1 files changed, 304 insertions, 55 deletions

diff --git a/modules/openxr/openxr_api.cpp b/modules/openxr/openxr_api.cpp
index 94095eb61c..8a69072793 100644
--- a/modules/openxr/openxr_api.cpp
+++ b/modules/openxr/openxr_api.cpp
@@ -41,6 +41,7 @@
 #endif
 
 #ifdef ANDROID_ENABLED
+#define OPENXR_LOADER_NAME "libopenxr_loader.so"
 #include "extensions/openxr_android_extension.h"
 #endif
 
@@ -48,7 +49,11 @@
 #include "extensions/openxr_vulkan_extension.h"
 #endif
 
+#include "extensions/openxr_composition_layer_depth_extension.h"
+#include "extensions/openxr_fb_passthrough_extension_wrapper.h"
+#include "extensions/openxr_hand_tracking_extension.h"
 #include "extensions/openxr_htc_vive_tracker_extension.h"
+#include "extensions/openxr_palm_pose_extension.h"
 
 #include "modules/openxr/openxr_interface.h"
 
@@ -184,6 +189,20 @@ bool OpenXRAPI::is_extension_supported(const String &p_extension) const {
 	return false;
 }
 
+bool OpenXRAPI::is_path_supported(const String &p_path) {
+	// This checks with extensions whether a path is *unsupported* and returns false if this is so.
+	// This allows us to filter out paths that are only available if related extensions are supported.
+	// WARNING: This method will return true for unknown/mistyped paths as we have no way to validate those.
+
+	for (OpenXRExtensionWrapper *wrapper : registered_extension_wrappers) {
+		if (!wrapper->is_path_supported(p_path)) {
+			return false;
+		}
+	}
+
+	return true;
+}
+
 void OpenXRAPI::copy_string_to_char_buffer(const String p_string, char *p_buffer, int p_buffer_len) {
 	CharString char_string = p_string.utf8();
 	int len = char_string.length();
@@ -284,6 +303,9 @@ bool OpenXRAPI::create_instance() {
 		0, // runtimeVersion, from here will be set by our get call
 		"" // runtimeName
 	};
+
+	OPENXR_API_INIT_XR_FUNC_V(xrGetInstanceProperties);
+
 	result = xrGetInstanceProperties(instance, &instanceProps);
 	if (XR_FAILED(result)) {
 		// not fatal probably
@@ -642,7 +664,7 @@ bool OpenXRAPI::is_swapchain_format_supported(int64_t p_swapchain_format) {
 	return false;
 }
 
-bool OpenXRAPI::create_main_swapchain() {
+bool OpenXRAPI::create_swapchains() {
 	ERR_FAIL_NULL_V(graphics_extension, false);
 	ERR_FAIL_COND_V(session == XR_NULL_HANDLE, false);
 
@@ -660,34 +682,36 @@ bool OpenXRAPI::create_main_swapchain() {
 		already rendering the next frame.
 
 		Finally an area we need to expand upon is that Foveated rendering is only enabled for the swap chain we create,
-		as we render 3D content into internal buffers that are copied into the swapchain, we don't get any of the performance gains
-		until such time as we implement VRS.
+		as we render 3D content into internal buffers that are copied into the swapchain, we do now have (basic) VRS support
 	*/
 
-	// Build a vector with swapchain formats we want to use, from best fit to worst
-	Vector<int64_t> usable_swapchain_formats;
-	int64_t swapchain_format_to_use = 0;
+	Size2 recommended_size = get_recommended_target_size();
 
-	graphics_extension->get_usable_swapchain_formats(usable_swapchain_formats);
+	// We start with our color swapchain...
+	{
+		// Build a vector with swapchain formats we want to use, from best fit to worst
+		Vector<int64_t> usable_swapchain_formats;
+		int64_t swapchain_format_to_use = 0;
 
