4.26 How to map cv::Mat of OpenCV to a shape of OpenGL as a texture?

/*
 * OpenGLCVImageViews.cpp 
 * Copyright (c) 2017 Antillia.com TOSHIYUKI ARAI. ALL RIGHTS RESERVED. 
 */
#include <sol/StringT.h>
#include <sol/opengl/OpenGLMainView.h>
#include <sol/opengl/OpenGLView.h>
#include <sol/opengl/OpenGLGC.h>

#include <sol/opengl/OpenGLTexture2D.h>
//#include <sol/opengl/OpenGLBulletinBoard.h>

#include <sol/opencv/OpenCVImageInfo.h>
#include <sol/opencv/OpenCVScrolledImageView.h>
#include <sol/opencv/OpenCVImageFileReader.h>

namespace SOL {

class MainView :public OpenGLMainView {
public:

private:
  //Inner OpenCVImageView class start
  class SimpleCVView: public OpenCVScrolledImageView {

  public:
    SimpleCVView(View* parent, const char* name, Args& args)
    :OpenCVScrolledImageView(parent, name, args)
    {
      try {
        const char* filename = (const char*)args.get(XmNimageFileName);
        int imageLoadingFlag = args.get(XmNimageLoadingFlag);
        loadImage(filename, imageLoadingFlag);

        rescale(60); //60%
      } catch (SOL::Exception ex) {
        caught(ex);
      }
    } 

    ~SimpleCVView()
    {
    }
  };

  //Inner OpenGLView class starts.
  class SimpleGLView: public OpenGLView {
  private:
    SmartPtr<OpenGLGC>         gc;
    SmartPtr<OpenGLTexture2D>  texture;
    bool             textured; 
    cv::Mat          blurredImage;
    StringT<char>    imageFile;
    int              imageLoadingFlag;

  private:
    void imageToTexture()
    {
      try {
        int width  = 0;
        int height = 0;
        OpenGLImageInfo imageInfo;

        OpenCVImageInfo cvImageInfo;
        cvImageInfo.getImageInfo(blurredImage, imageInfo); 
        
        texture->image(imageInfo);

      } catch (SOL::Exception& ex) {
        caught(ex);
      }
    }

  public:
    virtual void display()
    {
      if (gc == NULL) {
        return;
      }
      
      if (textured == false) {
        imageToTexture();
        textured = true;
      }
      //Set a proportional perspective.
      gc->matrixMode(GL_PROJECTION);
      gc->loadIdentity();
      gc->perspective(16.0, (double)width() / (double)height(), 0.3, 90.0); 
      gc->matrixMode(GL_MODELVIEW);

      gc->clearColor(1.0, 1.0, 1.0, 1.0);
      gc->clear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

      gc->rotate(20.0, 0.0, 0.0, 1.0);

      gc->begin(GL_QUADS);
      texture->coord(0.0, 0.0); 
      gc->vertex(-1.0,  1.0, 1.0);

      texture->coord(1.0, 0.0); 
      gc->vertex( 1.0,  1.0, 0.0);

      texture->coord(1.0, 1.0); 
      gc->vertex( 1.0, -1.0, 1.0);

      texture->coord(0.0, 1.0); 
      gc->vertex(-1.0, -1.0, 0.0);
      gc->end();
    }
 
    virtual void resize(int w, int h)
    {
      if (w == 0 || h == 0) {
        return;
      }
      if (gc) {
      gc->matrixMode(GL_PROJECTION);
      gc->loadIdentity();
      gc->ortho(-1.25, 1.25, -1.25, 1.25, 1., 20.);

      gc->matrixMode(GL_MODELVIEW);
      gc->loadIdentity();
      gc->lookAt(0., 0., 10., 0., 0., 0., 0., 1., 0.);
      }
    }

    virtual void initialize()
    {
      gc = new OpenGLGC();
      
      gc->enable(GL_DEPTH_TEST);
      gc->enable(GL_TEXTURE_2D);
      gc->rotate(20.0, 0.0, 0.0, 1.0);

      texture = new OpenGLTexture2D();
      
      texture->bind();

      texture->parameter(GL_TEXTURE_MIN_FILTER, GL_LINEAR);
      texture->parameter(GL_TEXTURE_MAG_FILTER, GL_LINEAR);
      texture->env(GL_TEXTURE_ENV_MODE, GL_MODULATE); 
      
    }

    void blur(cv::Mat& originalImage)
    {
      int ksize = 13;
      int sigma = 10;
      ksize = (ksize/2)*2 + 1;
      blurredImage = cv::Mat::zeros(originalImage.size(), 
                                originalImage.type() );
      //Blur operation is applied to the original image.
      cv::GaussianBlur(originalImage, blurredImage, cv::Size(ksize, ksize), 
            (double)sigma, //sigmaX, 
            (double)sigma); //sigmaY 
    }

  public:
    SimpleGLView(View* parent, const char* name, Args& args)
    :OpenGLView(parent, name, args)
    {
      textured = false;
      const char* filename = (const char*)args.get(XmNimageFileName);
      int   imageLoadingFlag = args.get(XmNimageLoadingFlag);

      if (filename) {
        OpenCVImageFileReader reader;
        cv::Mat image = reader.load(filename, imageLoadingFlag);
        blur(image);
      }
    } 

    ~SimpleGLView()
    {
    }

  };
  //Inner class ends.
    
private:
  SmartPtr<SimpleGLView>  glView;
  SmartPtr<SimpleCVView>  cvView;

  void resize(int w, int h)
  {
    if (cvView && glView) { 
      cvView -> reshape(0, 0, w/2-1, h);
      cvView->postResizeRequest(w/2-1, h);
      glView -> reshape(w/2+1, 0, w/2-2, h);
      glView ->postResizeRequest(w/2-2, h);
    }
  }

public:
  MainView(Application& applet, const char* name, Args& args)
  :OpenGLMainView(applet, name, args)
  {
    Args ar;    

    const char* filename = "..\\..\\opencv_app\\images\\flower.png"; 

    ar.reset();
    ar.set(XmNimageFileName, filename);
    ar.set(XmNimageLoadingFlag, cv::IMREAD_COLOR);
    glView = new SimpleGLView(this, "", ar);

    ar.reset();
    ar.set(XmNimageFileName, filename);
    ar.set(XmNimageLoadingFlag, cv::IMREAD_COLOR);
    cvView = new SimpleCVView(this, "", ar);

    char title[MAX_PATH];
    sprintf_s(title, CountOf(title), "%s - %s", filename, name);
    setText(title);
  }

  ~MainView()
  {
  }
};
}

//
void Main(int argc, char** argv) 
{
  try {
    const char*  name = appName(argv[0]);
    Application applet(name, argc, argv);

    Args args;
    args.set(XmNwidth, 800);
    args.set(XmNheight, 400);
    MainView view(applet, name, args);
    view.realize();
    applet.run();
    
  } catch (SOL::Exception& ex) {
    caught(ex);
  }
}