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history/006_snake/src/main/java/com/gitee/drinkjava2/frog/util/RandomUtils.java

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+/* Copyright 2018-2020 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by
+ * applicable law or agreed to in writing, software distributed under the
+ * License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS
+ * OF ANY KIND, either express or implied. See the License for the specific
+ * language governing permissions and limitations under the License.
+ */
+package com.gitee.drinkjava2.frog.util;
+
+import java.util.Random;
+
+import com.gitee.drinkjava2.frog.Animal;
+import com.gitee.drinkjava2.frog.brain.Organ;
+import com.gitee.drinkjava2.frog.brain.Zone;
+import com.gitee.drinkjava2.frog.organ.Line;
+import com.gitee.drinkjava2.frog.organ.frog.FrogBigEye;
+
+/**
+ * Random Utilities used in this project
+ * 
+ * @author Yong Zhu
+ * @since 1.0
+ */
+public class RandomUtils {
+
+	private RandomUtils() {
+	}
+
+	private static final Random rand = new Random();
+
+	public static int nextInt(int i) {
+		return rand.nextInt(i);
+	}
+
+	public static float nextFloat() {
+		return rand.nextFloat();
+	}
+
+	public static boolean percent(float percent) {// 有百分这percent的机率为true
+		return rand.nextFloat() * 100 < percent;
+	}
+
+	public static Zone randomZoneInZone(Zone o) { // 在一个区内随机取一个小小区
+		return new Zone(o.x - o.r + o.r * 2 * rand.nextFloat(), o.y - o.r + o.r * 2 * rand.nextFloat(),
+				o.z /*- o.r + o.r * 2 * rand.nextFloat()*/, o.r * rand.nextFloat() * .3f, o.h * rand.nextFloat() * .3f);
+	}
+
+	/** Return a random zone inside of frog's random organ */
+	public static Zone randomZoneInOrgans(Animal a) {
+		if (a.organs == null || a.organs.isEmpty())
+			throw new IllegalArgumentException("Can not call randomPosInRandomOrgan method when has no organ");
+		Organ o = null;
+		if (percent(10)) {// 增加选中大眼睛的机率，因为里面感光细胞多
+			Organ og = a.organs.get(1);// 第1个通常设定为大眼睛
+			if (og instanceof FrogBigEye) // 如果是蛙或蛇眼
+				o = og;
+		}
+		if (o == null)// 有时候大眼晴没被程序员加进来，这时o为null
+			o = a.organs.get(1 + RandomUtils.nextInt(a.organs.size() - 1)); // 跳过第一个器官
+		if (o instanceof Line) {
+			return randomZoneInZone(((Line) o).bodyZone);
+		} else {
+			return randomZoneInZone(o);
+		}
+	}
+
+	public static int vary(int v, int percet) {
+		if (percent(percet))
+			return vary(v);
+		return v;
+	}
+
+	public static int vary(int v) {// 随机有大概率小变异，小概率大变异，极小概率极大变异
+		if (percent(40))
+			v += v * .04 * (nextFloat() - 0.5); // v=v+-.04
+		if (percent(10))
+			v += v * .103 * (nextFloat() - 0.5); // v=v+-0.1
+		else if (percent(5))
+			v += v * 1 * (nextFloat() - 0.5); // v=v+-0.4
+		else if (percent(2))
+			v += v * 4 * (nextFloat() - 0.5); // v=v+-2
+		else if (percent(1f))
+			v += v * 8 * (nextFloat() - 0.5); // v=v+-6
+		return v;
+	}
+
+	public static float vary(float v) {// 随机有大概率小变异，小概率大变异，极小概率极大变异
+		if (percent(40))
+			v += v * .04 * (nextFloat() - 0.5); // v=v+-.04
+		if (percent(10))
+			v += v * .103 * (nextFloat() - 0.5); // v=v+-0.1
+		else if (percent(5))
+			v += v * 1 * (nextFloat() - 0.5); // v=v+-0.4
+		else if (percent(2))
+			v += v * 4 * (nextFloat() - 0.5); // v=v+-2
+		else if (percent(1f))
+			v += v * 8 * (nextFloat() - 0.5); // v=v+-6
+		return v;
+	}
+
+	public static int varyInLimit(int v, int from, int to) {// 让返回值在from和to之间随机变异
+		int i = vary(v);
+		if (i < from)
+			i = from;
+		if (i > to)
+			i = to;
+		return i;
+	}
+
+	public static float varyInLimit(float v, float from, float to) {// 让返回值在from和to之间随机变异
+		float i = vary(v);
+		if (i < from)
+			i = from;
+		if (i > to)
+			i = to;
+		return i;
+	}
+
+}