XNA Arrays and drawing textures? - arrays

Question

I am completely new to coding and have only been practicing for a few weeks and i have been assigned a task in which seems simple has hit a stumbling block
i have 4 sprites on screen drawn but i have to every time the game starts the sprites have to be random chosen between 1 sprite or the other as well out of the 2 sprites there must be at least one of each sprite on screen.
my tutor suggested that i use an array to store the textures and then code it so it randomly picks which one to draw each time
namespace GamesProgrammingAssement1
{
/// <summary>
/// This is the main type for your game
/// </summary>
public class Game1 : Microsoft.Xna.Framework.Game
{
GraphicsDeviceManager graphics;
SpriteBatch spriteBatch;
KeyboardState keys;
KeyboardState oldKeys;
GamePadState Pad1;
GamePadState oldPad1;
Texture2D gnome;
Texture2D troll;
Rectangle sprRect1;
Rectangle sprRect2;
Rectangle sprRect3;
Rectangle sprRect4;
SpriteFont Run;
SpriteFont Score;
int scoreNum = 0;
int runNum = 0;
Vector2 scorePos;
Vector2 runPos;
Texture2D[] sprite = new Texture2D[2];
public Game1()
{
graphics = new GraphicsDeviceManager(this);
Content.RootDirectory = "Content";
}
/// <summary>
/// Allows the game to perform any initialization it needs to before starting to run.
/// This is where it can query for any required services and load any non-graphic
/// related content. Calling base.Initialize will enumerate through any components
/// and initialize them as well.
/// </summary>
protected override void Initialize()
{
sprRect1 = new Rectangle(375, 100, 64, 64);
sprRect2 = new Rectangle(375, 300, 64, 64);
sprRect3 = new Rectangle(225, 200, 64, 64);
sprRect4 = new Rectangle(525, 200, 64, 64);
scorePos = new Vector2(5, 400);
runPos = new Vector2(5, 425);
sprite[0] = gnome;
sprite[1] = troll;
base.Initialize();
}
/// <summary>
/// LoadContent will be called once per game and is the place to load
/// all of your content.
/// </summary>
protected override void LoadContent()
{
// Create a new SpriteBatch, which can be used to draw textures.
spriteBatch = new SpriteBatch(GraphicsDevice);
gnome = Content.Load<Texture2D>("Gnome");
troll = Content.Load<Texture2D>("Troll");
Score = Content.Load<SpriteFont>("Score");
Run = Content.Load<SpriteFont>("Run");
}
/// <summary>
/// UnloadContent will be called once per game and is the place to unload
/// all content.
/// </summary>
protected override void UnloadContent()
{
// TODO: Unload any non ContentManager content here
}
/// <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)
{
KeyboardState keys = Keyboard.GetState();
KeyboardState oldkeys = keys;
if (keys.IsKeyDown(Keys.Escape)) this.Exit();
// TODO: Add your update logic here
base.Update(gameTime);
}
/// <summary>
/// This is called when the game should draw itself.
/// </summary>
/// <param name="gameTime">Provides a snapshot of timing values.</param>
protected override void Draw(GameTime gameTime)
{
GraphicsDevice.Clear(Color.CornflowerBlue);
spriteBatch.Begin();
spriteBatch.Draw(gnome,sprRect1,Color.White);
spriteBatch.Draw(troll, sprRect2,Color.White);
spriteBatch.Draw(troll, sprRect3, Color.White);
spriteBatch.Draw(troll, sprRect4, Color.White);
spriteBatch.DrawString(Score, "SCORE : "+ scoreNum, scorePos, Color.Black);
spriteBatch.DrawString(Run, "RUN OF TROLL : " + runNum, runPos, Color.Black);
spriteBatch.End();
base.Draw(gameTime);
}
}
}
any help would be great because i dont know if im storing the arrays properly or if im doing random right

Answer 1

I see you are storing your Textures in an Array. I do not see any code for Random in your sample.
That being said, consider the following function:
Random rand = new Random();
private Texture2D GetRandomTexture()
{
return sprite[rand.Next(0, 2)];
}
Calling this function, will return a random texture contained in your "sprite" array. Plugging this function call in your draw could resemble something like this:
spriteBatch.Draw(GetRandomTexture(), sprRect1, Color.White);
Since you declared that you are a beginner, I tried not to go too much into details. You should, however, considering looking into creating a new class "Sprite" that would contain the Texture2D, Position, Rectangle values of each of your sprites. Then instead of storing an array of Textures, you would be able of storing an array (or list) of Sprite objects.

Answer 2

You want to choose four sprites, therefore you should use an array (or similar structure) which can contain four elements:
Texture2D[] sprites = new Texture2D[4];
When initializing the Array there are three possible situations regarding how many of each sprite will exist:
1-3 (one troll, three gnomes)
2-2 (two of each)
3-1 (three trolls, one gnome)
So firstly, you have to pick one of these distributions:
var rnd = new Random();
var trolls = rnd.Next(1, 3);
var gnomes = 4 - trolls;
Then, you can fill the array:
for(int i = 0; i < 4; ++i)
{
if(gnomes == 0)
{
//choose the troll
sprites[i] = troll;
--trolls;
}
else if(trolls == 0)
{
//choose the gnome
sprites[i] = gnome;
--gnomes;
}
else
{
//choose randomly
if(rnd.Next(2) < 1)
{
sprites[i] = troll;
--trolls;
}
else
{
sprites[i] = gnome;
--gnomes;
}
}
}
You draw them like
spriteBatch.Draw(sprites[0], sprRect1,Color.White);
spriteBatch.Draw(sprites[1], , sprRect2,Color.White);
spriteBatch.Draw(sprites[2], , sprRect3, Color.White);
spriteBatch.Draw(sprites[3], , sprRect4, Color.White);