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XMLElemement not working in online applet

[6 Replies]
- 04-Dec-2010 10:40 PM
- Forum: Programming Questions
Hey Folks,

I'm working on a little boids modification that gets the number of boids from a nasdaq rss feed using XMLElement. The problem is that the code works great on my computer, but doesn't work at all when I put it online (I've tried in safari, firefox, and chrome). I'm putting both the processing code and the applet code on here for reference. I had originally tried doing this with the network library until I realized that the network library makes no claims to work on web, but it looks like XMLElement should, help?

Thanks so much!

// Modified Boids code

XMLElement xml;

int xmlIndex = 24;

Flock flock;

int numBoids; // 150, 300

PImage parchment;

PVector m;

boolean init = false;

void setup() {

  size(300, 300);

  parchment = loadImage("parch.jpg");

  noCursor();

  flock = new Flock();

  smooth();

  noFill();



xml = new XMLElement(this, "http://www.nasdaq.com/aspxcontent/NasdaqRSS.aspx?data=quotes&symbol=UDOW");

  XMLElement[] table = xml.getChildren("channel/item/description");

  String data = table[0].getContent();

  String[] pairs = splitTokens(data, "<>\n");

  int numBoids = int(pairs[xmlIndex]);

  if (numBoids < 10) { numBoids = 300; }

  for (int i = 0; i < numBoids; i++) {

   flock.addBoid(new Boid(new PVector(width/2,height/2), 2.0, 0.2)); // 3.0, 0.05

  }



}

void draw() {

  //initFlock();

  tint(255,100);

  image(parchment,0,0);

  flock.run();

}

// Add a new boid into the System

void mousePressed() {

  //flock.addBoid(new Boid(new PVector(mouseX,mouseY),2.0f,0.05f));

}

// The Boid class

class Boid {

  PVector loc;

  PVector vel;

  PVector acc;

  float r;

  float maxforce; // Maximum steering force

  float maxspeed; // Maximum speed

   Boid(PVector l, float ms, float mf) {

   acc = new PVector(0,0);

   vel = new PVector(random(-1,1),random(-1,1));

   loc = l.get();

   r = 2.0;

   maxspeed = ms;

   maxforce = mf;

  }

  void run(ArrayList boids) {

   flock(boids);

   update();

   borders();

   render();

  }

  // We accumulate a new acceleration each time based on three rules

  void flock(ArrayList boids) {

   PVector sep = separate(boids); // Separation

   PVector ali = align(boids); // Alignment

   PVector coh = cohesion(boids); // Cohesion

   // Arbitrarily weight these forces

   sep.mult(1.4); // 1.5

   ali.mult(1.0); // 1.0

   coh.mult(1.2); // 1.0

   // Add the force vectors to acceleration

   acc.add(sep);

   acc.add(ali);

   acc.add(coh);

  }

  // Method to update location

  void update() {

   // Update velocity

   vel.add(acc);

   // Limit speed

   vel.limit(maxspeed);

   loc.add(vel);

   // Reset accelertion to 0 each cycle

   acc.mult(0);

  }

  void seek(PVector target) {

   acc.add(steer(target,false));

  }

  void arrive(PVector target) {

   acc.add(steer(target,true));

  }



  void avoid(PVector target) {

   acc.sub(steer(target, false));

  }

  // A method that calculates a steering vector towards a target

  // Takes a second argument, if true, it slows down as it approaches the target

  PVector steer(PVector target, boolean slowdown) {

   PVector steer; // The steering vector

   PVector desired = target.sub(target,loc); // A vector pointing from the location to the target

   float d = desired.mag(); // Distance from the target is the magnitude of the vector

   // If the distance is greater than 0, calc steering (otherwise return zero vector)

   if (d > 0) {

   // Normalize desired

   desired.normalize();

   // Two options for desired vector magnitude (1 -- based on distance, 2 -- maxspeed)

   if ((slowdown) && (d < 100.0)) desired.mult(maxspeed*(d/100.0)); // This damping is somewhat arbitrary

   else desired.mult(maxspeed);

   // Steering = Desired minus Velocity

   steer = target.sub(desired,vel);

   steer.limit(maxforce); // Limit to maximum steering force

   }

   else {

   steer = new PVector(0,0);

   }

   return steer;

  }

  void render() {

   // Draw a triangle rotated in the direction of velocity

   float theta = vel.heading2D() + PI/2;

   stroke(100, 50); // 255

   strokeWeight(2);

