ESP32S3_vt/components/cam_wrapper/include/cam_wrapper.h

/* Union-free wrapper around the esp32-camera API.
 *
 * `camera_config_t` in esp_camera.h uses anonymous unions for the deprecated
 * SCCB pin names, which bindgen renders as unsafe union fields that are
 * awkward to build from Rust. This wrapper takes a plain struct and fills in
 * the unions on the C side, so the generated bindings stay trivial to use.
 *
 * The enum-valued config fields are declared as local enums whose values equal
 * the esp32-camera ones (`pixformat_t`, `framesize_t`, `camera_fb_location_t`,
 * `camera_grab_mode_t`). That keeps the numbers defined in exactly one place -
 * the esp32-camera headers - while still giving Rust named constants to use
 * instead of bare magic numbers.
 */

#pragma once

#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>

#include "esp_camera.h"
#include "esp_err.h"

/* Defined by esp32-camera's cam_hal.c but declared only in its private header,
 * which components outside esp32-camera cannot include. Redeclared here so the
 * wrapper can set the VSYNC polarity before esp_camera_init() and read back the
 * clock the driver used. */
void cam_set_vsync_invert(bool invert);
bool cam_get_vsync_invert(void);
void cam_set_xclk_hz(int hz);
int cam_get_xclk_hz(void);

#ifdef __cplusplus
extern "C" {
#endif

typedef enum {
    CAM_WRAPPER_PIXFORMAT_JPEG = PIXFORMAT_JPEG,
    CAM_WRAPPER_PIXFORMAT_RGB565 = PIXFORMAT_RGB565,
} cam_wrapper_pixel_format_t;

typedef enum {
    CAM_WRAPPER_FRAMESIZE_QQVGA = FRAMESIZE_QQVGA,
    CAM_WRAPPER_FRAMESIZE_QVGA = FRAMESIZE_QVGA,
    CAM_WRAPPER_FRAMESIZE_CIF = FRAMESIZE_CIF,
    CAM_WRAPPER_FRAMESIZE_HVGA = FRAMESIZE_HVGA,
    CAM_WRAPPER_FRAMESIZE_VGA = FRAMESIZE_VGA,
    CAM_WRAPPER_FRAMESIZE_SVGA = FRAMESIZE_SVGA,
    CAM_WRAPPER_FRAMESIZE_XGA = FRAMESIZE_XGA,
    CAM_WRAPPER_FRAMESIZE_SXGA = FRAMESIZE_SXGA,
    CAM_WRAPPER_FRAMESIZE_UXGA = FRAMESIZE_UXGA,
} cam_wrapper_framesize_t;

typedef enum {
    CAM_WRAPPER_FB_IN_PSRAM = CAMERA_FB_IN_PSRAM,
    CAM_WRAPPER_FB_IN_DRAM = CAMERA_FB_IN_DRAM,
} cam_wrapper_fb_location_t;

typedef enum {
    CAM_WRAPPER_GRAB_WHEN_EMPTY = CAMERA_GRAB_WHEN_EMPTY,
    CAM_WRAPPER_GRAB_LATEST = CAMERA_GRAB_LATEST,
} cam_wrapper_grab_mode_t;

/* Pin map of the camera connector. Use -1 for signals that are not wired. */
typedef struct {
    int pin_pwdn;
    int pin_reset;
    int pin_xclk;
    int pin_sccb_sda;
    int pin_sccb_scl;
    int pin_d[8]; /* index 0 -> pin_d0 .. index 7 -> pin_d7 */
    int pin_vsync;
    int pin_href;
    int pin_pclk;

    int xclk_freq_hz;
    int ledc_timer;
    int ledc_channel;

    cam_wrapper_pixel_format_t pixel_format;
    cam_wrapper_framesize_t frame_size;
    int jpeg_quality;
    size_t fb_count;
    cam_wrapper_fb_location_t fb_location;
    cam_wrapper_grab_mode_t grab_mode;
    int sccb_i2c_port;

    /* VSYNC polarity. 0 = active-high, 1 = active-low (esp32-camera's default,
     * correct for most DVP sensors). Getting this wrong does not fail: the
     * driver latches frames on the wrong edge and the result is a valid but
     * very low frame rate, so it is worth being able to flip it. */
    int vsync_invert;
} cam_wrapper_config_t;

/* Sensor hint. esp32-camera probes the sensor over SCCB and binds a driver by
 * its PID/ID, so AUTO is normally all that is needed; the others exist only to
 * disambiguate when the probe itself is unreliable. */
typedef enum {
    CAM_WRAPPER_SENSOR_AUTO = 0,
    CAM_WRAPPER_SENSOR_OV2640 = 1,
    CAM_WRAPPER_SENSOR_OV3660 = 2,
    CAM_WRAPPER_SENSOR_OV5640 = 3,
} cam_wrapper_sensor_t;

/* A single captured frame. `data` points into memory owned by the driver and
 * stays valid only until cam_wrapper_fb_release() is called on this struct.
 * The struct is caller-owned so it can live on the handler's stack. */
typedef struct {
    uint8_t *data;
    size_t len;
    size_t width;
    size_t height;
    int format;
    void *handle; /* internal driver frame; do not touch */
} cam_wrapper_fb_t;

esp_err_t cam_wrapper_init(const cam_wrapper_config_t *config, cam_wrapper_sensor_t sensor);

/* Acquire one frame into `out`. Returns ESP_OK on success, ESP_FAIL if the
 * driver could not hand out a frame (e.g. timeout or buffer starvation). */
esp_err_t cam_wrapper_fb_get(cam_wrapper_fb_t *out, cam_wrapper_sensor_t sensor);

void cam_wrapper_fb_release(cam_wrapper_fb_t *fb);

esp_err_t cam_wrapper_reconfigure(const cam_wrapper_config_t *config);

esp_err_t cam_wrapper_deinit(void);

/* Name of the sensor the driver detected, or "unknown". Never NULL. */
const char *cam_wrapper_sensor_name(void);

#ifdef __cplusplus
}
#endif