Null pointer error when attaching Env (amplitude envelope) to SoundFile

[trackme518]

Hi,
I am getting null pointer error when trying to attach SoundFile to amplitude envelope Env:

import processing.sound.*;
SoundFile soundfile;
Env env; 

// Times and levels for the ASR envelope
float attackTime = 0.001;
float sustainTime = 0.01;
float sustainLevel = 1.0;
float releaseTime = 0.2;

void setup() {
  size(640, 360);
  background(0);

  // Create triangle wave and start it
  soundfile = new SoundFile(this, dataPath("zvonkohra.wav") );
  //soundfile.loop(); //does not matter - I am getting null pointer regardless
  soundfile.amp(1.0);
  // Create the envelope 
  //env = new Env(this);
}

void mousePressed(){
    soundfile.play();
    env.play(soundfile, attackTime, sustainTime, sustainLevel, releaseTime); // NULL POINTER ERROR HERE
    println("file play");
}

void draw() { 
} 

With AudioSample it works...so once again method that would return AudioSample from SoundFile would come in handy. What about creating a new function that would return it so we don't have to modify play return type?

import processing.sound.*;
SoundFile soundfile;
Env env;
AudioSample sample;
// Times and levels for the ASR envelope
float attackTime = 0.001;
float sustainTime = 0.1;
float sustainLevel = 1.0;
float releaseTime = 0.5;

void setup() {
  size(640, 360);
  background(0);

  // Create triangle wave and start it
  soundfile = new SoundFile(this, dataPath("zvonkohra.wav") );
  //soundfile.loop();
  soundfile.amp(1.0);

  float[] bufferData = new float[soundfile.frames()];
  for (int i = 0; i < soundfile.frames(); i++) {
    bufferData[i] = soundfile.read(i, 0);
    //float right = soundfile.read(i, 1);
  }

  sample = new AudioSample(this, bufferData);
  // Create the envelope
  env = new Env(this);
}

void mousePressed() {
  sample.play();
  env.play(sample, attackTime, sustainTime, sustainLevel, releaseTime); // NULL POINTER ERROR
  println("file play");
}

void draw() {
}

[kevinstadler]

Hello,

based on the stack trace:

java.lang.NullPointerException: Cannot invoke "processing.sound.Env.play(processing.sound.SoundObject, float, float, float, float)" because "this.env" is null
	at sketch_231227a.mousePressed(sketch_231227a.java:45)

it looks like the NullPointerException is actually from your code and not the sound library: in the upper sketch you have

  //env = new Env(this);

which means env remains null and triggers an exception when trying to trigger the envelope.

Regarding returning or creating an AudioSample from a SoundFile: this should normally not be necessary, because in terms of the object hierarchy as well as all implementation details, a SoundFile already is an AudioSample. The only method in which SoundFile is different from AudioSample is the constructor, where external audio is decoded and loaded into memory. Once created a SoundFile and an AudioSample behave in exactly the same way.

Best,
Kevin

[trackme518]

Oh snap! You are right, sorry to bother you :-D I guess it's time to relax.