Example: opengl_texture_sizes_test

C++ example source code:

/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          https://www.mrpt.org/                         |
   |                                                                        |
   | Copyright (c) 2005-2024, 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/examples_config.h>
#include <mrpt/gui/CDisplayWindow3D.h>
#include <mrpt/img/CImage.h>
#include <mrpt/opengl/CText.h>
#include <mrpt/opengl/CTexturedPlane.h>

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

const std::string myTestFile(
    MRPT_EXAMPLES_BASE_DIRECTORY +
    std::string("img_basic_example/frame_color.jpg"));

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

// ------------------------------------------------------
//              TextureSizes_test
// ------------------------------------------------------
void TextureSizes_test()
{
    // Prepare a few test images: color & BW, random size and 2^N size.
    // -------------------------------------------------------------------
    CImage imgCol_N, imgBW_N;
    CImage imgCol_2N, imgBW_2N;

    if (!imgCol_N.loadFromFile(myTestFile))
    {
        cerr << "Cannot load " << myTestFile << endl;
        return;
    }

    imgCol_N.scaleImage(imgCol_2N, 512, 512);

    imgCol_N.grayscale(imgBW_N);
    imgCol_2N.grayscale(imgBW_2N);

    // Masks:
    const int W = imgCol_N.getWidth();
    const int H = imgCol_N.getHeight();

    CImage transpMask_N(W, H, CH_GRAY);
    for (int y = 0; y < H; y++)
        for (int x = 0; x < W; x++)
            *transpMask_N(x, y) = (((x + y) >> 5) & 1) ? 240 : 10;

    CImage transpMask_2N;
    transpMask_N.scaleImage(transpMask_2N, 512, 512);

    cout << "Loaded image size: " << imgCol_N.getWidth() << "x"
         << imgCol_N.getHeight() << endl;
    cout << "2^N image size   : " << imgCol_2N.getWidth() << "x"
         << imgCol_2N.getHeight() << endl;

    CDisplayWindow3D win("Test of MRPT's OpenGL textures", 640, 480);

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

    double off_x = 0;
    const double off_y_label = 4;
    const double STEP_X = 15;

    if (true)
    {
        opengl::CTexturedPlane::Ptr obj =
            opengl::CTexturedPlane::Create(-3, 3, -3, 3);
        obj->assignImage(imgCol_N);
        obj->setLocation(off_x, 0, 0);
        theScene->insert(obj);

        opengl::CText::Ptr gl_txt =
            opengl::CText::Create("Color texture, random size, w/o transp");
        gl_txt->setLocation(off_x, off_y_label, 0);
        theScene->insert(gl_txt);
    }
    off_x += STEP_X;

    if (true)
    {
        opengl::CTexturedPlane::Ptr obj =
            opengl::CTexturedPlane::Create(-3, 3, -3, 3);
        obj->assignImage(imgCol_N, transpMask_N);
        obj->setLocation(off_x, 0, 0);
        theScene->insert(obj);

        opengl::CText::Ptr gl_txt =
            opengl::CText::Create("Color texture, random size, with transp");
        gl_txt->setLocation(off_x, off_y_label, 0);
        theScene->insert(gl_txt);
    }
    off_x += STEP_X;

    if (true)
    {
        opengl::CTexturedPlane::Ptr obj =
            opengl::CTexturedPlane::Create(-3, 3, -3, 3);
        obj->assignImage(imgBW_N);
        obj->setLocation(off_x, 0, 0);
        theScene->insert(obj);

        opengl::CText::Ptr gl_txt =
            opengl::CText::Create("B/W texture, random size, w/o transp");
        gl_txt->setLocation(off_x, off_y_label, 0);
        theScene->insert(gl_txt);
    }
    off_x += STEP_X;

    if (true)
    {
        opengl::CTexturedPlane::Ptr obj =
            opengl::CTexturedPlane::Create(-3, 3, -3, 3);
        obj->assignImage(imgBW_N, transpMask_N);
        obj->setLocation(off_x, 0, 0);
        theScene->insert(obj);

        opengl::CText::Ptr gl_txt =
            opengl::CText::Create("B/W texture, random size, with transp");
        gl_txt->setLocation(off_x, off_y_label, 0);
        theScene->insert(gl_txt);
    }
    off_x += STEP_X;

    if (true)
    {
        opengl::CTexturedPlane::Ptr obj =
            opengl::CTexturedPlane::Create(-3, 3, -3, 3);
        obj->assignImage(imgCol_2N);
        obj->setLocation(off_x, 0, 0);
        theScene->insert(obj);

        opengl::CText::Ptr gl_txt =
            opengl::CText::Create("Color texture, 2^N size, w/o transp");
        gl_txt->setLocation(off_x, off_y_label, 0);
        theScene->insert(gl_txt);
    }
    off_x += STEP_X;

    if (true)
    {
        opengl::CTexturedPlane::Ptr obj =
            opengl::CTexturedPlane::Create(-3, 3, -3, 3);
        obj->assignImage(imgCol_2N, transpMask_2N);
        obj->setLocation(off_x, 0, 0);
        theScene->insert(obj);

        opengl::CText::Ptr gl_txt =
            opengl::CText::Create("Color texture, 2^N size, with transp");
        gl_txt->setLocation(off_x, off_y_label, 0);
        theScene->insert(gl_txt);
    }
    off_x += STEP_X;

    if (true)
    {
        opengl::CTexturedPlane::Ptr obj =
            opengl::CTexturedPlane::Create(-3, 3, -3, 3);
        obj->assignImage(imgBW_2N);
        obj->setLocation(off_x, 0, 0);
        theScene->insert(obj);

        opengl::CText::Ptr gl_txt =
            opengl::CText::Create("B/W texture, 2^N size, w/o transp");
        gl_txt->setLocation(off_x, off_y_label, 0);
        theScene->insert(gl_txt);
    }
    off_x += STEP_X;

    if (true)
    {
        opengl::CTexturedPlane::Ptr obj =
            opengl::CTexturedPlane::Create(-3, 3, -3, 3);
        obj->assignImage(imgBW_2N, transpMask_2N);
        obj->setLocation(off_x, 0, 0);
        theScene->insert(obj);

        opengl::CText::Ptr gl_txt =
            opengl::CText::Create("B/W texture, 2^N size, with transp");
        gl_txt->setLocation(off_x, off_y_label, 0);
        theScene->insert(gl_txt);
    }
    off_x += STEP_X;

    win.setCameraZoom(150);
    win.setCameraAzimuthDeg(90);

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

    cout << "Close the window to end.\n";
    while (win.isOpen())
    {
        win.addTextMessage(5, 5, format("%.02fFPS", win.getRenderingFPS()));
        std::this_thread::sleep_for(2ms);
        win.repaint();
    }
}

// ------------------------------------------------------
//                      MAIN
// ------------------------------------------------------
int main()
{
    try
    {
        TextureSizes_test();

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