# WML Utilities

From The Battle for Wesnoth Wiki

## Determining opposite coordinates

**Obsolete?** the Standard Location Filter now supports directions, which might be able to replace any uses of this utility.

# Using this, you can determine the coordinates on the "opposite side" of a # central hex, relative to another hex adjacent to it. What this really means # is illustrated below: # __ __ __ # __/ \__ __/2 \__ __/ \__ # / \__/1 \ / \__/ \ /2 \__/ \ C: central point # \__/C \__/ \__/C \__/ \__/C \__/ 1: the hex to "mirror" # /2 \__/ \ / \__/ \ / \__/1 \ 2: the result # \__/ \__/ \__/1 \__/ \__/ \__/ # \__/ \__/ \__/ # # The coordinates of the central point are given in {CENTER_X} and {CENTER_Y}, # and the coordinates of hex 1 in {X} and {Y}. The coordinates of hex 2 are # then stored in {VAR}, which will have member variables x and y. # # Note that this uses the IF macro given earlier on this page.

#define OPPOSITE_SIDE CENTER_X CENTER_Y X Y VAR {VARIABLE x_odd {X}}

{VARIABLE_OP x_odd modulo 2}

{VARIABLE c_x {CENTER_X}} {VARIABLE c_y {CENTER_Y}} {VARIABLE s_x {X}} {VARIABLE s_y {Y}}

{VARIABLE result_x {CENTER_X}} {VARIABLE result_y {CENTER_Y}}

{IF_VAR s_x greater_than $c_x ( [then] {VARIABLE_OP result_x add -1} [/then] )}

{IF_VAR s_x less_than $c_x ( [then] {VARIABLE_OP result_x add 1} [/then] )}

{IF_VAR s_x equals $c_x ( [then] {IF_VAR s_y less_than $c_y ( [then] {VARIABLE_OP result_y add 1} [/then] )}

{IF_VAR s_y greater_than $c_y ( [then] {VARIABLE_OP result_y add -1} [/then] )} [/then] )}

{IF_VAR x_odd equals 1 ( [then] {IF_VAR s_y equals $c_y ( [then] {VARIABLE_OP result_y add 1} [/then] )} [/then]

[else] {IF_VAR s_y equals $c_y ( [then] {VARIABLE_OP result_y add -1} [/then] )} [/else] )} {VARIABLE {VAR}.x $result_x} {VARIABLE {VAR}.y $result_y}

{CLEAR_VARIABLE c_x} {CLEAR_VARIABLE c_y} {CLEAR_VARIABLE s_x} {CLEAR_VARIABLE s_y} {CLEAR_VARIABLE result_x} {CLEAR_VARIABLE result_y} {CLEAR_VARIABLE x_odd} #enddef

## Find nearest hex(es)

#define FIND_NEARBY FILTER X Y LIMIT # Does a search for a nearby location that matches the given filter. # Basically just looks for such a location with increasing radius until it # finds at least one. This is sadly inefficient, but implementing BFS in # WML is... difficult. Once LIMIT is reached, the entire map is searched. # This macro creates the 'nearby_locations' and 'nearby_distance' # variables, which can be used to access a list of locations found and the # distance to those locations, respectively. They should eventually be # cleared, which can be accomplished using the CLEANUP_SEARCH macro. [clear_variable] name=nearby_locations [/clear_variable] [set_variable] name=nearby_distance value=0 [/set_variable] [while] [not] [variable] name=nearby_locations.length greater_than=0 [/variable] [/not] [and] [variable] name=nearby_distance less_than={LIMIT} [/variable] [/and] [do] {DEBUG "Searching depth $nearby_distance around ({X}, {Y})..."} [store_locations] variable=nearby_locations {FILTER} [and] x,y={X},{Y} radius=$nearby_distance [/and] [/store_locations] {DEBUG "...found $nearby_locations.length locations."} [set_variable] name=nearby_distance add=1 [/set_variable] [/do] [/while] [if] [variable] name=nearby_locations.length equals=0 [/variable] [then] [store_locations] variable=nearby_locations {FILTER} [/store_locations] [/then] [/if] #enddef #define CLEANUP_SEARCH # Clears variables involved in searching (the FIND_NEARBY macro). Put this # in your name=victory,defeat tag to clean up if you use FIND_NEARBY within # a scenario. [clear_variable] name=nearby_locations, nearby_distance [/clear_variable] #enddef

## See Also

This page was last edited on 2 July 2019, at 21:20.