Management and Lifecycle

This document outlines the management and lifecycle of plugins within the oglr game engine.

Plugin Loading

Plugins are loaded at runtime, using the oglr::plugin::PluginManager class.

Process:

1. The PluginManager searches for .dll files in a specified directory (plugins/ by default).
2. For each .dll file, the PluginManager attempts to load it using the LoadLibrary function.
3. If the library loads successfully, the PluginManager searches for a function named oglr_plugin_entry_point. This function should return a pointer to a Plugin object.
4. The PluginManager stores the loaded plugin’s entry point, along with other information.

Example:

// plugins/my_plugin.cpp
          #include "oglr/plugin/Plugin.h"
          
          class MyPlugin : public oglr::plugin::Plugin {
          public:
            MyPlugin() : Plugin("MyPlugin") {}
          };
          
          extern "C" OGLR_PLUGIN_EXPORT oglr::plugin::Plugin *oglr_plugin_entry_point() {
            return new MyPlugin();
          }
          

Source: oglr/plugin/PluginManager.cpp

Plugin Unloading

Plugins are unloaded when the game shuts down or when the PluginManager::unloadPlugin function is called.

Process:

1. The PluginManager calls the Plugin::onUnload function for each plugin.
2. The PluginManager calls the FreeLibrary function to unload the plugin’s library.

Source: oglr/plugin/PluginManager.cpp

Plugin Lifecycle

Plugins go through a series of states during their lifecycle.

States:

• Loading: The plugin is being loaded into memory.
• Ready: The plugin has been loaded and is ready to be used.
• Unloading: The plugin is being unloaded from memory.
• Unloaded: The plugin has been unloaded from memory.

Example:

// plugins/my_plugin.cpp
          #include "oglr/plugin/Plugin.h"
          
          class MyPlugin : public oglr::plugin::Plugin {
          public:
            MyPlugin() : Plugin("MyPlugin") {}
          
            void onReady() override {
              // Perform initialization tasks here
              std::cout << "MyPlugin is ready!" << std::endl;
            }
          
            void onUnload() override {
              // Perform cleanup tasks here
              std::cout << "MyPlugin is unloading!" << std::endl;
            }
          };
          

Source: oglr/plugin/Plugin.h

Plugin Configuration

Plugins can be configured using a PluginConfig object. This object is passed to the Plugin constructor.

Example:

// plugins/my_plugin.cpp
          #include "oglr/plugin/Plugin.h"
          
          class MyPlugin : public oglr::plugin::Plugin {
          public:
            MyPlugin(const PluginConfig& config) : Plugin("MyPlugin", config) {}
          
            void onReady() override {
              // Access configuration values here
              std::cout << "MyPlugin configuration: " << config.getString("my_config_value") << std::endl;
            }
          };
          
          extern "C" OGLR_PLUGIN_EXPORT oglr::plugin::Plugin *oglr_plugin_entry_point() {
            oglr::plugin::PluginConfig config;
            // Set configuration values here
            config.setString("my_config_value", "hello world");
            return new MyPlugin(config);
          }
          

Source: oglr/plugin/PluginConfig.h

Plugin Dependencies

Plugins can declare dependencies on other plugins. These dependencies are specified in the PluginConfig object.

Example:

// plugins/my_plugin.cpp
          #include "oglr/plugin/Plugin.h"
          
          class MyPlugin : public oglr::plugin::Plugin {
          public:
            MyPlugin(const PluginConfig& config) : Plugin("MyPlugin", config) {}
          
            void onReady() override {
              // Check if a dependency is available
              if (hasDependency("my_dependency")) {
                std::cout << "MyPlugin dependency is available!" << std::endl;
              } else {
                std::cout << "MyPlugin dependency is not available!" << std::endl;
              }
            }
          };
          
          extern "C" OGLR_PLUGIN_EXPORT oglr::plugin::Plugin *oglr_plugin_entry_point() {
            oglr::plugin::PluginConfig config;
            // Specify dependencies
            config.addDependency("my_dependency");
            return new MyPlugin(config);
          }
          

Source: oglr/plugin/Plugin.h, oglr/plugin/PluginConfig.h