How can I load all of the pixels that appear on the display window (so all of the PImages, PVectors, video's etc. that are drawn) into a new PImage? I'd like the new PImage to read/detect all of the white pixels that appear on the display window.

I'm trying several things, but I'm not sure how to do this exactly.

1. int w = 800;
   int h = 600;
   
   PImage detectPixels;
   
     detectPixels = createImage(w,h, RGB);
   
     detectPixels.loadPixels();
     detectPixels.pixels[w*h-1]=color(255,255,255);
     detectPixels.get(0,0,w,h);
     detectPixels.updatePixels();