OpenXR: Add support for frame synthesis

Author: BastiaanOlij

doc/classes/ProjectSettings.xml

@@ -3518,6 +3518,10 @@
 		<member name="xr/openxr/extensions/eye_gaze_interaction" type="bool" setter="" getter="" default="false">
 			Specify whether to enable eye tracking for this project. Depending on the platform, additional export configuration may be needed.
 		</member>
+		<member name="xr/openxr/extensions/frame_synthesis" type="bool" setter="" getter="" default="false">
+			If [code]true[/code] the frame synthesis extension will be activated if supported by the platform.
+			[b]Note:[/b] This feature should not be enabled in conjunction with Application Space Warp, if supported this replaces ASW.
+		</member>
 		<member name="xr/openxr/extensions/hand_interaction_profile" type="bool" setter="" getter="" default="false">
 			If [code]true[/code] the hand interaction profile extension will be activated if supported by the platform.
 		</member>

main/main.cpp

@@ -2710,6 +2710,7 @@ Error Main::setup(const char *execpath, int argc, char *argv[], bool p_second_ph
 	// OpenXR project extensions settings.
 	GLOBAL_DEF_BASIC(PropertyInfo(Variant::INT, "xr/openxr/extensions/debug_utils", PROPERTY_HINT_ENUM, "Disabled,Error,Warning,Info,Verbose"), "0");
 	GLOBAL_DEF_BASIC(PropertyInfo(Variant::INT, "xr/openxr/extensions/debug_message_types", PROPERTY_HINT_FLAGS, "General,Validation,Performance,Conformance"), "15");
+	GLOBAL_DEF_BASIC("xr/openxr/extensions/frame_synthesis", false);
 	GLOBAL_DEF_BASIC("xr/openxr/extensions/hand_tracking", false);
 	GLOBAL_DEF_BASIC("xr/openxr/extensions/hand_tracking_unobstructed_data_source", false); // XR_HAND_TRACKING_DATA_SOURCE_UNOBSTRUCTED_EXT
 	GLOBAL_DEF_BASIC("xr/openxr/extensions/hand_tracking_controller_data_source", false); // XR_HAND_TRACKING_DATA_SOURCE_CONTROLLER_EXT

modules/openxr/config.py

@@ -19,6 +19,7 @@ def get_doc_classes():
         "OpenXRAPIExtension",
         "OpenXRExtensionWrapper",
         "OpenXRExtensionWrapperExtension",
+        "OpenXRFrameSynthesisExtension",
         "OpenXRFutureResult",
         "OpenXRFutureExtension",
         "OpenXRInteractionProfile",

