Fun With Gravity

using System;
using System.Drawing;
using System.Collections;

namespace ParticleSwarm {
	public abstract class ParticleSystem {
		protected bool running = false;
		protected bool trace = false;
		protected bool showVel = false;
		protected bool showVelBox = false;
		protected bool showAcc = false;
		protected bool showAccBox = false;
		protected bool detectCol = true;
		protected Color backColor = Color.White;
		protected Color fade;
		protected ArrayList particles = new ArrayList();

		public ParticleSystem() {
			fade = Color.FromArgb(10, backColor.R, backColor.G, backColor.B);
		}

		public void Start(Graphics g, Rectangle bounds) {
			running = true;
			Draw(g, bounds);
		}

		public void Stop() {
			running = false;
		}

		public abstract void Draw(Graphics g, Rectangle bounds);
		
		public bool IsRunning {
			get { return this.running; }
			set { this.running = value; }
		}

		public bool Trace {
			get { return trace; }
			set { trace = value; }
		}

		public bool ShowVelocityVectors {
			get { return showVel; }
			set { showVel = value; }
		}

		public bool ShowVelocityBox {
			get { return showVelBox; }
			set { showVelBox = value; }
		}

		public bool ShowAccelerationVectors {
			get { return showAcc; }
			set { showAcc = value; }
		}

		public bool ShowAccelerationBox {
			get { return showAccBox; }
			set { showAccBox = value; }
		}

		public bool DetectCollisions {
			get { return detectCol; }
			set { detectCol = value; }
		}

		public Color BackgroundColor {
			get { return backColor; }
			set {
				backColor = value;
				trace = false;
				System.Windows.Forms.Application.DoEvents();
				trace = true;
			}
		}

		public ArrayList Particles {
			get { return this.particles; }
		}
	}
}