I've been able to use GLFW to create a window and accept user keyboard/mouse input. I was even able to load a texture from an image (with SOIL) and display that in the GLFW window. However, I'm having problems drawing simple lines with OpenGL. I'm compiling with mingw64 on Windows 7. I've created a pretty simple test program that I believe should show a few lines on screen, but all it shows is just a black background. I only have a relatively simple understanding of OpenGL, so I may be missing some small, but obviously important!, detail. Can anyone look at the code that I've pasted to pastebin and help me figure out what I might be doing wrong, or what settings I might be missing. The pastebin link is https://pastebin.com/YTt4DUWE
To give a little more info on the goal of the program, I'm trying to create a program that will display a 2D map in an orthographic projection. I plan on using keyboard and mouse callbacks to allow the user to pan around and zoom in and out of the map. I'll be drawing the map with simple lines so that zooming in/out will always look good. I've cobbled the main program together from various sources online, which has possibly led to my missing some details. Thanks in advance for any help anyone can provide.