Improvements to kart selection stats bars (#3371)

* Compute acceleration efficiency instead of raw engine power

* Improve kart stats display

* Fix conflict resolution error

* Fix conflict resolution error

src/guiengine/widgets/kart_stats_widget.cpp

@@ -89,37 +89,57 @@ KartStatsWidget::KartStatsWidget(core::recti area, const int player_id,
 void KartStatsWidget::setValues(const KartProperties* props,
                                 PerPlayerDifficulty d)
 {
-    // Use kart properties computed for "hard" difficulty to show the user, so
+    // Use kart properties computed for best difficulty to show the user, so
     // that properties don't change according to the the last used difficulty
-    // (And because this code uses arbitrary scaling factors to make them look
-    // nice and the arbitrary factors were optimised for hard difficulty)
     RaceManager::Difficulty previous_difficulty = race_manager->getDifficulty();
-    race_manager->setDifficulty(RaceManager::DIFFICULTY_HARD);
+    race_manager->setDifficulty(RaceManager::DIFFICULTY_BEST);
     KartProperties kp_computed;
     kp_computed.copyForPlayer(props, d);
     for (SkillLevelWidget* skills : m_skills)
         skills->setVisible(true);
 
     // Scale the values so they look better
-    // The scaling factor and offset were found by trial and error.
+    // A value of 100 takes the whole bar width, including borders.
-    // It should look nice and you should be able to see the difference between
+    // So values should be in the 0-99 range
-    // different masses or velocities.
+
+    // The base mass is of 350 ; 350/3.89 ~= 90
     m_skills[SKILL_MASS]->setValue((int)
-    	((kp_computed.getCombinedCharacteristic()->getMass() - 20) / 4));
+    	(kp_computed.getCombinedCharacteristic()->getMass()/3.89f));
     m_skills[SKILL_MASS]->setIcon(irr::core::stringc(
             file_manager->getAsset(FileManager::GUI, "mass.png").c_str()));    
-    m_skills[SKILL_MASS]->m_properties[PROP_ID] = StringUtils::insertValues("@p%i_mass", m_player_id);    
+    m_skills[SKILL_MASS]->m_properties[PROP_ID] = StringUtils::insertValues("@p%i_mass", m_player_id);
+    m_skills[SKILL_MASS]->m_iconbutton->setTooltip( _("Mass") );
     
+    // The base speed is of 25
+    // Here we are not fully proportional, because small differences matter more
     m_skills[SKILL_SPEED]->setValue((int)
-    	((kp_computed.getCombinedCharacteristic()->getEngineMaxSpeed() - 15) * 6));
+    	((kp_computed.getCombinedCharacteristic()->getEngineMaxSpeed() - 20) * 15));
     m_skills[SKILL_SPEED]->setIcon(irr::core::stringc(
             file_manager->getAsset(FileManager::GUI, "speed.png").c_str()));    
     m_skills[SKILL_SPEED]->m_properties[PROP_ID] = StringUtils::insertValues("@p%i_speed", m_player_id);
+    m_skills[SKILL_SPEED]->m_iconbutton->setTooltip( _("Maximum speed") );
     
