buffer callback + input

pog.cpp

@@ -114,3 +114,10 @@ int main() {
   glfwTerminate();
   return 0;
 }
+void framebuffer_size_callback(GLFWwindow *window, int width, int height) {
+  glViewport(0, 0, width, height);
+}
+void processInput(GLFWwindow *window) {
+  if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
+    glfwSetWindowShouldClose(window, true);
+}