Infite momentum glitch fix, and many tweaks.

- Fix infinite momentum bug due to minecraft's minecart movement code being a hot mess. See GitHub issue #6
- Default hard brake block changed from obsidian to sand soul. This souldn't affect existing configurations.
- Speed multiplier range now starts from 1 instead of 0.
- Hard brake fallback value now 8 instead of 1 when specifying invalid values in config.
- Build target changed from Java 8 to Java 11

Author: ergor

.idea/misc.xml

@@ -1,9 +1,9 @@
 # hsrails
 ### High Speed Rails
 
-A spigot/bukkit plugin to make minecarts worth building again.
+A spigot/bukkit plugin to make minecarts worth building.
 
-For Minecraft version **1.14** and tested working on **1.15, 1.16.3, 1.19**. Will most likely work just fine on **newer versions as well**.
+For Minecraft version **1.21.1** and tested working on **1.14, 1.15, 1.16.3, 1.19**. Will most likely work just fine on **newer versions as well**.
 
 Place a powered rail on a _boost block_ (`redstone block` by default) to build high-speed rail. Place on any other block to get a regular powered rail.
 
@@ -14,7 +14,7 @@ High-speed rails are by default 4x faster than regular powered rails, ie. 32 m/s
 The high-speed rail multiplier can be temporarily changed with the `/hsrails` command, or permanently changed in the config. 
 The boost block is also configurable. See _Usage_ section for commands and config options.
 
-To help cope with the higher speeds, there is also a _hard brake block_ available (`obsidian` by default). If you place an
+To help cope with the higher speeds, there is also a _hard brake block_ available (`soul sand` by default). If you place an
 _unpowered_ power rail on a hard brake block, the cart will decelerate faster than default. See _Usage_ section 
 for configuration options.
 
@@ -29,7 +29,7 @@ That means the carts will coast for longer, even though they appear to have the
 #### Commands
 
 Use `/hsrails <multiplier>` to tweak how fast high-speed rails are.
-Multiplier must be between 0 and 8.
+Multiplier must be between 1 and 8.
 
 Example: set multiplier to 4
 ```
@@ -44,13 +44,13 @@ This is the default `HsRails/config.yml`:
 speedMultiplier: 4.0
 boostBlock: "minecraft:redstone_block"
 hardBrakeMultiplier: 8.0
-hardBrakeBlock: "minecraft:obsidian"
+hardBrakeBlock: "minecraft:soul_sand"
 ```
 
 Allowed values are:
 
 - speedMultiplier:
-    - `> 0`
+    - `>= 1`
     - `<= 8`
 - boostBlock:
     - Namespaced block. Look up the ID name in [the id list](https://www.minecraftinfo.com/idnamelist.htm) 
@@ -81,6 +81,7 @@ These are my recommendations for building efficient high-speed tracks:
 - Minimize number of slopes: build tunnels, bridges, etc. to stay on the same level.
 - Before turns and slopes, put one (or sometimes a couple of) regular powered rails to slow down and avoid derailment.
 - After turns and slopes, allow room for acceleration again.
+- To maintain top speed in high speed state, place a high speed rail every 30 blocks (ie. 1 powered rail + 29 iron rails; rinse and repeat)
 
 To maintain high speeds you must of course build your tracks out of high-speed rails, because regular powered rails will slow you down. Only mix in regular powered rails in turns and slopes as mentioned above.
 

README.md

@@ -6,12 +6,10 @@
 
     <groupId>no.netb.mc.hsrails</groupId>
     <artifactId>hsrails</artifactId>
-    <version>1.3.1</version>
+    <version>1.4.0</version>
 
     <properties>
-        <java.version>1.8</java.version>
-        <maven.compiler.target>1.8</maven.compiler.target>
-        <maven.compiler.source>1.8</maven.compiler.source>
+        <maven.compiler.release>11</maven.compiler.release>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     </properties>
 