-	// now find out which one is supported
-	for (int i = 0; i < usable_swapchain_formats.size() && swapchain_format_to_use == 0; i++) {
-		if (is_swapchain_format_supported(usable_swapchain_formats[i])) {
-			swapchain_format_to_use = usable_swapchain_formats[i];
-		}
-	}
+		graphics_extension->get_usable_swapchain_formats(usable_swapchain_formats);
 
-	if (swapchain_format_to_use == 0) {
-		swapchain_format_to_use = usable_swapchain_formats[0]; // just use the first one and hope for the best...
-		print_line("Couldn't find usable swap chain format, using", get_swapchain_format_name(swapchain_format_to_use), "instead.");
-	} else {
-		print_line("Using swap chain format:", get_swapchain_format_name(swapchain_format_to_use));
-	}
+		// now find out which one is supported
+		for (int i = 0; i < usable_swapchain_formats.size() && swapchain_format_to_use == 0; i++) {
+			if (is_swapchain_format_supported(usable_swapchain_formats[i])) {
+				swapchain_format_to_use = usable_swapchain_formats[i];
+			}
+		}
 
-	Size2 recommended_size = get_recommended_target_size();
+		if (swapchain_format_to_use == 0) {
+			swapchain_format_to_use = usable_swapchain_formats[0]; // just use the first one and hope for the best...
+			print_line("Couldn't find usable color swap chain format, using", get_swapchain_format_name(swapchain_format_to_use), "instead.");
+		} else {
+			print_line("Using color swap chain format:", get_swapchain_format_name(swapchain_format_to_use));
+		}
 
-	if (!create_swapchain(swapchain_format_to_use, recommended_size.width, recommended_size.height, view_configuration_views[0].recommendedSwapchainSampleCount, view_count, swapchain, &swapchain_graphics_data)) {
-		return false;
+		if (!create_swapchain(XR_SWAPCHAIN_USAGE_SAMPLED_BIT | XR_SWAPCHAIN_USAGE_COLOR_ATTACHMENT_BIT, swapchain_format_to_use, recommended_size.width, recommended_size.height, view_configuration_views[0].recommendedSwapchainSampleCount, view_count, swapchains[OPENXR_SWAPCHAIN_COLOR].swapchain, &swapchains[OPENXR_SWAPCHAIN_COLOR].swapchain_graphics_data)) {
+			return false;
+		}
 	}
 
 	views = (XrView *)memalloc(sizeof(XrView) * view_count);
@@ -696,18 +720,73 @@ bool OpenXRAPI::create_main_swapchain() {
 	projection_views = (XrCompositionLayerProjectionView *)memalloc(sizeof(XrCompositionLayerProjectionView) * view_count);
 	ERR_FAIL_NULL_V_MSG(projection_views, false, "OpenXR Couldn't allocate memory for projection views");
 
+	// We create our depth swapchain if:
+	// - we support our depth layer extension
+	// - we have our spacewarp extension (not yet implemented)
+	if (OpenXRCompositionLayerDepthExtension::get_singleton()->is_available()) {
+		// Build a vector with swapchain formats we want to use, from best fit to worst
+		Vector<int64_t> usable_swapchain_formats;
+		int64_t swapchain_format_to_use = 0;
+
+		graphics_extension->get_usable_depth_formats(usable_swapchain_formats);
+
+		// now find out which one is supported
+		for (int i = 0; i < usable_swapchain_formats.size() && swapchain_format_to_use == 0; i++) {
+			if (is_swapchain_format_supported(usable_swapchain_formats[i])) {
+				swapchain_format_to_use = usable_swapchain_formats[i];
+			}
+		}
+
+		if (swapchain_format_to_use == 0) {
+			swapchain_format_to_use = usable_swapchain_formats[0]; // just use the first one and hope for the best...
+			print_line("Couldn't find usable depth swap chain format, using", get_swapchain_format_name(swapchain_format_to_use), "instead.");
+		} else {
+			print_line("Using depth swap chain format:", get_swapchain_format_name(swapchain_format_to_use));
+		}
+
+		if (!create_swapchain(XR_SWAPCHAIN_USAGE_SAMPLED_BIT | XR_SWAPCHAIN_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT, swapchain_format_to_use, recommended_size.width, recommended_size.height, view_configuration_views[0].recommendedSwapchainSampleCount, view_count, swapchains[OPENXR_SWAPCHAIN_DEPTH].swapchain, &swapchains[OPENXR_SWAPCHAIN_DEPTH].swapchain_graphics_data)) {
+			return false;
+		}
+
+		depth_views = (XrCompositionLayerDepthInfoKHR *)memalloc(sizeof(XrCompositionLayerDepthInfoKHR) * view_count);
+		ERR_FAIL_NULL_V_MSG(depth_views, false, "OpenXR Couldn't allocate memory for depth views");
+	}
+
+	// We create our velocity swapchain if:
+	// - we have our spacewarp extension (not yet implemented)
+	{
+		// TBD
+	}
+
 	for (uint32_t i = 0; i < view_count; i++) {
 		views[i].type = XR_TYPE_VIEW;
 		views[i].next = nullptr;
 
