you can make a screen shot into a image var

http://www.processing.org/reference/get_.html

in this example it's "c"

1. // new orbit example
2. //  nplanets and ncomets
3. import processing.opengl.*;
4. //
5. float timestep = 200.0 ;
6. float theta = 0.0;
7. int scl = 1;
8. // array of orbital info
9. String[] pname = {
10.   "SUN", "MER", "VEN", "STA", "EAR", "STB", "MAR", "P/2012 A3\nSOHO", "C/2012 S1\nISON", "C/2011 W3\nLovejoy"
11. };
12. float[] pnum = {
13.   0, 1, 2, 3, 4, 5, 6, 7, 8, 9
14. };
15. float[] ecc = {
16.   0, 0.206, 0.007, 0.009562656, 0.017, 0.004440, 0.093, 0.776, 0.995, 0.995
17. }; // eccenticity
18. float[] au = {
19.   0, 0.39, 0.72, 0.95539896, 1.0, 1.051887, 1.52, 2.568, 10.0, 78.68
20. }; // mean distance 1au
21. float[] rot = {
22.   0, 0.24, 0.62, 0.93326171, 1, 1.078152, 1.88, 4.12, 10.0, 10.0
23. }; // period of rotation 1yr
24. float[] eqtr = {
25.   3.0, 0.382, 0.949, 0.1, 1, 0.1, 0.532, 0.1, 0.1, 0.1
26. };   // 1 earth diam
27. float[] angl = {
28.   0.0, 29.124, 55.186, 259.41452171, 114.20783, 18.37796930629710, 286.537, 217.6673, 295.7576, 332.02321
29. }; // perri
30. //
31. PFont fontA = createFont("SanSerif", 12);
32. PFont fontB = createFont("SanSerif", 16);
33. //
34. //
35. PImage c;
36. 
    
37. void setup() {
38.   size(1024, 1024, OPENGL);
39.   //c = get();
40. }
41. void draw()
42. {
43.   background(0);
44.   if (c!=null) {
45.     image (c, 0, 0);
46.   }
47.   // Translate the origin point to the center of the screen
48.   translate(width/2, height/2)  ;
49.   ellipseMode(RADIUS);
50.   nplanets();  // draw planets
51.   ncomets() ;  // draw comets
52.   theta +=(0.00004109*(1+timestep));
53. }
54. void keyPressed() {
55.   c = get();
56. }
57. void keyReleased() {
58.   //
59.   if (key =='x') {
60.     exit();
61.   }
62.   if (key =='c') {
63.     background(0);
64.   }
65.   if (key =='[') {
66.     scl-=1 ;
67.     if (scl <= 0) {
68.       scl = 1;
69.     }
70.   }
71.   if (key ==']') {
72.     scl+=1 ;
73.     if (scl >= 100) {
74.       scl = 100;
75.     }
76.   }
77.   if (key =='-') {
78.     timestep-=100 ;
79.     if (timestep <= -1000) {
80.       timestep = -1000;
81.     }
82.   }
83.   if (key =='=') {
84.     timestep+=100 ;
85.     if (timestep >= 1000) {
86.       timestep = 1000;
87.     }
88.   }
89. }
90. void nplanets() {
91.   // draw planets
92.   for ( int np = 6 ; np > -1 ; np-=1 ) { 
93.     float e1 = ecc[np];
94.     float a1 = (au[np]*300  );
95.     float b1 = a1*sqrt(1-(e1*e1))  ;
96.     float c1 = a1*e1  ;
97.     float  l1 = (b1*b1)/a1  ;
98.     float r1 = l1/(1.0+(e1*cos(angl[np]+theta/rot[np])));
99.     float x1 = r1*cos(angl[np]+theta/rot[np]);
100.     float y1 = -r1*sin(angl[np]+theta/rot[np]);
101.     //draw orbit
102.     stroke(32);
103.     fill(255/(np+1), 255/(np+1), 16/(np+1), 16);
104.     strokeWeight(2);  // transparent orbit plane
105.     ellipse(0, 0, r1/scl, r1/scl);
106.     // draw planet at orbit angle
107.     stroke(200, 200, 200); 
108.     fill(36*(np+1), 36*(np+1), 16*(np+1), 255);
109.     ellipse(int(x1)/scl, int(y1)/scl, (3*eqtr[np])/scl, (3*eqtr[np])/scl);
110.     //sphere((3*eqtr[np])/scl );
111.     stroke(255); 
112.     fill(255);
113.     textFont(fontA, 12);
114.     textAlign(LEFT);
115.     text( np+" "+pname[np], (1+int(x1)/scl), (-1+int(y1)/scl));
116.   }
117. }
118. void ncomets() {
119.   // draw comets
120.   for ( int nc = 9 ; nc > 6 ; nc-=1 ) {
121.     float ec = ecc[nc];
122.     float ac = (au[nc]*300 );
123.     float bc = (ac*sqrt(1-(ec*ec)))  ;
124.     float cc = ac*ec  ;
125.     float  lc = (bc*bc)/ac  ;
126.     float rc = lc/(1.0+(ec*cos(angl[nc]+theta/rot[nc])));
127.     float xc = (rc*cos(angl[nc]+theta/rot[nc]))+(2*cc);
128.     float yc = (-rc*sin(angl[nc]+theta/rot[nc]));
129.     // draw at orbit angles
130.     stroke(200, 200, 200);
131.     fill(200, 200, 200);
132.     ellipse(int(xc)/scl, int(yc)/scl, (3*eqtr[nc]), (3*eqtr[nc]));
133.     stroke(255);
134.     fill(255);
135.     textFont(fontA, 12);
136.     textAlign(LEFT);
137.     text( pname[nc], (1+int(xc)/scl), (-1+int(yc)/scl));
138.   }
139. }

Search the forum for similar questions (can be "screen capture"). Hint: include "Robot" in the search for better results.

Thank you, this one works fine https://forum.processing.org/topic/get-screencapture

Now I got another problem =) :

yes, get() is only for the sketch itself. Sorry I thought you want that. I cannot help with your current issue.

Merry Christmas!

Do you really need to take 60 screenshots per second?

I think the OOME you got is related to a bug in the new version of Processing: the issue isn't the screen capture, but each time you use it with image(), it is put in a cache which is never cleaned.

IIRC, one solution is to call removeCache(image); after displaying the image.

Philho, thanks,  removeCache(image); works great.

Ah, OK, the " if i take screens continually in draw()" made me think you were taking lot of images. Which is still legitimate for a screencast or similar, of course.
But indeed, the OOME happened quite quickly anyway. Glad my trick solved your problem.