@@ -26,7 +24,7 @@
         <dependency>
             <groupId>org.spigotmc</groupId>
             <artifactId>spigot-api</artifactId>
-            <version>1.20.2-R0.1-SNAPSHOT</version>
+            <version>1.21.1-R0.1-SNAPSHOT</version>
             <scope>provided</scope>
         </dependency>
     </dependencies>

pom.xml

@@ -84,9 +84,9 @@ private void readHardBrakeBlock(FileConfiguration fileConfig, Logger logger) {
 
     private void readSpeedMultiplier(FileConfiguration fileConfig, Logger logger) {
         double speedMultiplier = fileConfig.getDouble("speedMultiplier");
-        if (speedMultiplier <= 0) {
-            logger.warning("Warning: speed multiplier set to 0 or below in config. Using value of 0.1 as fallback.");
-            speedMultiplier = 0.1;
+        if (speedMultiplier < 1d) {
+            logger.warning("Warning: speed multiplier set below 1 in config. Using value of 1 as fallback.");
+            speedMultiplier = 1d;
         } else if (speedMultiplier > 8) {
             logger.warning("Warning: speed multiplier set above 8 in config. Using value of 8 as fallback.");
             speedMultiplier = 8d;
@@ -104,8 +104,8 @@ private void readSpeedMultiplier(FileConfiguration fileConfig, Logger logger) {
     private void readHardBrakeMultiplier(FileConfiguration fileConfig, Logger logger) {
         double hardBrakeMultiplier = fileConfig.getDouble("hardBrakeMultiplier");
         if (hardBrakeMultiplier < 1.0) {
-            logger.warning("Warning: brake multiplier not set or set to below 1 in config. Using value of 1 as fallback.");
-            hardBrakeMultiplier = 1.0;
+            logger.warning("Warning: brake multiplier not set or set to below 1 in config. Using value of 8 as fallback.");
+            hardBrakeMultiplier = 8.0;
         }
         else {
             logger.info("Setting brake multiplier to " + hardBrakeMultiplier);

src/main/java/no/netb/mc/hsrails/Configuration.java

@@ -0,0 +1,21 @@
+package no.netb.mc.hsrails;
+
+import org.bukkit.entity.Player;
+
+public class DebugSubscription {
+    private final Player player;
+    private final boolean acceptsVerbose;
+
+    public DebugSubscription(Player player, boolean acceptsVerbose) {
+        this.player = player;
+        this.acceptsVerbose = acceptsVerbose;
+    }
+
+    public Player getPlayer() {
+        return player;
+    }
+
+    public boolean getAcceptsVerbose() {
+        return acceptsVerbose;
+    }
+}

src/main/java/no/netb/mc/hsrails/DebugSubscription.java

@@ -7,7 +7,10 @@
 import org.bukkit.plugin.PluginManager;
 import org.bukkit.plugin.java.JavaPlugin;
 
+import java.util.HashMap;
 import java.util.HashSet;
+import java.util.Map;
+import java.util.Optional;
 import java.util.Set;
 import java.util.logging.Logger;
 
@@ -19,7 +22,10 @@ public static Configuration getConfiguration() {
         return CONFIGURATION;
     }
 
-    private static Set<CommandSender> receivedHeadsUp = new HashSet<>();
+    private static final Set<CommandSender> receivedHeadsUp = new HashSet<>();
+
+    public static Map<Player, DebugSubscription> debuggers = new HashMap<>();
+    public static double coastFactor = 30d;
 
     @Override
     public void onEnable() {
@@ -36,6 +42,7 @@ public void onEnable() {
                 CONFIGURATION.getHardBrakeBlock(),
                 CONFIGURATION.isCheatMode()
         ), this);
+        pm.registerEvents(new PlayerDisconnectListener(logger), this);
     }
 
     @Override
@@ -53,6 +60,23 @@ public boolean onCommand(CommandSender sender, Command command, String label, St
                     player.sendMessage(ChatColor.RED + "You don't have permission to use this command");
                     return true;
                 }
+
+                if (args.length > 0 && (args[0].equalsIgnoreCase("d") || args[0].equalsIgnoreCase("dd"))) {
+                    Boolean currentMode = Optional.ofNullable(debuggers.get(player))
+                            .map(DebugSubscription::getAcceptsVerbose)
+                            .orElse(null);
+
+                    boolean verbose = args[0].equalsIgnoreCase("dd");
+                    if (currentMode == null || currentMode != verbose) {
+                        debuggers.put(player, new DebugSubscription(player, verbose));
+                        player.sendMessage("debug mode: " + (verbose ? "ON [VERBOSE]" : "ON [NORMAL]"));
+                        return true;
+                    }
+
+                    debuggers.remove(player);
+                    player.sendMessage("debug mode: OFF");
+                    return true;
+                }
             }
 
             try {
@@ -64,7 +88,7 @@ public boolean onCommand(CommandSender sender, Command command, String label, St
             }
 
             double speedMultiplier = CONFIGURATION.getSpeedMultiplier();
-            if (speedMultiplier > 0 && speedMultiplier <= 8) {
+            if (speedMultiplier >= 1d && speedMultiplier <= 8d) {
                 String message = ChatColor.AQUA + "Speed multiplier set to: " + speedMultiplier;
                 String headsUp =
                         ChatColor.YELLOW + "\nNote: multiplier set to more than 4x. Servers often struggle to provide max speeds above 4x,"
@@ -79,7 +103,7 @@ public boolean onCommand(CommandSender sender, Command command, String label, St
                 return true;
             }
 
