third-party/DPVO/Pangolin/examples/SimpleDisplayImage/main.cpp

#include <limits>
#include <iostream>

#include <pangolin/display/display.h>
#include <pangolin/display/view.h>
#include <pangolin/handler/handler.h>
#include <pangolin/gl/gldraw.h>

void setImageData(unsigned char * imageArray, int size){
  for(int i = 0 ; i < size;i++) {
    imageArray[i] = (unsigned char)(rand()/(RAND_MAX/255.0));
  }
}

int main(/*int argc, char* argv[]*/)
{
  // Create OpenGL window in single line
  pangolin::CreateWindowAndBind("Main",640,480);

  // 3D Mouse handler requires depth testing to be enabled
  glEnable(GL_DEPTH_TEST);
  
  pangolin::OpenGlRenderState s_cam(
    pangolin::ProjectionMatrix(640,480,420,420,320,240,0.1,1000),
    pangolin::ModelViewLookAt(-1,1,-1, 0,0,0, pangolin::AxisY)
  );

  // Aspect ratio allows us to constrain width and height whilst fitting within specified
  // bounds. A positive aspect ratio makes a view 'shrink to fit' (introducing empty bars),
  // whilst a negative ratio makes the view 'grow to fit' (cropping the view).
  pangolin::View& d_cam = pangolin::Display("cam")
      .SetBounds(0,1.0f,0,1.0f,-640/480.0)
      .SetHandler(new pangolin::Handler3D(s_cam));

  // This view will take up no more than a third of the windows width or height, and it
  // will have a fixed aspect ratio to match the image that it will display. When fitting
  // within the specified bounds, push to the top-left (as specified by SetLock).
  pangolin::View& d_image = pangolin::Display("image")
      .SetBounds(2/3.0f,1.0f,0,1/3.0f,640.0/480)
      .SetLock(pangolin::LockLeft, pangolin::LockTop);

  std::cout << "Resize the window to experiment with SetBounds, SetLock and SetAspect." << std::endl;
  std::cout << "Notice that the cubes aspect is maintained even though it covers the whole screen." << std::endl;

  const int width =  64;
  const int height = 48;

  unsigned char* imageArray = new unsigned char[3*width*height];
  pangolin::GlTexture imageTexture(width,height,GL_RGB,false,0,GL_RGB,GL_UNSIGNED_BYTE);

  // Default hooks for exiting (Esc) and fullscreen (tab).
  while(!pangolin::ShouldQuit())
  {
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    d_cam.Activate(s_cam);

    glColor3f(1.0,1.0,1.0);
    pangolin::glDrawColouredCube();

    //Set some random image data and upload to GPU
    setImageData(imageArray,3*width*height);
    imageTexture.Upload(imageArray,GL_RGB,GL_UNSIGNED_BYTE);

    //display the image
    d_image.Activate();
    glColor3f(1.0,1.0,1.0);
    imageTexture.RenderToViewport();

    pangolin::FinishFrame();
  }

  delete[] imageArray;

  return 0;
}