Difference between revisions of "Grand Theft Auto: San Andreas/Missions/Snail Trail"

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===Driving Behaviour===
 
===Driving Behaviour===
The taxi driver always seems to try to swerve around traffic (unlike random traffic, which does not always do that), but always stops at red traffic lights up to the first checkpoint, most of the time stops at red traffic lights up to the second checkpoint and apparently never stops at red traffic lights beyond that. Trying to scare the taxi driver (like hovering over it with a helicopter or ramming into the car) doesn't seem to change anything, even though he sometimes seems to drive like scared, he always behaves that way and also doesn't behave like a regular scared AI (which drives much faster).
+
The taxi driver always seems to try to swerve around traffic (unlike random traffic AIs, which do not always do that), but always stops at red traffic lights up to the first checkpoint, most of the time stops at red traffic lights up to the second checkpoint and apparently never stops at red traffic lights beyond that. Trying to scare the taxi driver (like hovering over it with a helicopter or ramming into the car) doesn't seem to change anything, even though he sometimes seems to drive like scared, he always behaves that way and also doesn't behave like a regular scared AI (which drives much faster).
  
 
The code that makes the taxi drive to the next checkpoint suggests that there may be different factors for running red lights (the number of passed checkpoints, threatening him, RNG), but it is not quite clear how the code works. It also seems like the speed of the taxi is defined in the script, but how that works is not quite clear as well.
 
The code that makes the taxi drive to the next checkpoint suggests that there may be different factors for running red lights (the number of passed checkpoints, threatening him, RNG), but it is not quite clear how the code works. It also seems like the speed of the taxi is defined in the script, but how that works is not quite clear as well.

Latest revision as of 10:00, 21 July 2014

General

Trigger area at Cranberry Station
Trigger areas around Market Station

Picking up the Sniper Rifle triggers the train coming into Cranberry Station. Not picking up the Sniper Rifle doesn't seem to fail the mission, so you can technicially take as long as you want.

After that the mission is mostly timed, but there are some triggers. The following table shows different sections of the mission. The timing starts when you pick up the sniper. Sections enclosed in [ ] refer to the first appearance of the corresponding subtitle. The exact times of course depend on what exactly is used as a reference point, so other tests might have slightly different results if they are not exactly the same.

Section Fastest If you don't trigger.. Comment
Picked up Sniper 00:00
+00:12
Train comes to a stop 00:12
Need to be at Cranberry Station to trigger +00:00 Fails mission after about 2:00 The train start driving slowly after about 1 minute, then it's another minute until you fail the mission. Also be careful not to be too fast, you need to trigger the train after it came to a stop.
[Reporter entered the train] 00:12
+03:12 The train always takes the same time, whether you are near it or not. You can however enter the train yourself and skip the trainride altogether. Press "get out" on Market Station to be thrown out of the train before the train stops.
[Train approaching Market Station] 03:24
Need to be near Market Station to trigger +00:20 Reporter leaves train after 2:19
[Reporter left the train] 03:44
+00:59 The reporter always takes the same time, whether you are near him or not. Although he may take a bit longer if you are too close and scare him (it seems like he stops a few seconds to look around then).
[Reporter looking for a taxi] 04:43
Need to be near the reporter for him to get into a taxi +0:13, +0:18 or longer Fails mission after 1:00 You have to be close enough, so the reporter can find a taxi. If he doesn't, the mission fails. It spawns the taxi on either the northern (13s) or southern (18s) road around the train station. If you weren't in the trigger area by the time the reporter starts searching for a taxi, you are loosing time. See #Taxi Spawn for more information.
[Reporter entered taxi]

When the reporter arrives at the end of the pier, you can shoot him and the one he meets as soon as the subtitle appears that tells you to kill them. Although it might be easier to hit both fast if you wait until they stand closer together. Shoot the reporter (left one) first, because the first shot spooks them and the reporter runs aways, while the guy he meets runs towards CJ and eventuelly starts shooting if he gets closer (which he normally won't though if you snipe them from far away).