modules/openxr/doc_classes/OpenXRExtensionWrapper.xml

@@ -217,12 +217,26 @@
 				[param layer] is a pointer to an [code]XrCompositionLayerBaseHeader[/code] struct.
 			</description>
 		</method>
+		<method name="_prepare_view_configuration" qualifiers="virtual">
+			<return type="void" />
+			<param index="0" name="view_count" type="int" />
+			<description>
+				Called before [method _set_view_configuration_and_get_next_pointer] to allow the extension to reserve data for the given number of views.
+			</description>
+		</method>
+		<method name="_print_view_configuration_info" qualifiers="virtual const">
+			<return type="void" />
+			<param index="0" name="view" type="int" />
+			<description>
+				Called to allow an extension to print additional information about its view configuration, if applicable. This will only be called if verbose output is enabled.
+			</description>
+		</method>
 		<method name="_set_android_surface_swapchain_create_info_and_get_next_pointer" qualifiers="virtual">
 			<return type="int" />
 			<param index="0" name="property_values" type="Dictionary" />
 			<param index="1" name="next_pointer" type="void*" />
 			<description>
-				Adds additional data structures to Android surface swapchains created by [OpenXRCompositionLayer].
+				Add additional data structures to Android surface swapchains created by [OpenXRCompositionLayer].
 				[param property_values] contains the values of the properties returned by [method _get_viewport_composition_layer_extension_properties].
 				[b]Note:[/b] This virtual method will be called on the render thread.
 			</description>
@@ -231,7 +245,7 @@
 			<return type="int" />
 			<param index="0" name="next_pointer" type="void*" />
 			<description>
-				Adds additional data structures to [code]XrFrameEndInfo[/code].
+				Add additional data structures to [code]XrFrameEndInfo[/code].
 				This will only be called if the extension previously registered itself with [method OpenXRAPIExtension.register_frame_info_extension].
 				[b]Note:[/b] This virtual method will be called on the render thread. Additionally, the data it returns will be used shortly after this method is called, so it needs to remain valid until the next time [method _on_pre_render] runs.
 			</description>
@@ -240,7 +254,7 @@
 			<return type="int" />
 			<param index="0" name="next_pointer" type="void*" />
 			<description>
-				Adds additional data structures to [code]XrFrameWaitInfo[/code].
+				Add additional data structures to [code]XrFrameWaitInfo[/code].
 				This will only be called if the extension previously registered itself with [method OpenXRAPIExtension.register_frame_info_extension].
 				[b]Note:[/b] This virtual method will be called on the render thread.
 			</description>
@@ -250,22 +264,22 @@
 			<param index="0" name="hand_index" type="int" />
 			<param index="1" name="next_pointer" type="void*" />
 			<description>
-				Adds additional data structures when each hand tracker is created.
+				Add additional data structures when each hand tracker is created.
 			</description>
 		</method>
 		<method name="_set_instance_create_info_and_get_next_pointer" qualifiers="virtual">
 			<return type="int" />
 			<param index="0" name="next_pointer" type="void*" />
 			<description>
-				Adds additional data structures when the OpenXR instance is created.
+				Add additional data structures when the OpenXR instance is created.
 			</description>
 		</method>
 		<method name="_set_projection_views_and_get_next_pointer" qualifiers="virtual">
 			<return type="int" />
 			<param index="0" name="view_index" type="int" />
 			<param index="1" name="next_pointer" type="void*" />
 			<description>
-				Adds additional data structures to the projection view of the given [param view_index].
+				Add additional data structures to the projection view of the given [param view_index].
 				[b]Note:[/b] This virtual method will be called on the render thread. Additionally, the data it returns will be used shortly after this method is called, so it needs to remain valid until the next time [method _on_pre_render] runs.
 			</description>
 		</method>
@@ -274,35 +288,43 @@
 			<param index="0" name="reference_space_type" type="int" />
 			<param index="1" name="next_pointer" type="void*" />
 			<description>
-				Adds additional data structures to [code]XrReferenceSpaceCreateInfo[/code].
+				Add additional data structures to [code]XrReferenceSpaceCreateInfo[/code].
 			</description>
 		</method>
 		<method name="_set_session_create_and_get_next_pointer" qualifiers="virtual">
 			<return type="int" />
 			<param index="0" name="next_pointer" type="void*" />
 			<description>
-				Adds additional data structures when the OpenXR session is created.
+				Add additional data structures when the OpenXR session is created.
 			</description>
 		</method>
 		<method name="_set_swapchain_create_info_and_get_next_pointer" qualifiers="virtual">
 			<return type="int" />
 			<param index="0" name="next_pointer" type="void*" />
 			<description>
-				Adds additional data structures when creating OpenXR swapchains.
+				Add additional data structures when creating OpenXR swapchains.
 			</description>
 		</method>
 		<method name="_set_system_properties_and_get_next_pointer" qualifiers="virtual">
 			<return type="int" />
 			<param index="0" name="next_pointer" type="void*" />
 			<description>
-				Adds additional data structures when querying OpenXR system abilities.
+				Add additional data structures when querying OpenXR system abilities.
+			</description>
+		</method>
+		<method name="_set_view_configuration_and_get_next_pointer" qualifiers="virtual">
+			<return type="int" />
+			<param index="0" name="view" type="int" />
+			<param index="1" name="next_pointer" type="void*" />
+			<description>
+				Add additional data structures when querying OpenXR view configuration.
 			</description>
 		</method>
 		<method name="_set_view_locate_info_and_get_next_pointer" qualifiers="virtual">
 			<return type="int" />
 			<param index="0" name="next_pointer" type="void*" />
 			<description>
-				Adds additional data structures to [code]XrViewLocateInfo[/code].
+				Add additional data structures to [code]XrViewLocateInfo[/code].
 				This will only be called if the extension previously registered itself with [method OpenXRAPIExtension.register_frame_info_extension].
 				[b]Note:[/b] This virtual method will be called on the render thread. Additionally, the data it returns will be used shortly after this method is called, so it needs to remain valid until the next time [method _on_pre_render] runs.
 			</description>
@@ -313,7 +335,7 @@
 			<param index="1" name="property_values" type="Dictionary" />
 			<param index="2" name="next_pointer" type="void*" />
 			<description>
-				Adds additional data structures to composition layers created by [OpenXRCompositionLayer].
+				Add additional data structures to composition layers created by [OpenXRCompositionLayer].
 				[param property_values] contains the values of the properties returned by [method _get_viewport_composition_layer_extension_properties].
 				[param layer] is a pointer to an [code]XrCompositionLayerBaseHeader[/code] struct.
 				[b]Note:[/b] This virtual method will be called on the render thread. Additionally, the data it returns will be used shortly after this method is called, so it needs to remain valid until the next time [method _on_pre_render] runs.

