Add random level rotation option for dedicated servers (#330)

* Add "vote rand" for random nextmap vote, and add "map_rand" to server command list

* update changelog, add new command to readme, add new command to rcon whitelist

* Added $DF Randomize Rotation to dedicated server config, fixed logic error with map_rand command, updated readme, updated changelog

* fix typo in readme

* Adjusted option name, optimized and consolidated code, swapped srand for rand

* Add alias vote random, fix changelog typo

* add "shuffle_maps" command to shuffle maplist, make readme more clear, update changelog

* better formatting for shuffle_level_array function

* avoid stomping current level index

* optimize random selection logic and properly handle case of just 1 map in the rotation

* Add DF Dynamic Rotation dedicated server config option, minor formatting improvement

* removed "shuffle_maps" command (unnecessary)

* Fix ordering of $DF options in readme, and made order of options in dedicated server config file make more sense

* shuffle rotation on server start, deleted Random Level Order option, introduced vastly improved RNG method (initialized in main.cpp so can be used elsewhere)

* utilize std::shuffle for shuffle_level_array

* adjusted random methods to consolidate, optimize, and improve type conversion safety

* improve get_rand_level_filename logic, clean up code

* fix type conversion regression, remove debug logging and unneeded var

* fix infinite loop

* Update game_patch/multi/server.cpp

Co-authored-by: is-this-c <87069698+is-this-c@users.noreply.github.com>

* reverting change causing error

* resolve pointer issue

* remove unneeded variable

* use g_ naming convention for rng

* Fix code structure

* Rename dynamic rotation to random rotation

Also reduce log level

* Fix changelog entries for random rotation being in wrong section

---------

Co-authored-by: Goober <gooberCP@gmail.com>
Co-authored-by: is-this-c <87069698+is-this-c@users.noreply.github.com>

README.md

@@ -73,6 +73,7 @@ Name                     | Description
 `map_ext`                | extend round
 `map_rest`               | restart current level
 `map_next`               | load next level
+`map_rand`               | load random level from rotation
 `map_prev`               | load previous level
 `kill_limit value`       | set kill limit
 `time_limit value`       | set time limit
@@ -152,6 +153,8 @@ Configuration example:
     $DF Vote Restart: true
     // Enable vote next
     $DF Vote Next: true
+    // Enable vote random
+    $DF Vote Random: true
     // Enable vote previous
     $DF Vote Previous: true
     // Duration of player invulnerability after respawn in ms (default is the same as in stock RF - 1500)
@@ -196,6 +199,8 @@ Configuration example:
     $DF Force Player Character: "enviro_parker"
     // Maximal horizontal FOV that clients can use for level rendering (unlimited by default)
     //$DF Max FOV: 125
+    // Shuffle the list of levels when the server starts and at the end of each full rotation
+    $DF Random Rotation: false
     // If enabled a private message with player statistics is sent after each round.
     //$DF Send Player Stats Message: true
     // Send a chat message to players when they join the server ($PLAYER is replaced by player name)

docs/CHANGELOG.md

@@ -68,6 +68,9 @@ Version 1.9.0 (not released yet)
 - Add `spectate_mode_follow_killer` command (when player you are spectating dies, spectate their killer)
 - Remove level editor popups that stop user from navigating between modes until rebuilding
 - Add `muzzle_flash` command
+- Add `map_rand` command to change to a random level on the rotation
+- Add `vote rand` vote type to initiate a level change to a random level on the rotation
+- Add `$DF Random Rotation` option in dedicated server config
 
 [@is-this-c](https://github.com/is-this-c)
 - Support `©` and `•` in TrueType fonts

game_patch/main/main.cpp

@@ -43,6 +43,7 @@
 
 GameConfig g_game_config;
 HMODULE g_hmodule;
+std::mt19937 g_rng;
 
 CallHook<void()> rf_init_hook{
     0x004B27CD,
@@ -269,6 +270,13 @@ void init_logging()
     xlog::info("Command line: {}", GetCommandLineA());
 }
 
+void initialize_random_generator()
+{
+    // seed rng with the current time
+    auto seed = std::chrono::steady_clock::now().time_since_epoch().count();
+    g_rng.seed(static_cast<unsigned long>(seed));
+}
+
 void log_system_info()
 {
     try {
@@ -338,6 +346,9 @@ extern "C" DWORD __declspec(dllexport) Init([[maybe_unused]] void* unused)
     init_logging();
     init_crash_handler();
 
