virtualx-engine/modules/openxr/openxr_api.h
Daniel Castellanos 771ec958af Fixing incorrect swapchain release timing
Applied a couple of checks suggested by @dhoverml for when the
XrResult is not XR_SUCCESS but is also not a failure. Also simplified
checks from @BastiaanOlij feedback.
2023-10-05 01:34:51 -06:00

426 lines
22 KiB
C++

/**************************************************************************/
/* openxr_api.h */
/**************************************************************************/
/* This file is part of: */
/* GODOT ENGINE */
/* https://godotengine.org */
/**************************************************************************/
/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur. */
/* */
/* 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. */
/**************************************************************************/
#ifndef OPENXR_API_H
#define OPENXR_API_H
#include "action_map/openxr_action.h"
#include "extensions/openxr_composition_layer_provider.h"
#include "extensions/openxr_extension_wrapper.h"
#include "util.h"
#include "core/error/error_macros.h"
#include "core/math/projection.h"
#include "core/math/transform_3d.h"
#include "core/math/vector2.h"
#include "core/os/memory.h"
#include "core/string/print_string.h"
#include "core/string/ustring.h"
#include "core/templates/rb_map.h"
#include "core/templates/rid_owner.h"
#include "core/templates/vector.h"
#include "servers/xr/xr_pose.h"
#include <openxr/openxr.h>
// Note, OpenXR code that we wrote for our plugin makes use of C++20 notation for initializing structs which ensures zeroing out unspecified members.
// Godot is currently restricted to C++17 which doesn't allow this notation. Make sure critical fields are set.
// forward declarations, we don't want to include these fully
class OpenXRInterface;
class OpenXRAPI {
private:
// our singleton
static OpenXRAPI *singleton;
// Registered extension wrappers
static Vector<OpenXRExtensionWrapper *> registered_extension_wrappers;
// linked XR interface
OpenXRInterface *xr_interface = nullptr;
// layers
uint32_t num_layer_properties = 0;
XrApiLayerProperties *layer_properties = nullptr;
// extensions
uint32_t num_supported_extensions = 0;
XrExtensionProperties *supported_extensions = nullptr;
Vector<CharString> enabled_extensions;
// composition layer providers
Vector<OpenXRCompositionLayerProvider *> composition_layer_providers;
// view configuration
uint32_t num_view_configuration_types = 0;
XrViewConfigurationType *supported_view_configuration_types = nullptr;
// reference spaces
uint32_t num_reference_spaces = 0;
XrReferenceSpaceType *supported_reference_spaces = nullptr;
// swapchains (note these are platform dependent)
uint32_t num_swapchain_formats = 0;
int64_t *supported_swapchain_formats = nullptr;
// system info
String runtime_name;
String runtime_version;
// configuration
XrFormFactor form_factor = XR_FORM_FACTOR_HEAD_MOUNTED_DISPLAY;
XrViewConfigurationType view_configuration = XR_VIEW_CONFIGURATION_TYPE_PRIMARY_STEREO;
XrReferenceSpaceType reference_space = XR_REFERENCE_SPACE_TYPE_STAGE;
bool submit_depth_buffer = false; // if set to true we submit depth buffers to OpenXR if a suitable extension is enabled.
