I've been using copy() and pixels a lot with images in memory. I can't make head nor tail of the new functions though. I don't know if I'm supposed to be using loadPixels on a PImage or from where I'm calling copy().

The idea is simple, I measure the difference between one frame and the next. I've added a bit of fade to it as I'm still working on it but I've ground to a halt trying to figure out p85 syntax.

Old Code:
Code:

boolean newFrame = false;
BImage swap;
BImage display;
BGraphics buf;
void setup()  {
  size(320, 240);
  swap = loadImage("a.gif");
  display = swap.copy();
  background(255);
  beginVideo(320, 240, 12);
}
void videoEvent() {
  newFrame = true;
}
void loop()  {
  //background(display);
  if(newFrame) {
    // noStroke();
    fill(255,255,255,30);
    rect(0,0,width,height);
    difference();
    newFrame = false;
    swap = video.copy();
  }
}
void difference(){
  for (int iy = 0; iy < video.height; iy++){
    for (int ix = 0; ix < video.width; ix++){
	color c1 = video.pixels[ix + iy * video.width];
	color c2 = swap.pixels[ix + iy * swap.width];
	int  r1=c1>>16&0xff;
	int  g1=c1>>8&0xff;
	int  b1=c1&0xff;
	int  r2=c2>>16&0xff;
	int  g2=c2>>8&0xff;
	int  b2=c2&0xff;
	//display.pixels[ix + iy * display.width] = color (255-abs(r1-r2),255-abs(g1-g2),255-abs(b1-b2), 50);
	if (abs(r1-r2) > 0 && abs(g1-g2) > 0 && abs(b1-b2) > 0){
	  stroke(color (255-abs(r1-r2),255-abs(g1-g2),255-abs(b1-b2), 50));
	  point(ix,iy);
	}
    }
  }
}
 

New, and still not working code:
Code:

import processing.video.*;
Capture myCapture;
PImage swap;
PImage display;
void setup()  {
  size(320, 240);
  String s = "Creative WebCam Live! Pro-WDM";
  myCapture = new Capture(this, s, width, height, 12);
  swap = loadImage("a.gif");
  display = loadImage("a.gif");//.copy(swap,0,0,swap.width,swap.height,0,0,swap.width,swap.height);
  //still can't figure out copy()
  background(255);
}
void captureEvent(Capture myCapture) {
  myCapture.read();
}
void draw()  {
  fill(255,255,255,30);
  rect(0,0,width,height);
  difference();
  swap.copy(myCapture,0,0,myCapture.width,myCapture.height,0,0,swap.width,swap.height);
  image(display, 0, 0);

}
void difference(){
  for (int iy = 0; iy < myCapture.height; iy++){
    for (int ix = 0; ix < myCapture.width; ix++){
	color c1 = myCapture.pixels[ix + iy * myCapture.width];
	color c2 = swap.pixels[ix + iy * swap.width];
	int  r1=c1>>16&0xff;
	int  g1=c1>>8&0xff;
	int  b1=c1&0xff;
	int  r2=c2>>16&0xff;
	int  g2=c2>>8&0xff;
	int  b2=c2&0xff;
	//display.pixels[ix + iy * display.width] = color (255-abs(r1-r2),255-abs(g1-g2),255-abs(b1-b2), 50);
	if (abs(r1-r2) > 0 && abs(g1-g2) > 0 && abs(b1-b2) > 0){
	  stroke(color (255-abs(r1-r2),255-abs(g1-g2),255-abs(b1-b2), 50));
	  point(ix,iy);
	}
    }
  }
}
 

Could somebody set me straight please?

you have to call updatePixels() so that opengl and java2d know that the image data has changed, because they both need to do post-processing on it.

we didn't need to do this before (because P2D and P3D don't need it) which was nice, but unfortunately it's just something we have to deal with in order to make opengl/java2d happen. (small price for opengl, right?)

loadPixels() just means "i'm reading to mess with things", and updatePixels() means "i'm done editing, make sure it gets updated on the next draw.