Feature/fmod plugins (#343)

* feat: Add plugin support for all platforms

Author: piiertho

SConstruct

@@ -39,7 +39,8 @@ sources = [
     Glob('src/helpers/*.cpp'),
     Glob('src/nodes/*.cpp'),
     Glob('src/resources/*.cpp'),
-    Glob('src/studio/*.cpp')
+    Glob('src/studio/*.cpp'),
+    Glob('src/plugins/*.cpp')
     ]
 
 lfix = ""

demo/.gitignore

@@ -20,4 +20,4 @@ mono_crash.*.json
 logs/
 **/*.aar
 android/build
-android/.build_version
+android/

demo/android/.build_version

@@ -1 +1 @@
-4.1.2.stable
+4.4.1.stable

demo/android/plugins/library-debug.aar

@@ -0,0 +1,55 @@
+# Plugins
+
+!!! warning
+    This feature is experimental. Please report any bug you find.
+
+This addon supports FMOD plugins.  
+First you'll need to add plugins libraries (`.dll`, `.dylib`, `.so`, `.a`) in a project's folder.  
+In this documentation we will use `assets/plugins` as an example.  
+In this directory you have to create one directory per os, like:  
+```
+assets
+└───── plugins
+       ├────── windows
+       │       └────── .dll for windows goes here
+       ├────── linux
+       │       └────── .so for linux goes here
+       ├────── macos
+       │       └────── .dylib for macos goes here
+       ├────── android
+       │       ├────── x86_64
+       │       │       └────── .so for android x86 goes here
+       │       └────── arm64
+       │               └────── .so for android arm64 goes here
+       └────── ios
+               └────── .a for ios goes here
+```  
+If there are some dependent libraries needed for a plugin, just place it next to plugin's library, all libraries in 
+those folders are exported.  
+
+In order to add plugins you first need to create an `FmodPluginsSettings` resource in your project:  
+![plugins-create-settings-resource]  
+First you need to configure the directory containing the plugins libraries. In this example `res://assets/plugins/`
+Then you have to configure the plugin lists.  
+There is two lists to configure:  
+- `Dynamic Plugin List` is used for all platforms except `iOS`
+- `Static Plugins Methods` is used for `iOS` only
+
+For dynamic plugins you have to enter the name of the library for the plugin (without the lib prefix). As an example for 
+steam plugin it will be `phonon_fmod`.  
+In static plugins methods you have to place the methods from the documentation of your plugin. As and example for steam 
+plugin it will be:  
+- `FMOD_SteamAudio_Spatialize_GetDSPDescription`, with DSP type
+- `FMOD_SteamAudio_MixerReturn_GetDSPDescription`, with DSP type
+- `FMOD_SteamAudio_Reverb_GetDSPDescription`, with DSP type
+
+Here is what the configuration looks like for this example:  
+![fmod-plugins-settings-resource]
+
+Then you have to set the path of this resource in project's settings, in the `Fmod/Plugins` section:  
+![plugins-project-settings]
+
+
+[plugins-create-settings-resource]: ./assets/plugins-create-settings-resource.png
+[fmod-plugins-settings-resource]: ./assets/fmod-plugins-settings-resource.png
+[plugins-project-settings]: ./assets/plugins-project-settings.png

demo/android/plugins/library-release.aar

@@ -2,15 +2,18 @@
 #include "fmod_cache.h"
 
 #include "helpers/common.h"
+#include "classes/project_settings.hpp"
 
 using namespace godot;
 
-FmodCache::FmodCache(FMOD::Studio::System* p_system) {
-    system = p_system;
+FmodCache::FmodCache(FMOD::Studio::System* p_system, FMOD::System* p_core_system) :
+    system(p_system), core_system(p_core_system) {
+
 }
 
 FmodCache::~FmodCache() {
     system = nullptr;
+    core_system = nullptr;
 }
 
 void FmodCache::update_pending() {
@@ -72,6 +75,43 @@ Ref<FmodBank> FmodCache::get_bank(const String& bankPath) {
     return banks.get(bankPath);
 }
 
+#ifndef IOS_ENABLED
+
+uint32_t FmodCache::add_plugin(const String& p_plugin_path, uint32_t p_priority) {
+    uint32_t handle;
+#if defined(ANDROID_ENABLED) && !defined(TOOLS_ENABLED)
+    const char* plugin_path = p_plugin_path.utf8().get_data();
+#else
+    const char* plugin_path = ProjectSettings::get_singleton()->globalize_path(p_plugin_path).utf8().get_data();
+#endif
+    ERROR_CHECK(core_system->loadPlugin(plugin_path, &handle, p_priority));
+    plugin_handles.append(handle);
+    return handle;
+}
+
+#else
+
+void FmodCache::add_plugin(uint32_t p_plugin_handle) {
+    plugin_handles.append(p_plugin_handle);
+}
+
+#endif
+
+bool FmodCache::has_plugin(uint32_t p_plugin_handle) const {
+    return plugin_handles.has(p_plugin_handle);
+}
+
+void FmodCache::remove_plugin(uint32_t p_plugin_handle) {
+    if (!has_plugin(p_plugin_handle)) {
+        GODOT_LOG_ERROR(vformat("Cannot unload plugin with handle %s, not in cache.", p_plugin_handle));
+        return;
+    }
+
+    ERROR_CHECK(core_system->unloadPlugin(p_plugin_handle));
+    plugin_handles.erase(p_plugin_handle);
+}
+
+
 Ref<FmodFile> FmodCache::add_file(const String& file_path, unsigned int flag) {
     FMOD::System* core = nullptr;
     ERROR_CHECK(system->getCoreSystem(&core));