-            sender.sendMessage(ChatColor.RED + "multiplier must be greater than 0 and max 8");
+            sender.sendMessage(ChatColor.RED + "multiplier must be at least 1 and at most 8");
             return true;
         }
 

src/main/java/no/netb/mc/hsrails/HsRails.java

@@ -9,20 +9,39 @@
 import org.bukkit.event.EventHandler;
 import org.bukkit.event.EventPriority;
 import org.bukkit.event.Listener;
+import org.bukkit.event.vehicle.VehicleDestroyEvent;
 import org.bukkit.event.vehicle.VehicleMoveEvent;
 import org.bukkit.util.Vector;
 
-import java.util.HashSet;
-import java.util.Set;
-
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Objects;
 
 public class MinecartListener implements Listener {
 
+    static class MinecartState {
+        int blocksCoasted = 0;
+
+        @Override
+        public boolean equals(Object obj) {
+            if (obj instanceof MinecartState) {
+                MinecartState s = (MinecartState) obj;
+                return s.blocksCoasted == this.blocksCoasted;
+            }
+            return super.equals(obj);
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(blocksCoasted);
+        }
+    }
+
     /**
      * Default speed, in meters per tick. A tick is 0.05 seconds, thus 0.4 * 1/0.05 = 8 m/s
      */
     private static final double DEFAULT_SPEED_METERS_PER_TICK = 0.4d;
-    private final Set<Integer> minecartBoosted = new HashSet<>();
+    private final Map<Integer, MinecartState> boostedMinecarts = new HashMap<>();
     private final Material boostBlock;
     private final Material hardBrakeBlock;
     private final boolean isCheatMode;
@@ -35,28 +54,46 @@ public MinecartListener(Material boostBlock, Material hardBrakeBlock, boolean is
 
     @EventHandler(priority = EventPriority.NORMAL)
     public void onVehicleMove(VehicleMoveEvent event) {
-
         if (event.getVehicle() instanceof Minecart) {
             Minecart cart = (Minecart) event.getVehicle();
-            Location cartLocation = cart.getLocation();
-            World cartsWorld = cart.getWorld();
+            final boolean isEnteredNewBlock = !event.getTo().getBlock().equals(event.getFrom().getBlock());
+            if (!HsRails.debuggers.isEmpty() && isEnteredNewBlock) {
+                Vector v = cart.getVelocity();
+                log(true, "velocity: [%f %f] |%f|", v.getX(), v.getZ(), v.length());
+            }
+
+            final Integer entityId = event.getVehicle().getEntityId();
+            final Location cartLocation = cart.getLocation();
+            final World cartsWorld = cart.getWorld();
 
-            Block rail = cartsWorld.getBlockAt(cartLocation);
+            final Block rail = cartsWorld.getBlockAt(cartLocation);
+            final double speedMultiplier = HsRails.getConfiguration().getSpeedMultiplier();
+            final double boostedMaxSpeed = DEFAULT_SPEED_METERS_PER_TICK * speedMultiplier;
 
             if (rail.getType() == Material.POWERED_RAIL) {
                 Block blockBelow = cartsWorld.getBlockAt(cartLocation.add(0, -1, 0));
 
