FalloffFunctions.cs

// Copyright (c) Ryan Schmidt (rms@gradientspace.com) - All Rights Reserved
// Distributed under the Boost Software License, Version 1.0. http://www.boost.org/LICENSE_1_0.txt
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using g3;

namespace gs
{
    public interface IFalloffFunction
    {
        /// <summary>
        /// t is value in range [0,1], returns value in range [0,1]
        /// </summary>
        double FalloffT(double t);

        /// <summary>
        /// In most cases, users of IFalloffFunction will make a local copy
        /// </summary>
        IFalloffFunction Duplicate();
    }



    /// <summary>
    /// returns 1 in range [0,ConstantRange], and then falls off to 0 in range [ConstantRange,1]
    /// </summary>
    public class LinearFalloff : IFalloffFunction
    {
        public double ConstantRange = 0;

        public double FalloffT(double t)
        {
            t = MathUtil.Clamp(t, 0.0, 1.0);
            if (ConstantRange <= 0)
                return 1.0 - t;
            else
                return (t < ConstantRange) ? 1.0 : 1.0 - ((t - ConstantRange) / (1 - ConstantRange));
        }


        public IFalloffFunction Duplicate()
        {
            return new WyvillFalloff() {
                ConstantRange = this.ConstantRange
            };
        }
    }



    /// <summary>
    /// returns 1 in range [0,ConstantRange], and then falls off to 0 in range [ConstantRange,1]
    /// </summary>
    public class WyvillFalloff : IFalloffFunction
    {
        public double ConstantRange = 0;

        public double FalloffT(double t)
        {
            t = MathUtil.Clamp(t, 0.0, 1.0);
            if (ConstantRange <= 0)
                return MathUtil.WyvillFalloff01(t);
            else
                return MathUtil.WyvillFalloff(t, ConstantRange, 1.0);
        }


        public IFalloffFunction Duplicate()
        {
            return new WyvillFalloff() {
                ConstantRange = this.ConstantRange
            };
        }

    }



}