rift_interface.h

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// Copyright 2025, Beyley Cardellio
// SPDX-License-Identifier: BSL-1.0
/*!
 * @file
 * @brief  Interface to Oculus Rift driver code.
 * @author Beyley Cardellio <ep1cm1n10n123@gmail.com>
 * @ingroup drv_rift
 */
 
#pragma once
 
#include "xrt/xrt_device.h"
#include "xrt/xrt_defines.h"
#include "xrt/xrt_prober.h"
 
#include "os/os_hid.h"
#include "os/os_threading.h"
 
#include "util/u_device.h"
#include "util/u_logging.h"
 
#include "math/m_imu_3dof.h"
#include "math/m_api.h"
#include "math/m_mathinclude.h"
 
#include <stdlib.h>
#include <stdio.h>
 
#ifdef __cplusplus
extern "C" {
#endif
 
#define REPORT_MAX_SIZE 69                // max size of a feature report (FEATURE_REPORT_CALIBRATE)
#define KEEPALIVE_INTERVAL_NS 10000000000 // 10 seconds
// give a 5% breathing room (at 10 seconds, this is 500 milliseconds of breathing room)
#define KEEPALIVE_SEND_RATE_NS ((KEEPALIVE_INTERVAL_NS * 19) / 20)
#define IMU_SAMPLE_RATE (1000)      // 1000hz
#define NS_PER_SAMPLE (1000 * 1000) // 1ms (1,000,000 ns) per sample
 
#define MICROMETERS_TO_METERS(microns) (float)microns / 1000000.0f
 
// value taken from LibOVR 0.4.4
#define DEFAULT_EXTRA_EYE_ROTATION DEG_TO_RAD(30.0f)
 
enum rift_feature_reports
{
        // DK1
        FEATURE_REPORT_CONFIG = 2,         // get + set
        FEATURE_REPORT_CALIBRATE = 3,      // get + set
        FEATURE_REPORT_RANGE = 4,          // get + set
        FEATURE_REPORT_REGISTER = 5,       // get + set
        FEATURE_REPORT_DFU = 6,            // get + set
        FEATURE_REPORT_DK1_KEEP_ALIVE = 8, // get + set
        FEATURE_REPORT_DISPLAY_INFO = 9,   // get + set
        FEATURE_REPORT_SERIAL = 10,        // get + set
 
        // DK2
        FEATURE_REPORT_TRACKING = 12,        // get + set
        FEATURE_REPORT_DISPLAY = 13,         // get + set
        FEATURE_REPORT_MAG_CALIBRATION = 14, // get + set
        FEATURE_REPORT_POS_CALIBRATION = 15, // get + set
        FEATURE_REPORT_CUSTOM_PATTERN = 16,  // get + set
        FEATURE_REPORT_KEEPALIVE_MUX = 17,   // get + set
        FEATURE_REPORT_MANUFACTURING = 18,   // get + set
        FEATURE_REPORT_UUID = 19,            // get + set
        FEATURE_REPORT_TEMPERATURE = 20,     // get + set
        FEATURE_REPORT_GYROOFFSET = 21,      // get only
        FEATURE_REPORT_LENS_DISTORTION = 22, // get + set
};
 
enum rift_config_report_flags
{
        // output the sample data raw from the sensors without converting them to known units
        RIFT_CONFIG_REPORT_USE_RAW = 1,
        // internal test mode for calibrating zero rate drift on gyro
        RIFT_CONFIG_REPORT_INTERNAL_CALIBRATION = 1 << 1,
        // use the calibration parameters stored on the device
        RIFT_CONFIG_REPORT_USE_CALIBRATION = 1 << 2,
        // recalibrate the gyro zero rate offset when the device is stationary
        RIFT_CONFIG_REPORT_AUTO_CALIBRATION = 1 << 3,
        // stop sending IN reports when the device has stopped moving for Interval milliseconds
        RIFT_CONFIG_REPORT_MOTION_KEEP_ALIVE = 1 << 4,
        // stop sending IN reports when the device has stopped receiving feature reports for Interval milliseconds
        RIFT_CONFIG_REPORT_COMMAND_KEEP_ALIVE = 1 << 5,
        // output the IN report data in the coordinate system used by LibOVR relative to the tracker, otherwise, report
        // in the coordinate system of the device
        RIFT_CONFIG_REPORT_USE_SENSOR_COORDINATES = 1 << 6,
        // override the power state of the USB hub, forcing it to act as if the external power source is connected (DK2
        // only, does nothing on DK1)
        RIFT_CONFIG_REPORT_OVERRIDE_POWER = 1 << 7,
};
 
enum rift_distortion_type
{
        RIFT_DISTORTION_TYPE_DIMS = 1,
        RIFT_DISTORTION_TYPE_K = 2,
};
 
enum rift_lens_type
{
        // firmware indirectly states lens type A is 0
        RIFT_LENS_TYPE_A = 0,
        // firmware does not state what lens type B is, 1 is an educated guess
        RIFT_LENS_TYPE_B = 1,
};
 
