057.74, 119.04),
4.   new PVector(079.07, 153.90),
5.   new PVector(083.95, 196.17),
6.   new PVector(107.40, 230.47),
7.   new PVector(146.86, 246.30),
8.   new PVector(186.85, 257.21),
9.   new PVector(229.05, 252.62),
10.   new PVector(270.10, 261.94),
11.   new PVector(308.35, 246.10),
12.   new PVector(391.80, 241.08),
13. };
14.  
15. void setup() {
16.   size(640, 360);
17.   strokeWeight(5);
18.   smooth();
19.   t = new Train(track);
20. }
21.  
22. void draw() {
23.   background(0);
24.   noStroke();
25.   fill(255, 0, 0);
26.   for (int i=0; i<track.length; i++) {
27.     ellipse(track[i].x, track[i].y, 5, 5);
28.   }
29.   t.update();
30.   t.display();
31. }
32.  
33. class Train {
34.   PVector begin, end, distance, current;
35.   float pct;
36.   float exponent = 4;
37.   float step = 0.01;
38.   int currentStation;
39.   PVector[] track;
40.  
41.   Train(PVector[] track) {
42.     begin = new PVector(random(width), random(height));
43.     end = new PVector();
44.     current = new PVector();
45.     this.track = track;
46.     setTarget(track[currentStation]);
47.   }
48.  
49.   void update() {
50.     pct += step;
51.     if (pct < 1.0) {
52.       current.x = begin.x + (pct * distance.x);
53.       current.y = begin.y + (pow(pct, exponent) * distance.y);
54.     } else {
55.       currentStation = (currentStation+1)%track.length;
56.       setTarget(track[currentStation]);
57.     }
58.   }
59.  
60.   void display() {
61.     noFill();
62.     stroke(255);
63.     ellipse(current.x, current.y, 20, 20);
64.   }
65.  
66.   void setTarget(PVector t) {
67.     begin.set(current.x, current.y, 0);
68.     end.set(t);
69.     distance = PVector.sub(end, begin);
70.     pct = 0;
71.   }
72. }

Hi Amnon.

Thank you so much for the help! Sorry for my poor English mixed with all the "name" of data types from the code within the sentence... I don't know what's more pathetic, my English, the lack of programming logic or the bad question. (-"'-)  ...> <...

I was really impressed by the fallowing video and design: http://www.guardian.co.uk/news/datablog/video/2012/jan/12/high-speed-2-hs2-rail-britain-mapped-animation?fb=native

http://www.openprocessing.org/sketch/50500

 

I have been trying to build a model railways and trains. The example of case study-Path Following- design by Daniel Shiffman <http://www.shiffman.net> was very good. However, in his code, the path pick up points randomly, which in my case, I want to run the path on the specific points (just like on the map). The number of points was too big and there are many railways on my map. so I can't just change the points of Daniel's code. I made a class of array list, all the points can use "lordStrings" from the data outside of Processing.( a lot of help from phi.lho) Now, I start to think the movement of the train, and interactive behavior like stop, or make signal.

Here is the video of my work so far.

 http://vimeo.com/39474226

you can see that if I use the code from Daniel's example the train never go to stop at each point. The behavior looks strange. That is why I try this PVector class.

 

I know it is extremely difficult for me (in this level (:-;)) to do something similar with OOP. (Believe me, I had already made a "car" class in January. @_@ that was a little too simple) "The use of constructor arguments to initialize object variables" really tripped me. (I also fight with "PVector"... It's just a chaos, completely chaos).

 

Now I am working on the code....

 

 

 

 

Yeah, I understand. When I first started to learn OOP it really took some time before I got it. You can read about it and check examples, but it just takes time before the concepts land in your brain. Your progress is looking good so far. Just keep at it (or maybe even take a break some time) and it will only get better.

For PVector, I can recommend the Plethora Project tutorials by Jose Sanchez. See episodes 11 & 12.