The Pixel Reality pack by Wedhro works Minecraft without any mods so you can play 100% vanilla. It brings realistic lighting with vanilla textures or any other pack, a perfect alternative to shaders if your machine just can’t handle them!
“The following pics are totally kosher, no shader or photo manipulation was used. I just designed the most awesome light map you ever saw.”
NOTE: because of how Minecraft’s lighting system works you need to keep your Brightness level as low as possible or the shading will basically be unnoticeable.