Changes for better script online compatibility

docs/src/includes/_enums.md

@@ -922,6 +922,7 @@ Name | Data | Description
 [BLOCKED_UPDATE](https://github.com/spelunky-fyi/overlunky/search?l=Lua&q=ON.BLOCKED_UPDATE) | ON::BLOCKED_UPDATE | Runs instead of POST_UPDATE when anything blocks a PRE_UPDATE. Even runs in Playlunky when [Overlunky](#Overlunky) blocks a PRE_UPDATE.<br/>
 [BLOCKED_GAME_LOOP](https://github.com/spelunky-fyi/overlunky/search?l=Lua&q=ON.BLOCKED_GAME_LOOP) | ON::BLOCKED_GAME_LOOP | Runs instead of POST_GAME_LOOP when anything blocks a PRE_GAME_LOOP. Even runs in Playlunky when [Overlunky](#Overlunky) blocks a PRE_GAME_LOOP.<br/>
 [BLOCKED_PROCESS_INPUT](https://github.com/spelunky-fyi/overlunky/search?l=Lua&q=ON.BLOCKED_PROCESS_INPUT) | ON::BLOCKED_PROCESS_INPUT | Runs instead of POST_PROCESS_INPUT when anything blocks a PRE_PROCESS_INPUT. Even runs in Playlunky when [Overlunky](#Overlunky) blocks a PRE_PROCESS_INPUT.<br/>
+[PRE_COPY_STATE](https://github.com/spelunky-fyi/overlunky/search?l=Lua&q=ON.PRE_COPY_STATE) | ON::PRE_COPY_STATE | Runs before the game copies a state to another in an online multiplayer game.<br/>Params: [StateMemory](#StateMemory) from, [StateMemory](#StateMemory) to<br/>
 
 ## PARTICLEEMITTER
 

docs/src/includes/_events.md

@@ -682,3 +682,10 @@ Runs instead of POST_GAME_LOOP when anything blocks a PRE_GAME_LOOP. Even runs i
 > Search script examples for [ON.BLOCKED_PROCESS_INPUT](https://github.com/spelunky-fyi/overlunky/search?l=Lua&q=ON.BLOCKED_PROCESS_INPUT)
 
 Runs instead of POST_PROCESS_INPUT when anything blocks a PRE_PROCESS_INPUT. Even runs in Playlunky when [Overlunky](#Overlunky) blocks a PRE_PROCESS_INPUT.<br/>
+
+## ON.PRE_COPY_STATE
+
+
+> Search script examples for [ON.PRE_COPY_STATE](https://github.com/spelunky-fyi/overlunky/search?l=Lua&q=ON.PRE_COPY_STATE)
+
+Runs before the game copies a state to another in an online multiplayer game.<br/>Params: [StateMemory](#StateMemory) from, [StateMemory](#StateMemory) to<br/>

docs/src/includes/_types.md

@@ -3084,6 +3084,7 @@ array<[THEME](#THEME), 9> | [journal_progress_theme_slots](https://github.
 [LiquidPhysics](#LiquidPhysics) | [liquid](https://github.com/spelunky-fyi/overlunky/search?l=Lua&q=liquid) | 
 int | [next_entity_uid](https://github.com/spelunky-fyi/overlunky/search?l=Lua&q=next_entity_uid) | Next entity spawned will have this uid
 [RoomOwnersInfo](#RoomOwnersInfo) | [room_owners](https://github.com/spelunky-fyi/overlunky/search?l=Lua&q=room_owners) | Holds info about owned rooms and items (shops, challenge rooms, vault etc.)
+ | [user_data](https://github.com/spelunky-fyi/overlunky/search?l=Lua&q=user_data) | You can put any arbitrary lua object here and it will work correctly in online multiplayer, by having a copy on each state and being copied when the game does.<br/> 
 
 ## Texture types
 

src/game_api/memory.cpp

@@ -192,10 +192,10 @@ size_t patch_and_redirect(size_t addr, size_t replace_size, const std::string_vi
     }
     else
     {
-        std::memcpy(new_code + data_size_to_move, payload.data(), payload.size());
+        std::memcpy(new_code, payload.data(), payload.size());
 
         if (!just_nop)
-            std::memcpy(new_code, (void*)addr, data_size_to_move);
+            std::memcpy(new_code + payload.size(), (void*)addr, data_size_to_move);
     }
 
     size_t return_addr = addr + replace_size;

src/game_api/savestate.cpp

@@ -13,11 +13,20 @@ size_t get_state_offset()
     return 0x4a0;
 }
 
+StateMemory* get_save_state_raw(int slot)
+{
+    size_t arr = get_address("save_states");
+    size_t base = memory_read<size_t>(arr + (slot - 1) * 8);
+    auto state = reinterpret_cast<StateMemory*>(base + get_state_offset());
+    return state;
+}
+
 void copy_save_slot(int from, int to)
 {
     if ((from == 5 && pre_save_state(to, get_save_state(to))) ||
         (to == 5 && pre_load_state(from, get_save_state(from))))
         return;
+    pre_copy_state_event(get_save_state_raw(from), get_save_state_raw(to));
     size_t arr = get_address("save_states");
     size_t fromBaseState = memory_read<size_t>(arr + (from - 1) * 8);
     size_t toBaseState = memory_read<size_t>(arr + (to - 1) * 8);
@@ -57,9 +66,7 @@ void copy_state(size_t fromBaseState, size_t toBaseState)
 
 StateMemory* get_save_state(int slot)
 {
-    size_t arr = get_address("save_states");
-    size_t base = memory_read<size_t>(arr + (slot - 1) * 8);
-    auto state = reinterpret_cast<StateMemory*>(base + get_state_offset());
+    auto state = get_save_state_raw(slot);
     if (state->screen)
         return state;
     return nullptr;

src/game_api/script/events.cpp

@@ -517,3 +517,13 @@ void post_event(ON event)
             return true;
         });
 }
+
+void pre_copy_state_event(StateMemory* from, StateMemory* to)
+{
+    LuaBackend::for_each_backend(
+        [&](LuaBackend::LockedBackend backend)
+        {
+            backend->pre_copy_state(from, to);
+            return true;
+        });
+}

src/game_api/script/events.hpp

@@ -26,6 +26,7 @@ bool pre_unload_level();
 bool pre_unload_layer(LAYER layer);
 bool pre_save_state(int slot, StateMemory* saved);
 bool pre_load_state(int slot, StateMemory* loaded);
+void pre_copy_state_event(StateMemory* from, StateMemory* to);
 
 void post_load_screen();
 void post_init_layer(LAYER layer);