Clean skill rust code (#37281)

src/character.cpp

@@ -2448,26 +2448,25 @@ std::string Character::enumerate_unmet_requirements( const item &it, const item
     return enumerate_as_string( unmet_reqs );
 }
 
-int Character::rust_rate( bool return_stat_effect ) const
+int Character::rust_rate() const
 {
     if( get_option<std::string>( "SKILL_RUST" ) == "off" ) {
         return 0;
     }
 
     // Stat window shows stat effects on based on current stat
     int intel = get_int();
-    /** @EFFECT_INT reduces skill rust */
+    /** @EFFECT_INT reduces skill rust by 10% per level above 8 */
     int ret = ( ( get_option<std::string>( "SKILL_RUST" ) == "vanilla" ||
-                  get_option<std::string>( "SKILL_RUST" ) == "capped" ) ? 500 : 500 - 35 * ( intel - 8 ) );
+                  get_option<std::string>( "SKILL_RUST" ) == "capped" ) ? 100 : 100 + 10 * ( intel - 8 ) );
 
     ret *= mutation_value( "skill_rust_multiplier" );
 
     if( ret < 0 ) {
         ret = 0;
     }
 
-    // return_stat_effect actually matters here
-    return ( return_stat_effect ? ret : ret / 10 );
+    return ret;
 }
 
 int Character::read_speed( bool return_stat_effect ) const
@@ -2596,29 +2595,21 @@ void Character::apply_skill_boost()
 
 void Character::do_skill_rust()
 {
-    const int rate = rust_rate();
-    if( rate <= 0 ) {
-        return;
-    }
-    for( auto &pair : *_skills ) {
-        if( rate <= rng( 0, 1000 ) ) {
-            continue;
-        }
-
+    for( std::pair<const skill_id, SkillLevel> &pair : *_skills ) {
         const Skill &aSkill = *pair.first;
         SkillLevel &skill_level_obj = pair.second;
 
         if( aSkill.is_combat_skill() &&
-            ( ( has_trait_flag( "PRED2" ) && one_in( 4 ) ) ||
-              ( has_trait_flag( "PRED3" ) && one_in( 2 ) ) ||
-              ( has_trait_flag( "PRED4" ) && x_in_y( 2, 3 ) ) ) ) {
+            ( ( has_trait_flag( "PRED2" ) && calendar::once_every( 8_hours ) ) ||
+              ( has_trait_flag( "PRED3" ) && calendar::once_every( 4_hours ) ) ||
+              ( has_trait_flag( "PRED4" ) && calendar::once_every( 3_hours ) ) ) ) {
             // Their brain is optimized to remember this
-            if( one_in( 15600 ) ) {
+            if( one_in( 13 ) ) {
                 // They've already passed the roll to avoid rust at
                 // this point, but print a message about it now and
                 // then.
                 //
-                // 13 combat skills, 600 turns/hr, 7800 tests/hr.
+                // 13 combat skills.
                 // This means PRED2/PRED3/PRED4 think of hunting on
                 // average every 8/4/3 hours, enough for immersion
                 // without becoming an annoyance.
@@ -2631,7 +2622,7 @@ void Character::do_skill_rust()
 
         const bool charged_bio_mem = get_power_level() > 25_kJ && has_active_bionic( bio_memory );
         const int oldSkillLevel = skill_level_obj.level();
-        if( skill_level_obj.rust( charged_bio_mem ) ) {
+        if( skill_level_obj.rust( charged_bio_mem, rust_rate() ) ) {
             add_msg_if_player( m_warning,
                                _( "Your knowledge of %s begins to fade, but your memory banks retain it!" ), aSkill.name() );
             mod_power_level( -25_kJ );

src/character.h

@@ -1296,7 +1296,7 @@ class Character : public Creature, public visitable<Character>
         std::string enumerate_unmet_requirements( const item &it, const item &context = item() ) const;
 
         /** Returns the player's skill rust rate */
-        int rust_rate( bool return_stat_effect = true ) const;
+        int rust_rate() const;
 
