Updated source code to reflect content changes (code re-work): advanced OpenGL and model-loading.

src/4.advanced_opengl/9.1.geometry_shader_houses/geometry_shader_houses.cpp

@@ -24,13 +24,13 @@ int main()
     // glfw window creation
     // --------------------
     GLFWwindow* window = glfwCreateWindow(SCR_WIDTH, SCR_HEIGHT, "LearnOpenGL", NULL, NULL);
-    glfwMakeContextCurrent(window);
     if (window == NULL)
     {
         std::cout << "Failed to create GLFW window" << std::endl;
         glfwTerminate();
         return -1;
     }
+    glfwMakeContextCurrent(window);
 
     // glad: load all OpenGL function pointers
     // ---------------------------------------