terrain.hpp

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/*
    Copyright (C) 2003 - 2025
    by David White <dave@whitevine.net>
    Part of the Battle for Wesnoth Project https://www.wesnoth.org/
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.
    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY.
 
    See the COPYING file for more details.
*/
 
#pragma once
 
#include "config.hpp"
#include "terrain/translation.hpp"
#include "utils/math.hpp"
 
class terrain_type
{
public:
 
    /**
     * Creates an instance for which is_nonnull() returns false.  Used for the
     * sentinel value when terrain_type_data::get_terrain_info() is called for
     * an unknown terrain code.
     */
    explicit terrain_type();
 
    /**
     * Constructor for terrains defined by a WML [terrain_type] tag.
     */
    explicit terrain_type(const config& cfg);
 
    /**
     * Used when a terrain code which hasn't been defined with a [terrain_type]
     * tag is used in a map, to build the terrain from already-defined terrains.
     */
    explicit terrain_type(const terrain_type& base, const terrain_type& overlay);
 
    const std::string& icon_image() const { return icon_image_; }
    const std::string& minimap_image() const { return minimap_image_; }
    const std::string& minimap_image_overlay() const { return minimap_image_overlay_; }
    const std::string& editor_image() const { return editor_image_; }
    const t_string& name() const { return name_; }
    const t_string& editor_name() const { return editor_name_.empty() ? description() : editor_name_; }
    const t_string& description() const { return description_.empty() ? name_ : description_; }
    const t_string& help_topic_text() const { return help_topic_text_; }
    const std::string& id() const { return id_; }
 
    /**
     * For instances created from a [terrain_type] tag, the value in the tag
     * (with default false).
     *
     * Always true for instances generated by the terrain_type(base, overlay)
     * constructor.
     */
    bool hide_help() const { return hide_help_; }
    bool hide_in_editor() const { return hide_in_editor_; }
    bool hide_if_impassable() const { return hide_if_impassable_; }
 
    //the character representing this terrain
    t_translation::terrain_code number() const { return number_; }
 
    /**
     * The underlying movement type of the terrain.
     *
     * The underlying terrain is the name of the terrain for game-logic purposes.
     * I.e. if the terrain is simply an alias, the underlying terrain name
     * is the name of the terrain(s) that it's aliased to.
     *
     * Whether "underlying" means "only the types used in [movetype]" is determined
     * by the terrain.cfg file, rather than the .cpp code - in 1.14, the terrain.cfg
     * file uses only the [movetype] terrains in its alias lists.
     *
     * This may start with a t_translation::PLUS or t_translation::MINUS to
     * indicate whether the movement should be calculated as a best-of or
     * worst-of combination. These may also occur later in the list, however if
     * both PLUS and MINUS appear in the list then the values calculated are
     * implementation defined behavior.
     */
    const t_translation::ter_list& mvt_type() const { return mvt_type_; }
    const t_translation::ter_list& def_type() const { return def_type_; }
    const t_translation::ter_list& union_type() const { return union_type_; }
 
    /**
     * Returns true if a terrain has no underlying types other than itself,
     * in respect of either union, movement or defense.
     *
     * If this returns false, then @a underlying must be non-empty.
     *
     * This function is to encapsulate the logic of whether such a terrain
     * is represented by a empty list, or whether it's represented by a list
     * including only itself; so that a refactor can switch between these two
     * possible implementations.
     *
     * This is not related to whether the terrain has an overlay. For example,
     * Gg^Uf (flat with old mushrooms) is indivisible (it's only Tt), although
     * Gg^Tf (flat with new mushrooms) can be divided (in to Gt and Tt).
     *
     * @param id the terrain
     * @param underlying the corresponding mvt_type(), def_type() or union_type()
     */
    static bool is_indivisible(t_translation::terrain_code id, const t_translation::ter_list& underlying) {
        return (underlying.empty()
            || (underlying.size() == 1 && underlying.front() == id));
    }
 
    /**
     * Returns true if this terrain has no underlying types other than itself.
     *
     * \todo what about a terrain where is_mvt_indivisible() != is_def_indivisible()?
     */
    bool is_indivisible() const {
        return (union_type_.empty()
            || (union_type_.size() == 1 && union_type_.front() == number_));
    }
    bool is_mvt_indivisible() const {
        return (mvt_type_.empty()
            || (mvt_type_.size() == 1 && mvt_type_.front() == number_));
    }
 
    /**
     * True if this object represents some sentinel values.
     *
     * \todo number_ should never be NONE_TERRAIN
     * \todo there's two different VOID_TERRAINS - see the comment attached to
     * the definition of VOID_TERRAIN.
     *
     * \todo unclear what this should mean, so replace it with a clearly-named
     * successor.
     */
    bool is_nonnull() const {
        return (number_ != t_translation::NONE_TERRAIN)
            && (number_ != t_translation::VOID_TERRAIN);
    }
 