 		projection_views[i].type = XR_TYPE_COMPOSITION_LAYER_PROJECTION_VIEW;
 		projection_views[i].next = nullptr;
-		projection_views[i].subImage.swapchain = swapchain;
+		projection_views[i].subImage.swapchain = swapchains[OPENXR_SWAPCHAIN_COLOR].swapchain;
 		projection_views[i].subImage.imageArrayIndex = i;
 		projection_views[i].subImage.imageRect.offset.x = 0;
 		projection_views[i].subImage.imageRect.offset.y = 0;
 		projection_views[i].subImage.imageRect.extent.width = recommended_size.width;
 		projection_views[i].subImage.imageRect.extent.height = recommended_size.height;
+
+		if (OpenXRCompositionLayerDepthExtension::get_singleton()->is_available() && depth_views) {
+			projection_views[i].next = &depth_views[i];
+
+			depth_views[i].type = XR_TYPE_COMPOSITION_LAYER_DEPTH_INFO_KHR;
+			depth_views[i].next = nullptr;
+			depth_views[i].subImage.swapchain = swapchains[OPENXR_SWAPCHAIN_DEPTH].swapchain;
+			depth_views[i].subImage.imageArrayIndex = 0;
+			depth_views[i].subImage.imageRect.offset.x = 0;
+			depth_views[i].subImage.imageRect.offset.y = 0;
+			depth_views[i].subImage.imageRect.extent.width = recommended_size.width;
+			depth_views[i].subImage.imageRect.extent.height = recommended_size.height;
+			depth_views[i].minDepth = 0.0;
+			depth_views[i].maxDepth = 1.0;
+			depth_views[i].nearZ = 0.01; // Near and far Z will be set to the correct values in fill_projection_matrix
+			depth_views[i].farZ = 100.0;
+		}
 	};
 
 	return true;
@@ -719,7 +798,7 @@ void OpenXRAPI::destroy_session() {
 	}
 
 	if (graphics_extension) {
-		graphics_extension->cleanup_swapchain_graphics_data(&swapchain_graphics_data);
+		graphics_extension->cleanup_swapchain_graphics_data(&swapchains[OPENXR_SWAPCHAIN_COLOR].swapchain_graphics_data);
 	}
 
 	if (views != nullptr) {
@@ -732,9 +811,16 @@ void OpenXRAPI::destroy_session() {
 		projection_views = nullptr;
 	}
 
-	if (swapchain != XR_NULL_HANDLE) {
-		xrDestroySwapchain(swapchain);
-		swapchain = XR_NULL_HANDLE;
+	if (depth_views != nullptr) {
+		memfree(depth_views);
+		depth_views = nullptr;
+	}
+
+	for (int i = 0; i < OPENXR_SWAPCHAIN_MAX; i++) {
+		if (swapchains[i].swapchain != XR_NULL_HANDLE) {
+			xrDestroySwapchain(swapchains[i].swapchain);
+			swapchains[i].swapchain = XR_NULL_HANDLE;
+		}
 	}
 
 	if (supported_swapchain_formats != nullptr) {
@@ -768,7 +854,7 @@ void OpenXRAPI::destroy_session() {
 	}
 }
 
