Example: gui_fbo_render_example

See: Tutorial: 3D scenes

C++ example source code:

/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          https://www.mrpt.org/                         |
   |                                                                        |
   | Copyright (c) 2005-2021, Individual contributors, see AUTHORS file     |
   | See: https://www.mrpt.org/Authors - All rights reserved.               |
   | Released under BSD License. See: https://www.mrpt.org/License          |
   +------------------------------------------------------------------------+ */

#include <mrpt/gui/CDisplayWindow.h>
#include <mrpt/img/CImage.h>
#include <mrpt/opengl/CAxis.h>
#include <mrpt/opengl/CFBORender.h>
#include <mrpt/opengl/CGridPlaneXY.h>
#include <mrpt/opengl/COpenGLScene.h>
#include <mrpt/opengl/CSphere.h>

#include <chrono>
#include <iostream>
#include <thread>

using namespace mrpt;
using namespace mrpt::gui;
using namespace mrpt::opengl;
using namespace mrpt::img;
using namespace std::literals;

// ------------------------------------------------------
//              TestDisplay3D
// ------------------------------------------------------
void TestDisplay3D()
{
    COpenGLScene scene;

    // Modify the scene:
    // ------------------------------------------------------
    {
        opengl::CGridPlaneXY::Ptr obj =
            opengl::CGridPlaneXY::Create(-20, 20, -20, 20, 0, 1);
        obj->setColor(0.4f, 0.4f, 0.4f);
        scene.insert(obj);
    }
    {
        opengl::CAxis::Ptr obj = opengl::CAxis::Create();
        obj->setFrequency(5);
        obj->enableTickMarks();
        obj->setAxisLimits(-10, -10, -10, 10, 10, 10);
        scene.insert(obj);
    }
    {
        opengl::CSphere::Ptr obj = opengl::CSphere::Create();
        obj->setColor(0, 0, 1);
        obj->setRadius(0.3f);
        obj->setLocation(0, 0, 1);
        obj->setName("ball_1");
        scene.insert(obj);
    }
    {
        opengl::CSphere::Ptr obj = opengl::CSphere::Create();
        obj->setColor(1, 0, 0);
        obj->setRadius(0.3f);
        obj->setLocation(-1, -1, 1);
        obj->setName("ball_2");
        scene.insert(obj);
    }

    CDisplayWindow win("output");

    int c = 0, width = 640, height = 480;

    CFBORender render(width, height);
    CImage frame(width, height, CH_RGB);

    {
        CCamera& camera = render.getCamera(scene);
        camera.setZoomDistance(50);
    }

    while (!mrpt::system::os::kbhit())
    {
        CRenderizable::Ptr obj = scene.getByName("ball_1");
        obj->setLocation(
            obj->getPoseX() + cos(obj->getPoseY() / 2) * 0.05,
            obj->getPoseY() - sin(obj->getPoseX() / 2) * 0.09,
            obj->getPoseZ() - sin(obj->getPoseX() / 2) * 0.08);

        obj = scene.getByName("ball_2");
        obj->setLocation(
            obj->getPoseX() + cos(obj->getPoseY() / 2) * 0.05,
            obj->getPoseY() - sin(obj->getPoseX() / 2) * 0.09,
            obj->getPoseZ() - sin(obj->getPoseX() / 2) * 0.08);

        // change the size
        if (++c > 100)
        {
            width = 800, height = 600;
            frame.resize(width, height, CH_RGB);
            render.resize(width, height);
        }

        // render the scene
        render.getFrame2(scene, frame);

        // show the redered image
        win.showImage(frame);

        std::this_thread::sleep_for(50ms);
    }
}

// ------------------------------------------------------
//                      MAIN
// ------------------------------------------------------
int main(int argc, char* argv[])
{
    try
    {
        TestDisplay3D();
        return 0;
    }
    catch (const std::exception& e)
    {
        std::cerr << "MRPT error: " << mrpt::exception_to_str(e) << std::endl;
        return -1;
    }
    catch (...)
    {
        printf("Untyped exception!!");
        return -1;
    }
}