Merge pull request godotengine#115022 from BastiaanOlij/openxr_custom_version

OpenXR: Allow setting a specific version of OpenXR to initialize.

Author: akien-mga

doc/classes/ProjectSettings.xml

@@ -3610,6 +3610,9 @@
 		<member name="xr/openxr/submit_depth_buffer" type="bool" setter="" getter="" default="false">
 			If [code]true[/code], OpenXR will manage the depth buffer and use the depth buffer for advanced reprojection provided this is supported by the XR runtime. Note that some rendering features in Godot can't be used with this feature.
 		</member>
+		<member name="xr/openxr/target_api_version" type="String" setter="" getter="" default="&quot;&quot;">
+			Optionally sets a specific API version of OpenXR to initialize in [code]major.minor.patch[/code] notation. Some XR runtimes gate old behavior behind version checks. This is non-standard OpenXR behavior.
+		</member>
 		<member name="xr/openxr/view_configuration" type="int" setter="" getter="" default="&quot;1&quot;" keywords="mono, stereo">
 			Specify the view configuration with which to configure OpenXR setting up either Mono or Stereo rendering.
 		</member>

main/main.cpp

@@ -2788,6 +2788,7 @@ Error Main::setup(const char *execpath, int argc, char *argv[], bool p_second_ph
 #ifndef _3D_DISABLED
 	// XR project settings.
 	GLOBAL_DEF_RST_BASIC("xr/openxr/enabled", false);
+	GLOBAL_DEF(PropertyInfo(Variant::STRING, "xr/openxr/target_api_version"), "");
 	GLOBAL_DEF_BASIC(PropertyInfo(Variant::STRING, "xr/openxr/default_action_map", PROPERTY_HINT_FILE, "*.tres"), "res://openxr_action_map.tres");
 	GLOBAL_DEF_BASIC(PropertyInfo(Variant::INT, "xr/openxr/form_factor", PROPERTY_HINT_ENUM, "Head Mounted,Handheld"), "0");
 	GLOBAL_DEF_BASIC(PropertyInfo(Variant::INT, "xr/openxr/view_configuration", PROPERTY_HINT_ENUM, "Mono,Stereo"), "1"); // "Mono,Stereo,Quad,Observer"

modules/openxr/openxr_api.cpp

@@ -659,12 +659,21 @@ XrResult OpenXRAPI::attempt_create_instance(XrVersion p_version) {
 bool OpenXRAPI::create_instance() {
 	// Create our OpenXR instance, this will query any registered extension wrappers for extensions we need to enable.
 
-	XrResult result = attempt_create_instance(XR_API_VERSION_1_1);
-	if (result == XR_ERROR_API_VERSION_UNSUPPORTED) {
-		// Couldn't initialize OpenXR 1.1, try 1.0
+	XrVersion init_version = XR_API_VERSION_1_1;
+
+	String custom_version = GLOBAL_GET("xr/openxr/target_api_version");
+	if (!custom_version.is_empty()) {
+		Vector<int> ints = custom_version.split_ints(".", false);
+		ERR_FAIL_COND_V_MSG(ints.size() != 3, false, "OpenXR target API version must be major.minor.patch.");
+		init_version = XR_MAKE_VERSION(ints[0], ints[1], ints[2]);
+	}
+
+	XrResult result = attempt_create_instance(init_version);
+	if (result == XR_ERROR_API_VERSION_UNSUPPORTED && init_version == XR_API_VERSION_1_1) {
 		print_verbose("OpenXR: Falling back to OpenXR 1.0");
 
-		result = attempt_create_instance(XR_API_VERSION_1_0);
+		init_version = XR_API_VERSION_1_0;
+		result = attempt_create_instance(init_version);
 	}
 	ERR_FAIL_COND_V_MSG(XR_FAILED(result), false, "Failed to create XR instance [" + get_error_string(result) + "].");