Time: Remove serverside getter, and use atomic operations

It isn't possible to use atomic operations for floats, so don't use them there.

Having a lock is good out of other reasons too, because this way the float time
and the integer time both match, and can't get different values in a race,
e.g. when two setTimeofDay() get executed simultaneously.

diff --git a/src/environment.cpp b/src/environment.cpp
index c15fe795ed326c84387c0e6c720027bb6211db89..2a42f18adef202e7a5e289678aea253f573663c3 100644 (file)
--- a/src/environment.cpp
+++ b/src/environment.cpp
@@ -52,9 +52,8 @@ Environment::Environment():
        m_time_of_day(9000),
        m_time_of_day_f(9000./24000),
        m_time_of_day_speed(0),
-       m_time_counter(0),
-       m_enable_day_night_ratio_override(false),
-       m_day_night_ratio_override(0.0f)
+       m_time_conversion_skew(0),
+       m_day_night_ratio_override_storage(0)
 {
        m_cache_enable_shaders = g_settings->getBool("enable_shaders");
 }
@@ -180,53 +179,46 @@ std::vector<Player*> Environment::getPlayers(bool ignore_disconnected)
 
 u32 Environment::getDayNightRatio()
 {
-       MutexAutoLock(this->m_time_lock);
-       if (m_enable_day_night_ratio_override)
-               return m_day_night_ratio_override;
+       u64 day_night_st = m_day_night_ratio_override_storage;
+       if (day_night_st & ((u64)1 << 63))
+               return day_night_st & U32_MAX;
+       MutexAutoLock lock(this->m_time_floats_lock);
        return time_to_daynight_ratio(m_time_of_day_f * 24000, m_cache_enable_shaders);
 }
 
 void Environment::setTimeOfDaySpeed(float speed)
 {
-       MutexAutoLock(this->m_time_lock);
        m_time_of_day_speed = speed;
 }
 
 float Environment::getTimeOfDaySpeed()
 {
-       MutexAutoLock(this->m_time_lock);
-       float retval = m_time_of_day_speed;
-       return retval;
+       return m_time_of_day_speed;
 }
 
 void Environment::setTimeOfDay(u32 time)
 {
-       MutexAutoLock(this->m_time_lock);
+       MutexAutoLock lock(this->m_time_floats_lock);
        m_time_of_day = time;
        m_time_of_day_f = (float)time / 24000.0;
 }
 
 u32 Environment::getTimeOfDay()
 {
-       MutexAutoLock(this->m_time_lock);
-       u32 retval = m_time_of_day;
-       return retval;
+       return m_time_of_day;
 }
 
 float Environment::getTimeOfDayF()
 {
-       MutexAutoLock(this->m_time_lock);
-       float retval = m_time_of_day_f;
-       return retval;
+       MutexAutoLock lock(this->m_time_floats_lock);
+       return m_time_of_day_f;
 }
 
 void Environment::stepTimeOfDay(float dtime)
 {
-       MutexAutoLock(this->m_time_lock);
-
-       m_time_counter += dtime;
+       MutexAutoLock lock(this->m_time_floats_lock);
        f32 speed = m_time_of_day_speed * 24000. / (24. * 3600);
-       u32 units = (u32)(m_time_counter * speed);
+       u32 units = (u32)((dtime + m_time_conversion_skew) * speed);
        bool sync_f = false;
        if (units > 0) {
                // Sync at overflow
@@ -237,10 +229,10 @@ void Environment::stepTimeOfDay(float dtime)
                        m_time_of_day_f = (float)m_time_of_day / 24000.0;
        }
        if (speed > 0) {
-               m_time_counter -= (f32)units / speed;
+               m_time_conversion_skew -= (f32)units / speed;
        }
        if (!sync_f) {
-               m_time_of_day_f += m_time_of_day_speed / 24 / 3600 * dtime;
+               m_time_of_day_f += m_time_of_day_speed / (24. * 3600.) * dtime;
                if (m_time_of_day_f > 1.0)
                        m_time_of_day_f -= 1.0;
                if (m_time_of_day_f < 0.0)