#define IN_REPORT_DK2 11
 
#define CATMULL_COEFFICIENTS 11
#define CHROMATIC_ABBERATION_COEFFEICENT_COUNT 4
 
enum rift_lens_distortion_version
{
        // no distortion data is stored
        RIFT_LENS_DISTORTION_NONE = 0,
        // standard distortion matrix
        RIFT_LENS_DISTORTION_LCSV_CATMULL_ROM_10_VERSION_1 = 1,
};
 
/*
 *
 * Packed structs for USB communication (borrowed from Rokid driver)
 *
 */
 
#if defined(__GNUC__)
#define RIFT_PACKED __attribute__((packed))
#else
#define RIFT_PACKED
#endif /* __GNUC__ */
 
#if defined(_MSC_VER)
#pragma pack(push, 1)
#endif
 
struct rift_config_report
{
        uint16_t command_id;
        uint8_t config_flags;
        // the IN report rate of the headset, rate is calculated as `sample_rate / (1 + interval)`
        uint8_t interval;
        // sample rate of the IMU, always 1000hz on DK1/DK2, read-only
        uint16_t sample_rate;
} RIFT_PACKED;
 
struct rift_display_info_report
{
        uint16_t command_id;
        uint8_t distortion_type;
        // the horizontal resolution of the display, in pixels
        uint16_t resolution_x;
        // the vertical resolution of the display, in pixels
        uint16_t resolution_y;
        // width in micrometers
        uint32_t display_width;
        // height in micrometers
        uint32_t display_height;
        // the vertical center of the display, in micrometers
        uint32_t center_v;
        // the separation between the two lenses, in micrometers
        uint32_t lens_separation;
        uint32_t lens_distance[2];
        float distortion[6];
} RIFT_PACKED;
 
struct rift_catmull_rom_distortion_report_data
{
        // eye relief setting, in micrometers from front surface of lens
        uint16_t eye_relief;
        // the k coeffecients of the distortion
        uint16_t k[CATMULL_COEFFICIENTS];
        uint16_t max_r;
        uint16_t meters_per_tan_angle_at_center;
        uint16_t chromatic_abberation[CHROMATIC_ABBERATION_COEFFEICENT_COUNT];
        uint8_t unused[14];
} RIFT_PACKED;
 
struct rift_lens_distortion_report
{
        uint16_t command_id;
        // the amount of distortions on this device
        uint8_t num_distortions;
        // the index of this distortion in the devices array
        uint8_t distortion_idx;
        // unused bitmask field
        uint8_t bitmask;
        // the type of the lenses
        uint16_t lens_type;
        // the version of the lens distortion data
        uint16_t distortion_version;
 
        union {
                struct rift_catmull_rom_distortion_report_data lcsv_catmull_rom_10;
        } RIFT_PACKED data;
} RIFT_PACKED;
 
struct dk2_report_keepalive_mux
{
        uint16_t command;
        uint8_t in_report;
        uint16_t interval;
} RIFT_PACKED;
 
enum rift_display_mode
{
        RIFT_DISPLAY_MODE_GLOBAL,
        RIFT_DISPLAY_MODE_ROLLING_TOP_BOTTOM,
        RIFT_DISPLAY_MODE_ROLLING_LEFT_RIGHT,
        RIFT_DISPLAY_MODE_ROLLING_RIGHT_LEFT,
};
 
enum rift_display_limit
{
        RIFT_DISPLAY_LIMIT_ACL_OFF = 0,
        RIFT_DISPLAY_LIMIT_ACL_30 = 1,
        RIFT_DISPLAY_LIMIT_ACL_25 = 2,
        RIFT_DISPLAY_LIMIT_ACL_50 = 3,
};
 
enum rift_display_flags
{
        RIFT_DISPLAY_USE_ROLLING = 1 << 6,
        RIFT_DISPLAY_REVERSE_ROLLING = 1 << 7,
        RIFT_DISPLAY_HIGH_BRIGHTNESS = 1 << 8,
        RIFT_DISPLAY_SELF_REFRESH = 1 << 9,
        RIFT_DISPLAY_READ_PIXEL = 1 << 10,
        RIFT_DISPLAY_DIRECT_PENTILE = 1 << 11,
};
 
struct rift_display_report
{
        uint16_t command_id;
        // relative brightness setting independent of pixel persistence, only effective when high brightness is disabled
        uint8_t brightness;
        // a set of flags, ordered from LSB -> MSB
        // - panel mode/shutter type (4 bits), read only, see rift_display_mode
        // - current limit (2 bits), see rift_display_limit
        // - use rolling (1 bit)
        // - reverse rolling (1 bit), unavailable on released DK2 firmware for unknown reason
        // - high brightness (1 bit), unavailable on released DK2 firmware for unpublished reason
        // - self refresh (1 bit)
        // - read pixel (1 bit)
        // - direct pentile (1 bit)
        uint32_t flags;
        // the length of time in rows that the display is lit each frame, defaults to the full size of the display, full
        // persistence
        uint16_t persistence;
        // the offset in rows from vsync that the panel is lit when using global shutter, no effect in rolling shutter,
        // disabled on released DK2 firmware for unknown reason
        uint16_t lighting_offset;
        // the time in microseconds it is estimated for a pixel to settle to one value after it is set, read only
        uint16_t pixel_settle;
        // the number of rows including active area and blanking period used with persistence and lightingoffset, read
        // only
        uint16_t total_rows;
} RIFT_PACKED;
 
