Context doesn't seem to update if outside the draw() method

[GoogleCodeExporter]

What steps will reproduce the problem?
1. Stop the draw() loop with noLoop()
2. Call context.update() and context.depthImage() or context.depthMap()
3. Notice the OpenNI information doesn't update, it's stil the most recent 
'frame' before calling noLoop()

What is the expected output? What do you see instead?

I expected to get updated depth values after calling context.update()

What version of the product are you using? On what operating system?

SimpleOpenNI 0.26 on osx 10.6.8 

Please provide any additional information below.
Here is a test sketch:
import SimpleOpenNI.*;

SimpleOpenNI  context;
boolean       recordFlag = true;

int frames = 0;

void setup(){
  context = new SimpleOpenNI(this);

  if(! recordFlag){
    if(! context.openFileRecording("test.oni") ){
      println("can't find recording !!!!");
      exit();
    }
    context.enableDepth();
  }else{  
    // recording
    context.enableDepth();
    // setup the recording 
    context.enableRecorder(SimpleOpenNI.RECORD_MEDIUM_FILE,"test.oni");
    // select the recording channels
    context.addNodeToRecording(SimpleOpenNI.NODE_DEPTH,SimpleOpenNI.CODEC_16Z_EMB_TABLES);
  }
  // set window size 
  if((context.nodes() & SimpleOpenNI.NODE_DEPTH) != 0)
    size(context.depthWidth() , context.depthHeight());
  else 
    exit();
}
void draw()
{
  background(0);
  context.update();
  if((context.nodes() & SimpleOpenNI.NODE_DEPTH) != 0) image(context.depthImage(),0,0);
  if(recordFlag) frames++;
}
void keyPressed(){
  if(key == ' '){
    if(recordFlag){
      saveStrings(dataPath("frames.txt"),split(frames+" ",' '));
      exit();
    }else saveONIToPLY();
  }
}
void saveONIToPLY(){
  frames = int(loadStrings(dataPath("frames.txt"))[0]);
  println("recording " + frames + " frames");
  int w = context.depthWidth();
  int h = context.depthHeight();
  noLoop();
  for(int i = 0 ; i < frames; i++){
    PrintWriter output = createWriter(dataPath("frame_"+i+".ply"));
    output.println("ply");
    output.println("format ascii 1.0");
    output.println("element vertex " + (w*h));
    output.println("property float x");
    output.println("property float y");
    output.println("property float z");
    output.println("end_header\n");
    context.update();
    int[]   depthMap = context.depthMap();
    int     index;
    PVector realWorldPoint;
    for(int y=0;y < h;y++){
      for(int x=0;x < w;x++){
        index = x + y * w;
        realWorldPoint = context.depthMapRealWorld()[index];
        output.println(realWorldPoint.x + " " + realWorldPoint.y + " " + realWorldPoint.z);
      }
    }
    output.flush();
    output.close();
    println("saved " + (i+1) + " of " + frames);
  }
  loop();
  println("recorded " + frames + " frames");
}

Also I couldn't find a way to determine how many frames the .oni file has, so 
I've used  a text file.

To get update to work I've done the saving in the draw loop and used delay() - 
quite hacky/not precise:

import SimpleOpenNI.*;

SimpleOpenNI  context;
boolean       recordFlag = false;
boolean       saving = false;
int frames = 0;
int savedFrames = 0;

void setup(){
  context = new SimpleOpenNI(this);

  if(! recordFlag){
    if(! context.openFileRecording("test.oni") ){
      println("can't find recording !!!!");
      exit();
    }
    context.enableDepth();
  }else{  
    // recording
    context.enableDepth();
    // setup the recording 
    context.enableRecorder(SimpleOpenNI.RECORD_MEDIUM_FILE,"test.oni");
    // select the recording channels
    context.addNodeToRecording(SimpleOpenNI.NODE_DEPTH,SimpleOpenNI.CODEC_16Z_EMB_TABLES);
  }
  // set window size 
  if((context.nodes() & SimpleOpenNI.NODE_DEPTH) != 0)
    size(context.depthWidth() , context.depthHeight());
  else 
    exit();
}
void draw()
{
  background(0);
  context.update();
  if((context.nodes() & SimpleOpenNI.NODE_DEPTH) != 0) image(context.depthImage(),0,0);
  if(recordFlag) frames++;
  if(saving && savedFrames < frames){
      delay(3000);//hack
      int i = savedFrames;
      int w = context.depthWidth();
      int h = context.depthHeight();
      PrintWriter output = createWriter(dataPath("frame_"+i+".ply"));
      output.println("ply");
      output.println("format ascii 1.0");
      output.println("element vertex " + (w*h));
      output.println("property float x");
      output.println("property float y");
      output.println("property float z");
      output.println("end_header\n");
      rect(random(width),random(height),100,100);
      int[]   depthMap = context.depthMap();
      int     index;
      PVector realWorldPoint;
      for(int y=0;y < h;y++){
        for(int x=0;x < w;x++){
          index = x + y * w;
          realWorldPoint = context.depthMapRealWorld()[index];
          output.println(realWorldPoint.x + " " + realWorldPoint.y + " " + realWorldPoint.z);
        }
      }
      output.flush();
      output.close();
      println("saved " + (i+1) + " of " + frames);
      savedFrames++;
  }
}
void keyPressed(){
  if(key == ' '){
    if(recordFlag){
      saveStrings(dataPath("frames.txt"),split(frames+" ",' '));
      exit();
    }else saveONIToPLY();
  }
}
void saveONIToPLY(){
  frames = int(loadStrings(dataPath("frames.txt"))[0]);
  saving = true;
  println("recording " + frames + " frames");
}

Original issue reported on code.google.com by Orgi...@gmail.com on 22 Jul 2012 at 10:01