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CGame.cpp

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// Copyright 2002 Kenneth Guy,
// 
// You are free to take the source and do as you wish with it.
// However it would be nice if you let me know if the code was useful
// to you and give me an acknowledgement if you use a significant portion
// of the code in an application.
// 
// CGame.cpp

#include <e32std.h>
#include <e32base.h>

#include "CMap.h"
#include "CGame.h"
#include "TBadGuy.h"
#include "TPlayersShip.h"
#include "TBullet.h"
#include "TGameData.h"

const TInt KMaxBadGuys=125;

const TInt KMaxBullets=8;


CGame* CGame::NewL(TGameData &aData) {
  CGame *self= new (ELeave) CGame(aData);
  CleanupStack::PushL(self);
  self->ConstructL();
  CleanupStack::Pop(self);
  return(self);
}

CGame::CGame(TGameData& aData) : iData(aData), iLastFired(0) {

};

CGame::~CGame() {
  iStatus.Close();
  delete iMap;
  delete [] iBadGuys;
  delete [] iBullets;
  delete iPlayersShip;
};


void CGame::ConstructL() {
  // create the status screen area
  User::LeaveIfError(iStatus.Open(iData.iLevel.iStatus));

  // create the players ship as defined by the level data
  iPlayersShip = new (ELeave) TPlayersShip(iData.iLevel.iShipStartXPos,
                                           iData.iLevel.iShipStartYPos,
                                           iData.iLevel.iShipStartHealth,
                                           iData.iLevel.iShipSprite,
                                           iData.iLevel.iShipDeathStartSprite,
                                           iData.iLevel.iShipDeathEndSprite);  

  // create slots for KMaxBadGuy bad guys
  // (TBadGuy is used for bonuses and sheilds as well as bad guys)
  iBadGuys= new (ELeave) TBadGuy[KMaxBadGuys];

  // set up players bullets at power one
  iBullets= new (ELeave) TBullet[KMaxBullets];
  for(TInt i=0;i<KMaxBullets;i++) {
    iBullets[i].Set(iData.iLevel.iBulletPower1_StartSprite+i,1);
  }

  TInt16 count=iData.iLevel.iShipPowerups;
  while(count--) {
    Bonus(EBonusPowerup);
  }

  // create the offscreen buffer, and plot the first screen full of
  // the map
  iMap=CMap::NewL(*this,iData.iLevel.iBackgrounds,iData.iLevel.iMapData);
  // CMap may calls back into CGame to add bad guys, if there
  // are any bad guys in the first 11 lines of the map this will
  // happen during construction, so CGame should be valid when
  // constructing iMap,
};


void CGame::Play() {
  TUint lasttick=0;

  while(!(iData.iKeys & TGameData::EQuit)) {
    // handle key presses
    HandleKeys();

    // move bullets and bad guys
    MoveThings();
    // plot the ship/bullets & badguys into offscreen buffer
    DrawEveryThing();
    
    // make sure each loop takes at least 2 ticks
    TUint tick = User::TickCount();
    while((tick-lasttick)<2)
      tick = User::TickCount();
    lasttick=tick;   

    // copy the offscreen buffer to the screen
    iMap->BlitAsm();

    // remove all the sprites we ploted in reverse order
    RemoveEveryThing();
    
    // handle bad guy collisions
    Collisions();
    
    // crash if player hit the landscape
    if(iPlayersShip->Hit()==TSprite32x24::EHitLandScape)
      iPlayersShip->SetHealth(0);

    
    // Handle crashing ship
    if(iPlayersShip->Dead()!=EFalse) {
      iData.iLives--;
      return;
    }

    // handle end of level (when map has finished, and player flies
    // off the right hand side of the screen)
    if(iMap->Finished()!=EFalse && iPlayersShip->iX==304 &&
       iPlayersShip->Dieing()==EFalse) {
      iData.iLevelCompleted=ETrue;
      // update level data so that next level can start with same
      // health / powerups
      iData.iLevel.iShipPowerups=iPowerups;
      iData.iLevel.iShipStartHealth=iPlayersShip->Health();
      return;
    }

    
    // plot status window
    if(iData.iForceRedraw==EFalse) {
      iStatus.Update(iData.iScore,iData.iLives,iPlayersShip->Health());
    } else {
      iStatus.Draw(iData.iScore,iData.iLives,iPlayersShip->Health());
      iData.iForceRedraw=EFalse;
    }
    
    // scroll the offset screen map, plot another line of map sprites
    // if nessesary.
    iMap->ScrollMap();
  }
};


void CGame::Bonus(TGameBonus aBonus) {
  switch(aBonus) {
  case EBonusLife:
    iData.iLives++;
    break;

  case EBonusPowerup: {    
    // remember the number of these so that if the player completes
    // the level they can be carried to the next level
    iPowerups++;
    // find the bullet with the least power and increase
    // its power by one, changing its sprite at the same time.
    // if all bullets are at full strength nothing happens.
    TInt16 minPower=iBullets[0].Strength();
    TInt powerUp=0;
    for(TInt i=1;i<KMaxBullets;i++) {
      const TInt16 strength=iBullets[i].Strength();
      if(strength < minPower) {
        powerUp=i;
        minPower = strength;
        }
    }
    switch(minPower) {
    case 0:
       iBullets[powerUp].Set(powerUp+iData.iLevel.iBulletPower1_StartSprite,1);
       break;
    case 1:
       iBullets[powerUp].Set(powerUp+iData.iLevel.iBulletPower2_StartSprite,2);
       break;
    case 2:
       iBullets[powerUp].Set(powerUp+iData.iLevel.iBulletPower3_StartSprite,3);
       break;
    case 3:
       iBullets[powerUp].Set(powerUp+iData.iLevel.iBulletPower4_StartSprite,4);
       break;
    }
  }
  break;  

