From 59e226a29ac1f627073a343f2778f23dfa09eb28 Mon Sep 17 00:00:00 2001
From: Jason Rohrer <jasonrohrer@fastmail.fm>
Date: Sat, 27 Jul 2019 13:34:45 -0700
Subject: [PATCH] Server biomes random generator reseeds itself after every map
 wipe.  A different map every time, with one of 4 billion possible seeds. 
 Made server wait 8 seconds after signalling apocalypse, to give clients
 plenty of time to white-out.

---
 documentation/changeLog.txt |  6 +++++
 server/makeFileList         |  3 ++-
 server/map.cpp              | 54 ++++++++++++++++++++++++++++++++++++-
 server/map.h                |  4 +++
 server/server.cpp           |  4 ++-
 5 files changed, 68 insertions(+), 3 deletions(-)

diff --git a/documentation/changeLog.txt b/documentation/changeLog.txt
index ec61ccc22..a05028c2f 100644
--- a/documentation/changeLog.txt
+++ b/documentation/changeLog.txt
@@ -51,6 +51,12 @@ Server Fixes
   most kinds of useful trees (at least ones that are sensibly hardwood, like
   maple, poplar, and rubber).
 
+--Server biomes random generator reseeds itself after every map wipe.  A
+  different map every time, with one of 4 billion possible seeds.
+
+--Made server wait 8 seconds after signalling apocalypse, to give clients
+  plenty of time to white-out.
+
 
 
 
diff --git a/server/makeFileList b/server/makeFileList
index a91997e11..ae99c1c43 100644
--- a/server/makeFileList
+++ b/server/makeFileList
@@ -95,4 +95,5 @@ NEEDED_MINOR_GEMS_OBJECTS = \
  ${PRINT_LOG_O} \
  ${PRINT_UTILS_O} \
  ${DOUBLE_PAIR_O} \
- ${STRING_TREE_O}
+ ${STRING_TREE_O} \
+ ${CRC32_O}
diff --git a/server/map.cpp b/server/map.cpp
index 68a9612bc..3daaa4443 100644
--- a/server/map.cpp
+++ b/server/map.cpp
@@ -26,6 +26,8 @@
 //#include "lineardb.h"
 #include "lineardb3.h"
 
+#include "minorGems/util/crc32.h"
+
 
 /*
 #define DB KISSDB
@@ -232,6 +234,8 @@ static int barrierOn = 1;
 static int longTermCullEnabled = 1;
 
 
+static unsigned int biomeRandSeed = 723;
+
 
 static SimpleVector<int> barrierItemList;
 
@@ -830,7 +834,7 @@ static int computeMapBiomeIndex( int inX, int inY,
     for( int i=0; i<numBiomes; i++ ) {
         int biome = biomes[i];
         
-        setXYRandomSeed( biome * 263 + 723 );
+        setXYRandomSeed( biome * 263 + biomeRandSeed );
 
         double randVal = getXYFractal(  inX,
                                         inY,
@@ -2553,9 +2557,57 @@ static void deleteFileByName( const char *inFileName ) {
     }
 
 
+void reseedMap( char inForceFresh ) {
+    
+    FILE *seedFile = NULL;
+    
+    if( ! inForceFresh ) {
+        seedFile = fopen( "biomeRandSeed.txt", "r" );
+        }
+    
+    if( seedFile != NULL ) {
+        fscanf( seedFile, "%d", &biomeRandSeed );
+        fclose( seedFile );
+        AppLog::infoF( "Reading map rand seed from file: %u\n", biomeRandSeed );
+        }
+    else {
+        // no seed set, or ignoring it, make a new one
+        
+        char *secret =
+            SettingsManager::getStringSetting( "statsServerSharedSecret", 
+                                               "secret" );
+        
+        unsigned int seedBase = 
+            crc32( (unsigned char*)secret, strlen( secret ) );
+        
+        unsigned int modTimeSeed = 
+            (unsigned int)fmod( Time::getCurrentTime() + seedBase, 
+                                4294967295U );
+        
+        JenkinsRandomSource tempRandSource( modTimeSeed );
+
+        biomeRandSeed = tempRandSource.getRandomInt();
+        
+        AppLog::infoF( "Generating fresh map rand seed and saving to file: "
+                       "%u\n", biomeRandSeed );
+
+        // and save it
+        seedFile = fopen( "biomeRandSeed.txt", "w" );
+        if( seedFile != NULL ) {
+            
+            fprintf( seedFile, "%d", biomeRandSeed );
+            fclose( seedFile );
+            }
+        }
+    }
+
+
 
 
 char initMap() {
+
+    reseedMap( false );
+    
     
     numSpeechPipes = getMaxSpeechPipeIndex() + 1;
     
diff --git a/server/map.h b/server/map.h
index e3222551b..2d5d6f9e9 100644
--- a/server/map.h
+++ b/server/map.h
@@ -40,6 +40,10 @@ char initMap();
 void freeMap( char inSkipCleanup = false );
 
 
+// loads seed from file, or generates a new one and saves it to file
+void reseedMap( char inForceFresh );
+
+
 // can only be called before initMap or after freeMap
 // deletes the underlying .db files for the map 
 void wipeMapFiles();
diff --git a/server/server.cpp b/server/server.cpp
index 8e1ff8b9e..767ee303d 100644
--- a/server/server.cpp
+++ b/server/server.cpp
@@ -8130,7 +8130,7 @@ void apocalypseStep() {
             }
 
         if( apocalypseRequest == NULL &&
-            Time::getCurrentTime() - apocalypseStartTime >= 7 ) {
+            Time::getCurrentTime() - apocalypseStartTime >= 8 ) {
             
             if( ! postApocalypseStarted  ) {
                 AppLog::infoF( "Enough warning time, %d players still alive",
@@ -8149,6 +8149,8 @@ void apocalypseStep() {
                 AppLog::infoF( "Apocalypse wipeMapFiles took %f sec",
                                Time::getCurrentTime() - startTime );
                 
+                reseedMap( true );
+                
                 initMap();
                 
                 AppLog::infoF( "Apocalypse initMap took %f sec",