The syntax is based on HLSL, adding useful features designed for developing post-processing effects. ReShade features its very own shading language and transcompiler, called ReShade FX. ReShade adds advanced depth-edge-detection-driven SMAA antialiasing, screen-space ambient occlusion, depth of field effects, chromatic aberration, dynamic film grain, automatic saturation, color correction cross processing, multi-pass blurring, and so much more. ReShade is designed to function by exposing an automated and generic way to access frame color and depth information (the latter is automatically disabled during multiplayer to prevent exploitation) and all the tools needed to facilitate the entire process.
Imagine seeing your favorite game with ambient occlusion, real depth of field effects, or color correction. ReShade, technically speaking, is a generic post-processing injector for games and video software. ReShade is an Open Source tool that helps improve the look of older games on modern video cards and allows the addition of newer display/video technologies to older games that do not support those technologies.