Changed order in which rendering and various updates are done, which

results in the physics reacting one frame earlier to user input.

src/karts/kart.cpp

@@ -1174,18 +1174,6 @@ void Kart::eliminate()
  */
 void Kart::update(float dt)
 {
-#ifdef DEBUG_TO_COMPARE_KART_PHYSICS
-    // This information is useful when comparing kart physics, e.g. to
-    // see top speed, acceleration (i.e. time to top speed) etc.
-    Log::verbose("physics", "%s t %f %f xyz %f %f %f v %f %f %f s %f a %f",
-        getIdent().c_str(),
-        World::getWorld()->getTime(), dt,
-        getXYZ().getX(), getXYZ().getY(), getXYZ().getZ(),
-        getVelocity().getX(), getVelocity().getY(), getVelocity().getZ(),
-        getControls().getSteer(),
-        getControls().getAccel());
-#endif
-
     // update star effect (call will do nothing if stars are not activated)
     m_stars_effect->update(dt);
 
@@ -1223,6 +1211,19 @@ void Kart::update(float dt)
     if(!history->replayHistory() && !RewindManager::get()->isRewinding())
         m_controller->update(dt);
 
+#undef DEBUG_TO_COMPARE_KART_PHYSICS
+#ifdef DEBUG_TO_COMPARE_KART_PHYSICS
+    // This information is useful when comparing kart physics, e.g. to
+    // see top speed, acceleration (i.e. time to top speed) etc.
+    Log::verbose("physics", "%s t %f %f xyz %f %f %f v %f %f %f s %f a %f",
+        getIdent().c_str(),
+        World::getWorld()->getTime(), dt,
+        getXYZ().getX(), getXYZ().getY(), getXYZ().getZ(),
+        getVelocity().getX(), getVelocity().getY(), getVelocity().getZ(),
+        getControls().getSteer(),
+        getControls().getAccel());
+#endif
+
     // if its view is blocked by plunger, decrease remaining time
     if(m_view_blocked_by_plunger > 0) m_view_blocked_by_plunger -= dt;
     //unblock the view if kart just became shielded

src/main_loop.cpp

@@ -213,6 +213,11 @@ void MainLoop::run()
 
         m_prev_time = m_curr_time;
         float dt   = getLimitedDt();
+        // Render the previous frame, and also handle all user input.
+        PROFILER_PUSH_CPU_MARKER("IrrDriver update", 0x00, 0x00, 0x7F);
+        irr_driver->update(dt);
+        PROFILER_POP_CPU_MARKER();
+
 
         if (World::getWorld())  // race is active if world exists
         {
@@ -238,10 +243,6 @@ void MainLoop::run()
             GUIEngine::update(dt);
             PROFILER_POP_CPU_MARKER();
 
-            PROFILER_PUSH_CPU_MARKER("IrrDriver update", 0x00, 0x00, 0x7F);
-            irr_driver->update(dt);
-            PROFILER_POP_CPU_MARKER();
-
             // Update sfx and music after graphics, so that graphics code
             // can use as many threads as possible without interfering
             // with audia
@@ -275,6 +276,10 @@ void MainLoop::run()
             PROFILER_POP_CPU_MARKER();
         }
 
+        // Update world time if world exists
+        if (World::getWorld())
+            World::getWorld()->updateTime(dt);
+
         PROFILER_POP_CPU_MARKER();
         PROFILER_SYNC_FRAME();
     }  // while !m_abort

src/modes/world.cpp

@@ -974,7 +974,7 @@ void World::scheduleTutorial()
 {
     m_schedule_exit_race = true;
     m_schedule_tutorial = true;
-}
+}   // scheduleTutorial
 
 //-----------------------------------------------------------------------------
 /** Updates the physics, all karts, the track, and projectile manager.
@@ -999,22 +999,14 @@ void World::update(float dt)
     }
 #endif
 
-    PROFILER_PUSH_CPU_MARKER("World::update (sub-updates)", 0x20, 0x7F, 0x00);
-    history->update(dt);
-    if(race_manager->isRecordingRace()) ReplayRecorder::get()->update(dt);
-    if(history->replayHistory()) dt=history->getNextDelta();
-    RewindManager::get()->setCurrentTime(World::getWorld()->getTime(), dt);
-    RewindManager::get()->saveStates();
     WorldStatus::update(dt);
-    if (m_script_engine) m_script_engine->update(dt);
+    RewindManager::get()->saveStates();
-    PROFILER_POP_CPU_MARKER();
-
-    if (!history->dontDoPhysics())
-    {
-        m_physics->update(dt);
-    }
 