struct dk2_sensor_sample
{
        uint8_t data[8];
} RIFT_PACKED;
 
struct dk2_sample_pack
{
        struct dk2_sensor_sample accel;
        struct dk2_sensor_sample gyro;
} RIFT_PACKED;
 
#define DK2_MAX_SAMPLES 2
struct dk2_in_report
{
        uint16_t command_id;
        uint8_t num_samples;
        uint16_t sample_count;
        uint16_t temperature;
        uint32_t sample_timestamp;
        struct dk2_sample_pack samples[DK2_MAX_SAMPLES];
        int16_t mag_x;
        int16_t mag_y;
        int16_t mag_z;
        uint16_t frame_count;
        uint32_t frame_timestamp;
        uint8_t frame_id;
        uint8_t tracking_pattern;
        uint16_t tracking_count;
        uint32_t tracking_timestamp;
} RIFT_PACKED;
 
#if defined(_MSC_VER)
#pragma pack(pop)
#endif
 
struct rift_catmull_rom_distortion_data
{
        // the k coeffecients of the distortion
        float k[CATMULL_COEFFICIENTS];
        float max_r;
        float meters_per_tan_angle_at_center;
        float chromatic_abberation[CHROMATIC_ABBERATION_COEFFEICENT_COUNT];
};
 
struct rift_lens_distortion
{
        // the version of the lens distortion data
        uint16_t distortion_version;
        // eye relief setting, in meters from surface of lens
        float eye_relief;
 
        union {
                struct rift_catmull_rom_distortion_data lcsv_catmull_rom_10;
        } RIFT_PACKED data;
};
 
struct rift_scale_and_offset
{
        struct xrt_vec2 scale;
        struct xrt_vec2 offset;
};
 
struct rift_viewport_fov_tan
{
        float up_tan;
        float down_tan;
        float left_tan;
        float right_tan;
};
 
struct rift_extra_display_info
{
        // gap left between the two eyes
        float screen_gap_meters;
        // the diameter of the lenses, may need to be extended to an array
        float lens_diameter_meters;
        // ipd of the headset
        float icd;
 
        // the fov of the headset
        struct rift_viewport_fov_tan fov;
        // mapping from tan-angle space to target NDC space
        struct rift_scale_and_offset eye_to_source_ndc;
        struct rift_scale_and_offset eye_to_source_uv;
};
 
enum rift_variant
{
        RIFT_VARIANT_DK1,
        RIFT_VARIANT_DK2,
};
 
#define OCULUS_VR_VID 0x2833
 
#define OCULUS_DK2_PID 0x0021
 
/*!
 * Probing function for Oculus Rift devices.
 *
 * @ingroup drv_rift
 * @see xrt_prober_found_func_t
 */
int
rift_found(struct xrt_prober *xp,
           struct xrt_prober_device **devices,
           size_t device_count,
           size_t index,
           cJSON *attached_data,
           struct xrt_device **out_xdev);
 
/*!
 * A rift HMD device.
 *
 * @implements xrt_device
 */
struct rift_hmd
{
        struct xrt_device base;
 
        struct xrt_pose pose;
 
        enum u_logging_level log_level;
 
        // has built-in mutex so thread safe
        struct m_relation_history *relation_hist;
 
        struct os_hid_device *hid_dev;
        struct os_thread_helper sensor_thread;
        bool processed_sample_packet;
        uint32_t last_remote_sample_time_us;
        int64_t last_remote_sample_time_ns;
 
        struct m_imu_3dof fusion;
        struct m_clock_windowed_skew_tracker *clock_tracker;
 
        int64_t last_keepalive_time;
        enum rift_variant variant;
        struct rift_config_report config;
        struct rift_display_info_report display_info;
 
        struct rift_lens_distortion *lens_distortions;
        uint16_t num_lens_distortions;
        uint16_t distortion_in_use;
 
        struct rift_extra_display_info extra_display_info;
};
 
/// Casting helper function
static inline struct rift_hmd *
rift_hmd(struct xrt_device *xdev)
{
        return (struct rift_hmd *)xdev;
}
 
struct rift_hmd *
rift_hmd_create(struct os_hid_device *dev, enum rift_variant variant, char *device_name, char *serial_number);
 
/*!
 * @dir drivers/rift
 *
 * @brief @ref drv_rift files.
 */
 
#ifdef __cplusplus
}
#endif