                 if (isCheatMode || blockBelow.getType() == boostBlock) {
-                    if (!minecartBoosted.contains(event.getVehicle().getEntityId())) {
-                        minecartBoosted.add(event.getVehicle().getEntityId());
-                        cart.setMaxSpeed(DEFAULT_SPEED_METERS_PER_TICK * HsRails.getConfiguration().getSpeedMultiplier());
+                    if (!boostedMinecarts.containsKey(entityId)) { // if cart is not in high speed state then make it high speed
+                        boostedMinecarts.put(entityId, new MinecartState());
+                        cart.setMaxSpeed(boostedMaxSpeed);
+                        log(false, "minecart [%d] added", entityId);
+                    } else { // the cart is already in high speed state; refresh the values since we are on a boost block.
+                        boostedMinecarts.get(entityId).blocksCoasted = 0;
+                        if (cart.getMaxSpeed() != boostedMaxSpeed) {
+                            cart.setMaxSpeed(boostedMaxSpeed);
+                            log(false, "minecart [%d] max speed refreshed", entityId);
+                        }
                     }
                 } else {
+                    // carts should NOT be in high speed state when passing over regular power rails; clear it.
                     if (cart.getMaxSpeed() != DEFAULT_SPEED_METERS_PER_TICK) {
-                        minecartBoosted.remove(event.getVehicle().getEntityId());
+                        boostedMinecarts.remove(entityId);
                         cart.setMaxSpeed(DEFAULT_SPEED_METERS_PER_TICK);
+                        log(false, "minecart [%d] evicted", entityId);
                     }
                 }
+
                 RedstoneRail railBlockData = (RedstoneRail) rail.getBlockData();
                 if (!railBlockData.isPowered()
                         && blockBelow.getType() == hardBrakeBlock) {
@@ -65,6 +102,54 @@ public void onVehicleMove(VehicleMoveEvent event) {
                     cart.setVelocity(cartVelocity);
                 }
             }
+            // This handles the infinite momentum bug as reported by GitHub issue #6.
+            else if (isEnteredNewBlock) {
+                MinecartState state = boostedMinecarts.get(entityId);
+                switch (rail.getType()) {
+                    case RAIL:
+                    case ACTIVATOR_RAIL:
+                    case DETECTOR_RAIL:
+                        if (state != null) { // state != null means the cart is in the high speed state.
+                            if (cart.getVelocity().length() < DEFAULT_SPEED_METERS_PER_TICK) {
+                                cart.setMaxSpeed(DEFAULT_SPEED_METERS_PER_TICK);
+                                boostedMinecarts.remove(entityId);
+                                log(false, "momentum: too slow, clearing boost state");
+                                break;
+                            }
+                            state.blocksCoasted++;
+                            if (state.blocksCoasted > HsRails.coastFactor) {
+                                double factor = Math.max(1d, speedMultiplier - ((state.blocksCoasted - HsRails.coastFactor) / HsRails.coastFactor));
+                                cart.setMaxSpeed(DEFAULT_SPEED_METERS_PER_TICK * factor);
+                                if (factor == 1) {
+                                    boostedMinecarts.remove(entityId);
+                                    log(false, "momentum: factor reached 1, clearing boost state");
+                                    break;
+                                }
+                                log(false, "momentum: adjusting speed factor: %f", factor);
+                            }
+                        }
+                        break;
+                }
+            }
+        }
+    }
+
+    @EventHandler(priority = EventPriority.NORMAL)
+    public void onVehicleDestroyed(VehicleDestroyEvent event) {
+        Integer vehicleId = event.getVehicle().getEntityId();
+        boolean wasPresent = boostedMinecarts.remove(vehicleId) != null;
+        if (wasPresent) {
+            log(false, "minecart [%d] evicted", vehicleId);
+        } else {
+            log(false, "minecart [%d] was already cleared", vehicleId);
+        }
+    }
+
+    private void log(boolean verbose, String template, Object... args) {
+        for (DebugSubscription subscriber : HsRails.debuggers.values()) {
+            if (!verbose || subscriber.getAcceptsVerbose()) {
+                subscriber.getPlayer().sendMessage(String.format(template, args));
+            }
         }
     }
 }

src/main/java/no/netb/mc/hsrails/MinecartListener.java

@@ -0,0 +1,25 @@
+package no.netb.mc.hsrails;
+
+import org.bukkit.event.EventHandler;
+import org.bukkit.event.EventPriority;
+import org.bukkit.event.Listener;
+import org.bukkit.event.player.PlayerQuitEvent;
+
+import java.util.logging.Logger;
+
+public class PlayerDisconnectListener implements Listener {
+
+    private final Logger logger;
+
+    public PlayerDisconnectListener(Logger logger) {
+        this.logger = logger;
+    }
+
+    @EventHandler(priority = EventPriority.NORMAL)
+    public void onPlayerDisconnect(PlayerQuitEvent event) {
+        boolean cleared = HsRails.debuggers.remove(event.getPlayer()) != null;
+        if (cleared) {
+            logger.info(String.format("removed %s from debuggers list", event.getPlayer().getDisplayName()));
+        }
+    }
+}

src/main/java/no/netb/mc/hsrails/PlayerDisconnectListener.java

@@ -1,4 +1,4 @@
 speedMultiplier: 4.0
 boostBlock: "minecraft:redstone_block"
 hardBrakeMultiplier: 8.0
-hardBrakeBlock: "minecraft:obsidian"
+hardBrakeBlock: "minecraft:soul_sand"