Develop Reference

game manager script for hierarchy

I have an issue I'd appreciate help with. I'm trying to create game manager script that simply dictates if I have 5 objective game objects, the player is only allowed to complete them from the smallest (the smallest available objective will be indicated by the game manager) and it becomes a foul if he attempts the 2nd objective if the first is still there.
public class gameobjects : MonoBehaviour {
// Use this for initialization
int ballsLeft = 0;
bool PocketedAllBalls = false;
void Start () {
ballsLeft = 10; // or more;
}
// Update is called once per frame
void Update () {
GameObject[] balls = GameObject.FindGameObjectsWithTag("balls");
ballsLeft = balls.Length;
if(Input.GetKeyDown(KeyCode.A))
{
ballsLeft --;
}
if(ballsLeft == 0)
{
endGame();
}
}
void endGame()
{
PocketedAllBalls = true;
}
void OnGUI()
{
if(PocketedAllBalls)
{
GUI.Label(new Rect (0,0,200,20),"all gone");
}
else
{
GUI.Label(new Rect (0,0,200,20),"Balls Remaining : " + ballsLeft);
}
}
}

Entity Component System c#

I'm currently creating a 2D game engine in C#. At the moment, I'm implementing an entity component system.
My structure is as follows:
Entity Class: Contains a list of IGameComponent's, you can add, remove and delete any component by class type. (ie; entity.RemoveComponent(typeof(Transform));. It also contains a parent Entity, and a list child entities.
IGameComponent Interface: For now, is just an empty interface. (Note that: Components only contain data, and not functionality)
Entity Pool: Contains a list of all the active objects in the game, it's also used to create and destroy entities.
Everything so far is great.
However, I'm faced with a problem. Since components only contain data I need a way to initialize, update and render the components and I'd rather not just add a bunch of virtual methods to a GameComponent class, however I don't know of any other way to resolve it.
What are my options?
EDIT:
I've seen that Unity uses methods like 'SendMessage' which I can only assume uses reflection to call methods. Should I implement something similar?

I don't know if you still need it, but I have made something similar a few years ago and it might help you. It's written in C# built on top of MonoGame/XNA
You GameObject class can look like this
public class GameObject
{
List<GameObjectComponent> _goComponent = new List<GameObjectComponent();
public T GetComponent<T>() where T : GameObjectComponent
{
foreach (GameObjectComponent goc in _goComponent)
if (goc.GetType().Equals(typeof(T)))
return (T)goc;
return null;
}
public void AddComponent(GameObjectComponent gameObjectComponent)
{
_goComponent.Add(gameObjectComponent);
gameObjectComponent.gameObject = this;
gameObjectComponent.Init();
}
public virtual void Update(GameTime gameTime)
{
foreach (GameObjectComponent _goc in _goComponent)
_goc.Update(gameTime);
}
public static void Instantiate(GameObject gameObject)
{
Scene._AddedGO.Add(gameObject);
}
public static void Destroy(GameObject gameObject)
{
Scene._RemoveGO.Add(gameObject);
}
}
GameObjectComponent is similar to MonoBehaivior from Unity3D
public class GameObjectComponent
{
public GameObject gameObject;
public GameObjectComponent()
{
}
public virtual void Init()
{
}
public virtual void Update(GameTime gameTime)
{
}
}
and then you Inherit other classes like so:
public class Sprite : GameObjectComponent
{
