AI Recruitment

From The Battle for Wesnoth Wiki
Revision as of 11:45, 12 September 2013 by Flixx (talk | contribs) (Combat Analysis)

This page is work in progress

The new Recruitment Candidate Action is highly configurable and supports multiple leader recruiting...

How it works

Map analyis

In a first step the CA will analyse the map and try to find "important hexes". Those are locations on the map where a fight will occur with high probability. The important hexes are used later in combat simulations to calculate a average defense for the combatants.

If the game runs in debug mode the important hexes will be displayed with a white circle on them.

Implementation details for interested readers: [...]

Score Map

For all leaders which are available for recruiting a score map will be created including all unit-types from the recruit- and recall lists. Then the scores are filled with values coming from different functions (see below).

Combat Analysis

For each unit-type our leaders can recruit the CA will simulate a fight with all enemy units on the map (If there are less then 5 enemy units, the enemies recruitment list(s) will be taken into account)

Implementation details for interested readers:

Combat Analysis will use the function compare_unit_types(a, b). It takes two unit-types and returns a positive value if unit-type a is better then b and a negative value if unit-type b is better then a. If the return value is 2.0 it means that unit-type a is twice as good as unit-type b.

Here is a important code-snipped of compare_unit_types():

double value_of_a = damage_to_b / (b_max_hp * a_cost);
double value_of_b = damage_to_a / (a_max_hp * b_cost);
if (value_of_a > value_of_b) {
  return value_of_a / value_of_b;
} else if (value_of_a < value_of_b) {
  return -value_of_b / value_of_a;
} else {
  return 0.;
}

Aspect recruitment_instruction

Examples

Recruit 3 Grunts (and nothing more) in turn 3-5.

[ai]
  [aspect]
    id=recruitment-instructions
    [facet]
      turns=3-5
      [value] 
        [recruit]
          type=Orcish Grunt
          number=3
        [/recruit]
      [/value]
    [/facet]
  [/aspect]
[/ai]

Recruit so, that there are at least 4 scouts in total and then recruit other units.

[ai]
  [aspect]
    id=recruitment-instructions
    [facet]
      [value] 
        [recruit]
          type=scout
          number=4
          total=yes
          importance=1
        [/recruit]
        [recruit]
          importance=0
        [/recruit]
      [/value]
    [/facet]
  [/aspect]
[/ai]

Recruit 6 Grunts or level 2 units (whatever seems better for the AI) and nothing more.

[ai]
  [aspect]
    id=recruitment-instructions
    [facet]
      [value] 
        [recruit]
          type=Orcish Grunt, 2
          number=6
        [/recruit]
      [/value]
    [/facet]
  [/aspect]
[/ai]

Recruit 5 scouts with leader1 and 5 Grunts with leader 2. Do even try to recruit the Grunts if leader1 can not recruit all of the scouts.

[ai]
  [aspect]
    id=recruitment-instructions
    [facet]
      [value] 
        [recruit]
          type=scout
          number=5
          importance=2
          leader_id=leader1
          blocker=no
        [/recruit]
        [recruit]
          type=Orcish Grunt
          number=5
          importance=1
          leader_id=leader2
        [/recruit]
      [/value]
    [/facet]
  [/aspect]
[/ai]

Do not recruit in turn 4.

[ai]
  [aspect]
    id=recruitment-instructions
    [facet]
      turns=4
      [value] 
        [recruit]
          importance=1
          number=0
        [/recruit]
      [/value]
    [/facet]
  [/aspect]
[/ai]

This will not work. Only one facet can be active.

[ai]
  [aspect]
    id=recruitment-instructions
    [facet]
      turns=1-10
      [value] 
        [recruit]
          type=scout
          number=5
          importance=1
        [/recruit]
      [/value]
    [/facet]
    [facet]
      turns=3
      [value] 
        [recruit]
          type=Orcish Grunt
          number=3
          importance=2
        [/recruit]
      [/value]
    [/facet]
  [/aspect]
[/ai]

To achieve this behavior one have to create a facet for turn 1-2, a facet for turn 3 and another facet for turn 4-10.

Other aspects

Examples