rs-distance.c

// License: Apache 2.0. See LICENSE file in root directory.
// Copyright(c) 2017 Intel Corporation. All Rights Reserved.

/* Include the librealsense C header files */
#include <librealsense2/rs.h>
#include <librealsense2/h/rs_pipeline.h>
#include <librealsense2/h/rs_option.h>
#include <librealsense2/h/rs_frame.h>
#include "../example.h"

#include <stdlib.h>
#include <stdint.h>
#include <stdio.h>


////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
//                                     These parameters are reconfigurable                                        //
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
#define STREAM          RS2_STREAM_DEPTH  // rs2_stream is a types of data provided by RealSense device           //
#define FORMAT          RS2_FORMAT_Z16    // rs2_format is identifies how binary data is encoded within a frame   //
#define WIDTH           640               // Defines the number of columns for each frame                         //
#define HEIGHT          480               // Defines the number of lines for each frame                           //
#define FPS             30                // Defines the rate of frames per second                                //
#define STREAM_INDEX    0                 // Defines the stream index, used for multiple streams of the same type //
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////


int main()
{
    rs2_error* e = 0;

    // Create a context object. This object owns the handles to all connected realsense devices.
    // The returned object should be released with rs2_delete_context(...)
    rs2_context* ctx = rs2_create_context(RS2_API_VERSION, &e);
    check_error(e);

    /* Get a list of all the connected devices. */
    // The returned object should be released with rs2_delete_device_list(...)
    rs2_device_list* device_list = rs2_query_devices(ctx, &e);
    check_error(e);

    int dev_count = rs2_get_device_count(device_list, &e);
    check_error(e);
    printf("There are %d connected RealSense devices.\n", dev_count);
    if (0 == dev_count)
        return EXIT_FAILURE;

    // Get the first connected device
    // The returned object should be released with rs2_delete_device(...)
    rs2_device* dev = rs2_create_device(device_list, 0, &e);
    check_error(e);

    print_device_info(dev);

    // Create a pipeline to configure, start and stop camera streaming
    // The returned object should be released with rs2_delete_pipeline(...)
    rs2_pipeline* pipeline =  rs2_create_pipeline(ctx, &e);
    check_error(e);

    // Create a config instance, used to specify hardware configuration
    // The retunred object should be released with rs2_delete_config(...)
    rs2_config* config = rs2_create_config(&e);
    check_error(e);

    // Request a specific configuration
    rs2_config_enable_stream(config, STREAM, STREAM_INDEX, WIDTH, HEIGHT, FORMAT, FPS, &e);
    check_error(e);

    // Start the pipeline streaming
    // The retunred object should be released with rs2_delete_pipeline_profile(...)
    rs2_pipeline_profile* pipeline_profile = rs2_pipeline_start_with_config(pipeline, config, &e);
    if (e)
    {
        printf("The connected device doesn't support depth streaming!\n");
        exit(EXIT_FAILURE);
    }

    while (1)
    {
        // This call waits until a new composite_frame is available
        // composite_frame holds a set of frames. It is used to prevent frame drops
        // The retunred object should be released with rs2_release_frame(...)
        rs2_frame* frames = rs2_pipeline_wait_for_frames(pipeline, 5000, &e);
        check_error(e);

        // Returns the number of frames embedded within the composite frame
        int num_of_frames = rs2_embedded_frames_count(frames, &e);
        check_error(e);

        int i;
        for (i = 0; i < num_of_frames; ++i)
        {
            // The retunred object should be released with rs2_release_frame(...)
            rs2_frame* frame = rs2_extract_frame(frames, i, &e);
            check_error(e);

            // Check if the given frame can be extended to depth frame interface
            // Accept only depth frames and skip other frames
            if (0 == rs2_is_frame_extendable_to(frame, RS2_EXTENSION_DEPTH_FRAME, &e))
                continue;

            // Get the depth frame's dimensions
            int width = rs2_get_frame_width(frame, &e);
            check_error(e);
            int height = rs2_get_frame_height(frame, &e);
            check_error(e);

            // Query the distance from the camera to the object in the center of the image
            float dist_to_center = rs2_depth_frame_get_distance(frame, width / 2, height / 2, &e);
            check_error(e);

            // Print the distance
            printf("The camera is facing an object %.3f meters away.\n", dist_to_center);

            rs2_release_frame(frame);
        }

        rs2_release_frame(frames);
    }

    // Stop the pipeline streaming
    rs2_pipeline_stop(pipeline, &e);
    check_error(e);

    // Release resources
    rs2_delete_pipeline_profile(pipeline_profile);
    rs2_delete_config(config);
    rs2_delete_pipeline(pipeline);
    rs2_delete_device(dev);
    rs2_delete_device_list(device_list);
    rs2_delete_context(ctx);

    return EXIT_SUCCESS;
}