From 5fcb4d2fabed164e0884d453647ce54ca4ec2c90 Mon Sep 17 00:00:00 2001
From: john01dav <john01dav@gmail.com>
Date: Thu, 28 Jul 2016 21:00:53 -0500
Subject: [PATCH] Optimized prime search utility methods and added timer to
 FalloffPerlinNoiseTest

---
 .../john01dav/jnoise/tests/FalloffPerlinNoiseTest.java    | 3 +++
 src/src/john01dav/jnoise/util/MathUtil.java               | 8 ++++++--
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/Tests/src/src/john01dav/jnoise/tests/FalloffPerlinNoiseTest.java b/Tests/src/src/john01dav/jnoise/tests/FalloffPerlinNoiseTest.java
index dbc4796..6e86fda 100644
--- a/Tests/src/src/john01dav/jnoise/tests/FalloffPerlinNoiseTest.java
+++ b/Tests/src/src/john01dav/jnoise/tests/FalloffPerlinNoiseTest.java
@@ -10,8 +10,11 @@
 public class FalloffPerlinNoiseTest{
 
     public static void main(String[] args) throws IOException{
+        long start = System.currentTimeMillis();
         HeightMap heightMap = new HeightMap(2048, new PerlinNoiseTemplate(0L, 9, 2, new FalloffPerlinNoiseController()));
         heightMap.generate();
+        System.out.println("Generation Time: " + (System.currentTimeMillis() - start));
+
         heightMap.saveImage("./falloffislandperlinnoise.png");
     }
 
diff --git a/src/src/john01dav/jnoise/util/MathUtil.java b/src/src/john01dav/jnoise/util/MathUtil.java
index f59cbac..6742715 100644
--- a/src/src/john01dav/jnoise/util/MathUtil.java
+++ b/src/src/john01dav/jnoise/util/MathUtil.java
@@ -5,7 +5,9 @@ public final class MathUtil{
     private MathUtil(){}
 
     public static boolean isPrime(int n){
-        for(int i=2;i<n;i++){
+        int sqrtOfN = (int) Math.ceil(Math.sqrt(n));
+
+        for(int i=2;i<sqrtOfN;i++){
             if(n % i == 0){
                 return false;
             }
@@ -15,7 +17,9 @@ public static boolean isPrime(int n){
     }
 
     public static int getNextPrime(int n){
-        while(!isPrime(n)) n++;
+        if(n % 2 == 0) n++;
+
+        while(!isPrime(n)) n+=2;
         return n;
     }