I'm trying to figure out how to enable GL_ALPHA_TEST and how to call glAlphaFunc(), as they are not wrapped in PGL.

Under Changes/The big stuff, I read this:

• OpenGL 2 – a new version of the OpenGL library has been implemented, and the old one has been removed. The new library is based on Andres Colubri's Android work (and his experiences developing the GLGraphics library). All the great things from Android have now been back-ported to the desktop version of Processing, so we have a super fast OpenGL library.

• OpenGL is now part of core 

 

Then I look at the reference and I'm lost: where do I find documentation about this "OpenGL library"? No such thing is listed among the core libraries in the Libraries reference

Hi,

Hi,

Hi,

I've followed all the instructions and installed everything on Ubuntu 10.10.

When I hit "Run in Emulator", the emulator launches, the desktop or home of the Android OS appears, and Processing IDE shows the message "Sketch launched on Emulator" and no error message, but the sketch is _not_ launched in the emulator.

What am I missing?

I can run the same sketch on a real device without issue.

Thanks
m.

Hi,
I know this is a common issue but I can't find a real solution. Every time I try to run a sketch on the emulator I get the error: Error: Android Virtual Device 'Processing-Android-7' already exists.

I know I can open the SDK Manager and delete the virtual device, but isn't there a way to avoid this? Also, this means I have to restart the emulator every time which takes ages.

From the wiki:

Common problems
IF you get an error that reads “Error: Android Virtual Device 'Processing-Android-7' already exists.”, select “Android SDK & AVD Manager” beneath the Processing “Android” menu, and delete the Processing-Android-7 AVD. It will be automatically re-created the next time you try to run a sketch.

That "If" seems to suggest that you may or may not get the error. So what are the conditions that make the error happen and how can I avoid them in the first place?


Also, this seems to contraddict this other statement from the wiki:

The emulator stays running, even after you hit stop. This is because it takes a fortnight to launch the emulator. You don't have that kind of time.

Yeah, exactly, I don't. But how am I supposed to keep the emulator running if I have to delete the virtual device?


Thanks in advance
m.

Hi,

I'm drawing in 3D with P3D and using beginRaw() and endRaw() to export to Pdf.

I'm drawing some (very very simple) shapes that I load with loadShape(), I draw them with noStroke(), fill(0) on a white background, and shape().

Everything works fine, except that in the output pdf you can see the triangles the shape is (automagically) decomposed into. INSIDE the black-filled shapes you can see superthin white edges for each triangle.

Is there a way I can this? Otherwise this renders beginRaw/endRaw pretty useless...

Thanks in advance
m.

Hi,

Does anybody know what the near and far parameters (last two parameters) of the ortho() function are supposed to change?

Whatever value I use for them I can't see any difference in the results.

The projection doesn't seem to change, nor does it affect which shapes are or aren't drawn.

See for example the following code:

1. float DEPTH=117;
2. size(100, 100, P3D);
3. noFill();
4. smooth();
5. ortho(0, width, 0, height, -10, 10);
6. translate(100, 100, DEPTH);
7. box(45);

Whatever values I choose for the near and far parameters, the box is always drawn (as a square in this case) if DEPTH <=117, and it disappears for DEPTH>117.

Why 117? And why doesn't it depend on near and far?

Besides the clipping, if I add rotations, the result doesn't change a bit by changing the values for near and far.

Is this expected behavior? If so what am I missing?
What are the near and far parameters for?

Thanks
m.

Hi,

I'm trying to understand the parameters of the perspective() method.

The explanation in the documentation is pretty vague about them.

In particular, given the values for fov, aspect, zNear and zFar (or even assuming aspect=width/height), I want to compute the value of Z at which I have to draw a rectangle so that it's drawn at it's exact x,y,width and height on the window.

That is:

1. size(800,600,P3D);
2. float fov=90;     //any arbitrary value
3. float zNear=10; //any arbitrary value
4. float zFar=10000;  //any arbitrary value
5. float rectanglez= //??? How do I compute this given fov, zNear and zFar?
6. perspective(fov,width/height,zNear,zFar);
7. translate(0,0,rectanglez); // I want rectanglez such that the following rectangle fills exactly the screen
8. rectangle(0,0,width,height);

How do I compute rectanglez?

Or even better, what is in detail the meaning of each of the prespective parameters so that I can understand by myself how to compute z?

Thanks
m.

Hi,

I can't find the part of the documentation that says whether Processing's coordinate system is left-handed or right-handed, or whether the z axis points into the screen or outwards from the screen.

It looks to me like it is left-handed (the z axis pointing outwards from the screen, towards the viewer, while the y asis is pointing downwards), which is the opposite to the prevailing convention in mathematics textbooks (as far as i can tell) _and_ in OpenGL, so I would expect it to be explicitly documented somewhere but I can't find it...

How do this relate to using OpenGL in Processing? I mean, things don't change if I use OPENGL instead of P3D, so what exactly is Processing doing to change OpenGL's default and how should I take it into account?

When it comes to manipulation of transform matrices, do the usual right-handed-system mathematics apply, or do I have to "think left-handed"? Or does it turn out to not be relevant?

Thanks in advance
m.

Hi,

I have an old sketch that used to work perfectly on an older version of Processing (it was around the end of 2009 - beginning of 2010 when I last run it). At that time I used Windows. I ran that sketch a lot of times on different machines and platforms and it was pretty robuts.

Now I've opened it with Processing 1.2.1 on Ubuntu, and I get a lot of error messages such as:

line 13:14: unexpected token: boolean
line 13:14: unexpected token: float

etc, (a few more of them). They all reference lines of code such as:

static final boolean CALIBRATE=false, READCALIBRATION=false;

static final float VIRTUAL_FRAMERATE=8.0;
static final int NSENSORS=4;

and the "unexpected" tokens as you can see are not that unexpected.


After a lot of errors like these, at the end I get a Null Pointer Exception which seems to be caused by the preprocessor itself, since my code doesn't even compile so it never gets to run:

Uncaught exception type:class java.lang.NullPointerException
java.lang.NullPointerException
    at processing.app.antlr.PdeRecognizer.constructorCast(PdeRecognizer.java:1263)
    at processing.app.antlr.PdeRecognizer.primaryExpression(PdeRecognizer.java:1568)
    at processing.app.antlr.PdeRecognizer.postfixExpression(PdeRecognizer.java:7304)
    at processing.app.antlr.PdeRecognizer.unaryExpressionNotPlusMinus(PdeRecognizer.java:7267)
    at processing.app.antlr.PdeRecognizer.unaryExpression(PdeRecognizer.java:7125)
    at processing.app.antlr.PdeRecognizer.multiplicativeExpression(PdeRecognizer.java:6988)
....... (much much longer than this)


I guess there has been some change in processing that is not backward compatible and my old code is not valid any more, but the problem cannot be in the lines where the "unexpected token" error points to, as they are perfectly valid, so the error must be somewhere else and must be driving the preprocessor crazy.



As I said my code used to work perfectly on older versions, though I don't know exactly which version of processing it was where it used to work (it was 1.something).

Does anybody know of some big non-backward-compatible changes that have happened in the last year that may cause this kind of issue? Wher should I start looking at?


The structure of my code is like this:

- variable declarations such as those listed above
- void setup() { ... }
- void draw() { ... }
- other event handlers such as void serialEvent(Serial p) {...}
- A COUPLE OF CLASS DEFINITIONS

May it be because of the class definitions? Should I put them in external files? It wasn't necessary before....

Thanks in advance
m.