     PROFILER_PUSH_CPU_MARKER("World::update (Kart::upate)", 0x40, 0x7F, 0x00);
+
+    // Update all the karts. This in turn will also update the controller,
+    // which causes all AI steering commands set. So in the following 
+    // physics update the new steering is taken into account.
     const int kart_amount = (int)m_karts.size();
     for (int i = 0 ; i < kart_amount; ++i)
     {
@@ -1030,6 +1022,18 @@ void World::update(float dt)
     }
     PROFILER_POP_CPU_MARKER();
 
+    PROFILER_PUSH_CPU_MARKER("World::update (sub-updates)", 0x20, 0x7F, 0x00);
+    history->update(dt);
+    if(race_manager->isRecordingRace()) ReplayRecorder::get()->update(dt);
+    if(history->replayHistory()) dt=history->getNextDelta();
+    if (m_script_engine) m_script_engine->update(dt);
+    PROFILER_POP_CPU_MARKER();
+
+    if (!history->dontDoPhysics())
+    {
+        m_physics->update(dt);
+    }
+
     PROFILER_PUSH_CPU_MARKER("World::update (weather)", 0x80, 0x7F, 0x00);
     if (UserConfigParams::m_graphical_effects && m_weather)
     {
@@ -1048,6 +1052,17 @@ void World::update(float dt)
 #endif
 }   // update
 
+// ----------------------------------------------------------------------------
+/** Compute the new time, and set this new time to be used in the rewind
+ *  manager.
+ *  \param dt Time step size.
+ */
+void World::updateTime(const float dt)
+{
+    WorldStatus::updateTime(dt);
+    RewindManager::get()->setCurrentTime(getTime(), dt);
+}   // updateTime
+
 // ----------------------------------------------------------------------------
 /** Only updates the track. The order in which the various parts of STK are
  *  updated is quite important (i.e. the track can't be updated as part of

src/modes/world.hpp

@@ -178,7 +178,7 @@ protected:
     virtual void  onGo() OVERRIDE;
     /** Returns true if the race is over. Must be defined by all modes. */
     virtual bool  isRaceOver() = 0;
-    virtual void  update(float dt);
+    virtual void  update(float dt) OVERRIDE;
     virtual void  createRaceGUI();
             void  updateTrack(float dt);
     // ------------------------------------------------------------------------
@@ -252,9 +252,10 @@ public:
     // =================
     virtual void    init();
     virtual void    terminateRace() OVERRIDE;
-    virtual void    reset();
+    virtual void    reset() OVERRIDE;
     virtual void    pause(Phase phase) OVERRIDE;
     virtual void    unpause() OVERRIDE;
+    virtual void    updateTime(const float dt) OVERRIDE;
     virtual void    getDefaultCollectibles(int *collectible_type,
                                            int *amount );
     virtual void    endRaceEarly() { return; }

src/modes/world_status.cpp

@@ -153,10 +153,21 @@ void WorldStatus::terminateRace()
 }   // terminateRace
 
 //-----------------------------------------------------------------------------
-/** Updates all status information, called once per frame.
+/** Update, called once per frame. Called early on before physics are
+ *  updated.
+ *  \param dt Time step.
+ */
+void WorldStatus::update(float dt)
+{
+}   // update
+
+//-----------------------------------------------------------------------------
+/** Updates the world time and clock (which might be running backwards), and
+ *  all status information, called once per frame at the end of the main
+ *  loop.
  *  \param dt Duration of time step.
  */
-void WorldStatus::update(const float dt)
+void WorldStatus::updateTime(const float dt)
 {
     switch (m_phase)
     {

src/modes/world_status.hpp

@@ -122,13 +122,14 @@ public:
              WorldStatus();
     virtual ~WorldStatus();
 
-    void     reset();
+    virtual void reset();
-    void     update(const float dt);
+    virtual void updateTime(const float dt);
-    void     setTime(const float time);
+    virtual void update(float dt);
     virtual void pause(Phase phase);
     virtual void unpause();
     virtual void enterRaceOverState();
     virtual void terminateRace();
+    void         setTime(const float time);
 
     // ------------------------------------------------------------------------
     // Note: GO_PHASE is both: start phase and race phase

src/network/rewind_manager.cpp

@@ -363,6 +363,7 @@ void RewindManager::rewindTo(float rewind_time)
 #ifdef SHOW_ROLLBACK
         irr_driver->update(dt);
 #endif
+        world->updateTime(dt);
 
     }
     m_is_rewinding = false;