Sets the gamma lookup tables for the display for each color component. +Each table is an array of 256 Uint16 values, representing a mapping +between the input and output for that channel. The input is the index +into the array, and the output is the 16-bit gamma value at that index, +scaled to the output color precision. You may pass NULL to any of the +channels to leave them unchanged.
This function adjusts the gamma based on lookup tables, you can also +have the gamma calculated based on a "gamma function" parameter with +SDL_SetGamma.
Not all display hardware is able to change gamma.