Implement XR_FB_space_warp extension

demo/.editorconfig

@@ -0,0 +1,4 @@
+root = true
+
+[*]
+charset = utf-8

demo/bone-cube.glb.import

@@ -0,0 +1,37 @@
+[remap]
+
+importer="scene"
+importer_version=1
+type="PackedScene"
+uid="uid://detbvmjyhigan"
+path="res://.godot/imported/bone-cube.glb-853e452a3ff35207a1fee3eefca16cf0.scn"
+
+[deps]
+
+source_file="res://bone-cube.glb"
+dest_files=["res://.godot/imported/bone-cube.glb-853e452a3ff35207a1fee3eefca16cf0.scn"]
+
+[params]
+
+nodes/root_type=""
+nodes/root_name=""
+nodes/apply_root_scale=true
+nodes/root_scale=1.0
+nodes/import_as_skeleton_bones=false
+nodes/use_node_type_suffixes=true
+meshes/ensure_tangents=true
+meshes/generate_lods=true
+meshes/create_shadow_meshes=true
+meshes/light_baking=1
+meshes/lightmap_texel_size=0.2
+meshes/force_disable_compression=false
+skins/use_named_skins=true
+animation/import=true
+animation/fps=30
+animation/trimming=false
+animation/remove_immutable_tracks=true
+animation/import_rest_as_RESET=false
+import_script/path=""
+_subresources={}
+gltf/naming_version=1
+gltf/embedded_image_handling=1

demo/bone_cube.gd

@@ -0,0 +1,8 @@
+extends Node3D
+
+@onready var skeleton := $Armature/Skeleton3D
+
+func _physics_process(delta: float) -> void:
+	var new_basis := basis.rotated(Vector3.FORWARD, TAU * (Time.get_ticks_msec() / 2000.0))
+	var quat := Quaternion(new_basis)
+	skeleton.set_bone_pose_rotation(0, quat)

demo/bone_cube.tscn

@@ -0,0 +1,7 @@
+[gd_scene load_steps=3 format=3 uid="uid://cfbmcnbws28t1"]
+
+[ext_resource type="PackedScene" uid="uid://detbvmjyhigan" path="res://bone-cube.glb" id="1_fud8w"]
+[ext_resource type="Script" path="res://bone_cube.gd" id="2_n023m"]
+
+[node name="BoneCube" instance=ExtResource("1_fud8w")]
+script = ExtResource("2_n023m")

demo/main.tscn

@@ -1,6 +1,8 @@
-[gd_scene load_steps=10 format=3 uid="uid://cqsodpswgup8w"]
+[gd_scene load_steps=17 format=3 uid="uid://cqsodpswgup8w"]
 
 [ext_resource type="Script" path="res://main.gd" id="1_fsva1"]
+[ext_resource type="Script" path="res://multi_mesh_move.gd" id="3_h2yge"]
+[ext_resource type="PackedScene" uid="uid://cfbmcnbws28t1" path="res://bone_cube.tscn" id="4_1bvp3"]
 [ext_resource type="Material" uid="uid://bdwh0vc86hsdb" path="res://assets/hand_silhouette_outline_mat.tres" id="7_tpkib"]
 
 [sub_resource type="ProceduralSkyMaterial" id="ProceduralSkyMaterial_0x6cv"]
@@ -30,6 +32,24 @@ size = Vector3(0.1, 0.1, 0.1)
 material = SubResource("StandardMaterial3D_k604q")
 size = Vector2(10, 10)
 
+[sub_resource type="ParticleProcessMaterial" id="ParticleProcessMaterial_yvvw4"]
+spread = 0.0
+initial_velocity_min = 3.0
+initial_velocity_max = 3.0
+gravity = Vector3(0, 0, 0)
+
+[sub_resource type="BoxMesh" id="BoxMesh_t5jnj"]
+
+[sub_resource type="BoxMesh" id="BoxMesh_0xm2m"]
+
+[sub_resource type="BoxMesh" id="BoxMesh_h2yge"]
+
+[sub_resource type="MultiMesh" id="MultiMesh_1bvp3"]
+transform_format = 1
+instance_count = 1
+mesh = SubResource("BoxMesh_h2yge")
+buffer = PackedFloat32Array(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0)
+
 [node name="Main" type="Node3D"]
 script = ExtResource("1_fsva1")
 
@@ -114,5 +134,46 @@ hand_tracker = &"/user/hand_tracker/right"
 [node name="Floor" type="MeshInstance3D" parent="."]
 mesh = SubResource("PlaneMesh_mjcgt")
 
