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SECONDARY FIRE

Here's how you PREPARE a turret to support the secondary fire mode. What the turret actually does can be altered at your discretion, because we'll be making a virtual function that could be overriden to your heart's content...

All modifications will be in the "dlls\func_tank.cpp"...

• In the definition of CFuncTank, you will see the definition for the Fire virtual function, as such:

  virtual void Fire( const Vector &barrelEnd, const Vector &forward,
                     entvars_t *pevAttacker );

  Right under it, we want to add our own secondary fire function...

  //*** NEW - SECONDARY FIRE
  virtual void SecondaryFire( const Vector &barrelEnd, const Vector &forward,
       entvars_t *pevAttacker );

• Now we need to give it some basic functionality, so that the non-overriden "children" of CFuncTank (CFuncTankLaser, CFuncTankGun, etc...) know how to deal with it. For arguments sake, we'll give the secondary fire the default functionality of the primary fire.
  
  Therefore, right after the body of CFuncTank::Fire...

  //*** NEW - SECONDARY FIRE
  void CFuncTank::SecondaryFire( const Vector &barrelEnd, const Vector &forward,
       entvars_t *pevAttacker )
  {
      Fire(barrelEnd, forward, pevAttacker);
  }

• Now the engine needs to call it. As was moderately discussed in the section header, all fire checking is done through the CFuncTank::ControllerPostFrame function. There, by default, it checks if the "IN_ATTACK" flag is set, which is the case when primary fire is in use. We want to check for secondary fire, or "IN_ATTACK2". Therefore, in the aforementioned CFuncTank::ControllerPostFrame function, we need to mirror the primary fire code:

  if ( m_pController->pev->button & IN_ATTACK )
  {
      Vector vecForward;
      UTIL_MakeVectorsPrivate( pev->angles, vecForward, NULL, NULL );
  
      m_fireLast = gpGlobals->time - (1/m_fireRate) - 0.01;
          // to make sure the gun doesn't fire too many bullets
  
      Fire( BarrelPosition(), vecForward, m_pController->pev );
         
      // HACKHACK -- make some noise (that the AI can hear)
      if ( m_pController && m_pController->IsPlayer() )
          ((CBasePlayer *)m_pController)->m_iWeaponVolume = LOUD_GUN_VOLUME;
  
      m_flNextAttack = gpGlobals->time + (1/m_fireRate);
  }
  
  //*** NEW - SECONDARY FIRE
  else if ( m_pController->pev->button & IN_ATTACK2 )
  {
      Vector vecForward;
      UTIL_MakeVectorsPrivate( pev->angles, vecForward, NULL, NULL );
  
      m_fireLast = gpGlobals->time - (1/m_fireRate) - 0.01;
          // to make sure the gun doesn't fire too many bullets
  
      SecondaryFire( BarrelPosition(), vecForward, m_pController->pev );
         
      // HACKHACK -- make some noise (that the AI can hear)
      if ( m_pController && m_pController->IsPlayer() )
          ((CBasePlayer *)m_pController)->m_iWeaponVolume = LOUD_GUN_VOLUME;
  
      m_flNextAttack = gpGlobals->time + (1/m_fireRate);
  }

  The only differences between the two is the check of "IN_ATTACK2" and the fact that it calls SecondaryFire and not Fire.

• That's pretty much all there is to it. Now, actually creating different secondary fire modes is another story altogether!

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