modules/openxr/doc_classes/OpenXRFrameSynthesisExtension.xml

@@ -0,0 +1,33 @@
+<?xml version="1.0" encoding="UTF-8" ?>
+<class name="OpenXRFrameSynthesisExtension" inherits="OpenXRExtensionWrapper" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../../../doc/class.xsd">
+	<brief_description>
+		The OpenXR Frame synthesis extension allows for advanced reprojection at low(er) framerates.
+	</brief_description>
+	<description>
+		This class implements the [url=https://registry.khronos.org/OpenXR/specs/1.1/html/xrspec.html#XR_EXT_frame_synthesis]OpenXR Frame synthesis extension[/url]. When enabled in the project settings and supported by the XR runtime in use, frame synthesis uses advanced reprojection techniques to inject additional frames so that your XR experience hits the full frame rate of the device.
+	</description>
+	<tutorials>
+	</tutorials>
+	<methods>
+		<method name="is_available" qualifiers="const">
+			<return type="bool" />
+			<description>
+				Returns [code]true[/code] if frame synthesis is enabled in the project settings and the current XR runtime supports frame synthesis. The value returned will only be valid once OpenXR has been initialized.
+			</description>
+		</method>
+		<method name="skip_next_frame">
+			<return type="void" />
+			<description>
+				Queues the next frame to be skipped when supplying motion vector and depth data. Call this after teleporting your player or a similar action has moved the player to prevent incorrect reprojection results due to this movement.
+			</description>
+		</method>
+	</methods>
+	<members>
+		<member name="enabled" type="bool" setter="set_enabled" getter="is_enabled" default="false">
+			Enable frame synthesis. When [code]true[/code] motion vector and depth data is provided to the XR runtime.
+		</member>
+		<member name="relax_frame_interval" type="bool" setter="set_relax_frame_interval" getter="get_relax_frame_interval" default="false">
+			If [code]true[/code] this informs the XR runtime we will be providing frames at a greatly reduced rate. Enable this when you expect your application to run at low framerates and wish to inject multiple reprojected frames.
+		</member>
+	</members>
+</class>

