htc_config.h

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// Copyright 2025-2026, Beyley Cardellio
// SPDX-License-Identifier: BSL-1.0
/*!
 * @file
 * @brief  Code to parse and handle the modern non-LH HTC configuration data.
 * @author Beyley Cardellio <ep1cm1n10n123@gmail.com>
 * @ingroup aux_htc
 */
 
#pragma once
 
#include "xrt/xrt_defines.h"
 
 
#ifdef __cplusplus
extern "C" {
#endif
 
enum htc_distortion_model
{
        HTC_DISTORTION_MODEL_INVALID = 0,
        HTC_DISTORTION_MODEL_TRADITIONAL_SIMPLE = 1,
        HTC_DISTORTION_MODEL_TRADITIONAL_WITH_TANGENTIAL = 2,
        HTC_DISTORTION_MODEL_NON_MODEL_SVR = 3,
        HTC_DISTORTION_MODEL_RATIONAL = 4,
        HTC_DISTORTION_MODEL_SECTIONAL = 5,
        HTC_DISTORTION_MODEL_TANGENTIAL_WEIGHT = 6,
        HTC_DISTORTION_MODEL_RADIAL_TANGENTIAL_PRISM = 7,
        HTC_DISTORTION_MODEL_PRISM_WITH_PROGRESSIVE = 8,
        HTC_DISTORTION_MODEL_STRENGTHEN_RADIAL = 9,
        HTC_DISTORTION_MODEL_STRENGTHEN = 10,
        HTC_DISTORTION_MODEL_STRENGTHEN_HIGH_ORDER = 11,
        HTC_DISTORTION_MODEL_WVR_RADIAL = 12,
        HTC_DISTORTION_MODEL_RADIAL_ROTATE_MODIFY = 13,
};
 
struct htc_eye_coefficients
{
        double k[13]; // radial
        double p[6];  // tangential
        double s[4];  // prism
};
 
struct htc_wvr_coefficients
{
        double k[6];
};
 
struct htc_modify_coefficients
{
        double k[11];
        double theta;
};
 
struct htc_distortion_version
{
        uint8_t major;
        uint8_t minor;
};
 
struct htc_warp_parameters
{
        struct xrt_matrix_3x3 post;
        struct xrt_matrix_3x3 pre;
        float max_radius;
};
 
struct htc_eye_distortion
{
        struct xrt_vec2 center;
        enum htc_distortion_model model;
 
        struct htc_eye_coefficients coeffecients[3];
 
        struct htc_wvr_coefficients wvr[3];
 
        struct htc_modify_coefficients modify; // Only contains blue
 
        double enlarge_ratio;
        double grow_for_undistort[4];
 
        struct xrt_matrix_3x3 intrinsics[2];
 
        struct xrt_vec2_i32 resolution;
        double scale;
        double scale_ratio;
 
        double normalized_radius;
 
        struct htc_distortion_version version;
 
        struct htc_warp_parameters warp;
};
 
struct htc_config
{
        struct
        {
                uint32_t eye_target_width_in_pixels;
                uint32_t eye_target_height_in_pixels;
        } device;
 
        struct
        {
                struct htc_eye_distortion eyes[2];
 
                struct xrt_vec2_i32 resolution; // The resolution to use for distorting
        } lens_correction;
};
 
/*!
 * Converts a string to an HTC distortion model enum value.
 *
 * @param model_str The string representation of the distortion model.
 * @return The corresponding htc_distortion_model enum value, or HTC_DISTORTION_MODEL_INVALID if the string is
 * unrecognized.
 */
enum htc_distortion_model
htc_string_to_distortion_model(const char *model_str);
 
bool
htc_config_parse(const char *config_data, size_t config_size, struct htc_config *out_config);
 
bool
htc_config_compute_distortion(struct htc_config *config,
                              int eye,
                              const struct xrt_vec2 *in,
                              struct xrt_uv_triplet *out_result);
 
void
htc_config_get_fov(struct htc_config *config, int eye, struct xrt_fov *out_fov);
 
#ifdef __cplusplus
}
#endif