The mod will allow you to install shaders for minecraft. Shaders is a “script” for the video card, allowing you to add different effects to the game, for example, change the lighting, texture mapping, reflection and refraction.
This mod only adds support for shaders themselves shaders need to download separately.

How to install GLSL Shaders Mod

For the regular version

1. Download mod
2. Run the file
   (If the file opens as an archive, then click the right mouse button and choose “Open with” -> “Java”)
3. Click Ok – > Ok – > Ok
4. Ready

For forge version

1. Download and install Minecraft Forge
2. Download and install OptiFine HD
3. Download mod
4. Do not unzip it, copy to C:\Users\User_Name\AppData\ Roaming\.minecraft\mods
5. Ready