84 lines
3.3 KiB
C#
84 lines
3.3 KiB
C#
using UnityEngine;
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namespace Cielonos.MainGame.Inventory
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{
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/// <summary>
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/// 提供基于 Luck 和 Curse 的通用随机结果。
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/// 返回值始终位于 0 到 1 之间；具体含义由调用者自行映射。
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/// </summary>
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public static class Randomizer
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{
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private const float MinimumValue = 0f;
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private const float MaximumValue = 1f;
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private const float BiasScale = 0.5f;
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private const float GoodChanceRange = 0.45f;
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private const float RegularStandardDeviation = 0.165f;
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private const float ExtremeStandardDeviation = 0.06f;
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private const float ExtremeGoodMean = 0.9f;
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private const float ExtremeBadMean = 0.1f;
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private const int MaximumNormalRollAttempts = 4;
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/// <summary>
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/// 获取一个不受属性影响的基础随机值。
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/// </summary>
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public static float Roll01()
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{
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return Random.Range(MinimumValue, MaximumValue);
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}
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/// <summary>
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/// 根据 Luck 和 Curse 获取一个表示结果好坏的随机值。
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/// 0 表示最坏结果，1 表示最好结果；两项属性均为 0 时使用中心为 0.5 的正态分布。
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/// </summary>
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public static float RollLuckCurse01(float luck, float curse)
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{
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GetDistributionParameters(luck, curse, out float bias, out float goodChance, out float extremeWeight);
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if (Random.value < extremeWeight)
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{
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float mean = Random.value < goodChance ? ExtremeGoodMean : ExtremeBadMean;
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return RollTruncatedNormal(mean, ExtremeStandardDeviation);
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}
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return RollTruncatedNormal(0.5f + 0.25f * bias, RegularStandardDeviation);
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}
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private static void GetDistributionParameters(float luck, float curse, out float bias, out float goodChance,
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out float extremeWeight)
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{
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float normalizedLuck = Mathf.Clamp01(luck / 100f);
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float normalizedCurse = Mathf.Clamp01(curse / 100f);
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bias = HyperbolicTangent((normalizedLuck - normalizedCurse) / BiasScale);
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goodChance = 0.5f + GoodChanceRange * bias;
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extremeWeight = normalizedLuck * normalizedCurse;
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}
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/// <summary>
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/// Unity 的 Mathf 未提供 Tanh，因此通过指数定义计算双曲正切。
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/// </summary>
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private static float HyperbolicTangent(float value)
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{
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float exponent = Mathf.Exp(2f * value);
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return (exponent - 1f) / (exponent + 1f);
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}
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private static float RollTruncatedNormal(float mean, float standardDeviation)
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{
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for (int attempt = 0; attempt < MaximumNormalRollAttempts; attempt++)
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{
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float value = mean + RollStandardNormal() * standardDeviation;
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if (value > MinimumValue && value < MaximumValue) return value;
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}
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return Mathf.Clamp(mean + RollStandardNormal() * standardDeviation, MinimumValue, MaximumValue);
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}
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private static float RollStandardNormal()
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{
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float u1 = Mathf.Max(Random.value, float.Epsilon);
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float u2 = Random.value;
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return Mathf.Sqrt(-2f * Mathf.Log(u1)) * Mathf.Cos(2f * Mathf.PI * u2);
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}
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}
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}
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