   //color c = get(int(loc.x), int(loc.y));

   //float b = brightness(c);

   //stroke(b-100,150);

   pushMatrix();

   translate(loc.x,loc.y);

   rotate(theta);

   line(0,-r*1,0,r*1);

   popMatrix();

  }

  // Keep in frame



  void borders() {

   int edge = 30;

   m = new PVector(mouseX, mouseY);

   if (loc.x < edge ||loc.y < edge ||loc.x > width-edge || loc.y > height-edge) seek(m);

   float d = loc.dist(m);

   if (d < 30) {avoid(m); avoid(m); avoid(m);}

  }



  // Separation

  // Method checks for nearby boids and steers away

  PVector separate (ArrayList boids) {

   float desiredseparation = 20.0;

   PVector steer = new PVector(0,0,0);

   int count = 0;

   // For every boid in the system, check if it's too close

   for (int i = 0 ; i < boids.size(); i++) {

   Boid other = (Boid) boids.get(i);

   float d = PVector.dist(loc,other.loc);

   // If the distance is greater than 0 and less than an arbitrary amount (0 when you are yourself)

   if ((d > 0) && (d < desiredseparation)) {

   // Calculate vector pointing away from neighbor

   PVector diff = PVector.sub(loc,other.loc);

   diff.normalize();

   diff.div(d); // Weight by distance

   steer.add(diff);

   count++; // Keep track of how many

   }

   }

   // Average -- divide by how many

   if (count > 0) {

   steer.div((float)count);

   }

   // As long as the vector is greater than 0

   if (steer.mag() > 0) {

   // Implement Reynolds: Steering = Desired - Velocity

   steer.normalize();

   steer.mult(maxspeed);

   steer.sub(vel);

   steer.limit(maxforce);

   }

   return steer;

  }

  // Alignment

  // For every nearby boid in the system, calculate the average velocity

  PVector align (ArrayList boids) {

   float neighbordist = 25.0;

   PVector steer = new PVector(0,0,0);

   int count = 0;

   for (int i = 0 ; i < boids.size(); i++) {

   Boid other = (Boid) boids.get(i);

   float d = PVector.dist(loc,other.loc);

   if ((d > 0) && (d < neighbordist)) {

   steer.add(other.vel);

   count++;

   }

   }

   if (count > 0) {

   steer.div((float)count);

   }

   // As long as the vector is greater than 0

   if (steer.mag() > 0) {

   // Implement Reynolds: Steering = Desired - Velocity

   steer.normalize();

   steer.mult(maxspeed);

   steer.sub(vel);

   steer.limit(maxforce);

   }

   return steer;

  }

  // Cohesion

  // For the average location (i.e. center) of all nearby boids, calculate steering vector towards that location

  PVector cohesion (ArrayList boids) {

   float neighbordist = 25.0;

   PVector sum = new PVector(0,0); // Start with empty vector to accumulate all locations

   int count = 0;

   for (int i = 0 ; i < boids.size(); i++) {

   Boid other = (Boid) boids.get(i);

   float d = loc.dist(other.loc);

   if ((d > 0) && (d < neighbordist)) {

   sum.add(other.loc); // Add location

   count++;

   }

   }

   if (count > 0) {

   sum.div((float)count);

   return steer(sum,false); // Steer towards the location

   }

   return sum;

  }

}

// The Flock (a list of Boid objects)

class Flock {

  ArrayList boids; // An arraylist for all the boids

  Flock() {

   boids = new ArrayList(); // Initialize the arraylist

  }

  void run() {

   for (int i = 0; i < boids.size(); i++) {

   Boid b = (Boid) boids.get(i);

   b.run(boids); // Passing the entire list of boids to each boid individually

   }

  }

// Applet code I'm using in an MySQL database - this has worked well for other sketches.
```
<APPLET name="applet6" WIDTH="300" HEIGHT="300" archive=" http://matthewmosher.us/processing/applet5/boidsClean2.jar" standby="Loading Processing software�" codebase=" http://matthewmosher.us/processing/applet6/" code="boidsClean2" mayscript="true" scriptable="true" image=" http://matthewmosher.us/processing/applet6/loading.gif" boxmessage="Loading Processing software�" boxcolor="#FFFFFF"> <IMG SRC=" http://matthewmosher.us/processing/applet6/loading.gif" WIDTH="1" HEIGHT="1" /> </APPLET>
```

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