public Texture2D texture;
public Vector2 origin = Vector2.Zero;
public Rectangle rect;
public Rectangle sourceRect;
public Color color = Color.White;
public float rotation = 0f;
private float layerDepth = 0f;
public int scale = 1;
public Sprite()
{
}
public void Load(string path)
{
texture = Setup.ContentDevice.Load<Texture2D>(path);
}
}
now you can finally create you Player GameObject
class Player : GameObjectComponent
{
float speed = 150f;
KeyboardState keyState;
float pos_X;
float pos_Y;
int rect_X;
int rect_Y;
public Player(float x, float y, int rx, int ry)
{
pos_X = x;
pos_Y = y;
rect_X = rx;
rect_Y = ry;
}
public override void Init()
{
Sprite sprite = new Sprite();
gameObject.AddComponent(sprite);
gameObject.GetComponent<Sprite>().Load("Sprites/MainGuySpriteSheet_0");
gameObject.GetComponent<Sprite>().scale = 1;
gameObject.GetComponent<Sprite>().rect = new Rectangle(46, 0, 32, 36);
Transform transform = new Transform();
gameObject.AddComponent(transform);
// gameObject.GetComponent<Transform>().position = new Vector2(Screen.width / 2 - gameObject.GetComponent<Sprite>().rect.Width, Screen.height / 2 - gameObject.GetComponent<Sprite>().rect.Height);
gameObject.GetComponent<Transform>().position = new Vector2(pos_X, pos_Y - 32 * (gameObject.GetComponent<Sprite>().scale - 1));
RectCollider collider = new RectCollider();
gameObject.AddComponent(collider);
gameObject.GetComponent<RectCollider>().Set(gameObject.GetComponent<Sprite>(), gameObject.GetComponent<Transform>());
SpriteRenderer render = new SpriteRenderer();
gameObject.AddComponent(render);
gameObject.GetComponent<SpriteRenderer>().layer = 1;
gameObject.GetComponent<SpriteRenderer>().Set(gameObject.GetComponent<Sprite>());
}
public override void Update(GameTime gameTime)
{
//movex = transform.position.X -= 25 * gameTime.DeltaTime();
if (Keyboard.GetState().IsKeyDown(Keys.Left))
gameObject.GetComponent<Transform>().Move(-speed * gameTime.DeltaTime(), 0);
else if (Keyboard.GetState().IsKeyDown(Keys.Right))
gameObject.GetComponent<Transform>().Move(speed * gameTime.DeltaTime(), 0);
else if (Keyboard.GetState().IsKeyDown(Keys.Down))
gameObject.GetComponent<Transform>().Move(0, speed * gameTime.DeltaTime());
else if (Keyboard.GetState().IsKeyDown(Keys.Up))
gameObject.GetComponent<Transform>().Move(0, -speed * gameTime.DeltaTime());
if (Keyboard.GetState().IsKeyDown(Keys.Space) && !keyState.IsKeyDown(Keys.Space))
{
GameObject tomato = new GameObject();
tomato.AddComponent(new Tomato());
tomato.GetComponent<Transform>().position = gameObject.GetComponent<Transform>().position;
GameObject.Instantiate(tomato);
}
if (Keyboard.GetState().IsKeyDown(Keys.Q) && !keyState.IsKeyDown(Keys.Q))
{
SceneManager.LoadScene(new AnotherOne());
}
keyState = Keyboard.GetState();
gameObject.GetComponent<Transform>().position.Y = MathHelper.Clamp(gameObject.GetComponent<Transform>().position.Y, 0, Screen.bounds.Height - gameObject.GetComponent<Sprite>().rect.Height * gameObject.GetComponent<Sprite>().scale);
gameObject.GetComponent<Transform>().position.X = MathHelper.Clamp(gameObject.GetComponent<Transform>().position.X, 0, Screen.bounds.Width - gameObject.GetComponent<Sprite>().rect.Width * gameObject.GetComponent<Sprite>().scale);
}
}
I hope it's not too confusing and helps you a little bit.
To make it clearer I leave a link to the git here: https://github.com/Memorix101/MonoGame_ComponentSystem
Cheers, Memorix101 :)

