PGraphics behaving unexpectedly

Processing
1

Hi there,

This is no longer behaving as it used to. If I’m not too sleepy, this program should draw a black screen, but I see it magenta. If inside draw() I remove everything except image(...) then it’s black.

PGraphics pg;
void setup() {  
  size(800, 800, P2D);
  background(255, 0, 255);
  pg = createGraphics(1000, 1000, P3D);
  pg.beginDraw();
  pg.background(0);
  pg.endDraw();
}
void draw() {
  pg.beginDraw();
  //pg.stroke(random(10));
  //pg.blendMode(ADD);
  //pg.line(0, random(height), width, random(height));
  pg.endDraw();  
  image(pg, 0, 0);
}

I also tried this but same magenta result:

PGraphics pg;
void setup() {  
  size(800, 800, P2D);
  background(255, 0, 255);
}
void draw() {
  if (pg == null) {
    pg = createGraphics(1000, 1000, P3D);
    pg.beginDraw();
    pg.background(0);
    pg.endDraw();
  }

  pg.beginDraw();
  //pg.stroke(random(10));
  //pg.blendMode(ADD);
  //pg.line(0, random(height), width, random(height));
  pg.endDraw();  
  image(pg, 0, 0);
}

Maybe someone could try this program to see if the issue is my OS? On Processing 3.5.4.

1 Like
2

Found an ugly workaround. I’m sad that old programs just stop working.

PGraphics pg;
void setup() {  
  size(800, 800, P2D);
  background(255, 0, 255);
  pg = createGraphics(1000, 1000, P3D);
}
void draw() {
  pg.beginDraw();
  if (frameCount == 2) {
    pg.background(200, 100, 50);
  }
  pg.stroke(random(10));
  pg.blendMode(ADD);
  pg.line(0, random(height), width, random(height));
  pg.blendMode(SUBTRACT);
  pg.line(random(pg.width), 0, random(pg.width), pg.height);
  pg.endDraw();  
  image(pg, 0, 0);
}

Screenshot with if(frameCount == 1) (PGraphics is transparent):

2020-03-16-194822_800x800_scrot
2020-03-16-194822_800x800_scrot800×800 65.8 KB

Screenshot with if(frameCount == 2) (PGraphics is opaque):

2020-03-16-194844_800x800_scrot
2020-03-16-194844_800x800_scrot800×800 128 KB

ps. I planned uploading one sketch per day from my collection, so here goes the first one:

3

Confirmed. Same thing here. The way until then will be

pg.fill(0); pg.rect(0,0,width,height);

1 Like
4

I tried the approach you suggest but doesn’t work for me. The background is still transparent.

5

True, sorry. I forgot that I changed PGraphics from P3D to default at the same time…

6

Very nice!
Interesting that if you put the class in the first tab, you get a size error. Setup() has to be in the first tab.

7

@hamoid On 3.4 (MacOS) I can confirm that your top post sketches 1 and 2 both show magenta for a single frame, then show blank from then on. So something changed since 3.4.

Have you opened an issue?