c-tutorial-3-pointcloud.c

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/* License: Apache 2.0. See LICENSE file in root directory.
   Copyright(c) 2015 Intel Corporation. All Rights Reserved. */

/***************************************************\
* librealsense tutorial #3 - Point cloud generation *
\***************************************************/

/* First include the librealsense C header file */
#include <librealsense/rs.h>
#include <stdlib.h>
#include <stdint.h>
#include <stdio.h>
#include <math.h>

/* Additionall,y include the librealsense utilities header file */
#include <librealsense/rsutil.h>

/* Also include GLFW to allow for graphical display */
#define GLFW_INCLUDE_GLU
#include <GLFW/glfw3.h>

/* Function calls to librealsense may raise errors of type rs_error */
rs_error * e = 0;
void check_error()
{
    if(e)
    {
        printf("rs_error was raised when calling %s(%s):\n", rs_get_failed_function(e), rs_get_failed_args(e));
        printf("    %s\n", rs_get_error_message(e));
        exit(EXIT_FAILURE);
    }
}

double yaw, pitch, lastX, lastY; int ml;
static void on_mouse_button(GLFWwindow * win, int button, int action, int mods)
{
    if(button == GLFW_MOUSE_BUTTON_LEFT) ml = action == GLFW_PRESS;
}
static double clamp(double val, double lo, double hi) { return val < lo ? lo : val > hi ? hi : val; }
static void on_cursor_pos(GLFWwindow * win, double x, double y)
{
    if(ml)
    {
        yaw = clamp(yaw - (x - lastX), -120, 120);
        pitch = clamp(pitch + (y - lastY), -80, 80);
    }
    lastX = x;
    lastY = y;
}

int main()
{
    /* Turn on logging. We can separately enable logging to console or to file, and use different severity filters for each. */
    rs_log_to_console(RS_LOG_SEVERITY_WARN, &e);
    check_error();
    /*rs_log_to_file(RS_LOG_SEVERITY_DEBUG, "librealsense.log", &e);
    check_error();*/

    /* Create a context object. This object owns the handles to all connected realsense devices. */
    rs_context * ctx = rs_create_context(RS_API_VERSION, &e);
    check_error();
    printf("There are %d connected RealSense devices.\n", rs_get_device_count(ctx, &e));
    check_error();
    if(rs_get_device_count(ctx, &e) == 0) return EXIT_FAILURE;

    /* This tutorial will access only a single device, but it is trivial to extend to multiple devices */
    rs_device * dev = rs_get_device(ctx, 0, &e);
    check_error();
    printf("\nUsing device 0, an %s\n", rs_get_device_name(dev, &e));
    check_error();
    printf("    Serial number: %s\n", rs_get_device_serial(dev, &e));
    check_error();
    printf("    Firmware version: %s\n", rs_get_device_firmware_version(dev, &e));
    check_error();

    /* Configure depth and color to run with the device's preferred settings */
    rs_enable_stream_preset(dev, RS_STREAM_DEPTH, RS_PRESET_BEST_QUALITY, &e);
    check_error();
    rs_enable_stream_preset(dev, RS_STREAM_COLOR, RS_PRESET_BEST_QUALITY, &e);
    check_error();
    rs_start_device(dev, &e);
    check_error();

    /* Open a GLFW window to display our output */
    glfwInit();
    GLFWwindow * win = glfwCreateWindow(1280, 960, "librealsense tutorial #3", NULL, NULL);
    glfwSetCursorPosCallback(win, on_cursor_pos);
    glfwSetMouseButtonCallback(win, on_mouse_button);
    glfwMakeContextCurrent(win);
    while(!glfwWindowShouldClose(win))
    {
        /* Wait for new frame data */
        glfwPollEvents();
        rs_wait_for_frames(dev, &e);
        check_error();

        /* Retrieve our images */
        const uint16_t * depth_image = (const uint16_t *)rs_get_frame_data(dev, RS_STREAM_DEPTH, &e);
        check_error();
        const uint8_t * color_image = (const uint8_t *)rs_get_frame_data(dev, RS_STREAM_COLOR, &e);
        check_error();

        /* Retrieve camera parameters for mapping between depth and color */
        rs_intrinsics depth_intrin, color_intrin;
        rs_extrinsics depth_to_color;
        rs_get_stream_intrinsics(dev, RS_STREAM_DEPTH, &depth_intrin, &e);
        check_error();
        rs_get_device_extrinsics(dev, RS_STREAM_DEPTH, RS_STREAM_COLOR, &depth_to_color, &e);
        check_error();
        rs_get_stream_intrinsics(dev, RS_STREAM_COLOR, &color_intrin, &e);
        check_error();
        float scale = rs_get_device_depth_scale(dev, &e);
        check_error();

        /* Set up a perspective transform in a space that we can rotate by clicking and dragging the mouse */
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
        glMatrixMode(GL_PROJECTION);
        glLoadIdentity();
        gluPerspective(60, (float)1280/960, 0.01f, 20.0f);
        glMatrixMode(GL_MODELVIEW);
        glLoadIdentity();
        gluLookAt(0,0,0, 0,0,1, 0,-1,0);
        glTranslatef(0,0,+0.5f);
        glRotated(pitch, 1, 0, 0);
        glRotated(yaw, 0, 1, 0);
        glTranslatef(0,0,-0.5f);

        /* We will render our depth data as a set of points in 3D space */
        glPointSize(2);
        glEnable(GL_DEPTH_TEST);
        glBegin(GL_POINTS);

        int dx, dy;
        for(dy=0; dy<depth_intrin.height; ++dy)
        {
            for(dx=0; dx<depth_intrin.width; ++dx)
            {
                /* Retrieve the 16-bit depth value and map it into a depth in meters */
                uint16_t depth_value = depth_image[dy * depth_intrin.width + dx];
                float depth_in_meters = depth_value * scale;

                /* Skip over pixels with a depth value of zero, which is used to indicate no data */
                if(depth_value == 0) continue;

                /* Map from pixel coordinates in the depth image to pixel coordinates in the color image */
                float depth_pixel[2] = {(float)dx, (float)dy};
                float depth_point[3], color_point[3], color_pixel[2];
                rs_deproject_pixel_to_point(depth_point, &depth_intrin, depth_pixel, depth_in_meters);
                rs_transform_point_to_point(color_point, &depth_to_color, depth_point);
                rs_project_point_to_pixel(color_pixel, &color_intrin, color_point);

                /* Use the color from the nearest color pixel, or pure white if this point falls outside the color image */
                const int cx = (int)roundf(color_pixel[0]), cy = (int)roundf(color_pixel[1]);
                if(cx < 0 || cy < 0 || cx >= color_intrin.width || cy >= color_intrin.height)
                {
                    glColor3ub(255, 255, 255);
                }
                else
                {
                    glColor3ubv(color_image + (cy * color_intrin.width + cx) * 3);
                }

                /* Emit a vertex at the 3D location of this depth pixel */
                glVertex3f(depth_point[0], depth_point[1], depth_point[2]);
            }
        }
        glEnd();

        glfwSwapBuffers(win);
    }
    
    return EXIT_SUCCESS;
}