-    m_skills[SKILL_POWER]->setValue((int)((kp_computed.getAvgPower() - 30) / 20));
+    // The acceleration depend on power and mass, and it changes depending on speed
-    m_skills[SKILL_POWER]->setIcon(irr::core::stringc(
+    // We call a function which gives us a single number to represent it
+    // power/mass gives numbers in the 1-10 range, so we multiply it by 10.
+
+    m_skills[SKILL_ACCELERATION]->setValue((int)(kp_computed.getAccelerationEfficiency()*10));
+    m_skills[SKILL_ACCELERATION]->setIcon(irr::core::stringc(
             file_manager->getAsset(FileManager::GUI, "power.png").c_str()));    
-    m_skills[SKILL_POWER]->m_properties[PROP_ID] = StringUtils::insertValues("@p%i_power", m_player_id);
+    m_skills[SKILL_ACCELERATION]->m_properties[PROP_ID] =
+        StringUtils::insertValues("@p%i_acceleration", m_player_id);
+    m_skills[SKILL_ACCELERATION]->m_iconbutton->setTooltip( _("Acceleration") );
+
+    // The base nitro consumption is 1, higher for heavier karts.
+    // Nitro efficiency is hence 90/nitro_consumption
+
+    m_skills[SKILL_NITRO_EFFICIENCY]->setValue((int)
+        (90.0f/kp_computed.getCombinedCharacteristic()->getNitroConsumption()));
+    m_skills[SKILL_NITRO_EFFICIENCY]->setIcon(irr::core::stringc(
+            file_manager->getAsset(FileManager::GUI, "nitro.png").c_str()));    
+    m_skills[SKILL_NITRO_EFFICIENCY]->m_properties[PROP_ID] =
+        StringUtils::insertValues("@p%i_nitro_efficiency", m_player_id);
+    m_skills[SKILL_NITRO_EFFICIENCY]->m_iconbutton->setTooltip( _("Nitro efficiency") );
     
     race_manager->setDifficulty(previous_difficulty);
 }   // setValues

src/guiengine/widgets/kart_stats_widget.hpp

@@ -65,7 +65,8 @@ namespace GUIEngine
         {
             SKILL_MASS,
             SKILL_SPEED,
-            SKILL_POWER,
+            SKILL_ACCELERATION,
+            SKILL_NITRO_EFFICIENCY,
             SKILL_COUNT
         };
 

src/karts/kart_properties.cpp

@@ -552,15 +552,32 @@ bool KartProperties::isInGroup(const std::string &group) const
 }   // isInGroups
 
 // ----------------------------------------------------------------------------
-float KartProperties::getAvgPower() const
+/** This function returns a weighted average of engine power divide by mass
+ *  for use as a single number summing-up acceleration's efficiency,
+ *  e.g. for use in kart selection. */
+float KartProperties::getAccelerationEfficiency() const
 {
-    float sum = 0;
     std::vector<float> gear_power_increase = m_combined_characteristic->getGearPowerIncrease();
-    float power = m_combined_characteristic->getEnginePower();
+    std::vector<float> gear_switch_ratio = m_combined_characteristic->getGearSwitchRatio();
-    for (unsigned int i = 0; i < gear_power_increase.size(); ++i)
+    int current_gear = 0;
-        sum += gear_power_increase[i] * power;
+    float sum = 0;
-    return sum / gear_power_increase.size();
+    float base_accel = m_combined_characteristic->getEnginePower()
-}   // getAvgPower
+                     / m_combined_characteristic->getMass();
+
+    // We evaluate acceleration at increments of 0.01x max speed
+    // up to 1,1x max speed.
+    // Acceleration at low speeds is made to matter more
+    for (unsigned int i = 1; i<=110; i++)
+    {
+        sum += gear_power_increase[current_gear] * base_accel * (150-i);
+        if (i/100 >= gear_switch_ratio[current_gear] &&
+            (current_gear+1 < gear_power_increase.size() ))
+            current_gear++;
+    }
+
+    // 10395 is the sum of the (150-i) factors
+    return (sum / 10395);
+}   // getAccelerationEfficiency
 
 // ----------------------------------------------------------------------------
 // Script-generated content generated by tools/create_kart_properties.py getter
@@ -1220,3 +1237,4 @@ bool KartProperties::getSkidEnabled() const
 }  // getSkidEnabled
 
 /* <characteristics-end kpgetter> */
+

src/karts/kart_properties.hpp

@@ -367,7 +367,7 @@ public:
     }   // getPhysicalWheelPosition
 
     // ------------------------------------------------------------------------
-    float getAvgPower() const;
+    float getAccelerationEfficiency() const;
 
 
     // Script-generated content generated by tools/create_kart_properties.py defs
@@ -518,3 +518,4 @@ public:
 };   // KartProperties
 
 #endif
+