Special:Badtitle/NS100:AI Scripting

What is a script?

A script is a set of instructions that Populous: the beginning reads and uses to command the computer controlled players.

Each level can have up to 3 scripts used at once, for each tribe respectively.

A script must also have an accompanying attribute file, which stores the default values for all internal_attribute_variables and the restrictions on buildings/spells similar to a header file used to set default restrictions for the player; I find it easier to simply set them all ON and simply not include them in the script if you do not wish the AI to use them. There is a built-in tool to do this on this scripter.

A script can be as simple as the following:

<syntax lang="popscript">

{

IF ( INT_MY_NUM_PEOPLE < 10 ) { DO GIVE_UP_AND_SULK ON } ELSE { SET INT_ATTR_EXPANSION 50 } ENDIF

} SCRIPT_END

</syntax>

Populous cannot read that and utilise it to control the AI so you need a compiler to compile it to the correct format, and stored in files such as cpscr010.dat (located in the …Bullfrog\Populous\levels directory)

The compiler we will be using for this tutorial is World Editor’s compiler, and can be found here. This also includes an attribute file editor, but as I have already stated – this is not really necessary. You will also need a plain text editor (such as notepad) to edit the scripts in their decompiled form.

A basic script layout

<syntax lang="popscript"> { IF ( INT_GAME_TURN == 0 ) { // set starting attributes SET INT_ATTR_EXPANSION 50 SET INT_ATTR_MAX_BUILDINGS_ON_GO 5 SET INT_ATTR_HOUSE_PERCENTAGE 20 } </syntax>	This part is triggered as soon as the level starts (game turn 0) And is usually used to set up initial attributes and anything else that has to be done immediately on level start.
<syntax lang="popscript"> ELSE { // rest of script DO CONVERT_AT_MARKER 10 DO SPELL_ATTACK INT_ANGEL_OF_DEATH 10 -1 } ENDIF } SCRIPT_END </syntax>	Everything else that you need to do is put in this area.

<syntax lang="popscript"> INT_GAME_TURN </syntax>	is an internal game variable and cannot be changed by the script – it is however changed by populous as the game progresses and can still be referenced to in order to trigger things, which is what happens initially at the start of the level with most scripts.

<syntax lang="popscript">INT_ATTR_EXPANSION</syntax>	is an internal attribute variable and be changed by the script and controls the ai’s behaviour throughout the level. You can tell it is an attribute variable as it starts with INT_ATTR.