refactor: fahrenheit to celsius in codebase, part 1

src/game.cpp

@@ -636,7 +636,6 @@ bool game::start_game()
     }
     u.process_turn(); // process_turn adds the initial move points
     u.set_stamina( u.get_stamina_max() );
-    get_weather().temperature = SPRING_TEMPERATURE;
     get_weather().update_weather();
     u.next_climate_control_check = calendar::before_time_starts; // Force recheck at startup
     u.last_climate_control_ret = false;

src/game_constants.h

@@ -78,34 +78,37 @@ static constexpr int PLUTONIUM_CHARGES = 500;
 // Temperature constants.
 namespace temperatures
 {
+
+/// Average annual temperature used for climate, weather and temperature calculation.
+constexpr units::temperature annual_average = 6_c;
+
 // temperature at which something starts is considered HOT.
-constexpr units::temperature hot = 100_f; // ~ 38 Celsius
+constexpr units::temperature hot = 38_c;
 
 // the "normal" temperature midpoint between cold and hot.
-constexpr units::temperature normal = 70_f; // ~ 21 Celsius
+constexpr units::temperature normal = 21_c;
 
-// Temperature inside an active fridge in Fahrenheit.
-constexpr units::temperature fridge = 37_f; // ~ 2.7 Celsius
+// Temperature inside an active fridge
+constexpr units::temperature fridge = 2_c;
 
 // Temperature at which things are considered "cold".
-constexpr units::temperature cold = 40_f; // ~4.4 C
+constexpr units::temperature cold = 5_c;
 
-// Temperature inside an active freezer in Fahrenheit.
-constexpr units::temperature freezer = 23_f; // -5 Celsius
+// Temperature inside an active freezer.
+constexpr units::temperature freezer = -5_c;
 
-// Temperature in which water freezes in Fahrenheit.
-constexpr units::temperature freezing = 32_f; // 0 Celsius
+// Temperature in which water freezes.
+constexpr units::temperature freezing = 0_c;
 
 // Arbitrary constant for root cellar temperature
-// Should be equal to AVERAGE_ANNUAL_TEMPERATURE, but is declared before it...
-constexpr units::temperature root_cellar = 43_f;
+constexpr units::temperature root_cellar = annual_average;
 } // namespace temperatures
 
 // Weight per level of LIFT/JACK tool quality.
-#define TOOL_LIFT_FACTOR 500_kilogram // 500kg/level
+static constexpr units::mass TOOL_LIFT_FACTOR = 500_kilogram; // 500kg/level
 
 // Cap JACK requirements to support arbitrarily large vehicles.
-#define JACK_LIMIT 8500_kilogram // 8500kg ( 8.5 metric tonnes )
+static constexpr units::mass JACK_LIMIT = 8500_kilogram;
 
 // Slowest speed at which a gun can be aimed.
 static constexpr int MAX_AIM_COST = 10;
@@ -139,18 +142,6 @@ static constexpr int BIO_CQB_LEVEL = 5;
 // Minimum size of a horde to show up on the minimap.
 static constexpr int HORDE_VISIBILITY_SIZE = 3;
 
-/**
- * Average annual temperature in F used for climate, weather and temperature calculation.
- * Average New England temperature = 43F/6C rounded to int.
-*/
-static constexpr int AVERAGE_ANNUAL_TEMPERATURE = 43;
-
-/**
- * Base starting spring temperature in F used for climate, weather and temperature calculation.
- * New England base spring temperature = 65F/18C rounded to int.
-*/
-static constexpr int SPRING_TEMPERATURE = 65;
-
 /**
  * Used to limit the random seed during noise calculation. A large value flattens the noise generator to zero.
  * Windows has a rand limit of 32768, other operating systems can have higher limits.

src/item.cpp

@@ -95,6 +95,7 @@
 #include "text_snippets.h"
 #include "translations.h"
 #include "units.h"
+#include "units_temperature.h"
 #include "units_utility.h"
 #include "value_ptr.h"
 #include "vehicle.h"
@@ -5610,78 +5611,57 @@ int item::spoilage_sort_order() const
     return bottom;
 }
 