// blend mode
XrEnvironmentBlendMode environment_blend_mode = XR_ENVIRONMENT_BLEND_MODE_OPAQUE;
uint32_t num_supported_environment_blend_modes = 0;
XrEnvironmentBlendMode *supported_environment_blend_modes = nullptr;
// state
XrInstance instance = XR_NULL_HANDLE;
XrSystemId system_id = 0;
String system_name;
uint32_t vendor_id = 0;
XrSystemTrackingProperties tracking_properties;
XrSession session = XR_NULL_HANDLE;
XrSessionState session_state = XR_SESSION_STATE_UNKNOWN;
bool running = false;
XrFrameState frame_state = { XR_TYPE_FRAME_STATE, NULL, 0, 0, false };
double render_target_size_multiplier = 1.0;
OpenXRGraphicsExtensionWrapper *graphics_extension = nullptr;
XrSystemGraphicsProperties graphics_properties;
uint32_t view_count = 0;
XrViewConfigurationView *view_configuration_views = nullptr;
XrView *views = nullptr;
XrCompositionLayerProjectionView *projection_views = nullptr;
XrCompositionLayerDepthInfoKHR *depth_views = nullptr; // Only used by Composition Layer Depth Extension if available
enum OpenXRSwapChainTypes {
OPENXR_SWAPCHAIN_COLOR,
OPENXR_SWAPCHAIN_DEPTH,
// OPENXR_SWAPCHAIN_VELOCITY,
OPENXR_SWAPCHAIN_MAX
};
struct OpenXRSwapChainInfo {
XrSwapchain swapchain = XR_NULL_HANDLE;
void *swapchain_graphics_data = nullptr;
uint32_t image_index = 0;
bool image_acquired = false;
bool skip_acquire_swapchain = false;
};
OpenXRSwapChainInfo swapchains[OPENXR_SWAPCHAIN_MAX];
XrSpace play_space = XR_NULL_HANDLE;
XrSpace view_space = XR_NULL_HANDLE;
bool view_pose_valid = false;
XRPose::TrackingConfidence head_pose_confidence = XRPose::XR_TRACKING_CONFIDENCE_NONE;
bool load_layer_properties();
bool load_supported_extensions();
bool is_extension_supported(const String &p_extension) const;
bool is_extension_enabled(const String &p_extension) const;
bool openxr_loader_init();
bool resolve_instance_openxr_symbols();
#ifdef ANDROID_ENABLED
// On Android we keep tracker of our external OpenXR loader
void *openxr_loader_library_handle = nullptr;
#endif
// function pointers
#ifdef ANDROID_ENABLED
// On non-Android platforms we use the OpenXR symbol linked into the engine binary.
PFN_xrGetInstanceProcAddr xrGetInstanceProcAddr = nullptr;
#endif
EXT_PROTO_XRRESULT_FUNC3(xrAcquireSwapchainImage, (XrSwapchain), swapchain, (const XrSwapchainImageAcquireInfo *), acquireInfo, (uint32_t *), index)
EXT_PROTO_XRRESULT_FUNC3(xrApplyHapticFeedback, (XrSession), session, (const XrHapticActionInfo *), hapticActionInfo, (const XrHapticBaseHeader *), hapticFeedback)
EXT_PROTO_XRRESULT_FUNC2(xrAttachSessionActionSets, (XrSession), session, (const XrSessionActionSetsAttachInfo *), attachInfo)
EXT_PROTO_XRRESULT_FUNC2(xrBeginFrame, (XrSession), session, (const XrFrameBeginInfo *), frameBeginInfo)
EXT_PROTO_XRRESULT_FUNC2(xrBeginSession, (XrSession), session, (const XrSessionBeginInfo *), beginInfo)
EXT_PROTO_XRRESULT_FUNC3(xrCreateAction, (XrActionSet), actionSet, (const XrActionCreateInfo *), createInfo, (XrAction *), action)
EXT_PROTO_XRRESULT_FUNC3(xrCreateActionSet, (XrInstance), instance, (const XrActionSetCreateInfo *), createInfo, (XrActionSet *), actionSet)
EXT_PROTO_XRRESULT_FUNC3(xrCreateActionSpace, (XrSession), session, (const XrActionSpaceCreateInfo *), createInfo, (XrSpace *), space)
EXT_PROTO_XRRESULT_FUNC2(xrCreateInstance, (const XrInstanceCreateInfo *), createInfo, (XrInstance *), instance)
EXT_PROTO_XRRESULT_FUNC3(xrCreateReferenceSpace, (XrSession), session, (const XrReferenceSpaceCreateInfo *), createInfo, (XrSpace *), space)
EXT_PROTO_XRRESULT_FUNC3(xrCreateSession, (XrInstance), instance, (const XrSessionCreateInfo *), createInfo, (XrSession *), session)
EXT_PROTO_XRRESULT_FUNC3(xrCreateSwapchain, (XrSession), session, (const XrSwapchainCreateInfo *), createInfo, (XrSwapchain *), swapchain)
EXT_PROTO_XRRESULT_FUNC1(xrDestroyAction, (XrAction), action)
EXT_PROTO_XRRESULT_FUNC1(xrDestroyActionSet, (XrActionSet), actionSet)
EXT_PROTO_XRRESULT_FUNC1(xrDestroyInstance, (XrInstance), instance)
EXT_PROTO_XRRESULT_FUNC1(xrDestroySession, (XrSession), session)
EXT_PROTO_XRRESULT_FUNC1(xrDestroySpace, (XrSpace), space)
EXT_PROTO_XRRESULT_FUNC1(xrDestroySwapchain, (XrSwapchain), swapchain)
EXT_PROTO_XRRESULT_FUNC2(xrEndFrame, (XrSession), session, (const XrFrameEndInfo *), frameEndInfo)