Train Skip

You can get on the train when it stops at Cranberry Station (San Fierro) and skip the train ride so almost immediately get to Market Station (Los Santos) where you can get out by jumping out before the train stops. Since you skipped the ride of the train you would usually have to wait for, this saves about 3 minutes, but of course you couldn't get the helicopter, so you'll have to find a fast vehicle for the drive back while following the repoter in the taxi. Even considering the slower drive back (e.g. Police Bike about 30s slower than Maverick), this saves a lot of time.

Taxi Spawn

Triggers
Once the Reporter stops at the sidewalk (The reporter is on the sidewalk looking for a cab.), the taxi can spawn, but only if you are also in the trigger zone (which is a cube around Market Station with a limited height). The reporter doesn't take a random taxi off the street, but instead there can be two places where one will spawn for him, north of Market Station or south of Market Station. From the spawn (The reporter is on the sidewalk looking for a cab.) to the reporter getting in (The reporter has climbed into a cab.) the northern spawn takes 13s and the southern spawn takes 18s (because the drive is a bit longer). The taxi might be obstructed a bit by traffic, but it usually shouldn't be in this part.

The taxi will always spawn on the southern spawn, unless you are in the trigger that makes it spawn in the north. This trigger is placed on the road south of Market Station, but is only a few metres of height (standing on a tall car will already not trigger it it).

Taxi Route

The routes
Once the reporter got into the taxi, it starts driving one of three routes, which seem to be randomly chosen (based on experimentation and some random number generation in the script in the area that seems to be responsible for the route selection). The taxi driver AI follows a few set checkpoints, which forces him on the set routes. The routes seem to be kind of the same length, the biggest time differences come from traffic light RNG (and some small difference also attribute to traffic).

Driving Behaviour

The taxi driver always seems to try to swerve around traffic (unlike random traffic AIs, which do not always do that), but always stops at red traffic lights up to the first checkpoint, most of the time stops at red traffic lights up to the second checkpoint and apparently never stops at red traffic lights beyond that. Trying to scare the taxi driver (like hovering over it with a helicopter or ramming into the car) doesn't seem to change anything, even though he sometimes seems to drive like scared, he always behaves that way and also doesn't behave like a regular scared AI (which drives much faster).

The code that makes the taxi drive to the next checkpoint suggests that there may be different factors for running red lights (the number of passed checkpoints, threatening him, RNG), but it is not quite clear how the code works. It also seems like the speed of the taxi is defined in the script, but how that works is not quite clear as well.

Pier Triggers

Triggers at the Pier
There are also two triggers at the top of the Pier (at which end the target of the taxi is located), one setting the player as "being on the Pier" the other one as "having left the Pier". If you enter the Pier before the taxi (and stay there), then the taxi will turn around and drive another round. If you drive onto the Pier before the taxi and leave it via another way than the trigger, then the taxi will never enter the Pier unless you enter the trigger again.

This should usually not be a problem in a speedrun, since you will just follow the taxi, but it is interesting to know to avoid, just in case.

Links

Addendum

Taxi Route Timing

This is timed from the first appearance of the subtitle "The reporter has climbed into a cab" to the first appearance of "The reporter is ready to meet the Target" (when the taxi gets to the end of the Pier). The timing was done manually off of VODs, so it may only be exact down to 1-2 seconds. The VODs were not selected by what route the taxi takes or something like that, they were just selected kind of randomly (search for VODs containing Snail Trail, PBs and stuff first since that is guaranteed to contain it).

I'm not sure how representative this data is, I just selected random runs, so decide for yourself how you take it. One interesting thing though: Even though the route selection in the mission script is clearly random (as far as I understand it correctly), some routes seem to appear more often. Either there are other factors involved, or the RNG is simply not that random (rather pseudo-random, but of course the distribution of values could be more even).

North-East route means the taxi route where it first drives north, then turns left at the second intersection, North-West where it drives north, then turns right at the first intersection and West where it drives West directly from Market Station. Helicopter means hovering over the Taxi to "scare" him (which probably has no effect) and then following the taxi with the Helicopter, Car/Bike means just following the taxi normally.

An overview of average values:

Average Time Number of Values
North-East 00:02:39 19
North-West 00:02:46 9
West 00:02:32 12
Helicopter 00:02:44 13
Car/Bike 00:02:35 27
Total 00:02:38 40

Time range is 00:02:13 to 00:03:16 which is 00:01:03 difference.