-bool OpenXRAPI::create_swapchain(int64_t p_swapchain_format, uint32_t p_width, uint32_t p_height, uint32_t p_sample_count, uint32_t p_array_size, XrSwapchain &r_swapchain, void **r_swapchain_graphics_data) {
+bool OpenXRAPI::create_swapchain(XrSwapchainUsageFlags p_usage_flags, int64_t p_swapchain_format, uint32_t p_width, uint32_t p_height, uint32_t p_sample_count, uint32_t p_array_size, XrSwapchain &r_swapchain, void **r_swapchain_graphics_data) {
 	ERR_FAIL_COND_V(session == XR_NULL_HANDLE, false);
 	ERR_FAIL_NULL_V(graphics_extension, false);
 
@@ -786,7 +872,7 @@ bool OpenXRAPI::create_swapchain(int64_t p_swapchain_format, uint32_t p_width, u
 		XR_TYPE_SWAPCHAIN_CREATE_INFO, // type
 		next_pointer, // next
 		0, // createFlags
-		XR_SWAPCHAIN_USAGE_SAMPLED_BIT | XR_SWAPCHAIN_USAGE_COLOR_ATTACHMENT_BIT, // usageFlags
+		p_usage_flags, // usageFlags
 		p_swapchain_format, // format
 		p_sample_count, // sampleCount
 		p_width, // width
@@ -850,7 +936,7 @@ bool OpenXRAPI::on_state_ready() {
 	// That will be very very ugly
 	// The other possibility is to create a separate OpenXRViewport type specifically for this goal as part of our OpenXR module
 
-	if (!create_main_swapchain()) {
+	if (!create_swapchains()) {
 		return false;
 	}
 
