ConicVariation.cs

using System;
using Waher.Script.Abstraction.Elements;
using Waher.Script.Model;
 
namespace Waher.Script.Fractals.IFS.Variations.Flame
{
    public class ConicVariation : FlameVariationMultipleParameters
    {
        private readonly double holes;
        private readonly double eccentricity;
 
        public ConicVariation(ScriptNode holes, ScriptNode eccentricity, int Start, int Length, Expression Expression)
            : base(new ScriptNode[] { holes, eccentricity }, new ArgumentType[] { ArgumentType.Scalar, ArgumentType.Scalar },
                  Start, Length, Expression)
        {
            this.holes = 0;
            this.eccentricity = 0;
        }
 
        private ConicVariation(double Holes, double Eccentricity,
            ScriptNode holes, ScriptNode eccentricity, int Start, int Length, Expression Expression)
            : base(new ScriptNode[] { holes, eccentricity }, new ArgumentType[] { ArgumentType.Scalar, ArgumentType.Scalar },
                  Start, Length, Expression)
        {
            this.holes = Holes;
            this.eccentricity = Eccentricity;
        }
 
        public override string[] DefaultArgumentNames
        {
            get
            {
                return new string[] { "holes", "eccentricity" };
            }
        }
 
        public override IElement Evaluate(IElement[] Arguments, Variables Variables)
        {
            double Holes = Expression.ToDouble(Arguments[0].AssociatedObjectValue);
            double Eccentricity = Expression.ToDouble(Arguments[1].AssociatedObjectValue);
 
            return new ConicVariation(Holes, Eccentricity, this.Arguments[0], this.Arguments[1], 
                this.Start, this.Length, this.Expression);
        }
 
        public override void Operate(ref double x, ref double y)
        {
            double r1;
 
            lock (this.gen)
            {
                r1 = this.gen.NextDouble();
            }
 
            double a = Math.Atan2(y, x);
            double r = (r1 - this.holes) * this.eccentricity / (1 + this.eccentricity + Math.Cos(a));
            x = r * Math.Cos(a);
            y = r * Math.Sin(a);
        }
 
        private readonly Random gen = new Random();
 
        public override string FunctionName => nameof(ConicVariation);
    }
}