OpenEuphoria

Help with "facing" routine

• Posted by Einar Mogen <nord.staernes at ROLLAG.MAIL.TELIA.COM> Jul 01, 1998
• 701 views

I would like some help on a function that should work like this:

I pass it two sequences, the first one containing the coordinates of the
active character, the second one containg the coordinates of the point that
the active character should look at. I have a total of 24 facings, the first
one being directly up, the second 15 degrees to the right, the second 30
degrees to the right, and so on. They are indexed 1-24. The function is
supposed to return the facing index that most closely matches the character
looking towards the point. If anyone out there which is more stable at
mathematics like this could help me with the routine (it should be as fast
as possible, since it will be called many times each frame of the game) then
I would be very grateful. I've started working on it, but now I'm both lazy
and tired, and I'm not too keen on this kind of mathematics. Following is an
outline of the function:

function determine_facing(sequence char_pos, sequence point)
    -- find the closest match of the 24 possibilites
    return facing -- 1 to 24
end function

Any help is greatly appreciated, the main thing I'm out for is the fastest
way to find the angle which the point is at, relative to the character,
either in degrees (or radians) or even better expressed with the indexes.

Einar (who hopes his english is not _totally_ hopeless)