Latern Guard (Thief 1)

Author: Sneaky Acolyte


Walking Lantern Guard Tutorial


--------------------------------------------------------------------------------


This is a tutorial for a guard that carries a lantern and lights up your visibility gem. This was made for Thief: TDP and

Thief: Gold. It is not for Thief II as one can use the renderer "Dynamic Light" instead. This was added to by

Dan "Thiefs_Pawn" Corder after being originally created by Daniel "Sneaky Acolyte" Garcia. We are not to be held

responsible for any damages caused by this document or the following of the directions held within. It is HIGHLY

recommended that you read a Tutorial on Sources and Receptrons prior to reading this document. It is assumed that all

preliminary actions of building a level have been implemented.



--------------------------------------------------------------------------------


Background

This tutorial will explain two ways of creating lantern guards, though the second is really just an extension of the first.

The default AI->Utility->Visibility Control settings for a Ramirez guard are shown below:


Low light 13

Mid light 19

High light 44

Slow 5.49

Fast 8.25

Slow mod 0

Norm mod 5

Fast mod 10

Wall dist 1.75

Crouch mod -3

Wall mod -1

Corner lean mod 1059481190


We are really only interested in the first three of these settings. It seems that these numbers represent the intensity of

light Garrett must be in to be regarded as being in low, medium, or high light by the AI. The other numbers modify the

light intensity depending on Garrett's posture and speed so we can leave them alone. So to make Garrett more visible all

we need to do is set the top three numbers to lower values.


Stuff you need for both methods

- A room not connected to the rest of your level (a 'blue room')

- At least two guards in the blue room. If you want x levels of light you'll want x + 1 guards. For the first example

we'll use 3 guards in the blue room. They will be called normal, high, and highest.

- A guard in your level to hold the lantern (lanternGuard)

- A lantern (note its ID number, for the purposes of this tutorial we will call it "X")


1) The easy way:

As we want 2 light levels we need to divide the light level numbers above by 2 and use these numbers as the increments,

which we'll reduce the numbers by.

So for 'highest' we need to add the property AI->Utility->Visibility Control as below


Low light 0

Mid light 0

High light 0

Slow 5.49

Fast 8.25

Slow mod 0

Norm mod 5

Fast mod 10

Wall dist 1.75

Crouch mod -3

Wall mod -1

Corner lean mod 1059481190


high:

Low light 6

Mid light 10

High light 22

.......


normal:

Low light 13

Mid light 19

High light 44

.......


We can also add

AI -> State -> Current Mode : Asleep

to all the guards as a safe-guard.


Now we need to create a custom stim


Open up the Object Hierarchy

Select Act/React Stimuli from the Show Tree drop-down box

Click on Stimulus, and then click Add, and type in what you want to call your stim (I used LanternStim).

Save the gamesys file. Make sure that you also save the mission and set that mission to use that gamesys with the

set_gamesys command.

Next we will set up the lantern


Open the lantern's properties

Add to lantern's properties

Renderer -> Self Lit: 250

Renderer -> Light: Set all numbers to zero.

Return to Main DromEd window

Add to lantern's properties

Act/React -> Sources

Click Add

Object: LanternGuard

Stimulus: LanternStim

Propagator: Radius

Edit Shape:

Radius: 50

Flags: None

Dispersion: Linear

Edit Life Cycle:

Flags: No Max Firings

Period: 100

Max Firings: 1

Intensity Slope: 0

Intensity: 50

Select LanternGuard and click on links.

Flavor: Creature Attachment

From: LanternGuard

To: "X"

Click OK

Select the link and click Data.

Set it to "Left Fingers"

Return to Main DromEd window

Now we need to make the new stim affect Garrett


Open up the Object Hierarchy

Go to Physical->Avatar->Garrett and click Edit

Now click Add->Act/React->Receptrons

Click Add

Object: Garrett (-2099)

Stimulus: LanternStim

Min intensity: No Min

Max intensity: 25

Effect: Set Property

Edit Effect:

Prop Name: AI_VisCtrl

Target obj: Me

Agent obj: normal

Click OK

Click Add

Object: Garrett (-2099)

Stimulus: LanternStim

Min intensity: 26

Max intensity: 38

Effect: Set Property

Edit Effect:

Prop Name: AI_VisCtrl

Target obj: Me

Agent obj: high

Click OK

Click Add

Object: Garrett (-2099)

Stimulus: LanternStim

Min intensity: 39

Max intensity: 50

Effect: Set Property

Edit Effect:

Prop Name: AI_VisCtrl

Target obj: Me

Agent obj: highest

Click OK

That's it, this method is relatively simple but does have a couple of drawbacks - the extra light doesn't know about walls

or corners and so will pass straight through them. In areas with thick walls and gentle bends this is not a problem and

this method is fine.

However if you want to make your lantern work in a more realistic manner you'll need to read on to....


2) The slightly harder way

Do all the stuff in method 1 using more light levels if you want. E.g. add two more guards (medium and higher) with

AI->Utility->Visibility Control set up as below:


higher:

Low light 3

Mid light 5

High light 11

.......


medium:

Low light 9

Mid light 15

High light 33

.......


And alter the receptrons on Garrett to use these new visibility levels.


The first thing we need to deal with is the light traveling through walls. This is actually surprisingly easy; all we need

to do is change the source on the lantern.


Open the lantern's properties

Edit the LanternStim source, click the 'edit shape' button and set up the box as follows:

Radius 50

Flags 'Line of sight (raycast)'

Dispersion Linear

Click OK

and voila you can sneak up on guard around a corner and not be lit up until you round the corner. The only problem now is

that if you duck back round the corner you'll still be lit up and will stay that way forever :(

A solution is to add another source to the guard carrying the lantern with a radius a lot larger than the light radius and

no 'Line of sight' flag set on the shape. To do this;


Open the guard's properties and add a source set up as follows

Stimulus LanternStim

Propagator Radius

Intensity -10

Click the 'edit shape' button and set up the box as follows

Radius 50

Flags 'None'

Dispersion None

Click OK

then click 'edit life cycle' and set up the box as follows

Flags 'No max firings'

Period 500

Max firings 1

Intensity slope 0

Click OK

The reason for adding the source to the guard and not the lantern is that if the guard is knocked out and falls forward

and is then picked up and dropped by the player the lantern drops completely below floor level and its sources seem to

stop having any effect (even without the 'Line of Sight' flag checked). This way the player will always revert to normal

visibility.


So there you go working lantern guards, which method you choose depends on whether or not you need the extra realism, as

it does cost extra processing power to do the second source and probably to calculate the line of sight for the first

source.


Notes: The values used in this tutorial for radii, light intensity and Source strength are only a guide. You can have a

much more powerful lantern if you wish, you'll just need to experiment with the LanternStim's range and the Receptron's

intensities until you get an effect that looks right. Just remember that in the second method the stim on the guard must

be much larger than radius at which Garrett starts to be lit.


Remember: You MUST include your custom gamesys in your .zip, so that other Thief players can play your mission.


Daniel "Sneaky Acolyte" Garcia

dgarcia@techie.com


with additions by


Dan "Thiefs_Pawn" Corder

thief@dancorder.com


Special Thanks to Totality and the TTLG Editor's Guild


    Comments