Example: gui_fbo_render_example

See: Tutorial: 3D scenes

C++ example source code:

/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          https://www.mrpt.org/                         |
   |                                                                        |
   | Copyright (c) 2005-2023, 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/CBox.h>
#include <mrpt/opengl/CFBORender.h>
#include <mrpt/opengl/CGridPlaneXY.h>
#include <mrpt/opengl/CSphere.h>
#include <mrpt/opengl/Scene.h>
#include <mrpt/system/CTimeLogger.h>

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

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

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

    // Modify the scene:
    // ------------------------------------------------------
    {
        auto obj = mrpt::opengl::CGridPlaneXY::Create(-20, 20, -20, 20, 0, 1);
        obj->setColor(0.4f, 0.4f, 0.4f);
        scene.insert(obj);
    }
    {
        auto obj = mrpt::opengl::CBox::Create(
            mrpt::math::TPoint3D(0, 0, 0), mrpt::math::TPoint3D(.1, .1, .1));
        obj->setColor(1.0f, 0.f, 0.f);
        obj->setName("x");
        obj->enableShowName(true);
        obj->setLocation(1.0, 0, 0);
        scene.insert(obj);
    }
    {
        auto obj = mrpt::opengl::CBox::Create(
            mrpt::math::TPoint3D(0, 0, 0), mrpt::math::TPoint3D(.1, .1, .1));
        obj->setColor(0.0f, 1.f, 0.f);
        obj->setName("y");
        obj->enableShowName(true);
        obj->setLocation(0, 1.0, 0);
        scene.insert(obj);
    }
    {
        auto obj = mrpt::opengl::CTexturedPlane::Create();
        obj->setPlaneCorners(-10, 10, -10, 10);
        obj->setColor_u8(0x00, 0xff, 0xff, 0xff);
        obj->setLocation(0, 0, -14);
        scene.insert(obj);
    }
    {
        auto obj = mrpt::opengl::CSphere::Create();
        obj->setColor(0, 0, 1);
        obj->setRadius(1.0f);
        obj->setLocation(0, 1, 0);
        obj->setName("ball_1");
        scene.insert(obj);
    }
    {
        auto obj = mrpt::opengl::CSphere::Create();
        obj->setColor(1, 0, 0);
        obj->setRadius(2.f);
        obj->setLocation(-3, -1, 1);
        obj->setName("ball_2");
        scene.insert(obj);
    }

    CDisplayWindow win("RGB"), winDepth("Depth");

    mrpt::system::CTimeLogger tl;

    int width = 500, height = 400;
    const double cameraFOVdeg = 90.0;

    mrpt::opengl::CFBORender renderer(width, height);
    CImage frame(width, height, CH_RGB);
    mrpt::math::CMatrixFloat depth;

    scene.getViewport()->setCustomBackgroundColor({0.3f, 0.3f, 0.3f, 1.0f});
    const float clipMax = 25.0f;
    scene.getViewport()->setViewportClipDistances(0.1, clipMax);

    {
        CCamera& camera = renderer.getCamera(scene);

#if 0
        mrpt::img::TCamera c1;
        c1.ncols = width;
        c1.nrows = height;
        c1.fx(width * 0.5);
        c1.fy(width * 0.5);
        c1.cx(width / 2);
        c1.cy(height / 2);

        camera.setProjectiveFromPinhole(c1);
#else
        camera.setProjectiveFOVdeg(cameraFOVdeg);
#endif

#if 0
        // Define camera by orbit
        camera.setZoomDistance(10);
        camera.setAzimuthDegrees(0);
        camera.setElevationDegrees(90);
#else

        // Defined by setPose() instead of orbit values:
        camera.set6DOFMode(true);

        // Reference camera pose:
        auto robotPose = mrpt::poses::CPose3D(
            0, 0, 10.0, 0.0_deg /*yaw*/, 90.0_deg /*pitch*/, 0.0_deg /*roll*/);

        // Convert to +Z pointing forward camera axes:
        auto camPose =
            robotPose +
            mrpt::poses::CPose3D::FromYawPitchRoll(
                90.0_deg /*yaw*/, 0.0_deg /*pitch*/, 90.0_deg /*roll*/);

        // std::cout << "Camera SE(3) HM:\n" <<
        // camPose.getHomogeneousMatrixVal<mrpt::math::CMatrixDouble44>() <<
        // "\n";

        camera.setPose(camPose);

#endif
    }

    while (win.isOpen())
    {
        CRenderizable::Ptr obj = scene.getByName("ball_1");

        const double t = mrpt::Clock::nowDouble();
        obj->setLocation(
            1 + cos(t + 0.2) * 2, -2 + sin(t + 0.9) * 4, sin(t + 1.2) * 5);

        obj = scene.getByName("ball_2");
        const auto p1 = obj->getPose();
        obj->setLocation(
            p1.x + cos(p1.y / 2) * 0.01, p1.y - sin(p1.x / 2) * 0.09,
            p1.z - sin(p1.x / 2) * 0.08);

        tl.enter("render_RGBD");
        renderer.render_RGBD(scene, frame, depth);
        tl.leave("render_RGBD");

        // show the rendered RGB image
        win.showImage(frame);

        // Show depth:
        if (!depth.empty())
        {
            std::cout << "minDepth (0=no echo): " << depth.minCoeff()
                      << " maxDepth: " << depth.maxCoeff() << std::endl;

            mrpt::img::CImage imDepth;
            depth *= (1.0f / clipMax);
            imDepth.setFromMatrix(depth, true);
            winDepth.showImage(imDepth);
        }

        std::this_thread::sleep_for(25ms);
    }
}

// ------------------------------------------------------
//                      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;
    }
}