+    // Init random number generator
+    initialize_random_generator();
+
     // Enable Data Execution Prevention
     if (!SetProcessDEPPolicy(PROCESS_DEP_ENABLE))
         xlog::warn("SetProcessDEPPolicy failed (error {})", GetLastError());

game_patch/main/main.h

@@ -1,8 +1,13 @@
 #pragma once
 
+#include <random>
 #include <common/config/GameConfig.h>
 
 extern GameConfig g_game_config;
+
+// random number generator
+extern std::mt19937 g_rng;
+
 #ifdef _WINDOWS_
 extern HMODULE g_hmodule;
 #endif

game_patch/multi/commands.cpp

@@ -5,6 +5,7 @@
 #include "../rf/level.h"
 #include "../rf/player/player.h"
 #include "../rf/crt.h"
+#include "server.h"
 #include "multi.h"
 #include <patch_common/AsmWriter.h>
 #include <patch_common/CallHook.h>
@@ -43,6 +44,11 @@ void load_prev_level()
     }
 }
 
+void load_rand_level()
+{
+    rf::multi_change_level(get_rand_level_filename());
+}
+
 bool validate_is_server()
 {
     if (!rf::is_server) {
@@ -97,6 +103,17 @@ ConsoleCommand2 map_next_cmd{
     "Load next level",
 };
 
+ConsoleCommand2 map_rand_cmd{
+    "map_rand",
+    []() {
+        if (validate_is_server() && validate_not_limbo()) {
+            rf::multi_chat_say("\xA6 Loading random level from rotation", false);
+            load_rand_level();
+        }
+    },
+    "Load random level from rotation",
+};
+
 ConsoleCommand2 map_prev_cmd{
     "map_prev",
     []() {
@@ -194,6 +211,7 @@ void init_server_commands()
     map_ext_cmd.register_cmd();
     map_rest_cmd.register_cmd();
     map_next_cmd.register_cmd();
+    map_rand_cmd.register_cmd();
     map_prev_cmd.register_cmd();
 
     AsmWriter(0x0047B6F0).jmp(ban_cmd_handler_hook);

game_patch/multi/server.cpp

@@ -40,6 +40,7 @@ const char* g_rcon_cmd_whitelist[] = {
     "map_ext",
     "map_rest",
     "map_next",
+    "map_rand",
     "map_prev",
 };
 
@@ -74,6 +75,7 @@ void load_additional_server_config(rf::Parser& parser)
     parse_vote_config("Vote Extend", g_additional_server_config.vote_extend, parser);
     parse_vote_config("Vote Restart", g_additional_server_config.vote_restart, parser);
     parse_vote_config("Vote Next", g_additional_server_config.vote_next, parser);
+    parse_vote_config("Vote Random", g_additional_server_config.vote_rand, parser);
     parse_vote_config("Vote Previous", g_additional_server_config.vote_previous, parser);
     if (parser.parse_optional("$DF Spawn Protection Duration:")) {
         g_additional_server_config.spawn_protection_duration_ms = parser.parse_uint();
@@ -169,6 +171,10 @@ void load_additional_server_config(rf::Parser& parser)
         }
     }
 
+    if (parser.parse_optional("$DF Random Rotation:")) {
+        g_additional_server_config.random_rotation = parser.parse_bool();
+    }
+
     if (parser.parse_optional("$DF Send Player Stats Message:")) {
         g_additional_server_config.stats_message_enabled = parser.parse_bool();
     }
@@ -208,6 +214,11 @@ CodeInjection dedicated_server_load_config_patch{
         auto& parser = *reinterpret_cast<rf::Parser*>(regs.esp - 4 + 0x4C0 - 0x470);
         load_additional_server_config(parser);
 
+        // if random rotation is on, shuffle rotation on server launch
+        if (g_additional_server_config.random_rotation) {
+            shuffle_level_array();
+        }
+
         // Insert server name in window title when hosting dedicated server
         std::string wnd_name;
         wnd_name.append(rf::netgame.name.c_str());
@@ -310,6 +321,32 @@ static void send_private_message_with_stats(rf::Player* player)
     send_chat_line_packet(str.c_str(), player);
 }
 