EXT_PROTO_XRRESULT_FUNC1(xrEndSession, (XrSession), session)
EXT_PROTO_XRRESULT_FUNC3(xrEnumerateApiLayerProperties, (uint32_t), propertyCapacityInput, (uint32_t *), propertyCountOutput, (XrApiLayerProperties *), properties)
EXT_PROTO_XRRESULT_FUNC6(xrEnumerateEnvironmentBlendModes, (XrInstance), instance, (XrSystemId), systemId, (XrViewConfigurationType), viewConfigurationType, (uint32_t), environmentBlendModeCapacityInput, (uint32_t *), environmentBlendModeCountOutput, (XrEnvironmentBlendMode *), environmentBlendModes)
EXT_PROTO_XRRESULT_FUNC4(xrEnumerateInstanceExtensionProperties, (const char *), layerName, (uint32_t), propertyCapacityInput, (uint32_t *), propertyCountOutput, (XrExtensionProperties *), properties)
EXT_PROTO_XRRESULT_FUNC4(xrEnumerateReferenceSpaces, (XrSession), session, (uint32_t), spaceCapacityInput, (uint32_t *), spaceCountOutput, (XrReferenceSpaceType *), spaces)
EXT_PROTO_XRRESULT_FUNC4(xrEnumerateSwapchainFormats, (XrSession), session, (uint32_t), formatCapacityInput, (uint32_t *), formatCountOutput, (int64_t *), formats)
EXT_PROTO_XRRESULT_FUNC5(xrEnumerateViewConfigurations, (XrInstance), instance, (XrSystemId), systemId, (uint32_t), viewConfigurationTypeCapacityInput, (uint32_t *), viewConfigurationTypeCountOutput, (XrViewConfigurationType *), viewConfigurationTypes)
EXT_PROTO_XRRESULT_FUNC6(xrEnumerateViewConfigurationViews, (XrInstance), instance, (XrSystemId), systemId, (XrViewConfigurationType), viewConfigurationType, (uint32_t), viewCapacityInput, (uint32_t *), viewCountOutput, (XrViewConfigurationView *), views)
EXT_PROTO_XRRESULT_FUNC3(xrGetActionStateBoolean, (XrSession), session, (const XrActionStateGetInfo *), getInfo, (XrActionStateBoolean *), state)
EXT_PROTO_XRRESULT_FUNC3(xrGetActionStateFloat, (XrSession), session, (const XrActionStateGetInfo *), getInfo, (XrActionStateFloat *), state)
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(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)
EXT_PROTO_XRRESULT_FUNC6(xrLocateViews, (XrSession), session, (const XrViewLocateInfo *), viewLocateInfo, (XrViewState *), viewState, (uint32_t), viewCapacityInput, (uint32_t *), viewCountOutput, (XrView *), views)
EXT_PROTO_XRRESULT_FUNC5(xrPathToString, (XrInstance), instance, (XrPath), path, (uint32_t), bufferCapacityInput, (uint32_t *), bufferCountOutput, (char *), buffer)
EXT_PROTO_XRRESULT_FUNC2(xrPollEvent, (XrInstance), instance, (XrEventDataBuffer *), eventData)
EXT_PROTO_XRRESULT_FUNC2(xrReleaseSwapchainImage, (XrSwapchain), swapchain, (const XrSwapchainImageReleaseInfo *), releaseInfo)
EXT_PROTO_XRRESULT_FUNC3(xrResultToString, (XrInstance), instance, (XrResult), value, (char *), buffer)
EXT_PROTO_XRRESULT_FUNC3(xrStringToPath, (XrInstance), instance, (const char *), pathString, (XrPath *), path)
EXT_PROTO_XRRESULT_FUNC2(xrSuggestInteractionProfileBindings, (XrInstance), instance, (const XrInteractionProfileSuggestedBinding *), suggestedBindings)
EXT_PROTO_XRRESULT_FUNC2(xrSyncActions, (XrSession), session, (const XrActionsSyncInfo *), syncInfo)
EXT_PROTO_XRRESULT_FUNC3(xrWaitFrame, (XrSession), session, (const XrFrameWaitInfo *), frameWaitInfo, (XrFrameState *), frameState)
EXT_PROTO_XRRESULT_FUNC2(xrWaitSwapchainImage, (XrSwapchain), swapchain, (const XrSwapchainImageWaitInfo *), waitInfo)
// instance
bool create_instance();
bool get_system_info();
bool load_supported_view_configuration_types();
bool load_supported_environmental_blend_modes();
bool is_view_configuration_supported(XrViewConfigurationType p_configuration_type) const;
bool load_supported_view_configuration_views(XrViewConfigurationType p_configuration_type);
void destroy_instance();
// session
bool create_session();
bool load_supported_reference_spaces();
bool is_reference_space_supported(XrReferenceSpaceType p_reference_space);
bool setup_spaces();
bool load_supported_swapchain_formats();
bool is_swapchain_format_supported(int64_t p_swapchain_format);
bool create_swapchains();
void destroy_session();
// swapchains
bool 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);
bool acquire_image(OpenXRSwapChainInfo &p_swapchain);
bool release_image(OpenXRSwapChainInfo &p_swapchain);
// action map
struct Tracker { // Trackers represent tracked physical objects such as controllers, pucks, etc.
