PShape not drawing

Core Library Questions

corporate..

in Core Library Questions • 7 months ago

Hi, I'm using a Windows 7 machine and Processing 2.0b8 and I'm simply trying to draw a PShape that will translate across the screen but the line is not showing up. Anybody see the problem?

private PShape shape;

private boolean left = false;

private int count = 0;

public void setup() {

size(1280, 720, P2D);

this.shape = createShape();

this.shape.beginShape();

this.shape.vertex(width / 2, 0);

this.shape.vertex(width / 2, height);

this.shape.endShape();

this.shape.setStroke(0);

this.shape.setStrokeWeight(10);

}

public void draw() {

background(255);

if (left)

this.shape.translate(1, 0);

else

this.shape.translate(-1, 0);

count++;

if (count == width) {

this.left = !this.left;

this.count = 0;

}

shape(this.shape);

System.out.println(this.shape.getVertexX(0));

}

Replies(9)

PhiLho

I see you come from a Java world.
You don't need all the "this.", "private", or "System.out." stuff, Processing simplified this...

Note that you use endShape() before the last drawing orders. Move it after them.

corporate..

Re: PShape not drawing

7 months ago

Haha yeah I know, but I switch back and forth between the two so I stick with java syntax. Anyway, changing the position of the stroke commands didn't fix the problem. Maybe this is a bug?

quarks

Re: PShape not drawing

7 months ago

It is not a bug because the shape examples that come with Processing work. I changed your setup code Highlighted) and it worked.

public void setup() {
size(1280, 720, P2D);
this.shape = createShape();
this.shape.stroke(0);
this.shape.strokeWeight(10);
this.shape.beginShape();
this.shape.vertex(width / 2, 0);
this.shape.vertex(width / 2, height);
this.shape.endShape();
}

corporate..

Re: PShape not drawing

7 months ago

Huh, that's odd because I changed my code to exactly that and I still only see a blank white screen. I also changed the frameRate to 2 thinking that maybe it was being drawn too quickly but that also didn't help. What platform are you on?

quarks

Re: PShape not drawing

7 months ago

I am using 2.0b8 on Windows 7 64 bit

Note the change from setStroke to stroke and setStrokeWeight to strokeWeight.

corporate..

Re: Re: PShape not drawing

7 months ago

Ah, it was the method name change that was the problem. Thank you.

GoToLoop

Re: PShape not drawing

7 months ago

I see you come from a Java world.
You don't need all the "this.", "private", or "System.out." stuff, Processing simplified this...

I'm the opposite; never made a Java program yet! :P
However, is it true I'd have to use this all the time when programming in Java?
I thought this would only be necessary to differentiate a local variable from a field variable.
Or even a child's method from its parent's method ( super).
And also when needed to pass a class instance's reference to an external method or constructor.

Since a sketch class extends Processing's PApplet, and our own classes are inner ones,
we can use all of Processing's API functions w/o any extra verbose!

corporate..

Re: PShape not drawing

7 months ago

You don't have to use this all the time. The only time it would be required to use this is if you have two variables with the same name - one a local variable, and the other a member of a class - and you want to differentiate between the two, then you would use this. Same with super.

Yes, it is true that you can do that with Processing within java, however for large programs where you are more worried about separation of concerns, then you'll want to structure things differently and will probably have to make explicit references to a PApplet class.

PhiLho

Re: PShape not drawing

7 months ago

" However, is it true I'd have to use this all the time when programming in Java?"
What ricardo.deamorim said...
I just want to add that sometime I see people prefixing systematically their fields with this., perhaps to mark them as fields of this class, not from as variables or parameters or stuff.
Personally, I find this habit annoying because it is verbose and noisy: it distracts reading.

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