Attempt to synchronized logic random seed

core/src/mindustry/core/NetClient.java

@@ -19,6 +19,7 @@ import mindustry.game.EventType.*;
 import mindustry.game.*;
 import mindustry.game.Teams.*;
 import mindustry.gen.*;
+import mindustry.logic.*;
 import mindustry.net.Administration.*;
 import mindustry.net.*;
 import mindustry.net.Packets.*;
@@ -452,7 +453,7 @@ public class NetClient implements ApplicationListener{
     }
 
     @Remote(variants = Variant.one, priority = PacketPriority.low, unreliable = true)
-    public static void stateSnapshot(float waveTime, int wave, int enemies, boolean paused, boolean gameOver, int timeData, byte tps, byte[] coreData){
+    public static void stateSnapshot(float waveTime, int wave, int enemies, boolean paused, boolean gameOver, int timeData, byte tps, long rand0, long rand1, byte[] coreData){
         try{
             if(wave > state.wave){
                 state.wave = wave;
@@ -466,6 +467,11 @@ public class NetClient implements ApplicationListener{
             state.serverPaused = paused;
             state.serverTps = tps & 0xff;
 
+            //note that this is far from a guarantee that random state is synced - tiny changes in delta and ping can throw everything off again.
+            //syncing will only make much of a difference when rand() is called infrequently
+            GlobalConstants.rand.seed0 = rand0;
+            GlobalConstants.rand.seed1 = rand1;
+
             universe.updateNetSeconds(timeData);
 
             netClient.byteStream.setBytes(coreData);

core/src/mindustry/core/NetServer.java

@@ -19,6 +19,7 @@ import mindustry.game.*;
 import mindustry.game.Teams.*;
 import mindustry.gen.*;
 import mindustry.graphics.*;
+import mindustry.logic.*;
 import mindustry.net.*;
 import mindustry.net.Administration.*;
 import mindustry.net.Packets.*;
@@ -867,7 +868,8 @@ public class NetServer implements ApplicationListener{
         dataStream.close();
 
         //write basic state data.
-        Call.stateSnapshot(player.con, state.wavetime, state.wave, state.enemies, state.serverPaused, state.gameOver, universe.seconds(), tps, syncStream.toByteArray());
+        Call.stateSnapshot(player.con, state.wavetime, state.wave, state.enemies, state.serverPaused, state.gameOver,
+            universe.seconds(), tps, GlobalConstants.rand.seed0, GlobalConstants.rand.seed1, syncStream.toByteArray());
 
         syncStream.reset();
 

core/src/mindustry/logic/GlobalConstants.java

@@ -2,6 +2,7 @@ package mindustry.logic;
 
 import arc.*;
 import arc.files.*;
+import arc.math.*;
 import arc.struct.*;
 import arc.util.*;
 import mindustry.*;
@@ -18,6 +19,8 @@ import java.io.*;
 public class GlobalConstants{
     public static final int ctrlProcessor = 1, ctrlPlayer = 2, ctrlFormation = 3;
     public static final ContentType[] lookableContent = {ContentType.block, ContentType.unit, ContentType.item, ContentType.liquid};
+    /** Global random state. */
+    public static final Rand rand = new Rand();
 
     private ObjectIntMap<String> namesToIds = new ObjectIntMap<>();
     private Seq<Var> vars = new Seq<>(Var.class);

core/src/mindustry/logic/LogicOp.java

@@ -34,13 +34,13 @@ public enum LogicOp{
     angle("angle", true, (x, y) -> Angles.angle((float)x, (float)y)),
     len("len", true, (x, y) -> Mathf.dst((float)x, (float)y)),
     noise("noise", true, (x, y) -> Simplex.raw2d(0, x, y)),
-    abs("abs", a -> Math.abs(a)),
+    abs("abs", a -> Math.abs(a)), //not a method reference because it fails to compile for some reason
     log("log", Math::log),
     log10("log10", Math::log10),
     floor("floor", Math::floor),
     ceil("ceil", Math::ceil),
     sqrt("sqrt", Math::sqrt),
-    rand("rand", d -> Mathf.rand.nextDouble() * d),
+    rand("rand", d -> GlobalConstants.rand.nextDouble() * d),
 
     sin("sin", d -> Math.sin(d * Mathf.doubleDegRad)),
     cos("cos", d -> Math.cos(d * Mathf.doubleDegRad)),

core/src/mindustry/net/NetworkIO.java

@@ -9,6 +9,7 @@ import mindustry.ctype.*;
 import mindustry.game.*;
 import mindustry.gen.*;
 import mindustry.io.*;
+import mindustry.logic.*;
 import mindustry.maps.Map;
 import mindustry.net.Administration.*;
 
@@ -41,6 +42,8 @@ public class NetworkIO{
             stream.writeInt(state.wave);
             stream.writeFloat(state.wavetime);
             stream.writeDouble(state.tick);
+            stream.writeLong(GlobalConstants.rand.seed0);
+            stream.writeLong(GlobalConstants.rand.seed1);
 
             stream.writeInt(player.id);
             player.write(Writes.get(stream));
@@ -63,6 +66,8 @@ public class NetworkIO{
             state.wave = stream.readInt();
             state.wavetime = stream.readFloat();
             state.tick = stream.readDouble();
+            GlobalConstants.rand.seed0 = stream.readLong();
+            GlobalConstants.rand.seed1 = stream.readLong();
 
             Groups.clear();
             int id = stream.readInt();

gradle.properties

@@ -24,4 +24,4 @@ android.useAndroidX=true
 #used for slow jitpack builds; TODO see if this actually works
 http.socketTimeout=80000
 http.connectionTimeout=80000
-archash=3400de3323150ba91c94fc07a6d4ca1958f4d943
+archash=bc9bbf8312f69d5e6882ce8dab4136d2126473e8