Updating screen events
Use it to easily capture parts of a web site, including text and images.It's also great for writing documentation that needs images of your application or web site.Nintendo declined the offer to release the game after id Software finished it.
EGA has several features that enable the adaptive tile refresh effect: Carmack used these capabilities to create a buffer that is 64 pixels wider and taller than the screen, leaving room for one extra row and column of tiles in the buffer off the edge of the screen.
To counteract this, the code calculates which tiles a moving sprite had previously covered and redraws them to erase the old sprite image, then draws the new sprite image in its new position.
This allows sprites to be animated independently of the scrolling with minimal computational effort.
Its principal innovation is a novel use of several EGA hardware features to perform the scrolling in hardware.
The technique is named for its other aspect, the tracking of moved graphical elements in order to minimize the amount of redrawing required in every frame.