  }
}

TInt16 CGame::FirstExplosionSprite() {
  return iData.iLevel.iBadGuyDeathStartSprite;
}

TInt16 CGame::LastExplosionSprite() {
  return iData.iLevel.iBadGuyDeathEndSprite;
}

void CGame::AddScore(TInt aScore) {
  iData.iScore+=aScore;
}

void CGame::DamageBadGuys(TInt16 aId,TInt16 aHealth) {
  for(TInt i=0;i<KMaxBadGuys;i++) {
    if(iBadGuys[i].Used()!= EFalse && aId == iBadGuys[i].Id()) {
      iBadGuys[i].Damage(aHealth,*this);
    }
  }      
}


void CGame::Collisions() {
  for(TInt i=KMaxBadGuys-1;i>=0;--i) {
    if(iBadGuys[i].Used()!=EFalse) {
      TSprite32x24::THit what=iBadGuys[i].Hit();
      
      if(what==TSprite32x24::EHitShip) {
        // badguy has hit player
        iBadGuys[i].HitShip(*iPlayersShip,*this);

      } else if(what >=TSprite32x24::EHitBullet1 &&
                what <=TSprite32x24::EHitBullet8) {
        // badguy has hit a bullet
        
        TInt bulletNo = what - TSprite32x24::EHitBullet1;
        iBadGuys[i].HitBullet(iBullets[bulletNo],*this);
      }
    }
  }
}

void CGame::RemoveEveryThing() {
  TInt i;
  for(i=KMaxBadGuys-1;i>=0;--i) {
    if(iBadGuys[i].Used()!=EFalse)
      iBadGuys[i].Remove();
  }
  for(i=KMaxBullets-1;i>=0;--i) {
    if(iBullets[i].Used()!=EFalse)
      iBullets[i].Remove();
  }
  iPlayersShip->Remove();
}


void CGame::DrawEveryThing() {
  const TUint16 *sprites=iData.iLevel.iSprites;

  iPlayersShip->Plot(*iMap,sprites);
  
  TInt i;
  for(i=0;i<KMaxBullets;++i) {
    if(iBullets[i].Used()!=EFalse)
      iBullets[i].Plot(*iMap,sprites);
  }
  
  for(i=0;i<KMaxBadGuys;++i) {
    if(iBadGuys[i].Used()!=EFalse)
      iBadGuys[i].Plot(*iMap,sprites);
  }
}

void CGame::MoveThings() {
  for(TInt k=0;k<KMaxBullets;k++) {
    if(iBullets[k].Used()!=EFalse) {
      iBullets[k].Move();
    }
  }
  
  for(TInt i=0;i<KMaxBadGuys;++i) {
    if(iBadGuys[i].Used()!=EFalse) {
      iBadGuys[i].Move(iPlayersShip->iX,iPlayersShip->iY,iData.iLevel.iPaths,*this);
    }
  }
};


void CGame::AddBadGuy(const TBadGuy &aBadGuy) {
  TInt empty=0;
  for(;empty<KMaxBadGuys && iBadGuys[empty].Used()!=EFalse;empty++) {};
  if(empty>=KMaxBadGuys) return;
  iBadGuys[empty]=aBadGuy;
}

void CGame::AddBadGuy(TInt16 aType,const  TInt16 aArgs[]) {
  TInt empty=0;
  for(;empty<KMaxBadGuys && iBadGuys[empty].Used()!=EFalse;empty++) {};
  if(empty>=KMaxBadGuys) return;
  iBadGuys[empty].Init(aType,aArgs);
};

void CGame::HandleKeys() {
  //movement
  TInt x=0;
  TInt y=0;
  if(iData.iKeys & TGameData::EUp)    y-=6;
  if(iData.iKeys & TGameData::EDown)  y+=6;
  if(iData.iKeys & TGameData::ELeft)  x-=6;
  if(iData.iKeys & TGameData::ERight) x+=6;
  iPlayersShip->MoveBy(x,y,iMap->Finished());


  // shooting  
  // can't shoot while dieing,
  if(iData.iKeys & TGameData::EAction3 && iPlayersShip->Dieing()==EFalse) {    
    // de-bounce fire key
    iData.iKeys = iData.iKeys & ~TGameData::EAction3;
    Shoot();
  }        
}

void CGame::Shoot() {
  // add another bullet if there is a free slot
  // try and rotate bullet slots,
  TInt i;
  for(i=iLastFired+1;i<KMaxBullets;i++) {
    if(iBullets[i].Used()==EFalse) {
      iLastFired=i;
      iBullets[i].Shoot(iPlayersShip->iX+12,iPlayersShip->iY);
      return;
    }
  }
  for(i=0;i<=iLastFired && i<KMaxBullets;i++) {
    if(iBullets[i].Used()==EFalse) {
      iLastFired=i;
      iBullets[i].Shoot(iPlayersShip->iX+12,iPlayersShip->iY);
      return;
    } 
  } 
}

TInt16 CGame::MapSpeed() {
  if(iMap->Finished()==EFalse) {
    return -2;
  } else {
    return 0;
  }
}

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