The raw data with sources (sorted by Vehicle, then Route, then Time):

Taxi-Spawn Vehicle Route Time Source
North Car/Bike North-East 00:02:14 http://www.twitch.tv/tirean/b/544973980?t=3h21m10s
North Car/Bike North-East 00:02:15 http://www.twitch.tv/misterpost/c/4388023?t=2h51m30s
North Car/Bike North-East 00:02:16 http://www.twitch.tv/ninkortek/c/4419563
North Car/Bike North-East 00:02:24 http://www.twitch.tv/ultimaomega07/b/548353047?t=2h39m30s
North Car/Bike North-East 00:02:30 http://www.twitch.tv/lotsofs/c/4638919
North Car/Bike North-East 00:02:34 http://www.twitch.tv/ultimaomega07/b/549063698?t=4h52m10s
North Car/Bike North-East 00:02:37 http://www.twitch.tv/ultimaomega07/c/4535625
North Car/Bike North-East 00:02:38 http://www.twitch.tv/ultimaomega07/c/4096990
North Car/Bike North-East 00:02:40 http://www.twitch.tv/joshimuz/c/4077371
North Car/Bike North-East 00:02:40 http://www.twitch.tv/joshimuz/c/1834365
North Car/Bike North-East 00:02:42 http://www.twitch.tv/ismokybacon/b/548474089?t=1h6m
North Car/Bike North-East 00:02:43 http://www.twitch.tv/joshimuz/b/544374846
North Car/Bike North-East 00:03:05 http://www.twitch.tv/ismokybacon/b/547792077?t=1h20m30s
North Car/Bike North-West 00:02:21 Segmented CannibalK9
North Car/Bike North-West 00:02:27 http://www.twitch.tv/misterpost/c/3944570
North Car/Bike North-West 00:02:36 http://www.twitch.tv/ultimaomega07/b/544375505?t=6h51m
North Car/Bike North-West 00:02:41 http://www.twitch.tv/tduva/c/4053924
North Car/Bike North-West 00:02:45 http://www.twitch.tv/tirean/b/541154498?t=3h6m25s
North Car/Bike North-West 00:02:46 http://www.twitch.tv/tirean/b/547738791
North Car/Bike North-West 00:03:03 http://www.twitch.tv/tirean/c/3752881
North Car/Bike West 00:02:13 http://www.twitch.tv/tirean/c/4506319
South Car/Bike West 00:02:16 http://www.twitch.tv/ismokybacon/b/548785475?t=2h1m30s
North Car/Bike West 00:02:32 http://www.twitch.tv/misterpost/b/528263332
North Car/Bike West 00:02:35 http://www.twitch.tv/ultimaomega07/b/545908204?t=5h45m
North Car/Bike West 00:02:43 http://www.twitch.tv/ultimaomega07/c/4273029
North Car/Bike West 00:02:44 http://www.twitch.tv/tirean/b/546818423?t=2h53m
North Car/Bike West 00:02:54 http://www.twitch.tv/joshimuz/c/4055584?t=2h53m50s
South Helicopter North-East 00:02:31 http://www.twitch.tv/lotsofs/c/2771887
South Helicopter North-East 00:02:33 http://www.twitch.tv/joshimuz/c/3482373?t=3h2m
South Helicopter North-East 00:02:40 http://www.twitch.tv/joshimuz/c/2336715?t=2h55m30s
South Helicopter North-East 00:02:54 http://www.twitch.tv/tirean/c/3185289
South Helicopter North-East 00:03:06 http://www.twitch.tv/joshimuz/c/1922409
South Helicopter North-East 00:03:10 ESA2013
South Helicopter North-West 00:03:02 http://www.twitch.tv/joshimuz/c/2191347
South Helicopter North-West 00:03:16 http://www.twitch.tv/ultimaomega07/c/3203164
South Helicopter West 00:02:19 http://www.twitch.tv/tirean/c/3588771
South Helicopter West 00:02:20 http://www.twitch.tv/ninkortek/c/2890299
South Helicopter West 00:02:27 http://www.twitch.tv/joshimuz/c/2866527?t=3h8m
South Helicopter West 00:02:29 http://www.twitch.tv/joshimuz/c/2048578
South Helicopter West 00:02:48 http://www.twitch.tv/tduva/c/3555978
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