@@ -992,9 +1078,94 @@ bool OpenXRAPI::is_running() {
 	return running;
 }
 
+bool OpenXRAPI::openxr_loader_init() {
+#ifdef ANDROID_ENABLED
+	ERR_FAIL_COND_V_MSG(openxr_loader_library_handle != nullptr, false, "OpenXR Loader library is already loaded.");
+
+	{
+		Error error_code = OS::get_singleton()->open_dynamic_library(OPENXR_LOADER_NAME, openxr_loader_library_handle);
+		ERR_FAIL_COND_V_MSG(error_code != OK, false, "OpenXR loader not found.");
+	}
+
+	{
+		Error error_code = OS::get_singleton()->get_dynamic_library_symbol_handle(openxr_loader_library_handle, "xrGetInstanceProcAddr", (void *&)xrGetInstanceProcAddr);
+		ERR_FAIL_COND_V_MSG(error_code != OK, false, "Symbol xrGetInstanceProcAddr not found in OpenXR Loader library.");
+	}
+#endif
+
+	// Resolve the symbols that don't require an instance
+	OPENXR_API_INIT_XR_FUNC_V(xrCreateInstance);
+	OPENXR_API_INIT_XR_FUNC_V(xrEnumerateApiLayerProperties);
+	OPENXR_API_INIT_XR_FUNC_V(xrEnumerateInstanceExtensionProperties);
+
+	return true;
+}
+
+bool OpenXRAPI::resolve_instance_openxr_symbols() {
+	ERR_FAIL_COND_V(instance == XR_NULL_HANDLE, false);
+
+	OPENXR_API_INIT_XR_FUNC_V(xrAcquireSwapchainImage);
+	OPENXR_API_INIT_XR_FUNC_V(xrApplyHapticFeedback);
+	OPENXR_API_INIT_XR_FUNC_V(xrAttachSessionActionSets);
+	OPENXR_API_INIT_XR_FUNC_V(xrBeginFrame);
+	OPENXR_API_INIT_XR_FUNC_V(xrBeginSession);
+	OPENXR_API_INIT_XR_FUNC_V(xrCreateAction);
+	OPENXR_API_INIT_XR_FUNC_V(xrCreateActionSet);
+	OPENXR_API_INIT_XR_FUNC_V(xrCreateActionSpace);
+	OPENXR_API_INIT_XR_FUNC_V(xrCreateReferenceSpace);
+	OPENXR_API_INIT_XR_FUNC_V(xrCreateSession);
+	OPENXR_API_INIT_XR_FUNC_V(xrCreateSwapchain);
+	OPENXR_API_INIT_XR_FUNC_V(xrDestroyAction);
+	OPENXR_API_INIT_XR_FUNC_V(xrDestroyActionSet);
+	OPENXR_API_INIT_XR_FUNC_V(xrDestroyInstance);
+	OPENXR_API_INIT_XR_FUNC_V(xrDestroySession);
+	OPENXR_API_INIT_XR_FUNC_V(xrDestroySpace);
+	OPENXR_API_INIT_XR_FUNC_V(xrDestroySwapchain);
+	OPENXR_API_INIT_XR_FUNC_V(xrEndFrame);
+	OPENXR_API_INIT_XR_FUNC_V(xrEndSession);
+	OPENXR_API_INIT_XR_FUNC_V(xrEnumerateReferenceSpaces);
+	OPENXR_API_INIT_XR_FUNC_V(xrEnumerateSwapchainFormats);
+	OPENXR_API_INIT_XR_FUNC_V(xrEnumerateViewConfigurations);
+	OPENXR_API_INIT_XR_FUNC_V(xrEnumerateViewConfigurationViews);
+	OPENXR_API_INIT_XR_FUNC_V(xrGetActionStateBoolean);
+	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(xrGetSystem);
+	OPENXR_API_INIT_XR_FUNC_V(xrGetSystemProperties);
+	OPENXR_API_INIT_XR_FUNC_V(xrLocateViews);
+	OPENXR_API_INIT_XR_FUNC_V(xrLocateSpace);
+	OPENXR_API_INIT_XR_FUNC_V(xrPathToString);
+	OPENXR_API_INIT_XR_FUNC_V(xrPollEvent);
+	OPENXR_API_INIT_XR_FUNC_V(xrReleaseSwapchainImage);
+	OPENXR_API_INIT_XR_FUNC_V(xrResultToString);
+	OPENXR_API_INIT_XR_FUNC_V(xrStringToPath);
+	OPENXR_API_INIT_XR_FUNC_V(xrSuggestInteractionProfileBindings);
+	OPENXR_API_INIT_XR_FUNC_V(xrSyncActions);
+	OPENXR_API_INIT_XR_FUNC_V(xrWaitFrame);
+	OPENXR_API_INIT_XR_FUNC_V(xrWaitSwapchainImage);
+
+	return true;
+}
+
+XrResult OpenXRAPI::get_instance_proc_addr(const char *p_name, PFN_xrVoidFunction *p_addr) {
+	XrResult result = xrGetInstanceProcAddr(instance, p_name, p_addr);
+
+	if (result != XR_SUCCESS) {
+		String error_message = String("Symbol ") + p_name + " not found in OpenXR instance.";
+		ERR_FAIL_COND_V_MSG(true, result, error_message.utf8().get_data());
+	}
+
+	return result;
+}
+
 bool OpenXRAPI::initialize(const String &p_rendering_driver) {
 	ERR_FAIL_COND_V_MSG(instance != XR_NULL_HANDLE, false, "OpenXR instance was already created");
 
+	if (!openxr_loader_init()) {
+		return false;
+	}
+
 	if (p_rendering_driver == "vulkan") {
 #ifdef VULKAN_ENABLED
 		graphics_extension = memnew(OpenXRVulkanExtension(this));
@@ -1017,6 +1188,10 @@ bool OpenXRAPI::initialize(const String &p_rendering_driver) {
 	}
 
 	// initialize
+	for (OpenXRExtensionWrapper *wrapper : registered_extension_wrappers) {
+		wrapper->on_before_instance_created();
+	}
+
 	if (!load_layer_properties()) {
 		destroy_instance();
 		return false;
@@ -1032,6 +1207,11 @@ bool OpenXRAPI::initialize(const String &p_rendering_driver) {
 		return false;
 	}
 
