Hello. Please  tell me how can i apply several shader for one rectangle? I trying to do this so.

2. .......
3. boolean mySwitch;
4. ......
5. 
   
6. void setup()
7. { 
8.   size(800,600,P2D);
9.   img = loadImage("background.jpg");
10.   for(int i=0;i<12;i++)
11.   {
12.     gliff[i] = new Gliff();   
13.   }
14.   shine = loadShader("shine.glsl");
15.   shine1 = loadShader("shine1.glsl");  
16.   shader(shine1);
17.   shader(shine);
18.   shine1.set("posLight",float(width/2),float(height/2));
19.   shine.set("posLight",float(width/2)+20,float(height/2));
20. }
21. 
    
22. void draw()
23. {
24.     rect(0,0,width,height); 
25.    if (mySwitch)
26.    {
27.      rect(0,0,width,height); 
28. 
    
29.      shine1.set("posLight",currX,float(currY));
30.      
31.      currX=currX + time;
32.      
33.      currY=currY + time*k;
34.      
35.      mySwitch = false;
36.      
37.      print("2 ");
38.    } 
39. 
    
40. else 
41. {
42.   
43.      rect(0,0,width,height); 
44.   
45.      shine.set("posLight",currX,float(currY));
46.      
47.      currX=currX + time;
48.      
49.      currY=currY + time*k;
50.      
51.      mySwitch = true;
52.      
53.      print("1 ");
54. }
55.      
56.          
57. }