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2D Java Fireworks Explosion

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2D Java Fireworks Explosion

 
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  #1
Feb 9th, 2008
Hey, I'm new to the Java arena, and am trying to create an application (using JForm and JPanel) displaying a fireworks show. The problem is creating an explosion for the display. Does anyone have any recommendations for creating an explosion? I've been stuck on this for quite some time and thought I'd see if anyone had any recommendations. Thanks for any advice you can provide.
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Re: 2D Java Fireworks Explosion

 
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Feb 10th, 2008
here you go buddy, this example has source code too.
http://javaboutique.internet.com/fireworks/
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Re: 2D Java Fireworks Explosion

 
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Feb 10th, 2008
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Originally Posted by majestic0110 View Post
here you go buddy, this example has source code too.
http://javaboutique.internet.com/fireworks/
Thanks majestic0110, I'll try that. I've been playing around with another version I found a while back, and have trouble integrating it into the rest of my app (get errors that G is null from a NullPointerException). I'll try this other one and see what I can get.
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Re: 2D Java Fireworks Explosion

 
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Feb 10th, 2008
ok let us all know how you got on! Send us the code if you are still struggling.
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Re: 2D Java Fireworks Explosion

 
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  #5
Feb 11th, 2008
You can use the following equation of projectile trajectory to make your explosions.

x = v*cos(a)*t
y = v*sin(a)*t - ½gt²

Keep an array of 100 or so particles that will make up the firework. Given a random velocity (v) for each particle and a random angle (a). Then just step through the time, updating their positions.
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Re: 2D Java Fireworks Explosion

 
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Feb 12th, 2008
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Originally Posted by Phaelax View Post
You can use the following equation of projectile trajectory to make your explosions.

x = v*cos(a)*t
y = v*sin(a)*t - ½gt²

Keep an array of 100 or so particles that will make up the firework. Given a random velocity (v) for each particle and a random angle (a). Then just step through the time, updating their positions.

Thanks Phaelax, I'll try some of that. Was about to post something when I saw your reply so I'll hold off posting problem code until I play with that a bit more.

Thanks.
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Re: 2D Java Fireworks Explosion

 
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  #7
Feb 15th, 2008
Forgive me if this is something obvious, but I'm still getting stuck on this. Right now the elements in the array don't seem to be initializing since I get NullPointerExceptions repeatedly in the loop. Does anyone see anything I'm missing? When I placed println statements within the code I could see that the initializations didn't work.

Java Syntax (Toggle Plain Text) 
  1. int gravity, a, v, T, L, x, y;
  2.            double valueA, valueB, dx, dy;
  3.            int t;
  4.            Random r = new Random();
  5.            for(t = 0; t < Explosion.length; t ++)
  6.           {
  7.            gravity = 20;
  8.            a = r.nextInt(50);
  9.            v = r.nextInt(50);
  10.            valueA = v*Math.sin(a)*t;
  11.            valueB = (.5)*gravity*(t*t);
  12.            dx = (int)v*Math.cos(a)*t;
  13.            dy = (int)valueA - valueB;
  14.            x = (int)dx;
  15.            y = (int)dy;
  16.            Explosion = new FireworksSprite[100];
  17.            //for(t = 0; t < Explosion.length; t ++)
  18.           //{
  19.                System.out.print("Iterating through Array" + t);
  20.                Explosion[t].setSpriteH(15);
  21.                Explosion[t].setSpriteW(10);
  22.                Explosion[t].setLocx(x);
  23.                Explosion[t].setLocy(y);
  24.                Explosion[t].setActive(true);
  25.                Explosion[t].setVisible(true);
  26.                Explosion[t].setVel(0, v); 
  27.  
  28.            }
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Re: 2D Java Fireworks Explosion

 
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  #8
Feb 16th, 2008
It WAS something simple, I left out a line initializing the array's objects. I'll leave this thread open in case I run into any further issues, and will close out once this is completed. Thanks to those who have replied, you've been great help.
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