+namespace
+{
+
 /**
- * Food decay calculation.
- * Calculate how much food rots per hour, based on 10 = 1 minute of decay @ 65 F.
+ * Hardcoded lookup table for food rots per hour calculation.
+ *
  * IRL this tends to double every 10c a few degrees above freezing, but past a certain
  * point the rate decreases until even extremophiles find it too hot. Here we just stop
- * further acceleration at 105 F. This should only need to run once when the game starts.
- * @see calc_rot_array
- * @see rot_chart
+ * further acceleration at 40C.
+ *
+ * Original formula:
+ * @see https://github.com/cataclysmbnteam/Cataclysm-BN/blob/033901af4b52ad0bfcfd6abfe06bca4e403d44b1/src/item.cpp#L5612-L5640
  */
-static int calc_hourly_rotpoints_at_temp( const int temp )
+constexpr auto rot_chart = std::array<int, 44>
 {
-    // default temp = 65, so generic->rotten() assumes 600 decay points per hour
-    const int dropoff = 38;     // ditch our fancy equation and do a linear approach to 0 rot at 31f
-    const int cutoff = 105;     // stop torturing the player at this temperature, which is
-    const int cutoffrot = 21240; // ..almost 6 times the base rate. bacteria hate the heat too
-
-    const int dsteps = dropoff - units::to_fahrenheit( temperatures::freezing );
-    const int dstep = ( 215.46 * std::pow( 2.0, static_cast<float>( dropoff ) / 16.0 ) / dsteps );
-
-    if( temp < units::to_fahrenheit( temperatures::freezing ) ) {
-        return 0;
-    } else if( temp > cutoff ) {
-        return cutoffrot;
-    } else if( temp < dropoff ) {
-        return ( temp - units::to_fahrenheit( temperatures::freezing ) ) * dstep;
-    } else {
-        return std::lround( 215.46 * std::pow( 2.0, static_cast<float>( temp ) / 16.0 ) );
-    }
-}
+    0, 372, 744, 1118, 1219, 1273, 1388, 1514, 1651, 1800,
+    1880, 2050, 2235, 2438, 2658, 2776, 3027, 3301, 3600, 3926,
+    4100, 4471, 4875, 5317, 5798, 6054, 6602, 7200, 7852, 8562,
+    8941, 9751, 10633, 11595, 12645, 13205, 14400, 15703, 17125, 18674,
+    19501,
+};
 
-/**
- * Initialize the rot table.
- * @see rot_chart
- */
-static std::vector<int> calc_rot_array( const size_t cap )
-{
-    std::vector<int> ret;
-    ret.reserve( cap );
-    for( size_t i = 0; i < cap; ++i ) {
-        ret.push_back( calc_hourly_rotpoints_at_temp( static_cast<int>( i ) ) );
-    }
-    return ret;
-}
+} // namespace
 
 /**
  * Get the hourly rot for a given temperature from the precomputed table.
  * @see rot_chart
  */
-int get_hourly_rotpoints_at_temp( const int temp )
+auto get_hourly_rotpoints_at_temp( const units::temperature temp ) -> int
 {
     /**
      * Precomputed rot lookup table.
      */
-    static const std::vector<int> rot_chart = calc_rot_array( 200 );
-
-    if( temp < 0 ) {
+    if( temp < temperatures::freezing ) {
         return 0;
     }
-    if( temp > 150 ) {
+    if( temp > 40_c ) {
         return 21240;
     }
-    return rot_chart[temp];
+    const int temp_c = units::to_celsius( temp );
+    return rot_chart[temp_c];
 }
 
-time_duration item::calc_rot( time_point time, int temp ) const
+auto item::calc_rot( time_point time, const units::temperature temp ) const -> time_duration
 {
     // Avoid needlessly calculating already rotten things.  Corpses should
     // always rot away and food rots away at twice the shelf life.  If the food
     // is in a sealed container they won't rot away, this avoids needlessly
     // calculating their rot in that case.
     if( !is_corpse() && get_relative_rot() > 2.0 ) {
-        return time_duration::from_seconds( 0 );
+        return 0_seconds;
     }
 
     // rot modifier
@@ -5690,7 +5670,7 @@ time_duration item::calc_rot( time_point time, int temp ) const
         factor = 0.75;
     }
 
-    time_duration added_rot = time_duration::from_seconds( 0 );
+    time_duration added_rot = 0_seconds;
     // simulation of different age of food at the start of the game and good/bad storage
     // conditions by applying starting variation bonus/penalty of +/- 20% of base shelf-life
     // positive = food was produced some time before calendar::start and/or bad storage
@@ -5699,34 +5679,38 @@ time_duration item::calc_rot( time_point time, int temp ) const
         time_duration spoil_variation = get_shelf_life() * 0.2f;
         added_rot += rng( -spoil_variation, spoil_variation );
     }
-
     time_duration time_delta = time - last_rot_check;
     added_rot += factor * time_delta / 1_hours * get_hourly_rotpoints_at_temp( temp ) * 1_turns;
     return added_rot;
 }
 
