Example: math_slerp_example

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/CDisplayWindow3D.h>
#include <mrpt/img/TColor.h>
#include <mrpt/math/slerp.h>
#include <mrpt/opengl/CGridPlaneXY.h>
#include <mrpt/opengl/stock_objects.h>
#include <mrpt/system/CTicTac.h>

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

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

// ------------------------------------------------------
//              TestSLERP
// ------------------------------------------------------
void TestSLERP()
{
    CDisplayWindow3D win("Example of SLERP animation", 640, 480);

    Scene::Ptr& theScene = win.get3DSceneAndLock();

    win.setCameraAzimuthDeg(-50);
    win.setCameraElevationDeg(40);
    win.setCameraZoom(19);
    win.setCameraPointingToPoint(2, 2, 0);

    // Modify the scene:
    // ------------------------------------------------------
    {
        auto obj = mrpt::opengl::CGridPlaneXY::Create(-20, 20, -20, 20, 0, 1);
        obj->setColor(0.4f, 0.4f, 0.4f);
        theScene->insert(obj);
    }

    // Initialize the start, end pose of the animation
    const TPose3D pose_a(0, 0, 0, 0.0_deg, 0.0_deg, 0.0_deg);
    const TPose3D pose_b(3, 4, 1, 120.0_deg, 40.0_deg, 50.0_deg);

    {
        // XYZ corner at A:
        auto obj = mrpt::opengl::stock_objects::CornerXYZSimple(1.0, 2.0);
        obj->setPose(pose_a);
        theScene->insert(obj);
    }
    {
        // XYZ corner at B:
        auto obj = mrpt::opengl::stock_objects::CornerXYZSimple(1.0, 2.0);
        obj->setPose(pose_b);
        theScene->insert(obj);
    }
    {
        // SLERP animated corner:
        auto obj = mrpt::opengl::stock_objects::CornerXYZSimple(1.0, 4.0);
        obj->setName("slerp_obj");
        obj->setPose(pose_a);
        theScene->insert(obj);
    }

    // IMPORTANT!!! IF NOT UNLOCKED, THE WINDOW WILL NOT BE UPDATED!
    win.unlockAccess3DScene();

    cout << "\n Close the window to exit.\n";

    mrpt::system::CTicTac tic;
    static const double MOVE_PERIOD = 1.0;
    static const double MOVE_PERIOD2 = 2 * MOVE_PERIOD;

    while (win.isOpen())
    {
        // Compute the time:
        double t = ::fmod(tic.Tac(), MOVE_PERIOD2);
        if (t < MOVE_PERIOD) t /= MOVE_PERIOD;
        else
            t = 1 - (t - MOVE_PERIOD) / MOVE_PERIOD;

        // SLERP & LERP interpolation:
        TPose3D pose_interp;
        mrpt::math::slerp(pose_a, pose_b, t, pose_interp);

        // Move the scene:
        Scene::Ptr& theScene = win.get3DSceneAndLock();

        auto obj1 = theScene->getByName("slerp_obj");
        obj1->setPose(pose_interp);

        // Show text:
        win.addTextMessage(5, 5, mrpt::format("t=%.03f", t), 0 /*id*/);

        // IMPORTANT!!! IF NOT UNLOCKED, THE WINDOW WILL NOT BE UPDATED!
        win.unlockAccess3DScene();

        // Update window:
        win.forceRepaint();
        std::this_thread::sleep_for(5ms);
    };
}

// ------------------------------------------------------
//                      MAIN
// ------------------------------------------------------
int main()
{
    try
    {
        TestSLERP();
        return 0;
    }
    catch (const std::exception& e)
    {
        std::cerr << "MRPT error: " << mrpt::exception_to_str(e) << std::endl;
        return -1;
    }
}