+[node name="GPUParticles3D" type="GPUParticles3D" parent="."]
+transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, -1, 1, -4)
+amount = 2
+process_material = SubResource("ParticleProcessMaterial_yvvw4")
+draw_pass_1 = SubResource("BoxMesh_t5jnj")
+
+[node name="Label3D" type="Label3D" parent="GPUParticles3D"]
+transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, -1, 0, 0)
+text = "GPU
+Particles"
+
+[node name="CPUParticles3D" type="CPUParticles3D" parent="."]
+transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, -1, 2.21267, -4)
+amount = 2
+mesh = SubResource("BoxMesh_0xm2m")
+spread = 0.0
+gravity = Vector3(0, 0, 0)
+initial_velocity_min = 3.0
+initial_velocity_max = 3.0
+
+[node name="Label3D" type="Label3D" parent="CPUParticles3D"]
+transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, -1, 0, 0)
+text = "CPU
+Particles"
+
+[node name="MultiMeshInstance3D" type="MultiMeshInstance3D" parent="."]
+transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 3.40488, -4)
+multimesh = SubResource("MultiMesh_1bvp3")
+script = ExtResource("3_h2yge")
+
+[node name="Label3D" type="Label3D" parent="MultiMeshInstance3D"]
+transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, -2, 0, 0)
+text = "MultiMesh"
+
+[node name="BoneCube" parent="." instance=ExtResource("4_1bvp3")]
+transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, -3, 1, -2)
+
+[node name="Label3D" type="Label3D" parent="BoneCube"]
+transform = Transform3D(0.5, 0, 0.866025, 0, 1, 0, -0.866025, 0, 0.5, 0, 1, 0)
+text = "Skeleton"
+
 [connection signal="openxr_fb_render_model_loaded" from="XROrigin3D/LeftHand/LeftControllerFbRenderModel" to="." method="_on_left_controller_fb_render_model_render_model_loaded"]
 [connection signal="openxr_fb_render_model_loaded" from="XROrigin3D/RightHand/RightControllerFbRenderModel" to="." method="_on_right_controller_fb_render_model_render_model_loaded"]

demo/multi_mesh_move.gd

@@ -0,0 +1,6 @@
+extends MultiMeshInstance3D
+
+func _physics_process(delta: float) -> void:
+	var origin := Vector3(sin(Time.get_ticks_msec() / 500.0), 0, 0)
+	var new_transform := Transform3D(basis, origin)
+	multimesh.set_instance_transform(0, new_transform)

demo/project.godot

@@ -12,7 +12,7 @@ config_version=5
 
 config/name="OpenXR Demo"
 run/main_scene="res://main.tscn"
-config/features=PackedStringArray("4.3", "GL Compatibility")
+config/features=PackedStringArray("4.4", "GL Compatibility")
 config/icon="res://icon.svg"
 
 [debug]