+	if (!resolve_instance_openxr_symbols()) {
+		destroy_instance();
+		return false;
+	}
+
 	if (!get_system_info()) {
 		destroy_instance();
 		return false;
@@ -1189,6 +1369,15 @@ bool OpenXRAPI::get_view_projection(uint32_t p_view, double p_z_near, double p_z
 		return false;
 	}
 
+	// if we're using depth views, make sure we update our near and far there...
+	if (depth_views != nullptr) {
+		for (uint32_t i = 0; i < view_count; i++) {
+			depth_views[i].nearZ = p_z_near;
+			depth_views[i].farZ = p_z_far;
+		}
+	}
+
+	// now update our projection
 	return graphics_extension->create_projection_fov(views[p_view].fov, p_z_near, p_z_far, p_camera_matrix);
 }
 
@@ -1327,15 +1516,15 @@ bool OpenXRAPI::process() {
 	return true;
 }
 
-bool OpenXRAPI::acquire_image(XrSwapchain p_swapchain, uint32_t &r_image_index) {
-	ERR_FAIL_COND_V(image_acquired, true); // this was not released when it should be, error out and re-use...
+bool OpenXRAPI::acquire_image(OpenXRSwapChainInfo &p_swapchain) {
+	ERR_FAIL_COND_V(p_swapchain.image_acquired, true); // this was not released when it should be, error out and re-use...
 
 	XrResult result;
 	XrSwapchainImageAcquireInfo swapchain_image_acquire_info = {
 		XR_TYPE_SWAPCHAIN_IMAGE_ACQUIRE_INFO, // type
 		nullptr // next
 	};
-	result = xrAcquireSwapchainImage(p_swapchain, &swapchain_image_acquire_info, &r_image_index);
+	result = xrAcquireSwapchainImage(p_swapchain.swapchain, &swapchain_image_acquire_info, &p_swapchain.image_index);
 	if (XR_FAILED(result)) {
 		print_line("OpenXR: failed to acquire swapchain image [", get_error_string(result), "]");
 		return false;
@@ -1347,7 +1536,7 @@ bool OpenXRAPI::acquire_image(XrSwapchain p_swapchain, uint32_t &r_image_index)
 		17000000 // timeout in nanoseconds
 	};
 
-	result = xrWaitSwapchainImage(p_swapchain, &swapchain_image_wait_info);
+	result = xrWaitSwapchainImage(p_swapchain.swapchain, &swapchain_image_wait_info);
 	if (XR_FAILED(result)) {
 		print_line("OpenXR: failed to wait for swapchain image [", get_error_string(result), "]");
 		return false;
@@ -1356,12 +1545,12 @@ bool OpenXRAPI::acquire_image(XrSwapchain p_swapchain, uint32_t &r_image_index)
 	return true;
 }
 
-bool OpenXRAPI::release_image(XrSwapchain p_swapchain) {
+bool OpenXRAPI::release_image(OpenXRSwapChainInfo &p_swapchain) {
 	XrSwapchainImageReleaseInfo swapchain_image_release_info = {
 		XR_TYPE_SWAPCHAIN_IMAGE_RELEASE_INFO, // type
 		nullptr // next
 	};
-	XrResult result = xrReleaseSwapchainImage(swapchain, &swapchain_image_release_info);
+	XrResult result = xrReleaseSwapchainImage(p_swapchain.swapchain, &swapchain_image_release_info);
 	if (XR_FAILED(result)) {
 		print_line("OpenXR: failed to release swapchain image! [", get_error_string(result), "]");
 		return false;
@@ -1382,6 +1571,10 @@ void OpenXRAPI::pre_render() {
 	// 2) It will use the previous timing to pause our thread so that rendering starts as close to displaying as possible
 	// This must thus be called as close to when we start rendering as possible
 	XrFrameWaitInfo frame_wait_info = { XR_TYPE_FRAME_WAIT_INFO, nullptr };
+	frame_state.predictedDisplayTime = 0;
+	frame_state.predictedDisplayPeriod = 0;
+	frame_state.shouldRender = false;
+
 	XrResult result = xrWaitFrame(session, &frame_wait_info, &frame_state);
 	if (XR_FAILED(result)) {
 		print_line("OpenXR: xrWaitFrame() was not successful [", get_error_string(result), "]");
@@ -1471,28 +1664,41 @@ bool OpenXRAPI::pre_draw_viewport(RID p_render_target) {
 
