A couple of (hopefully) simple problems from a nooooob!

brokenbeep

A couple of (hopefully) simple problems from a nooooob!

in Contributed Library Questions • 2 years ago

Hello everyone, this is my first post here. I've done a bit of reading around processing and finally decided to dive in with a project. I've predictably hit up against a couple of problems and was hoping that one of you might help me. I'm sure that this will be super easy to those of you with much more experience than me. So...

I started playing with Ess because I have a background in sonic art and was interested in the FFT bits and wanted to play around with them. I've got a patch up and running which kind of does what I want, here you go:

import krister.Ess.*;

FFT myfft;

AudioInput myinput;

int bufferSize=256;

void setup() {

size(1000,500, P3D);

frameRate(30);

background(255);

smooth();

Ess.start(this); //start this window

myinput=new AudioInput(bufferSize);

myfft=new FFT(bufferSize*2);

myinput.start();

myfft.damp(.3);

myfft.equalizer(true);

myfft.limits(.005,.05);

}

void draw() {

rotateY(radians(-17)); //rotates Y

rotateX(radians(-10)); // rotates X

background(255);

int d=0;

for (int i=0; i<bufferSize;i++) { //i defines the FFT to fill

if (i==0){

d++;

}

pushMatrix();

translate(i+400, height/2, d);

box(1, myfft.spectrum[i]*-400, 1);

popMatrix();

println(d);

}

}public void audioInputData(AudioInput theInput) {

myfft.getSpectrum(myinput);

}

One problem relates to the variable "d". What I would like to happen is that every time the variable "i" hits 0, 1 gets added to "d" and the final argument for translate gets increased, so bringing the image ever closer. I've created a println(d); object to monitor whats going on, but all that seems to happen is that the number 0 and 1 fluctuate (seemingly) randomly. I've highlighted the relevant parts in green.

My second problem is that I don't want what has transpired to be deleted with each frame. The idea is that FFT frequency analysis is carried out and, when the "i" variable hits 0, the image moves forward and the past FFT window can still be made out. What I want to end up with is a 3d representation of a sound wave.

Any help would be greatly appreciated!!!

Replies(3)

BlueThen

Re: A couple of (hopefully) simple problems from a nooooob!

2 years ago

Hi.

At every frame, you're resetting d to 0. I think what you intended was to move int d; to outside of the draw loop and where the program will remember its value.

In your for loop,

for (int i=0; i<bufferSize;i++)

i will == 0 either once (on the first iteration) or no times (when bufferSize == 0). I'd explain further, but I'm a little unsure of what you're trying to do here. If you're trying to have the analysis move backwards in space, perhaps something like millis()*speed for the z coordinate?

For your coordinates getting lost, you'll need to keep track of the data over time.

It appears krister.Ess is storing its data as myfft.spectrum[i]. You could save this into an ArrayList (One that is global, meaning its defined outside the other methods) . When you .add the array to the ArrayList, you can reference it using arraylist.get(arraylist.size()-time), and it'll return something similar to myfft.spectrum[i].

Hope that helps.

v.k.

Re: A couple of (hopefully) simple problems from a nooooob!

2 years ago

Well, in a quick look:

the for loop is like a detour, once the condition match, the "program" goes inside it and only pops out when the condition does not match anymore. The variable i is only accessible inside for loop and is reset every execution (to whatever is stated in the "for(int i = XX;condition to out;increment)). As u have made a condition [if (i==0)] inside the for loop "d" is always added 1 at the beginning of for loop. But when u state in the middle of draw() int d=0. Each loop the variable "d" is also reset to zero. So basically:

int d = 0; //<< sets d to 0 each time

for (int i=0; i<bufferSize;i++) { //<< sets i to zero

if (i==0){ //<< condition matched d (always zero) is added one, d is now 1

d++;

}

pushMatrix(); //<<< all this happens for each value of i _ and 1 as d value

translate(i+400, height/2, d);

box(1, myfft.spectrum[i]*-400, 1);

popMatrix();

println(d);

}//<<<< pops out of for loop i will be reset at next draw() loop...

code folow and start over from the beginning of draw() reseting "d" to zero before going inside the for again...

So u are alternating d value between 1 and 0.

I'm not sure what u want to do, but seems that u should make d a global variable (state it before setup())

so it will increment as expected. Also there is no need to increment inside the if() inside the for(), as it will be the same as increment it outside the for..

int d = 0;

void setup()

{

setup here

}

void draw()

{

code necessary

for (int i=0; i<bufferSize;i++) { //<< sets i to zero

pushMatrix();

translate(i+400, height/2, d); //<< d is zero now, will be 1 next run, 2 next next and so on...

box(1, myfft.spectrum[i]*-400, 1);

popMatrix();

println(d);

}

d++; // <<< increment d it will be 1 next run, 2 next next and so on...

the rest of the code...

}

hope that helps...