plugin/src/main/cpp/extensions/openxr_fb_space_warp_extension_wrapper.cpp

@@ -0,0 +1,199 @@
+/**************************************************************************/
+/*  openxr_fb_space_warp_extension_wrapper.cpp                            */
+/**************************************************************************/
+/*                       This file is part of:                            */
+/*                              GODOT XR                                  */
+/*                      https://godotengine.org                           */
+/**************************************************************************/
+/* Copyright (c) 2022-present Godot XR contributors (see CONTRIBUTORS.md) */
+/*                                                                        */
+/* Permission is hereby granted, free of charge, to any person obtaining  */
+/* a copy of this software and associated documentation files (the        */
+/* "Software"), to deal in the Software without restriction, including    */
+/* without limitation the rights to use, copy, modify, merge, publish,    */
+/* distribute, sublicense, and/or sell copies of the Software, and to     */
+/* permit persons to whom the Software is furnished to do so, subject to  */
+/* the following conditions:                                              */
+/*                                                                        */
+/* The above copyright notice and this permission notice shall be         */
+/* included in all copies or substantial portions of the Software.        */
+/*                                                                        */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,        */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF     */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. */
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY   */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,   */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE      */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                 */
+/**************************************************************************/
+
+#include "extensions/openxr_fb_space_warp_extension_wrapper.h"
+
+#include <godot_cpp/classes/open_xr_interface.hpp>
+#include <godot_cpp/classes/open_xrapi_extension.hpp>
+#include <godot_cpp/classes/xr_server.hpp>
+
+#define GL_RGBA16F 0x881A
+#define GL_DEPTH24_STENCIL8 0x88F0
+
+OpenXRFbSpaceWarpExtensionWrapper *OpenXRFbSpaceWarpExtensionWrapper::singleton = nullptr;
+
+OpenXRFbSpaceWarpExtensionWrapper *OpenXRFbSpaceWarpExtensionWrapper::get_singleton() {
+	if (singleton == nullptr) {
+		singleton = memnew(OpenXRFbSpaceWarpExtensionWrapper());
+	}
+	return singleton;
+}
+
+OpenXRFbSpaceWarpExtensionWrapper::OpenXRFbSpaceWarpExtensionWrapper() :
+		OpenXRExtensionWrapperExtension() {
+	ERR_FAIL_COND_MSG(singleton != nullptr, "An OpenXRFbSpaceWarpExtensionWrapper singleton already exists.");
+
+	request_extensions[XR_FB_SPACE_WARP_EXTENSION_NAME] = &fb_space_warp_ext;
+	singleton = this;
+}
+
+OpenXRFbSpaceWarpExtensionWrapper::~OpenXRFbSpaceWarpExtensionWrapper() {
+	singleton = nullptr;
+}
+
+godot::Dictionary OpenXRFbSpaceWarpExtensionWrapper::_get_requested_extensions() {
+	godot::Dictionary result;
+	for (auto ext : request_extensions) {
+		godot::String key = ext.first;
+		uint64_t value = reinterpret_cast<uint64_t>(ext.second);
+		result[key] = (godot::Variant)value;
+	}
+	return result;
+}
+
+uint64_t OpenXRFbSpaceWarpExtensionWrapper::_set_system_properties_and_get_next_pointer(void *p_next_pointer) {
+	if (fb_space_warp_ext) {
+		system_space_warp_properties.next = p_next_pointer;
+		return reinterpret_cast<uint64_t>(&system_space_warp_properties);
+	} else {
+		return reinterpret_cast<uint64_t>(p_next_pointer);
+	}
+}
+
+uint64_t OpenXRFbSpaceWarpExtensionWrapper::_set_projection_views_and_get_next_pointer(int p_view_index, void *p_next_pointer) {
+	if (enabled) {
+		return reinterpret_cast<uint64_t>(&space_warp_info[p_view_index]);
+	} else {
+		return 0;
+	}
+}
+
+void OpenXRFbSpaceWarpExtensionWrapper::_on_session_created(uint64_t p_instance) {
+	if (fb_space_warp_ext) {
+		get_openxr_api()->register_projection_views_extension(this);
+	}
+}
+
+void OpenXRFbSpaceWarpExtensionWrapper::_on_session_destroyed() {
+	if (fb_space_warp_ext) {
+		get_openxr_api()->unregister_projection_views_extension(this);
+	}
+}
+
+void OpenXRFbSpaceWarpExtensionWrapper::_on_state_ready() {
+	if (!fb_space_warp_ext) {
+		return;
+	}
+
+	Ref<OpenXRInterface> openxr_interface = XRServer::get_singleton()->find_interface("OpenXR");
+	int view_count = openxr_interface->get_view_count();
+	int width = system_space_warp_properties.recommendedMotionVectorImageRectWidth;