         // Mental skills and stats
         /** Returns the player's reading speed */

src/newcharacter.cpp

@@ -845,7 +845,7 @@ tab_direction set_stats( const catacurses::window &w, avatar &u, points_left &po
                            _( "Read times: %d%%" ), read_spd );
                 // NOLINTNEXTLINE(cata-use-named-point-constants)
                 mvwprintz( w_description, point( 0, 1 ), COL_STAT_PENALTY, _( "Skill rust: %d%%" ),
-                           u.rust_rate( false ) );
+                           u.rust_rate() );
                 mvwprintz( w_description, point( 0, 2 ), COL_STAT_BONUS, _( "Crafting bonus: %2d%%" ),
                            u.get_int() );
                 fold_and_print( w_description, point( 0, 4 ), getmaxx( w_description ) - 1, COL_STAT_NEUTRAL,

src/player_display.cpp

@@ -314,7 +314,7 @@ static void draw_stats_tab( const catacurses::window &w_stats, const catacurses:
                             string_format( _( "Crafting bonus: <color_white>%d%%</color>" ), you.get_int() ) );
         if( you.rust_rate() ) {
             print_colored_text( w_info, point( 1, 5 ), col_temp, c_light_gray,
-                                string_format( _( "Skill rust: <color_white>%d%%</color>" ), you.rust_rate( false ) ) );
+                                string_format( _( "Skill rust: <color_white>%d%%</color>" ), you.rust_rate() ) );
         }
     } else if( line == 3 ) {
         // Display information on player perception in appropriate window

src/skill.cpp

@@ -224,12 +224,12 @@ time_duration rustRate( int level )
 {
     // for n = [0, 7]
     //
-    // 2^15
+    // 2^18
     // -------
-    // 2^(n-1)
+    // 2^(18-n)
 
-    unsigned const n = level < 0 ? 0 : level > 7 ? 7 : level;
-    return time_duration::from_turns( 1 << ( 15 - n + 1 ) );
+    unsigned const n = clamp( level, 0, 7 );
+    return time_duration::from_turns( 1 << ( 18 - n ) );
 }
 } //namespace
 
@@ -239,10 +239,12 @@ bool SkillLevel::isRusting() const
            calendar::turn - _lastPracticed > rustRate( _level );
 }
 
-bool SkillLevel::rust( bool charged_bio_mem )
+bool SkillLevel::rust( bool charged_bio_mem, int character_rate )
 {
     const time_duration delta = calendar::turn - _lastPracticed;
-    if( _level <= 0 || delta <= 0_turns || delta % rustRate( _level ) != 0_turns ) {
+    const float char_rate = character_rate / 100.0;
+    if( _level <= 0 || delta <= 0_turns ||
+        delta % ( rustRate( _level ) * char_rate ) != 0_turns ) {
         return false;
     }
 
@@ -251,7 +253,7 @@ bool SkillLevel::rust( bool charged_bio_mem )
     }
 
     _exercise -= _level;
-    const auto &rust_type = get_option<std::string>( "SKILL_RUST" );
+    const std::string &rust_type = get_option<std::string>( "SKILL_RUST" );
     if( _exercise < 0 ) {
         if( rust_type == "vanilla" || rust_type == "int" ) {
             _exercise = ( 100 * _level * _level ) - 1;

src/skill.h

@@ -110,7 +110,7 @@ class SkillLevel
 {
         int _level = 0;
         int _exercise = 0;
-        time_point _lastPracticed = calendar::turn_zero;
+        time_point _lastPracticed = calendar::turn;
         bool _isTraining = true;
         int _highestLevel = 0;
 
@@ -150,7 +150,7 @@ class SkillLevel
 
         void train( int amount, bool skip_scaling = false );
         bool isRusting() const;
-        bool rust( bool charged_bio_mem );
+        bool rust( bool charged_bio_mem, int character_rate );
         void practice();
         bool can_train() const;
 

src/wish.cpp

@@ -672,6 +672,7 @@ void debug_menu::wishskill( player *p )
                     skmenu.entries[skill_id + skoffset].txt = string_format( _( "@ %d: %s  " ),
                             p->get_skill_level( skill.ident() ),
                             skill.name() );
+                    p->get_skill_level_object( skill.ident() ).practice();
                     skmenu.entries[skill_id + skoffset].text_color =
                         p->get_skill_level( skill.ident() ) == origskills[skill_id] ? skmenu.text_color : c_yellow;
                 }