package advanced.simpleParticles;



import java.util.ArrayList;



import javax.media.opengl.GL;



import org.mt4j.util.math.Tools3D;





import processing.core.PApplet;

import processing.core.PGraphics;

import processing.core.PVector;



// A class to describe a group of Particles

// An ArrayList is used to manage the list of Particles 



public class ParticleSystem {



	private ArrayList<Particle> particles;    // An arraylist for all the particles

	private PVector origin;        // An origin point for where particles are born

	private PApplet app;



	public ParticleSystem(PApplet app, int num, PVector v) {

		this.app = app;

		particles = new ArrayList<Particle>();              // Initialize the arraylist

		origin = v.get();                        // Store the origin point

		for (int i = 0; i < num; i++) {

			particles.add(new Particle(app, origin));    // Add "num" amount of particles to the arraylist

		}

	}



	public void run(PGraphics g) {

		GL gl = Tools3D.getGL(g);

		gl.glDisable(GL.GL_DEPTH_TEST);

//		gl.glDepthMask(false);//depth testing - makes depth buffer read-only

//		gl.glBlendFunc(GL.GL_SRC_ALPHA,GL.GL_ONE);//define blending as alpha blending

		gl.glBlendFunc(GL.GL_ONE,GL.GL_ONE);//define blending as alpha blending

		

		// Cycle through the ArrayList backwards b/c we are deleting

		for (int i = particles.size()-1; i >= 0; i--) {

			Particle p = (Particle) particles.get(i);

			p.run(g);

			if (p.isDead()) {

				particles.remove(i);

			}

		}

		

		gl.glBlendFunc(GL.GL_SRC_ALPHA, GL.GL_ONE_MINUS_SRC_ALPHA);

//		gl.glDepthMask(true);//depth testing - makes depth buffer read-only

		gl.glEnable(GL.GL_DEPTH_TEST);

	}



	public void addParticle() {

		particles.add(new Particle(app, origin));

	}



	public void addParticle(float x, float y) {

		particles.add(new Particle(app, new PVector(x,y)));

	}



	public void addParticle(Particle p) {

		particles.add(p);

	}

	

	public void addParticle(Particle p, float x, float y){

		p.loc.set(x,y,0);

		particles.add(p);

	}



	// A method to test if the particle system still has particles

	public boolean isDead() {

		if (particles.isEmpty()) {

			return true;

		} else {

			return false;

		}

	}



}