/*
 * GL01Hello.cpp: Test OpenGL C/C++ Setup
 */
#include <windows.h>  // For MS Windows
#include <GL/glut.h>  // GLUT, includes glu.h and gl.h'
#include <iostream>

/* Handler for window-repaint event. Call back when the window first appears and
   whenever the window needs to be re-painted. */
void display() {
   int const win_width  = glutGet(GLUT_WINDOW_WIDTH);
   int const win_height = glutGet(GLUT_WINDOW_HEIGHT);

   glClearColor(0.0f, 0.0f, 0.0f, 1.0f); // Set background color to black and opaque
   glClear(GL_COLOR_BUFFER_BIT);         // Clear the color buffer; this clears the whole window regardless of the set viewport

   glViewport(0, 0, win_width, win_height); // we can set the viewport after clearing

   // Draw a Red 1x1 Square centered at origin
   glBegin(GL_QUADS);              // Each set of 4 vertices form a quad
      glColor3f(1.0f, 0.0f, 0.0f); // Red
      glVertex2f(-0.5f, -0.5f);    // x, y
      glVertex2f( 0.5f, -0.5f);
      glVertex2f( 0.5f,  0.5f);
      glVertex2f(-0.5f,  0.5f);
   glEnd();

   glutSwapBuffers();
}

/* Main function: GLUT runs as a console application starting at main()  */
int main(int argc, char** argv) {
    std::cout<<"Hello, world!!"<<std::endl;
   glutInit(&argc, argv);                 // Initialize GLUT

   glutInitWindowSize(320, 320);   // Set the window's initial width & height
   glutInitWindowPosition(50, 50); // Position the window's initial top-left corner
   glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE);

   glutCreateWindow("OpenGL Setup Test"); // Create a window with the given title

   glutDisplayFunc(display); // Register display callback handler for window re-paint

   glutMainLoop();           // Enter the infinitely event-processing loop

   return 0;
}