Invulnerability colormap bug

From DoomWiki.org

Invulnerability colormap bug being demonstrated on E3M6: Mt. Erebus (see demo below)
The Invulnerability colormap bug is not limited to Doom; here in Heretic, the sky is not rendered as gold as it should be while the Ring of Invincibility is worn.

When a player becomes invulnerable, the colors in their display change to inverse monochrome. In vanilla Doom the sky retains its original color; long thought of as merely a property of the invulnerability power-up, this was found to be a bug after the release of the source code.

This effect can also be seen in Heretic, where an invulnerable player's display is golden monochrome.

Strife and Hexen are not subject to the problem; the former has no invulnerability powerup, while the latter displays invulnerable status via use of a rotating chess-rook icon.

Most source ports repair this problem, sometimes with a compatibility option.

Demo files[edit]