    /** Returns the light (lawful) bonus for this terrain when the time of day gives a @a base bonus. */
    int light_bonus(int base) const
    {
        return bounded_add(base, light_modification_, max_light_, min_light_);
    }
 
    int unit_height_adjust() const { return height_adjust_; }
    double unit_submerge() const { return submerge_; }
 
    int gives_healing() const { return heals_; }
    bool is_village() const { return village_; }
    bool is_castle() const { return castle_; }
    bool is_keep() const { return keep_; }
 
    //these descriptions are shown for the terrain in the mouse over
    //depending on the owner or the village
    const t_string& income_description() const { return income_description_; }
    const t_string& income_description_ally() const { return income_description_ally_; }
    const t_string& income_description_enemy() const { return income_description_enemy_; }
    const t_string& income_description_own() const { return income_description_own_; }
 
    const std::string& editor_group() const { return editor_group_; }
    void set_editor_group(const std::string& str) { editor_group_ = str; }
 
    bool is_overlay() const { return overlay_; }
 
    /**
     * True for instances created by the terrain_code(base, overlay) constructor.
     *
     * False for instances created by the terrain_type(config) constructor,
     * implying that they were created directly from a WML [terrain_type] tag.
     *
     * Note that this returns false for terrains such as Dd^Dc (crater) and
     * Mm^Xm (regular impassible mountains), because there are [terrain_type]
     * tags for those specific combinations of base^overlay.
     */
    bool is_combined() const { return combined_; }
 
    /**
     * Overlay terrains defined by a [terrain_type] can declare a fallback base
     * terrain, for use when the overlay is selected in the editor, or when the
     * overlay is placed on the map using [terrain]replace_if_failed=true.
     *
     * If there's no default, returns a sentinel value; see has_default_base().
     */
    t_translation::terrain_code default_base() const { return editor_default_base_; }
    bool has_default_base() const { return editor_default_base_ != t_translation::NONE_TERRAIN; }
 
    /**
     * Return the overlay part of this terrain, on the default_base(). Might
     * return an unknown terrain, if there's a typo in the default base.
     *
     * If this terrain has no overlay, it returns the terrain itself, ignoring
     * the default_base() even if the terrain has a default_base().
     *
     * This is intended for the editor's single-layer placement, or for
     * replacing terrains via ActionWML, where the user or WML author intends
     * to only use one layer of the current terrain.
     */
    t_translation::terrain_code terrain_with_default_base() const;
 
    /**
     * Returns true if most of the data matches. The ones that don't need to match:
     * - editor_group_
     * - icon_image_
     * - description_
     * - help_topic_text_
     * - income_description_ , ~ally_ , ~enemy_, ~own_
     * - hide_if_impassable_
     *
     * The intention seems to be to allow additional [terrain_type] tags to add
     * compatible definitions to multiple addon-specific editor groups. For
     * this purpose the description strings aren't too important, and
     * hide_if_impassable_ seems trivial.
     */
    bool operator==(const terrain_type& other) const;
private:
 
    /** The image used as symbol icon */
    std::string icon_image_;
 
    /** The image used in the minimap */
    std::string minimap_image_;
    std::string minimap_image_overlay_;
 
    /**
     *  The image used in the editor palette if not defined in WML it will be
     *  initialized with the value of minimap_image_
     */
    std::string editor_image_;
    std::string id_;
    t_string name_;
    t_string editor_name_;
    t_string description_;
    t_string help_topic_text_;
 
    //the 'number' is the number that represents this
    //terrain type. The 'type' is a list of the 'underlying types'
    //of the terrain. This may simply be the same as the number.
    //This is the internal number used, WML still uses character strings.
    t_translation::terrain_code number_;
    t_translation::ter_list mvt_type_;
    t_translation::ter_list def_type_;
    t_translation::ter_list union_type_;
 
    double submerge_;
    int height_adjust_;
 
    bool submerge_set_;
    bool height_adjust_set_;
 
    int light_modification_;
    int max_light_;
    int min_light_;
    int heals_;
 
    t_string income_description_;
    t_string income_description_ally_;
    t_string income_description_enemy_;
    t_string income_description_own_;
 
    std::string editor_group_;
    t_translation::terrain_code editor_default_base_;
 
    bool village_;
    bool castle_;
    bool keep_;
    bool overlay_;
    bool combined_;
    bool hide_help_;
    bool hide_in_editor_;
    bool hide_if_impassable_;
};