Add defense knowledge for AIs

src/karts/controller/soccer_ai.cpp

@@ -148,8 +148,18 @@ void SoccerAI::findClosestKart(bool use_difficulty)
 //-----------------------------------------------------------------------------
 void SoccerAI::findTarget()
 {
+    // Check whether any defense is needed
+    if ((m_world->getBallPosition() - NavMesh::get()->getNavPoly(m_world
+        ->getGoalNode(m_cur_team)).getCenter()).length_2d() < 50.0f &&
+        m_world->getDefender(m_cur_team) == (signed)m_kart->getWorldKartId())
+    {
+        m_target_node = m_world->getBallNode();
+        m_target_point = correctBallPosition(m_world->getBallPosition());
+        return;
+    }
+
     // Find a suitable target to drive to, either ball or powerup
-    if ((m_world->getBallPosition() - m_kart->getXYZ()).length_2d() > 10.0f &&
+    if ((m_world->getBallPosition() - m_kart->getXYZ()).length_2d() > 20.0f &&
         (m_kart->getPowerup()->getType() == PowerupManager::POWERUP_NOTHING &&
          m_kart->getAttachment()->getType() != Attachment::ATTACH_SWATTER))
         collectItemInArena(&m_target_point , &m_target_node);

src/modes/soccer_world.cpp

@@ -105,6 +105,8 @@ void SoccerWorld::reset()
     m_blue_scorers.clear();
     m_blue_score_times.clear();
     m_ball_hitter = -1;
+    m_red_defender = -1;
+    m_blue_defender = -1;
     PtrVector<TrackObject>& objects = tom->getObjects();
     for(unsigned int i=0; i<objects.size(); i++)
     {
@@ -149,7 +151,10 @@ void SoccerWorld::update(float dt)
 
     updateBallPosition();
     if (m_track->hasNavMesh())
+    {
         updateKartNodes();
+        updateDefenders();
+    }
 
     if (world->getPhase() == World::GOAL_PHASE)
     {
@@ -535,3 +540,54 @@ bool SoccerWorld::isCorrectGoal(unsigned int kart_id, bool first_goal) const
     }
     return false;
 }   // isCorrectGoal
+
+//-----------------------------------------------------------------------------
+void SoccerWorld::updateDefenders()
+{
+    if (isRaceOver()) return;
+
+    float distance = 99999.9f;
+    int defender = -1;
+
+    // Check for red team
+    for (unsigned int i = 0; i < (unsigned)m_karts.size(); ++i)
+    {
+        if (m_karts[i]->getController()->isPlayerController() ||
+            getKartTeam(m_karts[i]->getWorldKartId()) != SOCCER_TEAM_RED)
+            continue;
+
+        Vec3 d = NavMesh::get()->getNavPoly(this
+            ->getGoalNode(SOCCER_TEAM_RED)).getCenter()
+            - m_karts[i]->getXYZ();
+
+        if (d.length_2d() <= distance)
+        {
+            defender = i;
+            distance = d.length_2d();
+        }
+    }
+    if (defender != -1) m_red_defender = defender;
+
+    distance = 99999.9f;
+    defender = -1;
+
+    // Check for blue team
+    for (unsigned int i = 0; i < (unsigned)m_karts.size(); ++i)
+    {
+        if (m_karts[i]->getController()->isPlayerController() ||
+            getKartTeam(m_karts[i]->getWorldKartId()) != SOCCER_TEAM_BLUE)
+            continue;
+
+        Vec3 d = NavMesh::get()->getNavPoly(this
+            ->getGoalNode(SOCCER_TEAM_BLUE)).getCenter()
+            - m_karts[i]->getXYZ();
+
+        if (d.length_2d() <= distance)
+        {
+            defender = i;
+            distance = d.length_2d();
+        }
+    }
+    if (defender != -1) m_blue_defender = defender;
+
+}   // updateDefenders

src/modes/soccer_world.hpp

@@ -82,6 +82,9 @@ private:
     int m_red_goal_node;
     int m_blue_goal_node;
 
+    int m_red_defender;
+    int m_blue_defender;
+
     /** Set the team for the karts */
     void initKartList();
     /** Function to init the locations of two goals on the polygon map */
@@ -92,6 +95,7 @@ private:
     void updateBallPosition();
     /** Clean up */
     void resetAllNodes();
+    void updateDefenders();
 
 public:
 
@@ -155,6 +159,11 @@ public:
     }
     // ------------------------------------------------------------------------
     bool isCorrectGoal(unsigned int kart_id, bool first_goal) const;
+    // ------------------------------------------------------------------------
+    const int& getDefender(SoccerTeam team) const
+    {
+        return (team == SOCCER_TEAM_BLUE ? m_blue_defender : m_red_defender);
+    }
 
 };   // SoccerWorld