ns_hmd.h

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// Copyright 2019, Collabora, Ltd.
// SPDX-License-Identifier: BSL-1.0
/*!
 * @file
 * @brief  Interface between North Star distortion and HMD code.
 * @author Nova King <technobaboo@gmail.com>
 * @ingroup drv_ns
 */

#pragma once

#include "math/m_api.h"
#include "util/u_distortion_mesh.h"
#include "util/u_json.h"
#include "util/u_misc.h"
#include "xrt/xrt_defines.h"
#include "xrt/xrt_device.h"


#ifdef __cplusplus
extern "C" {
#endif


/*
 *
 * Defines
 *
 */

#define NS_SPEW(c, ...)                                                        \
        do {                                                                   \
                if (c->print_spew) {                                           \
                        fprintf(stderr, "%s - ", __func__);                    \
                        fprintf(stderr, __VA_ARGS__);                          \
                        fprintf(stderr, "\n");                                 \
                }                                                              \
        } while (false)

#define NS_DEBUG(c, ...)                                                       \
        do {                                                                   \
                if (c->print_debug) {                                          \
                        fprintf(stderr, "%s - ", __func__);                    \
                        fprintf(stderr, __VA_ARGS__);                          \
                        fprintf(stderr, "\n");                                 \
                }                                                              \
        } while (false)

#define NS_ERROR(c, ...)                                                       \
        do {                                                                   \
                fprintf(stderr, "%s - ", __func__);                            \
                fprintf(stderr, __VA_ARGS__);                                  \
                fprintf(stderr, "\n");                                         \
        } while (false)


/*
 *
 * Structs
 *
 */

/*!
 * Opaque struct for optical system C++ integration
 *
 * @ingroup drv_ns
 */
struct ns_optical_system;

/*!
 * Simple UV struct.
 *
 * @ingroup drv_ns
 */
struct ns_uv
{
        float u;
        float v;
};

/*!
 * Configuration information about the LMC or Rigel sensor according to the
 * configuration file.
 *
 * @ingroup drv_ns
 */
struct ns_leap
{
        const char *name;
        const char *serial;
        struct xrt_pose pose;
};

/*!
 * Distortion information about an eye parsed from the configuration file.
 *
 * @ingroup drv_ns
 */
struct ns_eye
{
        float ellipse_minor_axis;
        float ellipse_major_axis;

        struct xrt_vec3 screen_forward;
        struct xrt_vec3 screen_position;

        struct xrt_pose eye_pose;

        struct xrt_quat camera_projection;

        struct xrt_matrix_4x4 sphere_to_world_space;
        struct xrt_matrix_4x4 world_to_screen_space;

        struct ns_optical_system *optical_system;
};

/*!
 * Information about the whole North Star headset.
 *
 * @ingroup drv_ns
 */
struct ns_hmd
{
        struct xrt_device base;
        struct xrt_pose pose;

        const char *config_path;

        struct ns_eye eye_configs[2];
        struct ns_leap leap_config;

        struct xrt_device *tracker;

        bool print_spew;
        bool print_debug;
};

/*!
 * The mesh generator for the North Star distortion.
 *
 * @ingroup drv_ns
 */
struct ns_mesh
{
        struct u_uv_generator base;
        struct ns_hmd *ns;
};


/*
 *
 * Functions
 *
 */

/*!
 * Get the North Star HMD information from a @ref xrt_device.
 *
 * @ingroup drv_ns
 */
static inline struct ns_hmd *
ns_hmd(struct xrt_device *xdev)
{
        return (struct ns_hmd *)xdev;
}

/*!
 * Get the North Star mesh generator from a @ref u_uv_generator.
 *
 * @ingroup drv_ns
 */
static inline struct ns_mesh *
ns_mesh(struct u_uv_generator *gen)
{
        return (struct ns_mesh *)gen;
}

/*!
 * Convert the display UV to the render UV using the distortion mesh.
 *
 * @ingroup drv_ns
 */
void
ns_display_uv_to_render_uv(struct ns_uv display_uv,
                           struct ns_uv *render_uv,
                           struct ns_eye *eye);

struct ns_optical_system *
ns_create_optical_system(struct ns_eye *eye);


#ifdef __cplusplus
}
#endif