I wrote this code, but it's nog working properly. Every 2 seconds, you see a green or red ellipse in the left corner. This ellipse is supposes to stay there and then change color. Why is is disappearing again? This might be a noob question, but im not very good at this.

import processing.video.*;

int numPixels;
int[] previousFrame;
Capture video;
int r;
int g;
int getal = 0;
int frameratecounter = 50;
int startTime;
int time;
int restTime;
float score = 0;
PFont font;

void setup() {
 size(640, 500);
 r = color(255, 0, 0);
 g = color(0, 255, 0);
 frameRate(25);
 video = new Capture(this, width, height, 25);
 numPixels = video.width * video.height;
 previousFrame = new int[numPixels];
 loadPixels();
 rect(0,0,640,20);
 startTime = millis();
 font = loadFont("Ziggurat-HTF-Black-32.vlw");
}

void draw() {
  if (frameratecounter == 50){
   background (0,0,0);
   getal = int(random(25,75));
   println(getal);
   if (getal < 50) {
     fill(r);
     ellipse(25,25,50,50);
     }  
   else {
     fill(g);
     ellipse(25,25,50,50);
   }
  frameratecounter = 1;
 } else{
  frameratecounter++;
}  

 if (video.available()) {
   video.read();
   video.loadPixels();
 
   
   int movementSum = 0;
   float points = 0;
   time = millis() - startTime;
   restTime = ((10000 - time) / 1000);
   
   if (time < 10000) {
     for (int i = 0; i < numPixels; i++) {
       color currColor = video.pixels[i];
       color prevColor = previousFrame[i];
 
       int currR = (currColor >> 16) & 0xFF;
       int currG = (currColor >> 8) & 0xFF;
       int currB = currColor & 0xFF;
 
       int prevR = (prevColor >> 16) & 0xFF;
       int prevG = (prevColor >> 8) & 0xFF;
       int prevB = prevColor & 0xFF;
 
       int diffR = abs(currR - prevR);
       int diffG = abs(currG - prevG);
       int diffB = abs(currB - prevB);
 
       movementSum += diffR + diffG + diffB;
       
       pixels[i] = color(currColor);
       
       previousFrame[i] = currColor;
     }
     points = abs((movementSum - 3000000)/4000000);
     score += points;
     
     // To prevent flicker from frames that are all black (no movement),
     // only update the screen if the image has changed.
     if (movementSum > 0) {
       updatePixels();
       image(video, 0, 20);
       fill(255);
       rect(0, 0, 640, 20);
       fill(0, 255, 0);
       rect(0, 0, score, 20);
       fill(0);
       textFont(font, 16);
       text(restTime, 600, 18);
     }
   } else {
     fill(255);
     rect(0, 20, 640, 480);
     textFont(font, 32);
     textAlign(CENTER);
     fill(0);
     text("Je score is:", 320, 220);
     text(score, 320, 260);
     textFont(font, 16);
     text("Druk spatiebalk om opnieuw te starten.", 320, 290);
   }
 }
}

void keyPressed() {
 if (key == ' ') {
   //als de spatie balk gedruikt word,dan:
   startTime = millis();
   score = 0;
 }
}

Can someone help me?

No wonder, you draw the circle only once every 50 frames...
You have to put the calculation of getal in the test, but do the fill()/ellipse() every time. Since you draw at the same place, you can put only the fill in the conditional and put the ellipse() call after it (ie. same call whatever the fill() call).

CMD2 wrote on Jun 30^th, 2009, 1:43am:

Just declare fillColour before setup to make it global (it has limited scope in the given snippet), or follow my advice...

OK, to be explicit:
Code:

if (frameCount % 50 == 0){
   background (0,0,0);
   getal = int(random(25,75));
   println(getal);
 }
   if (getal < 50) {
     fill(r);
     }  
   else {
     fill(g);
   }
     ellipse(25,25,50,50);
 

Tested as much as blindfish's code... :-P