 	// TODO: at some point in time we may support multiple viewports in which case we need to handle that...
 
+	// Acquire our images
+	for (int i = 0; i < OPENXR_SWAPCHAIN_MAX; i++) {
+		if (!swapchains[i].image_acquired && swapchains[i].swapchain != XR_NULL_HANDLE) {
+			if (!acquire_image(swapchains[i])) {
+				return false;
+			}
+			swapchains[i].image_acquired = true;
+		}
+	}
+
 	return true;
 }
 
+RID OpenXRAPI::get_color_texture() {
+	if (swapchains[OPENXR_SWAPCHAIN_COLOR].image_acquired) {
+		return graphics_extension->get_texture(swapchains[OPENXR_SWAPCHAIN_COLOR].swapchain_graphics_data, swapchains[OPENXR_SWAPCHAIN_COLOR].image_index);
+	} else {
+		return RID();
+	}
+}
+
+RID OpenXRAPI::get_depth_texture() {
+	if (swapchains[OPENXR_SWAPCHAIN_DEPTH].image_acquired) {
+		return graphics_extension->get_texture(swapchains[OPENXR_SWAPCHAIN_DEPTH].swapchain_graphics_data, swapchains[OPENXR_SWAPCHAIN_DEPTH].image_index);
+	} else {
+		return RID();
+	}
+}
+
 void OpenXRAPI::post_draw_viewport(RID p_render_target) {
 	if (!can_render()) {
 		return;
 	}
 
-	// TODO: at some point in time we may support multiple viewports in which case we need to handle that...
-
-	// TODO: if we can get PR 51179 to work properly we can change away from this approach and move this into get_external_texture or something
-	if (!image_acquired) {
-		if (!acquire_image(swapchain, image_index)) {
-			return;
-		}
-		image_acquired = true;
-
-		// print_line("OpenXR: acquired image " + itos(image_index) + ", copying...");
-
-		// Copy our buffer into our swap chain (remove once PR 51179 is done)
-		graphics_extension->copy_render_target_to_image(p_render_target, swapchain_graphics_data, image_index);
-	}
+	// Nothing to do here at this point in time...
 };
 
 void OpenXRAPI::end_frame() {
@@ -1504,7 +1710,7 @@ void OpenXRAPI::end_frame() {
 		return;
 	}
 
-	if (frame_state.shouldRender && view_pose_valid && !image_acquired) {
+	if (frame_state.shouldRender && view_pose_valid && !swapchains[OPENXR_SWAPCHAIN_COLOR].image_acquired) {
 		print_line("OpenXR: No viewport was marked with use_xr, there is no rendered output!");
 	}
 
@@ -1512,7 +1718,7 @@ void OpenXRAPI::end_frame() {
 	// - shouldRender set to true
 	// - a valid view pose for projection_views[eye].pose to submit layer
 	// - an image to render
-	if (!frame_state.shouldRender || !view_pose_valid || !image_acquired) {
+	if (!frame_state.shouldRender || !view_pose_valid || !swapchains[OPENXR_SWAPCHAIN_COLOR].image_acquired) {
 		// submit 0 layers when we shouldn't render
 		XrFrameEndInfo frame_end_info = {
 			XR_TYPE_FRAME_END_INFO, // type
@@ -1533,10 +1739,12 @@ void OpenXRAPI::end_frame() {
 	}
 
 	// release our swapchain image if we acquired it
-	if (image_acquired) {
-		image_acquired = false; // whether we succeed or not, consider this released.
+	for (int i = 0; i < OPENXR_SWAPCHAIN_MAX; i++) {
+		if (swapchains[i].image_acquired) {
+			swapchains[i].image_acquired = false; // whether we succeed or not, consider this released.
 
