OpenXR: Add support for retrieving play area

modules/openxr/openxr_api.cpp

@@ -87,7 +87,7 @@ String OpenXRAPI::get_default_action_map_resource_name() {
 	return name;
 }
 
-String OpenXRAPI::get_error_string(XrResult result) {
+String OpenXRAPI::get_error_string(XrResult result) const {
 	if (XR_SUCCEEDED(result)) {
 		return String("Succeeded");
 	}
@@ -1261,6 +1261,7 @@ bool OpenXRAPI::resolve_instance_openxr_symbols() {
 	OPENXR_API_INIT_XR_FUNC_V(xrGetActionStateFloat);
 	OPENXR_API_INIT_XR_FUNC_V(xrGetActionStateVector2f);
 	OPENXR_API_INIT_XR_FUNC_V(xrGetCurrentInteractionProfile);
+	OPENXR_API_INIT_XR_FUNC_V(xrGetReferenceSpaceBoundsRect);
 	OPENXR_API_INIT_XR_FUNC_V(xrGetSystem);
 	OPENXR_API_INIT_XR_FUNC_V(xrGetSystemProperties);
 	OPENXR_API_INIT_XR_FUNC_V(xrLocateViews);
@@ -2072,6 +2073,25 @@ void OpenXRAPI::set_foveation_dynamic(bool p_foveation_dynamic) {
 	}
 }
 
+Size2 OpenXRAPI::get_play_space_bounds() const {
+	Size2 ret;
+
+	ERR_FAIL_COND_V(session == XR_NULL_HANDLE, Size2());
+
+	XrExtent2Df extents;
+
+	XrResult result = xrGetReferenceSpaceBoundsRect(session, reference_space, &extents);
+	if (XR_FAILED(result)) {
+		print_line("OpenXR: failed to get play space bounds! [", get_error_string(result), "]");
+		return ret;
+	}
+
+	ret.width = extents.width;
+	ret.height = extents.height;
+
+	return ret;
+}
+
 OpenXRAPI::OpenXRAPI() {
 	// OpenXRAPI is only constructed if OpenXR is enabled.
 	singleton = this;

modules/openxr/openxr_api.h

@@ -199,6 +199,7 @@ class OpenXRAPI {
 	EXT_PROTO_XRRESULT_FUNC3(xrGetActionStateVector2f, (XrSession), session, (const XrActionStateGetInfo *), getInfo, (XrActionStateVector2f *), state)
 	EXT_PROTO_XRRESULT_FUNC3(xrGetCurrentInteractionProfile, (XrSession), session, (XrPath), topLevelUserPath, (XrInteractionProfileState *), interactionProfile)
 	EXT_PROTO_XRRESULT_FUNC2(xrGetInstanceProperties, (XrInstance), instance, (XrInstanceProperties *), instanceProperties)
+	EXT_PROTO_XRRESULT_FUNC3(xrGetReferenceSpaceBoundsRect, (XrSession), session, (XrReferenceSpaceType), referenceSpaceType, (XrExtent2Df *), bounds)
 	EXT_PROTO_XRRESULT_FUNC3(xrGetSystem, (XrInstance), instance, (const XrSystemGetInfo *), getInfo, (XrSystemId *), systemId)
 	EXT_PROTO_XRRESULT_FUNC3(xrGetSystemProperties, (XrInstance), instance, (XrSystemId), systemId, (XrSystemProperties *), properties)
 	EXT_PROTO_XRRESULT_FUNC4(xrLocateSpace, (XrSpace), space, (XrSpace), baseSpace, (XrTime), time, (XrSpaceLocation *), location)
@@ -317,7 +318,7 @@ class OpenXRAPI {
 
 	XrResult try_get_instance_proc_addr(const char *p_name, PFN_xrVoidFunction *p_addr);
 	XrResult get_instance_proc_addr(const char *p_name, PFN_xrVoidFunction *p_addr);
-	String get_error_string(XrResult result);
+	String get_error_string(XrResult result) const;
 	String get_swapchain_format_name(int64_t p_swapchain_format) const;
 
 	void set_xr_interface(OpenXRInterface *p_xr_interface);
@@ -380,6 +381,9 @@ class OpenXRAPI {
 	bool get_foveation_dynamic() const;
 	void set_foveation_dynamic(bool p_foveation_dynamic);
 
+	// Play space.
+	Size2 get_play_space_bounds() const;
+
 	// action map
 	String get_default_action_map_resource_name();
 

modules/openxr/openxr_interface.cpp

@@ -690,6 +690,42 @@ bool OpenXRInterface::set_play_area_mode(XRInterface::PlayAreaMode p_mode) {
 	return false;
 }
 
+PackedVector3Array OpenXRInterface::get_play_area() const {
+	XRServer *xr_server = XRServer::get_singleton();
+	ERR_FAIL_NULL_V(xr_server, PackedVector3Array());
+	PackedVector3Array arr;
+
+	Vector3 sides[4] = {
+		Vector3(-0.5f, 0.0f, -0.5f),
+		Vector3(0.5f, 0.0f, -0.5f),
+		Vector3(0.5f, 0.0f, 0.5f),
+		Vector3(-0.5f, 0.0f, 0.5f),
+	};
+
+	if (openxr_api != nullptr && openxr_api->is_initialized()) {
+		Size2 extents = openxr_api->get_play_space_bounds();
+		if (extents.width != 0.0 && extents.height != 0.0) {
+			Transform3D reference_frame = xr_server->get_reference_frame();
+
+			for (int i = 0; i < 4; i++) {
+				Vector3 coord = sides[i];
+
+				// Scale it up.
+				coord.x *= extents.width;
+				coord.z *= extents.height;
+
+				// Now apply our reference.
+				Vector3 out = reference_frame.xform(coord);
+				arr.push_back(out);
+			}
+		} else {
+			WARN_PRINT_ONCE("OpenXR: No extents available.");
+		}
+	}
+
+	return arr;
+}
+
 float OpenXRInterface::get_display_refresh_rate() const {
 	if (openxr_api == nullptr) {
 		return 0.0;

modules/openxr/openxr_interface.h

@@ -125,6 +125,7 @@ class OpenXRInterface : public XRInterface {
 	virtual bool supports_play_area_mode(XRInterface::PlayAreaMode p_mode) override;
 	virtual XRInterface::PlayAreaMode get_play_area_mode() const override;
 	virtual bool set_play_area_mode(XRInterface::PlayAreaMode p_mode) override;
+	virtual PackedVector3Array get_play_area() const override;
 
 	float get_display_refresh_rate() const;
 	void set_display_refresh_rate(float p_refresh_rate);