/// <summary>
/// Allows the game to run logic such as updating the world,
/// checking for collisions, gathering input, and playing audio.
/// </summary>
/// <param name="gameTime">Provides a snapshot of timing values.</param>
protected override void Update(GameTime gameTime)
{
// Allows the game to exit
if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed)
{
this.Exit();
}
// These statements check to see if there are any invaders remaining to shoot
bool IsInvaderRemaining = false;
for (int Count = 0; Count < 11; Count++)
{
if (Invaders[Count] != null)
{
IsInvaderRemaining = true;
break;
}
}
// If there are no invaders then move to end game state
if (!IsInvaderRemaining)
{
this.Exit();
}
if (MissileFired != null)
{
MissileFired.Move();
}
if (Keyboard.GetState().IsKeyDown(Keys.Space))
{
MissileFired = new Missile(RocketXPos, 650);
}
// TODO: Add your update logic here
if (Keyboard.GetState().IsKeyDown(Keys.Left))
{
RocketXPos = RocketXPos - 4;
}
if (Keyboard.GetState().IsKeyDown(Keys.Right))
{
RocketXPos = RocketXPos + 4;
}
if (RocketXPos < 100)
{
RocketXPos = 100;
}
if (RocketXPos > 924)
{
RocketXPos = 924;
}
Ticks = Ticks + gameTime.ElapsedGameTime.TotalMilliseconds;
if (Ticks > 500)
{
for (int Count = 0; Count < 11; Count++)
{
if (Invaders[Count] != null)
{
Invaders[Count].MoveHorizontal(AlienSpeed * AlienDirection);
}
}
Invader LeftMostInvader = null;
Invader RightMostInvader = null;
for (int Count = 0; Count < 11; Count++)
{
if (Invaders[Count] != null)
{
LeftMostInvader = Invaders[Count];
break;
}
}
for (int Count = 10; Count > 0; Count--)
{
if (Invaders[Count] != null)
{
RightMostInvader = Invaders[Count];
break;
}
}
if (LeftMostInvader.GetXPos() < 96)
{
AlienDirection = +1;
int XPos = 96;
for (int Count = 0; Count < 11; Count++)
{
if (Invaders[Count] != null)
{
Invaders[Count].MoveVertical(4);
Invaders[Count].SetXPos(XPos);
}
XPos = XPos + InvaderImg.Width;
}
}
if (RightMostInvader.GetXPos() > 924)
{
AlienDirection = -1;
int XPos = 924 - InvaderImg.Width * 10;
for (int Count = 0; Count < 11; Count++)
{
if (Invaders[Count] != null)
{
Invaders[Count].MoveVertical(4);
Invaders[Count].SetXPos(XPos);
}
XPos = XPos + InvaderImg.Width;
}
}
Ticks = 0;
}
if (MissileFired != null)
{
Rectangle rectMissile = new Rectangle((int)MissileFired.GetPosition().X, (int)MissileFired.GetPosition().Y, MissileImg.Width, MissileImg.Height);
for (int Count = 0; Count < 11; Count++)
{
if (Invaders[Count] != null)
{
Rectangle rectInvader = new Rectangle(Invaders[Count].GetXPos(), Invaders[Count].GetYPos(), InvaderImg.Width, InvaderImg.Height);
if (rectMissile.Intersects(rectInvader))
{
Invaders[Count] = null;
MissileFired = null;
break;
}
}
}
}
base.Update(gameTime);
}
// Main Update
public void UpdatePlaying(GameTime currentTime)
{
//stop the theme song during the gameplay
ThemeSoundInstance.Stop();
// Allows the game to exit
if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed)
{
this.Exit();
}
// These statements check to see if there are any invaders remaining to shoot
bool IsInvaderRemaining = false;
for (int Count = 0; Count < 55; Count++)
{
if (Invaders[Count] != null)
{
IsInvaderRemaining = true;
break;
}
}
// If there are no invaders then move to end game state
if (!IsInvaderRemaining)
{
GameState = 4;
return;
}
//move missle if active
if (MissileFired != null)
{
MissileFired.Move();
}
//if space is pressed, initiate missile
if (Keyboard.GetState().IsKeyDown(Keys.Space))
{
//i found it irritating that pressing space would remove the existing missile
//now, a missile will only shoot if there is no existing missile
if (MissileFired == null)
{
//at location of rocket
MissileFired = new Missile(RocketXPos, 650);
//play shooting sound
ShootSoundInstance.Play();
}
}
//with the added code for pressing space,
//we need to kill the missile if it goes off the screen.
