Eclipse multiple classes question

migmigmig

Eclipse multiple classes question

in Integration and Hardware • 10 months ago

Hello, everyone.

I am currently working on an applet which was started in Processing but which I then decided to finish using Eclipse. I've encountered a small issue however :

is it possible to create multiple instances with different parameters directly ?

By this I mean that the Eclipse Processing syntax, when using multiple classes would be
//PApplet
class blabla extends PApplet {
public void setup(){   ...
}

public void draw(){    ....
}
etc...
whatev = new Whatever(this)
...
}

class Whatever {
int thinga;
int thingb;

//Constructor
Public Whatever(int a, int b){
thing a = a;
thingb = b;
}

Whatever(PApplet p){
parent = p;

thing a = 1;
thing b = 2;

}

}

the parts in bold are what I have an issue with.

When I create a new instance in the class which extends PApplet, it will always start with 1 and 2 as parameters for thinga and thingb.
Isn't there any way to instantiate the way one does in Java without Processing ?
i.e.      whatev1 = new Whatever(1,2);
           whatev2 = new Whatever(2,3);

As such, I don't have to write a few extra lines to set whatev2's parameters to 2 and 3. If I want to create 1000 instances with different parameters, Processing's way of creating instances makes it slightly less practical. That is, unless I am missing something.

I also ecountered an issue when trying to load an image :
a huge OutOfMemory Exception when loading an image from data :

the following line inside setup() :

img = loadImage("carte_vhd_5240.jpg");
yields

Exception in thread "Image Fetcher 0" java.lang.OutOfMemoryError: Java heap space
    at java.awt.image.DataBufferInt.<init>(Unknown Source)
    at java.awt.image.Raster.createPackedRaster(Unknown Source)
    at java.awt.image.DirectColorModel.createCompatibleWritableRaster(Unknown Source)
    at sun.awt.image.ImageRepresentation.createBufferedImage(Unknown Source)
    at sun.awt.image.ImageRepresentation.setPixels(Unknown Source)
    at sun.awt.image.ImageDecoder.setPixels(Unknown Source)
    at sun.awt.image.JPEGImageDecoder.sendPixels(Unknown Source)
    at sun.awt.image.JPEGImageDecoder.readImage(Native Method)
    at sun.awt.image.JPEGImageDecoder.produceImage(Unknown Source)
    at sun.awt.image.InputStreamImageSource.doFetch(Unknown Source)
    at sun.awt.image.ImageFetcher.fetchloop(Unknown Source)
    at sun.awt.image.ImageFetcher.run(Unknown Source)
Exception in thread "Animation Thread" java.lang.OutOfMemoryError: Java heap space
    at processing.core.PImage.<init>(PImage.java:285)
    at processing.core.PApplet.loadImageMT(PApplet.java:5300)
    at processing.core.PApplet.loadImage(PApplet.java:5145)
    at processing.core.PApplet.loadImage(PApplet.java:5071)
    at interfacegraphique.setup(interfacegraphique.java:23)
    at processing.core.PApplet.handleDraw(PApplet.java:2103)
    at processing.core.PGraphicsJava2D.requestDraw(PGraphicsJava2D.java:190)
    at processing.core.PApplet.run(PApplet.java:2006)
    at java.lang.Thread.run(Unknown Source)

i am trying to make a small applet to visualise object trajectories. I am also wondering whether I should drop Processing altogether and stick with Eclipse, as the applet will require data processed with java and I have trouble linking Processing and Eclipse. How much more difficult would this applet be to create using Eclipse only ?

Replies(5)

quarks

Re: Eclipse multiple classes question

10 months ago

With regard to Whatever class combine the ctors e.g.

public class Whatever {
private PApplet app;
private int thingA;
private int thingB;
public Whatever(PApplet papplet, int a, int b){
app = papplet;
thingA = a;
thingB = b;
}
// rest of class

May has misunderstood whats wrong with

whatev = new Whatever(3,6);

since you already have a suitable constructor

//Constructor
public Whatever(int a, int b){
thingA = a;
thingB = b;
}

and replacing the 3 and the 6 for each instance.

The image problem I am not sure of but what is the resolution of "carte_vhd_5240.jpg" the actual size on disc is irrelevant because it will be unzipped in memory? Also if using P2D and P3D which are based on OpenGL it creates a texture and may create multiple versions of the image in different sizes to speed up rendering. So even a small file on disc can use a lot of memory.

migmigmig

Re: Eclipse multiple classes question

10 months ago

Thank you for your reply. The instantiation method worked fine.

[Edit] Image loading problem partially solved. I simply haven't found a way to load images of size 1.5Mb or larger.

Anyway, I have encountered another problem :

I have a main function in the class extending PApplet, in which I call a method from another class applied to an instance of the same class created in the main function. However, here's the setback :
that instance has no parent. So if my method has, for example, the following line :

parent.noStroke();

and is called by the instance created in the main function, I will automatically get a NullPointerException. I haven't found a way around that, nor what I should replace 'parent' with in this case. What am I doing wrong ?

PhiLho

Re: Eclipse multiple classes question

10 months ago

Your explanation is hard to follow (probably my fault, having little time right now).
Can you show a small code snippet illustrating your problem, please?

migmigmig

Re: Eclipse multiple classes question

10 months ago

Here's a portion of code with the relevant information :

//'Main' class
import processing.core.*;
import java.util.*;
public class Interface extends PApplet {

void setup(){
...
}

void draw(){

Boat bateau1 = new Boat(...);
bateau1.dessiner();    //no problems here, parent well-defined
}

public static void main(String args[]) {
    PApplet.main(new String[] { "--present", "Interface" });
    Boat bateau3 = new Boat(...);
    bateau3.dessiner(); // no parent, which causes the exception
}
}

import processing.core.*;
class Boat {
PApplet parent;
...

public void dessiner(){
    parent.noStroke();   //line where the main call fails and the exception is launched.
...
}
}

Thank you for your reply, by the way.

[Edit] : Found a workaround.

PhiLho

Re: Eclipse multiple classes question

10 months ago

Your parent field isn't initialized. Usually, the parent constructs the class by passing itself as parameter:
Boat bateau = new Boat(this, ...);
and the constructor takes this in account:
public Boat(PApplet pa, ...) {
parent = pa;
}

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