error when I call loadPixels() after CreateGraphics(w,h) version 3.0

brainwashed

In Processing 3.0 I get an error when I call loadPixels() after CreateGraphics(w,h).

Some code like this works fine in v2.2.1.

PGraphics pg;

public void setup() {
  size(800, 600);
  pg = createGraphics(width, height); 

  pg.loadPixels();
  for (int i=0; i < pg.width*pg.height; i++) 
    pg.pixels[i] = i % 255;
  pg.updatePixels();

  background(pg);
}

But in version 3.0 returns me that:

Exception in thread "Animation Thread" java.lang.NullPointerException
    at processing.awt.PGraphicsJava2D.getRaster(PGraphicsJava2D.java:2710)
    at processing.awt.PGraphicsJava2D.loadPixels(PGraphicsJava2D.java:2734)
    at myTemplate.setup(myTemplate.java:23)
    at processing.core.PApplet.handleDraw(PApplet.java:2373)
    at processing.awt.PSurfaceAWT$12.callDraw(PSurfaceAWT.java:1523)
    at processing.core.PSurfaceNone$AnimationThread.run(PSurfaceNone.java:316)

I don't understand why my P3 version is calling any AWT code: processing.awt.PGraphicsJava2D.loadPixels

Any idea?

GoToLoop

// forum.processing.org/two/discussion/12915/
// error-when-i-call-loadpixels-after-creategraphics-w-h-version-3-0

// 2015-Oct-09

PGraphics pg;

public void setup() {
  size(800, 600);
  noLoop();

  pg = createGraphics(width, height, JAVA2D);

  //Before P3, loadPixels() could replace beginDraw() entirely:
  pg.beginDraw();

  pg.loadPixels();
  for (int i = 0, dim = pg.width * pg.height; i != dim
    ; pg.pixels[i] = i++ % 0400 | #000000);
  pg.updatePixels();

  background(pg);
}

brainwashed

Great !!! Thank you very much!!!

The expressionpg.pixels[i] = i++ % 0400 | #000000is quite cryptic for me @-) . What does it mean?

GoToLoop

i++ % 0400 | #000000:

• ++ there is the post incremental operator.
• % is the modulo or remainder operator. Just to make sure i is always less than 0400: https://Processing.org/reference/modulo.html
• 0400 = 0x100 = 256.
• | is the bitwise OR operator: https://Processing.org/reference/bitwiseOR.html
• #000000 = 0xff000000 = PImage.ALPHA_MASK.

brainwashed

Thanks!!!! ^:)^

koogs

I do hate it when he does this. All he needed to do was add pg.beginDraw() but instead he had to rewrite the entire thing and ends up raising more questions than he answers.

i think he's also introduced a bug....

brainwashed

Really thinks that, koogs? I do like this kind of response, it opens new ways for resolve a problem. I enjoy analyzing GoToLoop answers!!!