//otherwise if the missile misses an invader, it will continue forever you you will be unable to shoot another
//if there is a missile
if (MissileFired != null)
{
//above 1 Y co-ordinate
if (MissileFired.GetPosition().Y < 1)
{
//kill
MissileFired = null;
}
}
// Move the rocket left and right
if (Keyboard.GetState().IsKeyDown(Keys.Left))
{
RocketXPos = RocketXPos - 4;
}
if (Keyboard.GetState().IsKeyDown(Keys.Right))
{
RocketXPos = RocketXPos + 4;
}
//Keep the rocket on the screen
if (RocketXPos < 100)
{
RocketXPos = 100;
}
if (RocketXPos > 924)
{
RocketXPos = 924;
}
//Moving The Invaders
Ticks = Ticks + currentTime.ElapsedGameTime.TotalMilliseconds;
//variable for changing speed
int speedInt = 500;
//vairable for choosing invader
int invaderChoose = 0;
//find the first invader which isnt dead
do
{
invaderChoose = invaderChoose + 1;
}while (Invaders[invaderChoose] == null);
//assign speed depending on y position of selected invader
if (Invaders[invaderChoose].GetYPos() < 200)
{
speedInt = 500;
}
else if (Invaders[invaderChoose].GetYPos() > 200)
{
speedInt = 300;
}
else if (Invaders[invaderChoose].GetYPos() > 400)
{
speedInt = 100;
}
// move invaders
if (Ticks > speedInt)
{
//Play sound each time they move
InvaderSoundInstance.Play();
//setting initial speed and direction
for (int Count = 0; Count < 55; Count++)
{
if (Invaders[Count] != null)
{
Invaders[Count].MoveHorizontal(AlienSpeed * AlienDirection);
}
}
Invader LeftMostInvader = null;
Invader RightMostInvader = null;
for (int Count = 0; Count < 11; Count++)
{
if (Invaders[Count] != null)
{
LeftMostInvader = Invaders[Count];
break;
}
}
for (int Count = 10; Count > 0; Count--)
{
if (Invaders[Count] != null)
{
RightMostInvader = Invaders[Count];
break;
}
}
if (LeftMostInvader.GetXPos() < 96)
{
AlienDirection = +1;
int XPos = 96;
for (int Count = 0; Count < 11; Count++)
{
if (Invaders[Count] != null)
{
Invaders[Count].MoveVertical(8);
Invaders[Count].SetXPos(XPos);
}
XPos = XPos + InvaderImg.Width;
}
XPos = 96;
for (int Count = 11; Count < 22; Count++)
{
if (Invaders[Count] != null)
{
Invaders[Count].MoveVertical(8);
Invaders[Count].SetXPos(XPos);
}
XPos = XPos + InvaderImg.Width;
}
XPos = 96;
for (int Count = 22; Count < 33; Count++)
{
if (Invaders[Count] != null)
{
Invaders[Count].MoveVertical(8);
Invaders[Count].SetXPos(XPos);
}
XPos = XPos + InvaderImg.Width;
}
XPos = 96;
for (int Count = 33; Count < 44; Count++)
{
if (Invaders[Count] != null)
{
Invaders[Count].MoveVertical(8);
Invaders[Count].SetXPos(XPos);
}
XPos = XPos + InvaderImg.Width;
}
XPos = 96;
for (int Count = 44; Count < 55; Count++)
{
if (Invaders[Count] != null)
{
Invaders[Count].MoveVertical(8);
Invaders[Count].SetXPos(XPos);
}
XPos = XPos + InvaderImg.Width;
}
}
// Keeping launcher in constraints of invaders
if (RocketXPos < LeftMostInvader.GetXPos())
{
RocketXPos = LeftMostInvader.GetXPos();
}
if (RocketXPos > RightMostInvader.GetXPos())
{
RocketXPos = RightMostInvader.GetXPos();
}
// Moving Invaders left and right
if (RightMostInvader.GetXPos() > 924)
{
AlienDirection = -1;
int XPos = 924 - InvaderImg.Width * 11;
for (int Count = 0; Count < 11; Count++)
{
if (Invaders[Count] != null)
{
Invaders[Count].MoveVertical(8);
Invaders[Count].SetXPos(XPos);
}
XPos = XPos + InvaderImg.Width;
}
XPos = 924 - InvaderImg.Width * 11;
for (int Count = 11; Count < 22; Count++)
{
if (Invaders[Count] != null)
{
Invaders[Count].MoveVertical(8);
Invaders[Count].SetXPos(XPos);
}
XPos = XPos + InvaderImg.Width;
}
XPos = 924 - InvaderImg.Width * 11;
for (int Count = 22; Count < 33; Count++)
{
if (Invaders[Count] != null)
{
Invaders[Count].MoveVertical(8);
Invaders[Count].SetXPos(XPos);
}
XPos = XPos + InvaderImg.Width;
}
XPos = 924 - InvaderImg.Width * 11;
for (int Count = 33; Count < 44; Count++)
{
if (Invaders[Count] != null)
{
Invaders[Count].MoveVertical(8);
Invaders[Count].SetXPos(XPos);
}
XPos = XPos + InvaderImg.Width;
}
XPos = 924 - InvaderImg.Width * 11;
for (int Count = 44; Count < 55; Count++)
{
if (Invaders[Count] != null)
{
Invaders[Count].MoveVertical(8);
Invaders[Count].SetXPos(XPos);
}
XPos = XPos + InvaderImg.Width;
}
}
//Resetting millisecond count for moving invaders.
