Created the proof of concept for the compass. Not a real compass, though, I mean markers along the rim of the minimap that show you the direction to different points of interest.
Finally got it to work (#working _with_angles), but an interesting bug appeared – in the test room the player is spawned directly adjacent to the object that the compass is tracking. And if you rotate, the compass displays the direction properly. However if you take as stroll (of whatever magnitude), the method for calculating the angle suddenly looses the abolity to work in the proximity of 0 ° and 180 ° – the statement that calculates the direction to the object starts behaving strangely – the angle, for some reason, avoids -20 ° to 20 ° (thereabout). The general behavior is that when the angle reaches certain low threshold (looks like 20 °, but I have to do some more testing) it jumps to the negative of the same, completely ignoring the values in between. Same in the other direction. Same for 180 degrees opposite. Whuh??
P.S. Yeah, a lead – the angle is calculated based on a simple direction spell (target_position – my_position). Apparently this fails when the angle is too small. Grid resolution?