import javax.media.opengl.*;
import processing.opengl.*;
import java.nio.*;

//JOGL's
PGraphicsOpenGL pgl;
GL gl;

//constant numbers for particle
float DAMPING_VELOCITY = 0.98;
float GRAVITY = 0;
int AGE_MAX = 30;
int NUM_GENERATION_AT_ONE_LOOP = 30;

//particle list
ArrayList particles;
ArrayList clearParticles;

//texture
PImage texImage;
int[] texID;

//screen capture
PImage cp;
boolean isCap = false;
int cpTimer = 0;

void setup(){
  int i;

  size(480, 360, OPENGL);
  background(0);
  frameRate(30);
  noSmooth();

  //initialize JOGL's
  pgl = (PGraphicsOpenGL) g;
  gl = pgl.gl;

  randomSeed(int(random(1,1000)));

  //initialize particle list
  particles = new ArrayList();
  clearParticles = new ArrayList();

  //load image for texture
  texImage = loadImage("p.png");

  //generate texture and bind texture
  pgl.beginGL();
  gl.glEnable(GL.GL_TEXTURE_2D);
  texID = new int[1];
  gl.glGenTextures(1,texID,0);
  gl.glBindTexture(GL.GL_TEXTURE_2D, texID[0]);
  gl.glTexImage2D(
    GL.GL_TEXTURE_2D, 0, 4, texImage.width, texImage.height,
    0, GL.GL_RGBA, GL.GL_UNSIGNED_BYTE, IntBuffer.wrap(texImage.pixels)
  );
  gl.glTexParameteri(GL.GL_TEXTURE_2D, GL.GL_TEXTURE_MIN_FILTER, GL.GL_LINEAR);
  gl.glTexParameteri(GL.GL_TEXTURE_2D, GL.GL_TEXTURE_MAG_FILTER, GL.GL_LINEAR);
  pgl.endGL();

  //initialize image for screen capture
  cp = createImage(width,height,RGB);
}

void draw(){
  int i;
  Particle p;
  Iterator it;

  background(0);

  //generate
  for(i=0; i

  //brend func
  pgl.beginGL();
  gl.glDisable(GL.GL_DEPTH_TEST);
  gl.glEnable(GL.GL_BLEND);
  gl.glBlendFunc(GL.GL_SRC_ALPHA, GL.GL_ONE);
  pgl.endGL();

  //update and draw
  clearParticles.clear();
  it = particles.iterator();
  while(it.hasNext()){
    p = (Particle)it.next();
    p.update();
    p.drawMe();
    if(p.age>AGE_MAX){
	clearParticles.add(p);
    }
  }

  //clear
  if(clearParticles.size() != 0){
    it = clearParticles.iterator();
    while(it.hasNext()){
	p = (Particle)it.next();
	particles.remove(p);
    }
  }

  // screen capture
  if(isCap){
    cp = get();
    cp.save("cap/cp_"+cpTimer+".jpg");
    cpTimer++;
  }
}

void keyPressed(){
  if(key=='s'){
    isCap = true;
  }else if(key=='a'){
    isCap = false;
  }
}

///////////////////Color4f///////////////////
class Color4f {
  float r, g, b, a;
  public Color4f(){
    r = g = b = a = 0.0;
  }
  public Color4f(float inR, float inG, float inB, float inA){
    r = inR;
    g = inG;
    b = inB;
    a = inA;
  }
}

///////////////////Particle///////////////////
class Particle {
  float x, y;
  float vx, vy;
  float size = 100;
  int age = 0;
  Color4f c;

  public Particle(float inX, float inY, float inVx, float inVy){
    x = inX;
    y = inY;
    vx = inVx;
    vy = inVy;
    age = 0;
    c = new Color4f(random(0,1), random(0,1), random(0,1), 1);
  }

  void drawMe(){
    float helfSize = size/2;
    float d = 1.0-(float)age/AGE_MAX;
    c.a = d;

    pgl.beginGL();
    gl.glBindTexture(GL.GL_TEXTURE_2D, texID[0]);
    gl.glColor4f(c.r, c.g, c.b, c.a);
    gl.glBegin(GL.GL_QUADS);
    gl.glTexCoord2f(0,0);
    gl.glVertex2f(x-helfSize, y-helfSize);
    gl.glTexCoord2f(1,0);
    gl.glVertex2f(x+helfSize, y-helfSize);
    gl.glTexCoord2f(1,1);
    gl.glVertex2f(x+helfSize, y+helfSize);
    gl.glTexCoord2f(0,1);
    gl.glVertex2f(x-helfSize, y+helfSize);
    gl.glEnd();
    pgl.endGL();
  }

  void update(){
    vy += GRAVITY;
    x += vx;
    y += vy;
    vx *= DAMPING_VELOCITY;
    vy *= DAMPING_VELOCITY;
    age++;
  }
}
 

OPENGL error at 1281 at top ENDRAW(): Invalid value