Ticks = 0;
}
// UFO
//Generate Random Value Between 1 and 500
int ReturnValue = RandomNumber(1, 500);
//If There is no active UFO and The Random Number Is 1, Then Set ufoalive To True
if (ufo.ufoAlive == false && ReturnValue == 1)
{
ufo.ufoAlive = true;
}
//Count milliseconds
ufoTime = ufoTime + currentTime.ElapsedGameTime.TotalMilliseconds;
// If Ufoalive is true, i.e. there is an active ufo, increment X position by 10 pixels every 100 milliseconds
// then reset ufotime variable to zero
if (ufo.ufoAlive == true)
{
if (ufoTime > 100)
{
ufo.UFOxPos = ufo.UFOxPos + 10;
ufoTime = 0;
}
}
// if ufo position goes further than 1000 pixels, set ufoalive to false, i.e. kill the ufo. so a new one can be generated.
if (ufo.UFOxPos > 1000)
{
ufo.ufoAlive = false;
ufo.UFOxPos = 10;
}
// if a missile is fired
if (MissileFired != null)
{
//rectangle for missile
Rectangle rectMissile = new Rectangle((int)MissileFired.GetPosition().X, (int)MissileFired.GetPosition().Y, MissileImg.Width, MissileImg.Height);
//for each invader
for (int Count = 0; Count < 55; Count++)
{
if (Invaders[Count] != null)
{
Rectangle rectInvader = new Rectangle(Invaders[Count].GetXPos(), Invaders[Count].GetYPos(), InvaderImg.Width, InvaderImg.Height);
//Check for invader collision with the missile
if (rectMissile.Intersects(rectInvader))
{
//set invader and missile to null
Invaders[Count] = null;
MissileFired = null;
//increase score and play collision sound
PlayerScore = PlayerScore + 100;
CollisionSoundInstance.Play();
break;
}
}
}
//checking for collison with ufo
Rectangle rectUfo = new Rectangle(ufo.UFOxPos, 10, UFOimg.Width, UFOimg.Height);
if (rectMissile.Intersects(rectUfo))
{
//add score, jump UFO to end position, Play Collision Sound
PlayerScore = PlayerScore + 1000;
ufo.UFOxPos = 1000;
CollisionSoundInstance.Play();
}
}
//check for collision between invader and rocker launcher
for (int Count2 = 0; Count2 < 55; Count2++)
{
if (Invaders[Count2] != null)
{
Rectangle rectInvader2 = new Rectangle(Invaders[Count2].GetXPos(), Invaders[Count2].GetYPos(), InvaderImg.Width, InvaderImg.Height);
Rectangle rectRocket = new Rectangle(RocketXPos, 650, RocketLauncherImg.Width, RocketLauncherImg.Height);
if (rectInvader2.Intersects(rectRocket))
{
//if collision occurs, remove a life
GameLives = GameLives - 1;
}
}
}
//Makeing the invaders fire back
//using a new missile class which goes the opposite direction to the existing missile class
// i felt it was easier to seperate the two classes completely than create another instance of the existing missile class and creating a reverse move.
//if an invader isnt currently firing
if (invaderMissile == null)
{
//generate random number for possibility of fire
int RandomInvaderMissileFired = RandomNumber(1, 500);
//if random number is equal to 1, fire a missle
if (RandomInvaderMissileFired == 1)
{
//generate second random number for choosing which invader
int ChooseInvader = RandomNumber(1, 55);
//if the invader is not dead
if (Invaders[ChooseInvader] != null)
{
//create new missile
invaderMissile = new Missile(Invaders[ChooseInvader].GetXPos(), Invaders[ChooseInvader].GetYPos());
}
}
}
//if missile is existant
if (invaderMissile != null)
{
//check for collisions
Rectangle rectRocket = new Rectangle(RocketXPos, 650, RocketLauncherImg.Width, RocketLauncherImg.Height);
Rectangle rectInvaderMissile = new Rectangle((int)invaderMissile.GetPosition().X, (int)invaderMissile.GetPosition().Y, MissileImg.Width, MissileImg.Height);
if (rectInvaderMissile.Intersects(rectRocket))
{
//if collision, remove life
GameLives = GameLives - 1;
invaderMissile = null;
}
//kill if no longer visible
else if (invaderMissile.GetPosition().Y > 700)
{
invaderMissile = null;
}
// else move the missile
else
{
invaderMissile.MoveReverse();
}
}
//check remaining lives
if (GameLives < 0)
{
//end game to end screen if none left
GameState = 3;
return;
}
}