Sometimes the automap shows areas that haven't actually been seen by the player (or at least it's not obvious to the player that they saw them). It seems that this takes the form of a line of squares starting at the edge of the other side of a doorway. This can be seen when starting a new game in Wolf3D episode 1, then moving backward against the wall and strafing side to side. Sometimes it takes a while to appear.
Perhaps the game is actually momentarily rendering a single column of pixels showing what is on the other side of the door, but if so it is not obvious.
Sometimes the automap shows areas that haven't actually been seen by the player (or at least it's not obvious to the player that they saw them). It seems that this takes the form of a line of squares starting at the edge of the other side of a doorway. This can be seen when starting a new game in Wolf3D episode 1, then moving backward against the wall and strafing side to side. Sometimes it takes a while to appear.
Perhaps the game is actually momentarily rendering a single column of pixels showing what is on the other side of the door, but if so it is not obvious.