Particle tutorial error

beginners
#1

Hi, I’m trying to learn from the particle tutorial, http://wiki.openframeworks.cc/index.php-…-cle-system , but I’m getting the following error when I try to build the code:

error: ISO C++ forbids declaration of Particle' with no type error: expected;’ before ‘*’ token
error: expected `;’ before “int”

:slight_smile:

the code looks like this, with the error on the first line:

  
  
Particle* create() {  
_ncreated += 1;  
return new Particle(_x, _y, _x_velocity, _y_velocity, _r, _g, _b);  
}

If someone could help me with this, that would be awesome!

#2

You have to define the particle class first.

#3

ding, thank you so much for taking the time to help me out here!

I did define the class… but it’s defined under the class that the code I showed you is in.

I changed the particle and source class around, and then I got a whole bunch of other errors… switched around some more stuff in the .ccp file and now i get 41 errors, with all kinds of different errors:

  
error: no `void testApp::create_particles()' member function declared in class `testApp'  
In member function `void testApp::create_particles()':  
error: `list' was not declared in this scope  
  
... 39 more errors ...

Is it actually useful to try and figure this out, or should I just start on a somewhat simpler code?

#4

It sounds like alot of bad c++ grammar on your part. If you post much more code than maybe I or others can help.

[edit] dont be afraid to post some not so good code. It’s friendly around here.

#5

there is some sample particle system code here, which might be a helpful alternative –

http://www.makingthingsmove.org/blog/?cat=5

it’s a different style then the code on the tutorial, but it’s fairly useful.

you can take the code from any of the days (day 5 and day 6 have particle code) and you must add all of the src code to an OF project (and use the vectorMath addon example as a base, since the particles use the vector math addon*). be sure to include all the .h and .cpp files for all targets.

* there is one example that uses opencv addon too, so you’ll need to base that off the all addons example.

take care!!
zach

#6

I also attempted to assemble this example and ended up in a similar position. Does anyone have a more put-together version so that I can see what exactly is wrong with our setupz?

#7

thanks!

yes, so the only thing I did with the particle tutorial is paste it in the OF example app… and then all the errors got pooped out by the debugger…
I added nothing else.

I will try the other particle system posted by zach…

#8

I realize this is 18 months later, but if anyone else is looking for the solution to this:

Adding

  
#include "Particle.h"

to the top of your Source.h file will fix this issue.

#9

:slight_smile:
Sometimes the solution can be easy…
As I am a beginner and trying to learn C++ I struggle all the time over small mistakes.
Is the tutorial corrected at all?

#10

Well, not sure about the wiki tutorial. I kept going and had some issues that I wasn’t able to fix.

I did find this tutorial from Stephen Braitsch:

http://www.quietless.com/kitchen/gettin-…-rameworks/

I’m an AS3 guy coming to oF, so this was hugely helpful.

Cheers,

gabi