+void shuffle_level_array()
+{
+    std::ranges::shuffle(rf::netgame.levels, g_rng);
+    xlog::info("Shuffled level rotation");
+}
+
+const char* get_rand_level_filename()
+{
+    const std::size_t num_levels = rf::netgame.levels.size();
+
+    if (num_levels <= 1) {
+        // nowhere else to go, we're staying here!
+        return rf::level_filename_to_load.c_str();
+    }
+
+    std::uniform_int_distribution<std::size_t> dist_levels(0, num_levels - 1);
+    std::size_t rand_level_index = dist_levels(g_rng);
+
+    // avoid selecting current level filename (unless it appears more than once on map list)
+    if (rf::netgame.levels[rand_level_index] == rf::level_filename_to_load) {
+        rand_level_index = (rand_level_index + 1) % num_levels;
+    }
+
+    return rf::netgame.levels[rand_level_index].c_str();
+}
+
 bool handle_server_chat_command(std::string_view server_command, rf::Player* sender)
 {
     auto [cmd_name, cmd_arg] = strip_by_space(server_command);
@@ -664,6 +701,18 @@ CodeInjection multi_limbo_init_injection{
     },
 };
 
+CodeInjection multi_level_init_injection{
+    0x0046E450,
+    []() {
+        if (g_additional_server_config.random_rotation && rf::netgame.current_level_index ==
+                    rf::netgame.levels.size() - 1 && rf::netgame.levels.size() > 1) {
+                // if this is the last level in the list and dynamic rotation is on, shuffle
+                xlog::info("Reached end of level rotation, shuffling");
+                shuffle_level_array();
+            }
+    },
+};
+
 void server_init()
 {
     // Override rcon command whitelist
@@ -729,6 +778,9 @@ void server_init()
 
     // Reduce limbo duration if server is empty
     multi_limbo_init_injection.install();
+
+    // Shuffle rotation when the last map in the list is loaded
+    multi_level_init_injection.install();
 }
 
 void server_do_frame()

game_patch/multi/server.h

@@ -12,3 +12,5 @@ bool check_server_chat_command(const char* msg, rf::Player* sender);
 bool server_is_saving_enabled();
 void server_reliable_socket_ready(rf::Player* player);
 bool server_weapon_items_give_full_ammo();
+const char* get_rand_level_filename();
+void shuffle_level_array();

game_patch/multi/server_internal.h

@@ -33,6 +33,7 @@ struct ServerAdditionalConfig
     VoteConfig vote_extend;
     VoteConfig vote_restart;
     VoteConfig vote_next;
+    VoteConfig vote_rand;
     VoteConfig vote_previous;
     int spawn_protection_duration_ms = 1500;
     std::optional<float> spawn_life;
@@ -50,6 +51,7 @@ struct ServerAdditionalConfig
     std::optional<float> max_fov;
     int anticheat_level = 0;
     bool stats_message_enabled = true;
+    bool random_rotation = false;
     std::string welcome_message;
     bool weapon_items_give_full_ammo = false;
     float kill_reward_health = 0.0f;
@@ -69,6 +71,7 @@ void init_server_commands();
 void extend_round_time(int minutes);
 void restart_current_level();
 void load_next_level();
+void load_rand_level();
 void load_prev_level();
 void server_vote_on_limbo_state_enter();
 void process_delayed_kicks();

game_patch/multi/votes.cpp

@@ -323,6 +323,30 @@ struct VoteNext : public Vote
     }
 };
 
+struct VoteRandom : public Vote
+{
+    [[nodiscard]] std::string get_title() const override
+    {
+        return "LOAD RANDOM LEVEL";
+    }
+
+    void on_accepted() override
+    {
+        send_chat_line_packet("\xA6 Vote passed: loading random level from rotation", nullptr);
+        load_rand_level();
+    }
+
+    [[nodiscard]] bool is_allowed_in_limbo_state() const override
+    {
+        return false;
+    }
+
+    [[nodiscard]] const VoteConfig& get_config() const override
+    {
+        return g_additional_server_config.vote_rand;
+    }
+};
+
 struct VotePrevious : public Vote
 {
     [[nodiscard]] std::string get_title() const override
@@ -449,6 +473,8 @@ void handle_vote_command(std::string_view vote_name, std::string_view vote_arg,
         g_vote_mgr.StartVote<VoteRestart>(vote_arg, sender);
     else if (vote_name == "next")
         g_vote_mgr.StartVote<VoteNext>(vote_arg, sender);
+    else if (vote_name == "random" || vote_name == "rand")
+        g_vote_mgr.StartVote<VoteRandom>(vote_arg, sender);
     else if (vote_name == "previous" || vote_name == "prev")
         g_vote_mgr.StartVote<VotePrevious>(vote_arg, sender);
     else if (vote_name == "yes" || vote_name == "y")