I want all coordinates to stay within a certain distance to the center. I have succeeded to get both the distance and the angle from the center with help of dist(); and atan2(); 

I guess it's trigonometry but my math skills haven't been refreshed since college. Could anyone help me out?

I'm working on a script where some coordinates are moving randomly around checking if other points are close to them and if so draws a line to the those points. This is the first thing I make in processing so the code isn't beautiful but it works. 

The next step i would like to introduce to this script to keep these points within a vector shape. My guess is that I would need to use some kind of collision detection to make that work. But I have not been able to find any library  or guide that I can understand. Would anyone be so kind and nudge me in the right direction?

Thanks.  

Here is my code as it is now:

2. //import fullscreen.*; 
3. import processing.opengl.*;
4. //FullScreen fs; 
5. import controlP5.*;
6. 
   
7. ControlP5 controlP5;
8. Slider2D s;
9. 
   
10. float[] pointx = new float[2000];
11. float[] pointy = new float[2000];
12. float[] rand1 = new float[2000];
13. float[] rand2 = new float[2000];
14. float intense;
15. float limiter;
16. float state;
17. float counter;
18. int amount;
19. float move1;
20. float move2;
21. float move3;
22. float move4;
23. float swtop;
24. float q;
25. int sw;
26. int l;
27. int e;
28. int f;
29. int g;
30. float fader;
31. int opac;
32. int divider;
33. void setup() {
34.   controlP5 = new ControlP5(this);
35.   controlP5.addSlider("fader",0,800,128,20,100,10,100);
36.   controlP5.addSlider("swtop",1,80,20,40,100,10,100);
37.   controlP5.addSlider("opac",0,80,3,60,100,10,100);
38.   smooth();
39.   size(1500, 1200, OPENGL);
40.   stroke(0, 80);
41.   background(255);
42.   frameRate(20);
43.   divider = 7;
44.   opac = 3;
45.   amount = divider*divider;
46.   q = 300;
47.   l = 1;
48.   e = 1;
49.   g = 1;
50.  // fs = new FullScreen(this); 
51.   
52. 
    
53.    for(int k = 0; k < (amount); k = k+1) {
54.      pointx[k] = width/(divider+1)*l;
55.      if(e < divider) { e = e+1;}
56.      else 
57.      {
58.        e = 1;
59.        l = l+1;
60.      }
61. 
    
62.    }
63.    for(int h = 0; h < (amount); h = h+1) {
64.      pointy[h] = height/(divider+1)*g;
65.      if(g < divider) { g = g+1;}
66.      else 
67.      {
68.        g = 1;
69.       
70.      }
71.      
72. 
    
73.    }
74.  
75. 
    
76. }
77. 
    
78. void draw(){
79.   stroke(255, 0);
80.   fill(255, opac);
81.   if(sw < swtop) {
82.   sw = sw + 1; 
83.   }
84.   else if(sw > swtop) {
85.    sw = 0; 
86.   }
87.   else {
88.   rect(0, 0, width, height);
89. 
    
90.  sw = 0; 
91.   }
92.   
93.   for (int i = 0; i < amount; i = i+1) {
94.         for (int n = 0; n < amount; n = n+1) {
95. 
    
96.               
97.               if(q == 300) {
98.                 for (int v = 1; v < amount; v = v + 1) {
99.                 rand1[i] =  random(0,1);
100.                 rand2[i] = random(0,1);
101.                 }
102.                  q = 0;
103. 
     
104.               }
105.               else
106.               {
107.                 q = q+1;
108.                 
109.               }
110.               
111.              
112.               limiter = dist(pointx[i], pointy[i], pointx[n], pointy[n]);
113.                 if (limiter > fader) {
114.               limiter = fader;
115.                 }
116.                 
117.             intense = 100-limiter/(fader/100);
118.             stroke(0, intense);
119. 
     
120.              if (i != n) {
121.             line(pointx[i], pointy[i], pointx[n], pointy[n]);
122.              }
123.             
124.             if (rand2[i] < 0.5 && pointx[i] < width) {
125.             pointx[i] = pointx[i] + random(0, 1)/4;
126.             }
127.             else if(pointx[i] > 0) {
128.               pointx[i] = pointx[i] - random(0,1)/4;
129.             }
130.             else 
131.             {
132.               pointx[i] = pointx[i] + random(0, 1)/4;
133.             
134.             }
135.             
136.              if (rand1[i] < 0.5 && pointy[i] < height) {
137.             pointy[i] = pointy[i] + random(0, 1)/4;
138.             }
139.             else if(pointy[i] > 0)
140.             {
141.               pointy[i] = pointy[i] - random(0, 1)/4;
142.             }
143.             else
144.             {
145.               pointy[i] = pointy[i] + random(0, 1)/4;
146.             } 
147.   };
148.   };
149. 
     
150. }
151.