String name; // Name for this tracker (i.e. "/user/hand/left")
XrPath toplevel_path; // OpenXR XrPath for this tracker
RID active_profile_rid; // RID of the active profile for this tracker
};
RID_Owner<Tracker, true> tracker_owner;
RID get_tracker_rid(XrPath p_path);
struct ActionSet { // Action sets define a set of actions that can be enabled together
String name; // Name for this action set (i.e. "godot_action_set")
bool is_attached; // If true our action set has been attached to the session and can no longer be modified
XrActionSet handle; // OpenXR handle for this action set
};
RID_Owner<ActionSet, true> action_set_owner;
struct ActionTracker { // Links and action to a tracker
RID tracker_rid; // RID of the tracker
XrSpace space; // Optional space for pose actions
bool was_location_valid; // If true the last position we obtained was valid
};
struct Action { // Actions define the inputs and outputs in OpenXR
RID action_set_rid; // RID of the action set this action belongs to
String name; // Name for this action (i.e. "aim_pose")
XrActionType action_type; // Type of action (bool, float, etc.)
Vector<ActionTracker> trackers; // The trackers this action can be used with
XrAction handle; // OpenXR handle for this action
};
RID_Owner<Action, true> action_owner;
RID get_action_rid(XrAction p_action);
struct InteractionProfile { // Interaction profiles define suggested bindings between the physical inputs on controller types and our actions
String name; // Name of the interaction profile (i.e. "/interaction_profiles/valve/index_controller")
XrPath path; // OpenXR path for this profile
Vector<XrActionSuggestedBinding> bindings; // OpenXR action bindings
};
RID_Owner<InteractionProfile, true> interaction_profile_owner;
RID get_interaction_profile_rid(XrPath p_path);
XrPath get_interaction_profile_path(RID p_interaction_profile);
// state changes
bool poll_events();
bool on_state_idle();
bool on_state_ready();
bool on_state_synchronized();
bool on_state_visible();
bool on_state_focused();
bool on_state_stopping();
bool on_state_loss_pending();
bool on_state_exiting();
// convenience
void copy_string_to_char_buffer(const String p_string, char *p_buffer, int p_buffer_len);
public:
XrInstance get_instance() const { return instance; };
XrSystemId get_system_id() const { return system_id; };
XrSession get_session() const { return session; };
String get_runtime_name() const { return runtime_name; };
String get_runtime_version() const { return runtime_version; };
// helper method to convert an XrPosef to a Transform3D
Transform3D transform_from_pose(const XrPosef &p_pose);
// helper method to get a valid Transform3D from an openxr space location
XRPose::TrackingConfidence transform_from_location(const XrSpaceLocation &p_location, Transform3D &r_transform);
XRPose::TrackingConfidence transform_from_location(const XrHandJointLocationEXT &p_location, Transform3D &r_transform);
void parse_velocities(const XrSpaceVelocity &p_velocity, Vector3 &r_linear_velocity, Vector3 &r_angular_velocity);
bool xr_result(XrResult result, const char *format, Array args = Array()) const;
bool is_top_level_path_supported(const String &p_toplevel_path);
bool is_interaction_profile_supported(const String &p_ip_path);
bool interaction_profile_supports_io_path(const String &p_ip_path, const String &p_io_path);
static bool openxr_is_enabled(bool p_check_run_in_editor = true);
_FORCE_INLINE_ static OpenXRAPI *get_singleton() { return singleton; }
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_swapchain_format_name(int64_t p_swapchain_format) const;
void set_xr_interface(OpenXRInterface *p_xr_interface);
static void register_extension_wrapper(OpenXRExtensionWrapper *p_extension_wrapper);
static void unregister_extension_wrapper(OpenXRExtensionWrapper *p_extension_wrapper);
static void register_extension_metadata();
static void cleanup_extension_wrappers();
void set_form_factor(XrFormFactor p_form_factor);
XrFormFactor get_form_factor() const { return form_factor; }
void set_view_configuration(XrViewConfigurationType p_view_configuration);