Disappearing Objects

so for my first project with MonoGame I decided to make a tetris clone but I have an issue which I don't know how to solve.
Currently my code is generating a block and moves it downwards until it reach a specific y position. The block need to stay at this position and a new block spawns. I'm doing this with a List which contains object of the block class and then just draw all the blocks in this list.
I took out parts which I believe are not involved in the problem:
public class PlayField : DrawableGameComponent
{
private Game1 gameRef;
private Texture2D fieldTexture;
private BlockGenerator blockGenerator;
private Texture2D[] allBlocks;
private Block currentBlock;
public bool[,] fieldFilled;
private int down_Blocks = 22;
private int side_Blocks = 10;
public List<Block> placedBlocks;
public PlayField(Game game) : base(game)
{
placedBlocks = new List<Block>();
allBlocks = new Texture2D[4];
blockGenerator = new BlockGenerator(allBlocks,gameRef);
}
public override void Update(GameTime gameTime)
{
base.Update(gameTime);
try
{
if (currentBlock.isMoving == false)
{
placedBlocks.Add(currentBlock);
currentBlock = null;
currentBlock = blockGenerator.GenerateBlock();
}
else
{
currentBlock.UpdatePosition(gameTime);
if (InputManager.CheckForKeyBoardRelease(Keys.A))
{
currentBlock.MoveLeft();
}
if (InputManager.CheckForKeyBoardRelease(Keys.D))
{
currentBlock.MoveRight();
}
}
}
catch(NullReferenceException e)
{
currentBlock = blockGenerator.GenerateBlock();
}
}
public override void Draw(GameTime gameTime)
{
gameRef.SpriteBatch.Begin();
if(currentBlock != null)
{
currentBlock.DrawBlocks();
}
foreach(Block b in placedBlocks)
{
b.DrawBlocks();
}
gameRef.SpriteBatch.End();
base.Draw(gameTime);
}
The method "GenerateBlock" returns a object of type "Block"
public class Block : DrawableGameComponent
{
Game1 gameRef;
public Texture2D blockTexture;
public Vector2[] blockPositions;
TimeSpan lastMove;
TimeSpan blockMove = TimeSpan.FromMilliseconds(500);
public bool isMoving;
public Block(Game game, Texture2D _blockTexture, Vector2[] _blockPositions) : base(game)
{
gameRef = (Game1)game;
blockTexture = _blockTexture;
blockPositions = _blockPositions;
isMoving = true;
}
public void UpdatePosition(GameTime gameTime)
{
Vector2 bottomBlockPositon = FindBottomBlock();
if(bottomBlockPositon.Y < 550)
{
if (WaitTillMove(gameTime))
{
for (int i = 0; i < blockPositions.Length; i++)
{
blockPositions[i] = new Vector2(blockPositions[i].X, blockPositions[i].Y + 25);
}
}
}
else
{
isMoving = false;
Console.WriteLine("X: " +blockPositions[0].X + " Y:" + blockPositions[0].Y);
}
}
public Vector2 FindBottomBlock()
{
Vector2 result = new Vector2(0, 0);
for(int i = 0; i < blockPositions.Length; i++)
{
if(blockPositions[i].Y > result.Y)
{
result = blockPositions[i];
}
}
return result;
}
public bool WaitTillMove(GameTime gameTime)
{
if (lastMove + blockMove < gameTime.TotalGameTime)
{
lastMove = gameTime.TotalGameTime;
return true;
}
return false;
}
public void DrawBlocks()
{
gameRef.SpriteBatch.Draw(blockTexture, blockPositions[0], Color.White);
gameRef.SpriteBatch.Draw(blockTexture, blockPositions[1], Color.White);
gameRef.SpriteBatch.Draw(blockTexture, blockPositions[2], Color.White);
gameRef.SpriteBatch.Draw(blockTexture, blockPositions[3], Color.White);
}
}
Debugging says that my List contains an Element even though it has the wrong positions. But this shouldn't matter because I still only "see" one Block at the same time.
Hopefully someone can toss me into the right direction.
Edit:
public class BlockGenerator
{
Random random;
Texture2D[] allBlocks;
Vector2[] blockPositions;
Texture2D currentBlock;
BlockEnums currentBlockEnum;
Game1 gameRef;
public BlockGenerator(Texture2D[] blocks, Game1 game)
{
gameRef = (Game1)game;
allBlocks = blocks;
currentBlock = allBlocks[1];
blockPositions = new Vector2[4];
random = new Random();
}
public Block GenerateBlock()
{
int colorValue = random.Next(0, 4); //0 = blue, 1 = green, 2 = red, 3 = yellow
currentBlock = allBlocks[colorValue];
currentBlockEnum = BlockEnums.Line;
blockPositions[0] = new Vector2(100, 0);
blockPositions[1] = new Vector2(125, 0);
blockPositions[2] = new Vector2(150, 0);
blockPositions[3] = new Vector2(175, 0);
Block generatedBlock = new Block(gameRef,currentBlock, blockPositions);
return generatedBlock;
}

public class BlockGenerator
{
Random random;
Texture2D[] allBlocks;
Vector2[] blockPositions; // delete this
Then move the initialization code from the constructor into GenerateBlock (add var).
var blockPositions = new Vector2[4];
Then it should work. You were creating new vectors each time you created a block but re-using the same instance of blockPositions each time, so both blocks do exist but will always have the exact same positions.
I haven't had time to test but I think it's right...let me know :)
edit: I'd also suggest moving blockPositions entirely into the Block class. I see no value (in the code you have posted, maybe you have plans for later) in having that logic outside of the class that really owns it...and if it was contained within the class to begin with you would have avoided this problem. Just a suggestion :)

Can't describe a collision between two objects in different class to add a health bar

