CurlVariation.cs

using Waher.Script.Abstraction.Elements;
using Waher.Script.Model;
 
namespace Waher.Script.Fractals.IFS.Variations.Flame
{
    public class CurlVariation : FlameVariationMultipleParameters
    {
        private readonly double c1;
        private readonly double c2;
 
        public CurlVariation(ScriptNode c1, ScriptNode c2, int Start, int Length, Expression Expression)
            : base(new ScriptNode[] { c1, c2 }, new ArgumentType[] { ArgumentType.Scalar, ArgumentType.Scalar },
                  Start, Length, Expression)
        {
            this.c1 = 0;
            this.c2 = 0;
        }
 
        private CurlVariation(double C1, double C2, ScriptNode c1, ScriptNode c2, int Start, int Length, Expression Expression)
            : base(new ScriptNode[] { c1, c2 }, new ArgumentType[] { ArgumentType.Scalar, ArgumentType.Scalar },
                  Start, Length, Expression)
        {
            this.c1 = C1;
            this.c2 = C2;
        }
 
        public override string[] DefaultArgumentNames
        {
            get
            {
                return new string[] { "c1", "c2" };
            }
        }
 
        public override IElement Evaluate(IElement[] Arguments, Variables Variables)
        {
            double C1 = Expression.ToDouble(Arguments[0].AssociatedObjectValue);
            double C2 = Expression.ToDouble(Arguments[1].AssociatedObjectValue);
 
            return new CurlVariation(C1, C2, this.Arguments[0], this.Arguments[1],
                this.Start, this.Length, this.Expression);
        }
 
        public override void Operate(ref double x, ref double y)
        {
            double t1 = 1 + this.c1 * x + this.c2 * (x * x - y * y);
            double t2 = this.c1 * y + 2 * this.c2 * x * y;
            double r = t1 * t1 + t2 * t2 + 1e-6;
            x = (x * t1 + y * t2) / r;
            y = (y * t1 - x * t2) / r;
        }
 
        public override string FunctionName => nameof(CurlVariation);
    }
}