XrViewConfigurationType get_view_configuration() const { return view_configuration; }
void set_reference_space(XrReferenceSpaceType p_reference_space);
XrReferenceSpaceType get_reference_space() const { return reference_space; }
void set_submit_depth_buffer(bool p_submit_depth_buffer);
bool get_submit_depth_buffer() const { return submit_depth_buffer; }
bool is_initialized();
bool is_running();
bool initialize(const String &p_rendering_driver);
bool initialize_session();
void finish();
XrSpace get_play_space() const { return play_space; }
XrTime get_next_frame_time() { return frame_state.predictedDisplayTime + frame_state.predictedDisplayPeriod; }
bool can_render() { return instance != XR_NULL_HANDLE && session != XR_NULL_HANDLE && running && view_pose_valid && frame_state.shouldRender; }
Size2 get_recommended_target_size();
XRPose::TrackingConfidence get_head_center(Transform3D &r_transform, Vector3 &r_linear_velocity, Vector3 &r_angular_velocity);
bool get_view_transform(uint32_t p_view, Transform3D &r_transform);
bool get_view_projection(uint32_t p_view, double p_z_near, double p_z_far, Projection &p_camera_matrix);
bool process();
void pre_render();
bool pre_draw_viewport(RID p_render_target);
XrSwapchain get_color_swapchain();
RID get_color_texture();
RID get_depth_texture();
void post_draw_viewport(RID p_render_target);
void end_frame();
// Display refresh rate
float get_display_refresh_rate() const;
void set_display_refresh_rate(float p_refresh_rate);
Array get_available_display_refresh_rates() const;
// Render Target size multiplier
double get_render_target_size_multiplier() const;
void set_render_target_size_multiplier(double multiplier);
// Foveation settings
bool is_foveation_supported() const;
int get_foveation_level() const;
void set_foveation_level(int p_foveation_level);
bool get_foveation_dynamic() const;
void set_foveation_dynamic(bool p_foveation_dynamic);
// action map
String get_default_action_map_resource_name();
RID tracker_create(const String p_name);
String tracker_get_name(RID p_tracker);
void tracker_check_profile(RID p_tracker, XrSession p_session = XR_NULL_HANDLE);
void tracker_free(RID p_tracker);
RID action_set_create(const String p_name, const String p_localized_name, const int p_priority);
String action_set_get_name(RID p_action_set);
bool attach_action_sets(const Vector<RID> &p_action_sets);
void action_set_free(RID p_action_set);
RID action_create(RID p_action_set, const String p_name, const String p_localized_name, OpenXRAction::ActionType p_action_type, const Vector<RID> &p_trackers);
String action_get_name(RID p_action);
void action_free(RID p_action);
RID interaction_profile_create(const String p_name);
String interaction_profile_get_name(RID p_interaction_profile);
void interaction_profile_clear_bindings(RID p_interaction_profile);
bool interaction_profile_add_binding(RID p_interaction_profile, RID p_action, const String p_path);
bool interaction_profile_suggest_bindings(RID p_interaction_profile);
void interaction_profile_free(RID p_interaction_profile);
bool sync_action_sets(const Vector<RID> p_active_sets);
bool get_action_bool(RID p_action, RID p_tracker);
float get_action_float(RID p_action, RID p_tracker);
Vector2 get_action_vector2(RID p_action, RID p_tracker);
XRPose::TrackingConfidence get_action_pose(RID p_action, RID p_tracker, Transform3D &r_transform, Vector3 &r_linear_velocity, Vector3 &r_angular_velocity);
bool trigger_haptic_pulse(RID p_action, RID p_tracker, float p_frequency, float p_amplitude, XrDuration p_duration_ns);
void register_composition_layer_provider(OpenXRCompositionLayerProvider *provider);
void unregister_composition_layer_provider(OpenXRCompositionLayerProvider *provider);
const XrEnvironmentBlendMode *get_supported_environment_blend_modes(uint32_t &count);
bool is_environment_blend_mode_supported(XrEnvironmentBlendMode p_blend_mode) const;
bool set_environment_blend_mode(XrEnvironmentBlendMode p_blend_mode);
XrEnvironmentBlendMode get_environment_blend_mode() const { return environment_blend_mode; }
OpenXRAPI();
~OpenXRAPI();
};
#endif // OPENXR_API_H