Heretic's end text screen displayed by the Eternity Engine.
ENDOOM is the colorful screen shown when Doom exits. Note that ZDoom and some other ports do not show ENDOOM, and authors of modern WADs often do not bother to include replacement ENDOOM lumps.
ENDOOM consists of 4,000 bytes representing a 80 by 25 block of text. Each character on the screen takes up two bytes in the resource: the first byte gives color information, while the second byte is simply the character's 8-bit ASCII value. This means that the line-drawing characters in the extended ASCII character set can be used.
The first byte is further broken down into three pieces. Bits 0-3 give the foreground color, 4-6 give the background color, and bit 7 is a flag that tells whether the character should blink. The colors are standard ANSI colors used by DOS. The reason why the foreground has an extra bit is because the higher colors are all bright, and the background is restricted to display darker colors only. So the first eight colors can be used for anything, the last eight colors can be used for the foreground only.
Background and foreground:
| Code | Color |
|---|---|
| 0 | Black |
| 1 | Blue |
| 2 | Green |
| 3 | Cyan |
| 4 | Red |
| 5 | Magenta |
| 6 | Yellow |
| 7 | White |
Foreground only:
| Code | Color |
|---|---|
| 8 | Gray |
| 9 | Light Blue |
| A | Light Green |
| B | Light Cyan |
| C | Light Red |
| D | Light Magenta |
| E | Light Yellow |
| F | Bright White |
This information is from the Unofficial Doom Specs and the DOS "color" command.