-static int temperature_flag_to_highest_temperature( temperature_flag temperature )
+namespace
+{
+
+auto temperature_flag_to_highest_temperature( temperature_flag temperature ) -> units::temperature
 {
     switch( temperature ) {
         case temperature_flag::TEMP_NORMAL:
-            return INT_MAX;
         case temperature_flag::TEMP_HEATER:
-            return INT_MAX;
+            return units::temperature_max;
         case temperature_flag::TEMP_FRIDGE:
-            return to_fahrenheit( temperatures::fridge );
+            return temperatures::fridge;
         case temperature_flag::TEMP_FREEZER:
-            return to_fahrenheit( temperatures::freezer );
+            return temperatures::freezer;
         case temperature_flag::TEMP_ROOT_CELLAR:
-            return to_fahrenheit( temperatures::root_cellar );
+            return temperatures::root_cellar;
     }
 
-    return INT_MAX;
+    return units::temperature_max;
 }
 
+} // namespace
+
+
 time_duration item::minimum_freshness_duration( temperature_flag temperature ) const
 {
-    int temperature_f = temperature_flag_to_highest_temperature( temperature );
-    unsigned long long rot_per_hour = get_hourly_rotpoints_at_temp( temperature_f );
+    const units::temperature temp = temperature_flag_to_highest_temperature( temperature );
+    unsigned long long rot_per_hour = get_hourly_rotpoints_at_temp( temp );
 
     if( rot_per_hour <= 0 || !type->comestible ) {
         return calendar::INDEFINITELY_LONG_DURATION;
@@ -9008,7 +8992,7 @@ bool item::process_rot( const bool seals, const tripoint &pos,
 
     // process rot at most once every 100_turns (10 min)
     // note we're also gated by item::processing_speed
-    time_duration smallest_interval = 10_minutes;
+    constexpr time_duration smallest_interval = 10_minutes;
 
     units::temperature temp = units::from_fahrenheit( weather.get_temperature( pos ) );
     temp = clip_by_temperature_flag( temp, flag );
@@ -9040,17 +9024,13 @@ bool item::process_rot( const bool seals, const tripoint &pos,
                         calendar::config, seed );
                 env_temperature_raw = weather_temperature + local_mod;
             } else {
-                env_temperature_raw = units::from_fahrenheit( AVERAGE_ANNUAL_TEMPERATURE ) + local_mod;
+                env_temperature_raw = temperatures::annual_average + local_mod;
             }
 
             units::temperature env_temperature_clipped = clip_by_temperature_flag( env_temperature_raw, flag );
 
-            // Lookup table is in F
-            int final_temperature_in_fahrenheit = static_cast<int>( std::round( units::to_fahrenheit<float>
-                                                  ( env_temperature_clipped ) ) );
-
             // Calculate item rot
-            rot += calc_rot( time, final_temperature_in_fahrenheit );
+            rot += calc_rot( time, env_temperature_clipped );
             last_rot_check = time;
 
             if( has_rotten_away() && carrier == nullptr && !seals ) {
@@ -9063,10 +9043,7 @@ bool item::process_rot( const bool seals, const tripoint &pos,
     // Remaining <1 h from above
     // and items that are held near the player
     if( now - time > smallest_interval ) {
-        int final_temperature_in_fahrenheit = static_cast<int>( std::round( units::to_fahrenheit<float>
-                                              ( temp ) ) );
-
-        rot += calc_rot( now, final_temperature_in_fahrenheit );
+        rot += calc_rot( now, temp );
         last_rot_check = now;
 
         return has_rotten_away() && carrier == nullptr && !seals;

src/item.h

@@ -771,7 +771,7 @@ class item : public visitable<item>
          * @param time Time point to which rot is calculated
          * @param temp Temperature at which the rot is calculated
          */
-        time_duration calc_rot( time_point time, int temp ) const;
+        auto calc_rot( time_point time, const units::temperature temp ) const -> time_duration;
 
         /**
          * Time that this item is guaranteed to stay fresh.

src/timed_event.cpp

@@ -283,7 +283,7 @@ void timed_event::per_turn()
                 }
             }
 
-            if( calendar::once_every( time_duration::from_seconds( 10 ) ) && faults ) {
+            if( calendar::once_every( 10_seconds ) && faults ) {
                 add_msg( m_info, "You hear someone whispering \"%s\"",
                          SNIPPET.random_from_category( "amigara_whispers" ).value_or( translation() ) );
             }

src/units_temperature.h

@@ -148,6 +148,11 @@ inline constexpr units::temperature operator"" _c( const unsigned long long v )
     return units::from_celsius<int>( v );
 }
 
+inline constexpr units::temperature operator"" _c( const long double v )
+{
+    return units::from_celsius<double>( static_cast<double>( v ) );
+}
+
 inline constexpr units::temperature operator"" _f( const unsigned long long v )
 {
     return units::from_fahrenheit<int>( v );