Dynamic loading of OpenXR Loader on Android

This change implements dynamic loading of the OpenXR Loader library
on Android. If an OpenXR Loader library is not found,
Godot will still function with OpenXR disabled.

Also, on every platform, the OpenXR symbols are resolved at runtime
using xrGetInstanceProcAddr.

On Windows and Linux the OpenXR loader is included in the main
engine binary.

On Android, the OpenXR Loader is not built with the engine. Separately
distributed Android plugins will be provided with the correct loader
library for each device.

Co-authored-by: Gábor Pál Korom <gabor.p.korom@migeran.com>
Co-authored-by: Gábor Koncz <gabor.koncz@migeran.com>

1 files changed, 11 insertions, 9 deletions

diff --git a/modules/openxr/extensions/openxr_android_extension.cpp b/modules/openxr/extensions/openxr_android_extension.cpp
index 3bd4db169c..8f6d5c28db 100644
--- a/modules/openxr/extensions/openxr_android_extension.cpp
+++ b/modules/openxr/extensions/openxr_android_extension.cpp
@@ -29,7 +29,12 @@
 /*************************************************************************/
 
 #include "openxr_android_extension.h"
+#include "java_godot_wrapper.h"
+#include "os_android.h"
+#include "thread_jandroid.h"
 
+#include <jni.h>
+#include <modules/openxr/openxr_api.h>
 #include <openxr/openxr.h>
 #include <openxr/openxr_platform.h>
 
@@ -42,19 +47,16 @@ OpenXRAndroidExtension *OpenXRAndroidExtension::get_singleton() {
 OpenXRAndroidExtension::OpenXRAndroidExtension(OpenXRAPI *p_openxr_api) :
 		OpenXRExtensionWrapper(p_openxr_api) {
 	singleton = this;
-
 	request_extensions[XR_KHR_ANDROID_THREAD_SETTINGS_EXTENSION_NAME] = nullptr; // must be available
+}
 
-	// Initialize the loader
-	PFN_xrInitializeLoaderKHR xrInitializeLoaderKHR;
-	result = xrGetInstanceProcAddr(XR_NULL_HANDLE, "xrInitializeLoaderKHR", (PFN_xrVoidFunction *)(&xrInitializeLoaderKHR));
-	ERR_FAIL_COND_MSG(XR_FAILED(result), "Failed to retrieve pointer to xrInitializeLoaderKHR");
+void OpenXRAndroidExtension::on_before_instance_created() {
+	EXT_INIT_XR_FUNC(xrInitializeLoaderKHR);
 
-	// TODO fix this code, this is still code from GDNative!
-	JNIEnv *env = android_api->godot_android_get_env();
+	JNIEnv *env = get_jni_env();
 	JavaVM *vm;
 	env->GetJavaVM(&vm);
-	jobject activity_object = env->NewGlobalRef(android_api->godot_android_get_activity());
+	jobject activity_object = env->NewGlobalRef(static_cast<OS_Android *>(OS::get_singleton())->get_godot_java()->get_activity());
 
 	XrLoaderInitInfoAndroidKHR loader_init_info_android = {
 		.type = XR_TYPE_LOADER_INIT_INFO_ANDROID_KHR,
@@ -62,7 +64,7 @@ OpenXRAndroidExtension::OpenXRAndroidExtension(OpenXRAPI *p_openxr_api) :
 		.applicationVM = vm,
 		.applicationContext = activity_object
 	};
-	xrInitializeLoaderKHR((const XrLoaderInitInfoBaseHeaderKHR *)&loader_init_info_android);
+	XrResult result = xrInitializeLoaderKHR((const XrLoaderInitInfoBaseHeaderKHR *)&loader_init_info_android);
 	ERR_FAIL_COND_MSG(XR_FAILED(result), "Failed to call xrInitializeLoaderKHR");
 }