diff --git a/src/environment.h b/src/environment.h
index cb8be71b2f524ddfceada31727d17f88a24d4e6a..7100bc5d359c6b0b967da570ffb9214ec66f5452 100644 (file)
--- a/src/environment.h
+++ b/src/environment.h
@@ -40,6 +40,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "mapnode.h"
 #include "mapblock.h"
 #include "threading/mutex.h"
+#include "threading/atomic.h"
 #include "network/networkprotocol.h" // for AccessDeniedCode
 
 class ServerEnvironment;
@@ -94,8 +95,7 @@ public:
 
        void setDayNightRatioOverride(bool enable, u32 value)
        {
-               m_enable_day_night_ratio_override = enable;
-               m_day_night_ratio_override = value;
+               m_day_night_ratio_override_storage = value | ((u64)enable << 63);
        }
 
        // counter used internally when triggering ABMs
@@ -105,23 +105,25 @@ protected:
        // peer_ids in here should be unique, except that there may be many 0s
        std::vector<Player*> m_players;
 
+       // Time of day in milli-hours (0-23999); determines day and night
+       Atomic<u32> m_time_of_day;
 
        /*
-        *  Below: values under m_time_lock
-        */
-       // Time of day in milli-hours (0-23999); determines day and night
-       u32 m_time_of_day;
+        * Below: values managed by m_time_floats_lock
+       */
        // Time of day in 0...1
        float m_time_of_day_f;
        float m_time_of_day_speed;
-       // Used to buffer dtime for adding to m_time_of_day
-       float m_time_counter;
-       // Overriding the day-night ratio is useful for custom sky visuals
-       bool m_enable_day_night_ratio_override;
-       u32 m_day_night_ratio_override;
+       // Stores the skew created by the float -> u32 conversion
+       // to be applied at next conversion, so that there is no real skew.
+       float m_time_conversion_skew;
        /*
-        * Above: values under m_time_lock
-        */
+        * Above: values managed by m_time_floats_lock
+       */
+
+       // Overriding the day-night ratio is useful for custom sky visuals
+       // lowest 32 bits store the overriden ratio, highest bit stores whether its enabled
+       Atomic<u64> m_day_night_ratio_override_storage;
 
        /* TODO: Add a callback function so these can be updated when a setting
         *       changes.  At this point in time it doesn't matter (e.g. /set
@@ -135,7 +137,7 @@ protected:
        bool m_cache_enable_shaders;
 
 private:
-       Mutex m_time_lock;
+       Mutex m_time_floats_lock;
 
        DISABLE_CLASS_COPY(Environment);
 };

diff --git a/src/server.cpp b/src/server.cpp
index 327591c60e60f5b3a465ccaeb57d92da755bee5f..8c42ab5fd29d550ea04a35c72e7b21ac8c1979cb 100644 (file)
--- a/src/server.cpp
+++ b/src/server.cpp
@@ -1232,11 +1232,6 @@ void Server::setTimeOfDay(u32 time)
        m_time_of_day_send_timer = 0;
 }
 
-u32 Server::getTimeOfDay()
-{
-       return m_env->getTimeOfDay();
-}
-
 void Server::onMapEditEvent(MapEditEvent *event)
 {
        if(m_ignore_map_edit_events)

diff --git a/src/server.h b/src/server.h
index 3ec889971f409adcce2e7639e37ce791fdbec9da..bee978de2505b9ec95d772853226c08962643191 100644 (file)
--- a/src/server.h
+++ b/src/server.h
@@ -223,7 +223,6 @@ public:
        // Both setter and getter need no envlock,
        // can be called freely from threads
        void setTimeOfDay(u32 time);
-       inline u32 getTimeOfDay();
 
        /*
                Shall be called with the environment locked.