inter mod communication

docs/modding.md

@@ -16,7 +16,8 @@ Mods are shared libraries packaged into a `.dusk` zip archive. The loader scans
    - [Post-hooks](#post-hooks)
    - [Replace hooks](#replace-hooks)
    - [Reading and writing arguments](#reading-and-writing-arguments)
-9. [Full Example](#full-example)
+9. [Inter-Mod Communication](#inter-mod-communication)
+10. [Full Example](#full-example)
 
 ---
 
@@ -98,6 +99,8 @@ The `api` pointer is valid for the lifetime of the mod. When using `hook.hpp`, c
 | `register_tab_content` | Add a panel to the mod manager's per-mod tab |
 | `register_menu_item` | Add an item to the quick-access menu |
 | `hook_dispatch_pre` / `hook_dispatch_post` | Called by the trampoline, do not call directly |
+| `service_publish` | Register a named pointer in the global service registry |
+| `service_get` | Look up a named pointer registered by another mod |
 
 ---
 
@@ -248,6 +251,39 @@ dusk::hookAddPre<&daEnemy_c::takeDamage>(on_takeDamage_pre);
 For reference parameters (e.g. `const cXyz& pos`), use `argRef<cXyz>` to get a direct reference.
 
 
+---
+
+## Inter-Mod Communication
+
+Mods can expose a public API to each other through a global service registry. The convention for names is `"mod_name/service_name"`.
+
+**Mod A — publishing:**
+
+```cpp
+struct MyModAPI {
+    void (*do_thing)(int value);
+};
+
+static void my_do_thing(int value) { ... }
+static MyModAPI g_api = { my_do_thing };
+
+extern "C" void mod_init(DuskModAPI* api) {
+    api->service_publish("my_mod/api", &g_api);
+}
+```
+
+**Mod B — consuming:**
+
+```cpp
+#include "my_mod_api.h"
+
+static MyModAPI* g_my_mod = nullptr;
+
+extern "C" void mod_init(DuskModAPI* api) {
+    g_my_mod = static_cast<MyModAPI*>(api->service_get("my_mod/api"));
+}
+```
+
 ---
 
 ## Full Example

include/dusk/mod_api.h

@@ -38,6 +38,9 @@ typedef struct DuskModAPI {
 
     bool (*hook_dispatch_pre) (void* fn_addr, void* args);
     void (*hook_dispatch_post)(void* fn_addr, void* args);
+
+    void  (*service_publish)(const char* name, void* ptr);
+    void* (*service_get)    (const char* name);
 } DuskModAPI;
 
 void mod_init(DuskModAPI* api);

src/dusk/mod_loader.cpp

@@ -6,6 +6,7 @@
 #include <cstdarg>
 #include <filesystem>
 #include <string>
+#include <unordered_map>
 
 #include "imgui.h"
 #include "miniz.h"
@@ -59,6 +60,7 @@ static constexpr const char* k_libExt = ".so";
 #endif
 
 static dusk::LoadedMod* g_currentMod = nullptr;
+static std::unordered_map<std::string, void*> g_services;
 
 namespace dusk {
 void* g_dusk_hook_current_mod = nullptr;
@@ -134,6 +136,20 @@ static void cb_register_tab_content(void (*draw_fn)(void*), void* userdata) {
         g_currentMod->tab_content.push_back({draw_fn, userdata});
 }
 
+static void cb_service_publish(const char* name, void* ptr) {
+    if (name) {
+        g_services[name] = ptr;
+    }
+}
+
+static void* cb_service_get(const char* name) {
+    if (!name) {
+        return nullptr;
+    }
+    auto it = g_services.find(name);
+    return it != g_services.end() ? it->second : nullptr;
+}
+
 static void cb_register_menu_item(void (*draw_fn)(void*), void* userdata) {
     if (g_currentMod && draw_fn)
         g_currentMod->menu_items.push_back({draw_fn, userdata});
@@ -174,6 +190,8 @@ void ModLoader::buildAPI(LoadedMod& mod) {
     mod.api.hook_replace = api_hook_replace;
     mod.api.hook_dispatch_pre = hookDispatchPre;
     mod.api.hook_dispatch_post = hookDispatchPost;
+    mod.api.service_publish = cb_service_publish;
+    mod.api.service_get     = cb_service_get;
 }
 
 void ModLoader::tryLoadDusk(const std::filesystem::path& modPath) {
@@ -365,6 +383,7 @@ void ModLoader::shutdown() {
         }
     }
     m_mods.clear();
+    g_services.clear();
     DuskLog.info("ModLoader: all mods unloaded");
 }