Trying to get first OF program working....

beginners
#1

Hi everyone…

I’ve just started using OF, and it looks pretty good.(I have successfully run the openframeworks examples, so everything is installed and working OK). I thought I’d start by converting one of my simple Processing programs to C++, to get me started (and I’m also curious to see whether it will run faster in C++). I’ve run into a bit of a problem, though…my main class is called “brownian”, and I am getting an error:

||=== brownian, release ===|
C:\Documents and Settings\Compaq_Administrator\Desktop\Open Frameworks\apps\Giles\brownian\src\main.cpp||In function int main()':| C:\Documents and Settings\Compaq\_Administrator\Desktop\Open Frameworks\apps\Giles\brownian\src\main.cpp|15|error: no matching function for call tobrownian::brownian()’
C:\Documents and Settings\Compaq_Administrator\Desktop\Open Frameworks\apps\Giles\brownian\src\brownian.h|12|note: candidates are: brownian::brownian(const brownian&)|
||=== Build finished: 1 errors, 0 warnings ===|

If anyone could help me get past this hurdle, that would be great (it’s not quite as straightforward as Processing).

And the code is here:

main.cpp:

  
#include "ofMain.h"  
#include "brownian.h"  
//#include "ofAppGlutWindow.h"  
  
//========================================================================  
int main()  
{  
  
    //ofAppGlutWindow window;  
	ofSetupOpenGL(500,500, OF_WINDOW);			// <-------- setup the GL context  
  
	// this kicks off the running of my app  
	// can be OF_WINDOW or OF_FULLSCREEN  
	// pass in width and height too:  
	ofRunApp(new brownian());  
}

brownian.h:

  
#ifndef _BROWNIAN  
#define _BROWNIAN  
  
  
#include "ofMain.h"  
#include "particle.h"  
  
#define numparticles 100  
  
  
class brownian : public ofBaseApp  
{  
	public:  
		void setup();  
		void update();  
		void draw();  
        particle particles[numparticles];  
};  
  
#endif

brownian.cpp:

  
#include "ofMain.h"  
#include "brownian.h"  
  
  
//--------------------------------------------------------------  
void brownian::setup()  
{  
   ofBackground(255,255,255);  
   ofEnableSmoothing();  
   int i;  
   for(i=0; i<numparticles; i++)  
  {  
    particles[i] = particle(ofRandom(450, ofGetWidth()-20), ofRandom(450, ofGetHeight()-20), 10, 10, 5, 0.9);  
  
  }  
  
}  
//------------------------------------------------------------  
void brownian::update()  
{  
  int i;  
  for(i=0; i<numparticles; i++)  
  {  
    particles[i].collide();  
    particles[i].move();  
    particles[i].xspeed*=particles[i].dampfactor;  
    particles[i].yspeed*=particles[i].dampfactor;  
  }  
  
}  
//--------------------------------------------------------------  
void brownian::draw()  
{  
    int i;  
    for(i=0; i<numparticles; i++)  
  {  
     particles[i].render();  
  }  
}  
//--------------------------------------------------------------

particle.h:

  
#ifndef _PARTICLE  
#define _PARTICLE  
  
  
  
class particle  
{  
  
	public:  
		float xpos, ypos;  
        float xspeed, yspeed;  
        float ewidth;  
        float eheight;  
        float speedfactor;  
        float dampfactor;  
        particle(float x, float y,int ew, int eh, float sf, float df);  
        void collide();  
        void move();  
        void render();  
  
};  
  
#endif

particle.cpp:

  
#include "particle.h"  
  
particle::particle(float x, float y,int ew, int eh, float sf, float df)  
{  
    xpos=x;  
    ypos=y;  
    xspeed=0;  
    yspeed=0;  
    ewidth=ew;  
    eheight=eh;  
    speedfactor=sf;  
    dampfactor=df;  
}  
  
void particle::collide()  
{  
    float leftcols = ofRandom(0, eheight+1);  
    float rightcols= ofRandom(0, eheight+1);  
    float topcols= ofRandom(0, ewidth+1);  
    float botcols= ofRandom(0, ewidth+1);  
  
  xspeed+= (leftcols-rightcols)/speedfactor;  
  yspeed+= (topcols-botcols)/speedfactor;  
}  
  
void particle::move()  
{  
   xpos+=xspeed;  
   ypos+=yspeed;  
   if (xpos+ewidth> ofGetWidth() || xpos-ewidth<0) xspeed*=-1;  
   if (ypos+eheight> ofGetHeight() || ypos-eheight<0) yspeed*=-1;  
}  
  
void particle::render()  
{  
   ofFill();  
   ofSetColor(0,0,0);  
   ofEllipse(xpos, ypos, ewidth, eheight);  
}
#2

hi,

it’s asking for a default constructor. in your .h file where you declare the brownian class, just add this:

  
public:  
  // default constructor  
  brownian() {};  
  ... setup(), draw(), etc
#3

Thanks…that got it going. I also had to add another constructor to particle.h which took no parameters… even though whenever I call particle it is always with the set of parameters it needs… I don’t quite understand why I had to do this…