Hi,

I am quite new to processing and can't seem to get the answer to this query anywhere. My apologies about this.

I am trying to get an applet working. However, there is probably some slight syntax error. It uses the Geomerative library which can downloaded here:

http://www.ricardmarxer.com/geomerative/

The issue is that I keep getting Null Pointer exceptions. I can not work out why as I have put the relevant ttf file in my data folder. The code I have is here:

[code]/*

----------------------------------------------------------------
Copyright (C) 2005 Ricard Marxer Piñón

email (at) ricardmarxer.com
http://www.ricardmarxer.com/
----------------------------------------------------------------

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

----------------------------------------------------------------
Built with Processing (Beta) v098
uses Geomerative (Alpha) v004
----------------------------------------------------------------

Created 17 January 2006

----------------------------------------------------------------
hilos
----------------------------------------------------------------

*/


//import processing.opengl.*;
import geomerative.*;

RFont f;
RGroup grupo;
Particle[] psys;
int numPoints, numParticles;
float toldist = 20;
float maxvel;
float maxalph;
float backalpha;
boolean restart = true;
float t=0;


//------------------------ Runtime properties ----------------------------------
// Save each frame
boolean SAVEVIDEO = false;
boolean SAVEFRAME = false;
boolean APPLICATION = false;

String DEFAULTAPPLETRENDERER = P3D;
int DEFAULTAPPLETWIDTH = 680;
int DEFAULTAPPLETHEIGHT = 480;

String DEFAULTAPPLICRENDERER = OPENGL;
int DEFAULTAPPLICWIDTH = 800;
int DEFAULTAPPLICHEIGHT = 600;
//------------------------------------------------------------------------------


// The text to be written
String STRNG = "Srings";

// The font to be used
String FONT = "Thonburi.ttf";

// The inertie of the particles
float INERTIE[] = {
 0.5, 1.3};

// The coefficient with which to reach the target
float TARGET[] = {
 0.028, 0.029};

// The trail coefficient: 0 no trail - 1 infinite trail
float TRAILCOEFF = 0.96;

// The brightness coefficient: 0 no brightness - 1 full brightness
float BRIGHTCOEFF = 0.7;

// The brightness error coefficient: inf no error in brightness (the brightness is completely independent on the velocity)
float BRIGHTERRCOEFF = 2.2;//1.2;

// The velocity of the drawing
int VELOCITY = 2;

String newString = "";

void setup(){

 int w = DEFAULTAPPLICWIDTH, h = DEFAULTAPPLICHEIGHT;
 String r = DEFAULTAPPLICRENDERER;

 if(!APPLICATION){
   // Specify the widtha and height at runtime
   w = int(param("width"));
   h = int(param("height"));
   r = (String)param("renderer");


   // (String) will return null if param("renderer") doesn't exist
   if (r != OPENGL && r != P3D && r != JAVA2D && r != P2D) {
     r = DEFAULTAPPLETRENDERER;
   }
   // int() will return 0 if param("width") doesn't exist
   if (w <= 0) {
     w = DEFAULTAPPLETWIDTH;
   }
   // int() will return 0 if param("height") doesn't exist
   if (h <= 0) {
     h = DEFAULTAPPLETHEIGHT;
   }
 }

 size(w,h,r);
 frameRate(25);
 try{
   smooth();
 }
 catch(Exception e){
 }
 background(0);

 f = new RFont(this,FONT,372,RFont.CENTER);

 initialize();

}

void draw(){
 translate(width/2, height/2);
 noStroke();
 fill(0, backalpha);
 rect(-width/2, -height/2, width, height);

   for(int j=0;j<VELOCITY;j++){
     for(int i=0;i<numParticles;i++){
       psys[i].update(grupo);
       psys[i].draw(g);
     }
   }
   INERTIE[0] = 0.75*float(constrain(mouseX,1,width))/float(width);
   INERTIE[1] = INERTIE[0]+ 0.4*float(constrain(mouseX,1,width))/float(width);

   TARGET[0] = 0.4*float(constrain(mouseY,1,height))/float(height);
   TARGET[1] = TARGET[0]+ 0.5*float(constrain(mouseY,1,height))/float(height);
   t++;
 
 if(SAVEVIDEO) saveFrame("hilos-####.tga");
 toldist += 0.009;
}

void initialize(){
 maxvel = width/90 * constrain(BRIGHTERRCOEFF,0.01,BRIGHTERRCOEFF) * (6F/(STRNG.length()+1));
 maxalph = constrain(BRIGHTCOEFF,0,1)*255;
 backalpha = 255-constrain(TRAILCOEFF,0,1)*255;
 toldist = 20;
 
 grupo = f.toGroup(STRNG);

 RCommand.setSegmentStep(2);
 RCommand.setSegmentator(RCommand.UNIFORMSTEP);

 grupo = grupo.toPolygonGroup();
 grupo.centerIn(g, 10, 1, 1);

 RPoint[] ps = grupo.getPoints();
 numPoints = ps.length;
 numParticles = floor(numPoints);

 int lasthuev = int(random(0,255));
 psys = new Particle[numParticles];
 for(int i=0;i<numParticles;i++){
   int huev = lasthuev + int(random(-12,12));
   huev = (huev + 255) % 255;
   lasthuev = huev;
   psys[i] = new Particle(g,i,huev);
   psys[i].pos = new RPoint(ps[i]);
 }
}

void keyReleased(){
 if(keyCode==ENTER){
   STRNG = newString;
   newString = "";
   initialize();
 }
 else if(keyCode==BACKSPACE){
   if(newString.length() !=0 ){
     newString = newString.substring(0,newString.length()-1);
   }
 }
 else if(keyCode!=SHIFT){
   newString += key;
 }
}

void mousePressed(){
 saveFrame(STRNG+".tga");
}

public class Particle{
 // Velocity
 RPoint vel;

 // Position
 RPoint pos;
 RPoint lastpos;

 // Caracteristics
 int col;
 int hueval;
 float sz;

 // ID
 int id;

 // Constructor
 public Particle(PGraph

Note 1: You can edit any of your previous messages, it is better than duplicating rather long code.
Note 2: When reporting an error or an exception, you should point out which line causes the problem. It is not always possible to run a code pasted in the forum (often lacking files or even libraries) so this can help in the diagnostic.

No need to apologies, I was just informative. Unless it is disabled for new users, you should have a "Modify" button in each of your messages, you can trim down or modify the messages as needed.

You cannot attach stuff to this forum, but the library is freely available.

But showing where the problem is is enough in this case: param() value gets the given parameter in the applet definition (in the HTML file) and uses it. If it is not defined, you will get the exception.
Note that all this is quite redundant as Processing is able to take the size() line (which should be the first one of setup()) to generate these parameters! Perhaps the example code was old.
But well, define these parameters (add something like <param name="width" value="200"/> in the <object> tag) to get you going.

Hi PhilLo,

Just to say thank you again for the advice. But in fact I tried the code in an older version of processing and deleted the initial applet defining area of the above code and it worked (which is a relief)!

I thought I would mention it just incase anyone happens to read this and are also trying to get the geomerative library to work. If they want the code for it then just message me on processing.

Thank you