“Hello OpenGL”

During my research period I came across many times on OpenGL when reading AR related articles and paper. Unforturnately I did not have time to actually play with it. So I promised myself that I am going to have to look into it later on (which I believe this is the time!)

Pre-requisite installation

env variable: Go to envirnment setting under “System” in the controrl panel and add PATH to the binary files.

Cbuild: CMake then build lib via VS studio.

1. Freeglut (download ➡ Cbuild ➡ env variable)
2. GLEW (downlaod ➡ env variable)
3. GLFW3 (downliad ➡ Cbuild)

“#include” package

For development on Windows platform, include both “GLEW” and “freeglut”

#include <gl/glew.h>
#include <gl/GL.h>
#include <gl/freeglut.h>

“GLFW” will be used to handle the window and the keyboard input

#include <GLFW/glfw3.h>

GLM for math algorithm

#include <glm/glm.hpp> 
using namespace glm;

Creating a window

Full usage explanation on window reference should be referred to official API documentation.

1. Configure GLFW setting

glwWindowHint(GLFW_SAMPLES, 4) means 4x anti-aliasing.

The version of GLFW is “3.3”

glfwWindowHint(GLFW_SAMPLES, 4);
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

2. Create window and draw simple content

Create a “window”

 window = glfwCreateWindow( 1024, 768, "Tutorial 01", NULL, NULL);
 if( window == NULL ){
  fprintf( stderr, "Failed to open GLFW window.\n" );
  getchar();
  glfwTerminate();
  return -1;
 }
 glfwMakeContextCurrent(window);

Initialise GLEW

if (glewInit() != GLEW_OK) {
  fprintf(stderr, "Failed to initialize GLEW\n");
  getchar();
  glfwTerminate();
  return -1;
 }

Set “window” to listen to keyboard

glfwSetInputMode(window, GLFW_STICKY_KEYS, GL_TRUE);

Enter the main loop and exit when uesr presses Esc button.

do {
   glClear(GL_COLOR_BUFFER_BIT);
   // STUFF HAPPENS HERE
   glfwSwapBuffers(window);
   glfwPollEvents();
}while (glfwGetKey(window, GLFW_KEY_ESCAPE) != GLFW_PRESS && glfwWindowShouldClose(window) == 0);
 glfwTerminate();