NoiseHelper.cs

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using System;
using Microsoft.Xna.Framework;
using Terraria.Utilities;
 
namespace Terraria.GameContent.RGB;
 
public static class NoiseHelper
{
    private const int RANDOM_SEED = 1;
 
    private const int NOISE_2D_SIZE = 32;
 
    private const int NOISE_2D_SIZE_MASK = 31;
 
    private const int NOISE_SIZE_MASK = 1023;
 
    private static readonly float[] StaticNoise = CreateStaticNoise(1024);
 
    private static float[] CreateStaticNoise(int length)
    {
        UnifiedRandom r = new UnifiedRandom(1);
        float[] array = new float[length];
        for (int i = 0; i < array.Length; i++)
        {
            array[i] = r.NextFloat();
        }
        return array;
    }
 
    public static float GetDynamicNoise(int index, float currentTime)
    {
        float num = StaticNoise[index & 0x3FF];
        float num2 = currentTime % 1f;
        return Math.Abs(Math.Abs(num - num2) - 0.5f) * 2f;
    }
 
    public static float GetStaticNoise(int index)
    {
        return StaticNoise[index & 0x3FF];
    }
 
    public static float GetDynamicNoise(int x, int y, float currentTime)
    {
        return GetDynamicNoiseInternal(x, y, currentTime % 1f);
    }
 
    private static float GetDynamicNoiseInternal(int x, int y, float wrappedTime)
    {
        x &= 0x1F;
        y &= 0x1F;
        return Math.Abs(Math.Abs(StaticNoise[y * 32 + x] - wrappedTime) - 0.5f) * 2f;
    }
 
    public static float GetStaticNoise(int x, int y)
    {
        x &= 0x1F;
        y &= 0x1F;
        return StaticNoise[y * 32 + x];
    }
 
    public static float GetDynamicNoise(Vector2 position, float currentTime)
    {
        position *= 10f;
        currentTime %= 1f;
        Vector2 vector = new Vector2((float)Math.Floor(position.X), (float)Math.Floor(position.Y));
        Point point = new Point((int)vector.X, (int)vector.Y);
        Vector2 vector2 = new Vector2(position.X - vector.X, position.Y - vector.Y);
        float value = MathHelper.Lerp(GetDynamicNoiseInternal(point.X, point.Y, currentTime), GetDynamicNoiseInternal(point.X, point.Y + 1, currentTime), vector2.Y);
        float value2 = MathHelper.Lerp(GetDynamicNoiseInternal(point.X + 1, point.Y, currentTime), GetDynamicNoiseInternal(point.X + 1, point.Y + 1, currentTime), vector2.Y);
        return MathHelper.Lerp(value, value2, vector2.X);
    }
 
    public static float GetStaticNoise(Vector2 position)
    {
        position *= 10f;
        Vector2 vector = new Vector2((float)Math.Floor(position.X), (float)Math.Floor(position.Y));
        Point point = new Point((int)vector.X, (int)vector.Y);
        Vector2 vector2 = new Vector2(position.X - vector.X, position.Y - vector.Y);
        float value = MathHelper.Lerp(GetStaticNoise(point.X, point.Y), GetStaticNoise(point.X, point.Y + 1), vector2.Y);
        float value2 = MathHelper.Lerp(GetStaticNoise(point.X + 1, point.Y), GetStaticNoise(point.X + 1, point.Y + 1), vector2.Y);
        return MathHelper.Lerp(value, value2, vector2.X);
    }
}