Get the number of 2D rendering drivers available for the current display.
Returns a number >= 0 on success or a negative error code on failure; call SDL_GetError() for more information.
A render driver is a set of code that handles rendering and texture management on a particular display. Normally there is only one, but some drivers may have several available with different capabilities.
There may be none if SDL was compiled without render support.
This function is available since SDL 2.0.0.