Simplified GLFW template

test-opengl.cpp

#define GLFW_EXPOSE_NATIVE_X11
#define GLFW_EXPOSE_NATIVE_GLX

/* -------------------------------------------- */

#include <stdlib.h>
#include <stdio.h>
#include <sstream>
#include <glad/glad.h>
#include <GLFW/glfw3.h>
#include <GLFW/glfw3native.h>

/* -------------------------------------------- */

void button_callback(GLFWwindow* win, int bt, int action, int mods);
void cursor_callback(GLFWwindow* win, double x, double y);
void key_callback(GLFWwindow* win, int key, int scancode, int action, int mods);
void char_callback(GLFWwindow* win, unsigned int key);
void error_callback(int err, const char* desc);
void resize_callback(GLFWwindow* window, int width, int height);
void scroll_callback(GLFWwindow* window, double xoffset, double yoffset);

/* -------------------------------------------- */

int win_w = 1280;
int win_h = 720;

/* -------------------------------------------- */
  
int main(int argc, char* argv[]) {

  glfwSetErrorCallback(error_callback);
  
  if(!glfwInit()) {
    printf("Error: cannot setup glfw.\n");
    exit(EXIT_FAILURE);
  }

  glfwWindowHint(GLFW_SAMPLES, 4);
  glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 4);
  glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
  glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
  glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
  glfwWindowHint(GLFW_COCOA_RETINA_FRAMEBUFFER, GL_FALSE);
  glfwWindowHint(GLFW_RESIZABLE, GL_FALSE);
  glfwWindowHint(GLFW_DECORATED, GL_FALSE);
 
  GLFWwindow* win = NULL;

  win = glfwCreateWindow(win_w, win_h, "OpenGL", NULL, NULL);
  if(!win) {
    glfwTerminate();
    exit(EXIT_FAILURE);
  }

  glfwSetFramebufferSizeCallback(win, resize_callback);
  glfwSetKeyCallback(win, key_callback);
  glfwSetCharCallback(win, char_callback);
  glfwSetCursorPosCallback(win, cursor_callback);
  glfwSetMouseButtonCallback(win, button_callback);
  glfwSetScrollCallback(win, scroll_callback);
  glfwMakeContextCurrent(win);
  glfwSwapInterval(1);

  if (!gladLoadGL()) {
    printf("Cannot load GL.\n");
    exit(1);
  }

  /* -------------------------------------------- */
  
  glDisable(GL_DEPTH_TEST);
  glDisable(GL_DITHER);
  glEnable(GL_BLEND);
  glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

  while(!glfwWindowShouldClose(win)) {
    
    glBindFramebuffer(GL_FRAMEBUFFER, 0);
    glViewport(0, 0, win_w, win_h);
    glClearColor(0.13f, 0.13f, 0.13f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    
    glfwSwapBuffers(win);
    glfwPollEvents();
  }

  /* -------------------------------------------- */
  
  glfwTerminate();

  return EXIT_SUCCESS;
}

/* -------------------------------------------- */

void key_callback(GLFWwindow* win, int key, int scancode, int action, int mods) {

  if (GLFW_RELEASE == action) {
    return;
  }
  
  switch(key) {
    case GLFW_KEY_ESCAPE: {
      glfwSetWindowShouldClose(win, GL_TRUE);
      break;
    }
  };
}

void error_callback(int err, const char* desc) {
  printf("GLFW error: %s (%d)\n", desc, err);
}

/* -------------------------------------------- */

void resize_callback(GLFWwindow* window, int width, int height) { }
void cursor_callback(GLFWwindow* win, double x, double y) { }
void scroll_callback(GLFWwindow* window, double xoffset, double yoffset) { }
void button_callback(GLFWwindow* win, int bt, int action, int mods) { }
void char_callback(GLFWwindow* win, unsigned int key) { }

/* -------------------------------------------- */