What is the difference between shaders and resource packs?

What is the difference between shaders and resource packs? Shader packs tend to need your minecraft to be modded by adding new folder and files to the internal game. These add shadows and many different lighting changes although are very very resource intensive. tl;dr Resource packs changes the look and sound of the game. Shader packs add different lighting etc to the game.

Shader packs tend to need your minecraft to be modded by adding new folder and files to the internal game. These add shadows and many different lighting changes although are very very resource intensive. tl;dr Resource packs changes the look and sound of the game. Shader packs add different lighting etc to the game.