It is hard to tell what you got as a result. Could you modify your shader to output the actual texture data instead of those frac() operations. At the end your depth buffer is supposed to look something like this (the depth value is simply a shade of red) :

You can also use the visual studio graphic debugger tool to visualize the textures that you loaded so you don't need to write a shader and tons of code just to visualize your result.

Also be aware that since you used a perspective projection you are actually running a spot light and not a directional light.