-		release_image(swapchain);
+			release_image(swapchains[i]);
+		}
 	}
 
 	for (uint32_t eye = 0; eye < view_count; eye++) {
@@ -1643,7 +1851,11 @@ OpenXRAPI::OpenXRAPI() {
 #endif
 
 	// register our other extensions
+	register_extension_wrapper(memnew(OpenXRPalmPoseExtension(this)));
+	register_extension_wrapper(memnew(OpenXRCompositionLayerDepthExtension(this)));
 	register_extension_wrapper(memnew(OpenXRHTCViveTrackerExtension(this)));
+	register_extension_wrapper(memnew(OpenXRHandTrackingExtension(this)));
+	register_extension_wrapper(memnew(OpenXRFbPassthroughExtensionWrapper(this)));
 }
 
 OpenXRAPI::~OpenXRAPI() {
@@ -1669,6 +1881,13 @@ OpenXRAPI::~OpenXRAPI() {
 		layer_properties = nullptr;
 	}
 
+#ifdef ANDROID_ENABLED
+	if (openxr_loader_library_handle) {
+		OS::get_singleton()->close_dynamic_library(openxr_loader_library_handle);
+		openxr_loader_library_handle = nullptr;
+	}
+#endif
+
 	singleton = nullptr;
 }
 
@@ -1745,6 +1964,18 @@ void OpenXRAPI::parse_velocities(const XrSpaceVelocity &p_velocity, Vector3 &r_l
 	}
 }
 
+bool OpenXRAPI::xr_result(XrResult result, const char *format, Array args) const {
+	if (XR_SUCCEEDED(result))
+		return true;
+
+	char resultString[XR_MAX_RESULT_STRING_SIZE];
+	xrResultToString(instance, result, resultString);
+
+	print_error(String("OpenXR ") + String(format).format(args) + String(" [") + String(resultString) + String("]"));
+
+	return false;
+}
+
 RID OpenXRAPI::get_tracker_rid(XrPath p_path) {
 	List<RID> current;
 	tracker_owner.get_owned_list(&current);
@@ -2063,6 +2294,11 @@ XrPath OpenXRAPI::get_interaction_profile_path(RID p_interaction_profile) {
 }
 
 RID OpenXRAPI::interaction_profile_create(const String p_name) {
+	if (!is_path_supported(p_name)) {
+		// The extension enabling this path must not be active, we will silently skip this interaction profile
+		return RID();
+	}
+
 	InteractionProfile new_interaction_profile;
 
 	XrResult result = xrStringToPath(instance, p_name.utf8().get_data(), &new_interaction_profile.path);
@@ -2099,6 +2335,11 @@ void OpenXRAPI::interaction_profile_clear_bindings(RID p_interaction_profile) {
 }
 
 bool OpenXRAPI::interaction_profile_add_binding(RID p_interaction_profile, RID p_action, const String p_path) {
+	if (!is_path_supported(p_path)) {
+		// The extension enabling this path must not be active, we will silently skip this binding
+		return false;
+	}
+
 	InteractionProfile *ip = interaction_profile_owner.get_or_null(p_interaction_profile);
 	ERR_FAIL_NULL_V(ip, false);
 
@@ -2426,3 +2667,11 @@ bool OpenXRAPI::trigger_haptic_pulse(RID p_action, RID p_tracker, float p_freque
 
 	return true;
 }
+
+void OpenXRAPI::register_composition_layer_provider(OpenXRCompositionLayerProvider *provider) {
+	composition_layer_providers.append(provider);
+}
+
+void OpenXRAPI::unregister_composition_layer_provider(OpenXRCompositionLayerProvider *provider) {
+	composition_layer_providers.erase(provider);
+}