Re: [TuxKart-devel] Ideas for AI

[Charles G. <ch...@ve...>]

On Tue, 2004-06-29 at 22:03 -0500, Steve Baker wrote:
> When I model a track, I build a second model which is just a set of
> points that describe what I believe is a reasonable 'racing line'.
> 
> The AI attempts to follow that line.
> 
> However, there are some serious problems with that right now.
> 
> 2) The waypoints are in 2D - not 3D.  Hence, tracks with crossovers
>     in them (eg Gowns Bow) just flat out don't work.  Head-butting
>     happens all the time in these tracks because the AI's forget
>     whether they are going over or under the bridge.

Well this is addressed by the aforementioned "2 corner" technique
because you can't forget which corner you are heading towards, right?
As for going over/under the bridge, you'd want to put a waypoint both on
and under said bridge.

> 1) Think about a righthand hairpin turn (eg the first corner
>     in Oliver's math class where the 'walls' between the track
>     sections are very thin books and the track sections are very
>     wide).  What happens is that if you are on the entry to that
>     curve and you hug the right-hand wall, you are actually closer
>     to the 'waypoint' on the other side of the wall than you are
>     to the waypoint on your side of the wall.  This causes the AI
>     characters to head-butt the wall endlessly.

Perhaps waypoints should come in multiple forms, where for cases like
hairpins you'd want two vectors (in / out angle) instead of a single
point.

> 3) 3D waypoints don't work when there are jumps and such.  The player
>     can sail over a waypoint at sufficient height that we cause problem
>     (1) but in 3 dimensions instead of 2.

Way points need to become 'only a guide'.  There must be some way by
which Tuxkart establishes whether a human player is a certain portion
around the track to stop the player cutting across the track and missing
out entire sections.  The AI should use that as it's ultimate decision,
then pick the nearest waypoint _ahead_ so that ones left behind are
ignored once they are behind.

> 4) Computer players only hit the powerups by luck.

This is part of the decision making stuff, whether to hug the racing
line or go for a power up.

Again this would probably be done by overloading waypoints, a 'powerup
waypoint' so to speak.

> 5) You can't have tracks with alternative routes through them.  There
>     is a really GREAT track on MarioKart'64 that's almost a maze.  My
>     scheme can't cope with that.
> 
> 6) You can't easily have tracks with dynamically changing routes through them.
>     I'd like stuff like large turntables that you have to hit at just the
>     right time if you want to take the shortcut - otherwise you're stuck
>     with taking the long way around.   Things like in WaveRacer'64 where a
>     shortcut opens up only on the last lap.

...so we need a new scheme. ;)
-- 
- Charlie

Charles Goodwin <ch...@ve...>
Online @ www.charlietech.com