I'm trying to add a health bar to my 2d platformer. Atm i'm trying to define a collision between two objects (a rocket and the player), but I don't know how to refer/use them. I've written the error as a comment in the code.
This is the health class:
using Microsoft.Xna.Framework;
class Health : GameObjectList
{
public Health(int layer = 3, string id = "") : base(layer, id)
{
for(int i = 0; i < 255; i+=85)
if(i % 85 == 0)
{
SpriteGameObject health = new SpriteGameObject("Sprites/spr_health", 3);
health.Position = new Vector2(120 + i, 15);
this.Add(health);
}
}
public override void Update(GameTime gameTime)
{
base.Update(gameTime);
Player player = GameWorld.Find("player") as Player;
Rocket rocket = GameWorld.Find("rocket") as Rocket;
foreach (GameObject obj in gameObjects)
{
SpriteGameObject h = obj as SpriteGameObject;
if (rocket.CollidesWith(player))
//This is wat it says as an error:
//An unhandled exception of type 'System.NullReferenceException' occurred in TickTick.exe
//Additional information: Object reference not set to an instance of an object.
{
this.Remove(h);
return;
}
}
}
}
I've used the same GameWorld.find method in the rocket class when there was no health bar and that worked:
public void CheckPlayerCollision()
{
Player player = GameWorld.Find("player") as Player;
if (this.CollidesWith(player) && this.Visible)
player.Die(false);
// CURRENTLY DON'T WANT THIS TO HAPPEN BECAUSE OF HEALTH BAR
}
This is the GameWorld Find method:
public GameObject Find(string id)
{
foreach (GameObject obj in gameObjects)
{
if (obj.ID == id)
return obj;
if (obj is GameObjectList)
{
GameObjectList objlist = obj as GameObjectList;
GameObject subobj = objlist.Find(id);
if (subobj != null)
return subobj;
}
}
return null;
}
The Rocket class:
using Microsoft.Xna.Framework;
class Rocket : AnimatedGameObject
{
protected double spawnTime;
protected Vector2 startPosition;
public Rocket(bool moveToLeft, Vector2 startPosition)
{
this.LoadAnimation("Sprites/Rocket/spr_rocket#3", "default", true, 0.2f);
this.PlayAnimation("default");
this.Mirror = moveToLeft;
this.startPosition = startPosition;
Reset();
}
public override void Reset()
{
this.Visible = false;
this.position = startPosition;
this.velocity = Vector2.Zero;
this.spawnTime = GameEnvironment.Random.NextDouble() * 5;
}
public override void Update(GameTime gameTime)
{
base.Update(gameTime);
if (spawnTime > 0)
{
spawnTime -= gameTime.ElapsedGameTime.TotalSeconds;
return;
}
this.Visible = true;
this.velocity.X = 600;
if (Mirror)
this.velocity.X *= -1f;
CheckPlayerCollision();
// check if we are outside the screen
Rectangle screenBox = new Rectangle(0, 0, GameEnvironment.Screen.X, GameEnvironment.Screen.Y);
if (!screenBox.Intersects(this.BoundingBox))
this.Reset();
}
public void CheckPlayerCollision()
{
Player player = GameWorld.Find("player") as Player;
if (this.CollidesWith(player) && this.Visible)
player.Die(false);
// CURRENTLY DON'T WANT THIS TO HAPPEN BECAUSE OF HEALTH BAR
}
}
I just have no idea how i can get this to work, to decrease the health by 1 and eventually let the player die when there is no health left.

it seems to me that one or both the lines
Player player = GameWorld.Find("player") as Player;
Rocket rocket = GameWorld.Find("rocket") as Rocket;
returns null, do that check, ensure that the gameObjects list cointains what you are looking for and that they are of the type you expect
check even if when your player Die, you remove it from the world before the code part where it gives you errors, maybe at the time of your check the player (or the rocket) has been removed from the world

Problems with trying to use a bool in 2 classes

I'm trying to add a shield that is active for a limited to my game but right now it doesn't work for some reason and I just can't figure out why.
First, this is the shield class:
class Shield : SpriteGameObject
{
protected float counter;
protected float limit;
public bool isShieldOn;
protected bool startCounting;
public Shield(int layer = 0, string id = "") : base("Sprites/spr_shield", layer, id)
{
counter = 0;
limit = 5;
isShieldOn = false;
startCounting = false;
}
public override void Update(GameTime gameTime)
{
//Stuff here
while (startCounting)
counter += (float)gameTime.ElapsedGameTime.TotalSeconds;
if (counter >= limit)
{
isShieldOn = false;
counter = 0;
startCounting = false;
}
Player player = GameWorld.Find("player") as Player;
if (this.visible && this.CollidesWith(player))
{
isShieldOn = true;
startCounting = true;
this.visible = false; GameEnvironment.AssetManager.PlaySound("Sounds/snd_shieldcollected");
}
}
}
Right now the game freezes when the player touches the shield but that has something to do with the while statement that contains the counter. I don't know why but first let me explain the isShieldOn bool I've been having problems with.
Here is where is use the isShieldOn bool:
class Health : GameObjectList
{
Shield shield;
public Health(int layer = 3, string id = "") : base(layer, id)
{
//Stuff here
shield = new Shield(1, "shields");
}
public override void Update(GameTime gameTime)
{
base.Update(gameTime);
if (shield.isShieldOn == false)
{
//Remove health
}
}
}
At the moment the shield works when I just give it the value true in the constructor. But it doesn't become true if I try to assign it the if statement in the Update method of the Shield class. I'm 100% sure the if statement is performed because the shield does disappear when touched (this.visible = false) and the soundeffect plays.
If you have any ideas on how to fix this problem I'd be really thankfull, also if you have an idea on how to fix the timer.

Replace
while (startCounting)
counter += (float)gameTime.ElapsedGameTime.TotalSeconds;
to
counter += (float)gameTime.ElapsedGameTime.TotalSeconds;
in your Update method().