+	int height = system_space_warp_properties.recommendedMotionVectorImageRectHeight;
+
+	motion_vector_swapchain_info = get_openxr_api()->openxr_swap_chain_info_create(0, XR_SWAPCHAIN_USAGE_SAMPLED_BIT | XR_SWAPCHAIN_USAGE_COLOR_ATTACHMENT_BIT, GL_RGBA16F, width, height, 1, view_count);
+	motion_vector_depth_swapchain_info = get_openxr_api()->openxr_swap_chain_info_create(0, XR_SWAPCHAIN_USAGE_SAMPLED_BIT | XR_SWAPCHAIN_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT, GL_DEPTH24_STENCIL8, width, height, 1, view_count);
+}
+
+void OpenXRFbSpaceWarpExtensionWrapper::_on_main_swapchains_created() {
+	if (!fb_space_warp_ext) {
+		return;
+	}
+
+	Ref<OpenXRInterface> openxr_interface = XRServer::get_singleton()->find_interface("OpenXR");
+	int view_count = openxr_interface->get_view_count();
+
+	XrPosef identity_pose = { { 0.0, 0.0, 0.0, 1.0 }, { 0.0, 0.0, 0.0 } };
+
+	space_warp_info = memnew_arr(XrCompositionLayerSpaceWarpInfoFB, 2);
+	for (int i = 0; i < view_count; i++) {
+		space_warp_info[i].type = XR_TYPE_COMPOSITION_LAYER_SPACE_WARP_INFO_FB;
+
+		space_warp_info[i].next = nullptr;
+
+		// @todo Provide a way to set XR_COMPOSITION_LAYER_SPACE_WARP_INFO_FRAME_SKIP_BIT_FB.
+		space_warp_info[i].layerFlags = 0;
+
+		space_warp_info[i].motionVectorSubImage.swapchain = (XrSwapchain)get_openxr_api()->openxr_swap_chain_info_get_swapchain(motion_vector_swapchain_info);
+		space_warp_info[i].motionVectorSubImage.imageRect.offset.x = 0;
+		space_warp_info[i].motionVectorSubImage.imageRect.offset.y = 0;
+		space_warp_info[i].motionVectorSubImage.imageRect.extent.width = system_space_warp_properties.recommendedMotionVectorImageRectWidth;
+		space_warp_info[i].motionVectorSubImage.imageRect.extent.height = system_space_warp_properties.recommendedMotionVectorImageRectHeight;
+		space_warp_info[i].motionVectorSubImage.imageArrayIndex = i;
+
+		// @todo Update this to account for locomotion.
+		space_warp_info[i].appSpaceDeltaPose = identity_pose;
+
+		space_warp_info[i].depthSubImage.swapchain = (XrSwapchain)get_openxr_api()->openxr_swap_chain_info_get_swapchain(motion_vector_depth_swapchain_info);
+		space_warp_info[i].depthSubImage.imageRect.offset.x = 0;
+		space_warp_info[i].depthSubImage.imageRect.offset.y = 0;
+		space_warp_info[i].depthSubImage.imageRect.extent.width = system_space_warp_properties.recommendedMotionVectorImageRectWidth;
+		space_warp_info[i].depthSubImage.imageRect.extent.height = system_space_warp_properties.recommendedMotionVectorImageRectHeight;
+		space_warp_info[i].depthSubImage.imageArrayIndex = i;
+
+		space_warp_info[i].minDepth = 0.0;
+		space_warp_info[i].maxDepth = 1.0;
+
+		space_warp_info[i].farZ = get_openxr_api()->get_render_state_z_near();
+		space_warp_info[i].nearZ = get_openxr_api()->get_render_state_z_far();
+	}
+}
+
+void OpenXRFbSpaceWarpExtensionWrapper::_on_pre_render() {
+	if (!fb_space_warp_ext) {
+		return;
+	}
+
+	get_openxr_api()->openxr_swap_chain_info_acquire(motion_vector_swapchain_info);
+	get_openxr_api()->openxr_swap_chain_info_acquire(motion_vector_depth_swapchain_info);
+
+	RID motion_vector_swapchain_image = get_openxr_api()->openxr_swap_chain_info_get_image(motion_vector_swapchain_info);
+	get_openxr_api()->set_motion_vector_texture(motion_vector_swapchain_image);
+	RID motion_vector_depth_swapchain_image = get_openxr_api()->openxr_swap_chain_info_get_image(motion_vector_depth_swapchain_info);
+	get_openxr_api()->set_motion_vector_depth_texture(motion_vector_depth_swapchain_image);
+
+	int target_width = system_space_warp_properties.recommendedMotionVectorImageRectWidth;
+	int target_height = system_space_warp_properties.recommendedMotionVectorImageRectHeight;
+	Size2i render_target_size = { target_width, target_height };
+
+	get_openxr_api()->set_motion_vector_target_size(render_target_size);
+
+	Ref<OpenXRInterface> openxr_interface = XRServer::get_singleton()->find_interface("OpenXR");
+	int view_count = openxr_interface->get_view_count();
+	for (int i = 0; i < view_count; i++) {
+		space_warp_info[i].farZ = get_openxr_api()->get_render_state_z_near();
+		space_warp_info[i].nearZ = get_openxr_api()->get_render_state_z_far();
+	}
+}
+
+void OpenXRFbSpaceWarpExtensionWrapper::_on_post_draw_viewport(const RID &p_render_target) {
+	get_openxr_api()->openxr_swap_chain_info_release(motion_vector_swapchain_info);
+	get_openxr_api()->openxr_swap_chain_info_release(motion_vector_depth_swapchain_info);
+}
+
+bool OpenXRFbSpaceWarpExtensionWrapper::is_available() {
+	return available;
+}
+
+void OpenXRFbSpaceWarpExtensionWrapper::set_space_warp_enabled(bool p_enable) {
+	enabled = p_enable;
+}
+
+void OpenXRFbSpaceWarpExtensionWrapper::_bind_methods() {
+	ClassDB::bind_method(D_METHOD("set_space_warp_enabled", "enable"), &OpenXRFbSpaceWarpExtensionWrapper::set_space_warp_enabled);
+}