I'm using vc_dispmanx as a display engine and noticed the presence of vc_vchi_dispmanx library who looks quite close to vc_dispmanx.
Dispmanx seems to be a broadcom proprietary alternative to openGL, SDL, OpenMax, and so on ... It's a C library used in program such as raspivid/raspistill or pngview.
What is the difference / When should we use vc_vchi_dispmanx ?