modules/openxr/extensions/openxr_extension_wrapper.cpp

@@ -45,6 +45,9 @@ void OpenXRExtensionWrapper::_bind_methods() {
 	GDVIRTUAL_BIND(_set_frame_end_info_and_get_next_pointer, "next_pointer");
 	GDVIRTUAL_BIND(_set_view_locate_info_and_get_next_pointer, "next_pointer");
 	GDVIRTUAL_BIND(_set_reference_space_create_info_and_get_next_pointer, "reference_space_type", "next_pointer");
+	GDVIRTUAL_BIND(_prepare_view_configuration, "view_count");
+	GDVIRTUAL_BIND(_set_view_configuration_and_get_next_pointer, "view", "next_pointer");
+	GDVIRTUAL_BIND(_print_view_configuration_info, "view");
 	GDVIRTUAL_BIND(_get_composition_layer_count);
 	GDVIRTUAL_BIND(_get_composition_layer, "index");
 	GDVIRTUAL_BIND(_get_composition_layer_order, "index");
@@ -185,6 +188,24 @@ void *OpenXRExtensionWrapper::set_frame_end_info_and_get_next_pointer(void *p_ne
 	return nullptr;
 }
 
+void OpenXRExtensionWrapper::prepare_view_configuration(uint32_t p_view_count) {
+	GDVIRTUAL_CALL(_prepare_view_configuration, p_view_count);
+}
+
+void *OpenXRExtensionWrapper::set_view_configuration_and_get_next_pointer(uint32_t p_view, void *p_next_pointer) {
+	uint64_t pointer = 0;
+
+	if (GDVIRTUAL_CALL(_set_view_configuration_and_get_next_pointer, p_view, GDExtensionPtr<void>(p_next_pointer), pointer)) {
+		return reinterpret_cast<void *>(pointer);
+	}
+
+	return nullptr;
+}
+
+void OpenXRExtensionWrapper::print_view_configuration_info(uint32_t p_view) const {
+	GDVIRTUAL_CALL(_print_view_configuration_info, p_view);
+}
+
 void *OpenXRExtensionWrapper::set_view_locate_info_and_get_next_pointer(void *p_next_pointer) {
 	uint64_t pointer = 0;
 

modules/openxr/extensions/openxr_extension_wrapper.h

@@ -85,6 +85,10 @@ class OpenXRExtensionWrapper : public Object {
 	virtual void *set_view_locate_info_and_get_next_pointer(void *p_next_pointer); // Add additional data structures when calling xrLocateViews
 	virtual void *set_frame_end_info_and_get_next_pointer(void *p_next_pointer); // Add additional data structures when calling xrEndFrame
 
+	virtual void prepare_view_configuration(uint32_t p_view_count);
+	virtual void *set_view_configuration_and_get_next_pointer(uint32_t p_view, void *p_next_pointer); // Add additional data structures when calling xrEnumerateViewConfiguration
+	virtual void print_view_configuration_info(uint32_t p_view) const;
+
 	//TODO workaround as GDExtensionPtr<void> return type results in build error in godot-cpp
 	GDVIRTUAL1R(uint64_t, _set_system_properties_and_get_next_pointer, GDExtensionPtr<void>);
 	GDVIRTUAL1R(uint64_t, _set_instance_create_info_and_get_next_pointer, GDExtensionPtr<void>);
@@ -99,6 +103,9 @@ class OpenXRExtensionWrapper : public Object {
 	GDVIRTUAL0R(int, _get_composition_layer_count);
 	GDVIRTUAL1R(uint64_t, _get_composition_layer, int);
 	GDVIRTUAL1R(int, _get_composition_layer_order, int);
+	GDVIRTUAL1(_prepare_view_configuration, int);
+	GDVIRTUAL2R(uint64_t, _set_view_configuration_and_get_next_pointer, uint32_t, GDExtensionPtr<void>);
+	GDVIRTUAL1C(_print_view_configuration_info, int);
 
 	virtual PackedStringArray get_suggested_tracker_names();