Randomly Generated Background

[jw405]

Hi!

 

Does anyone know how I might be able to load a different background each time a game is started?

 

I have three different preloaded backgrounds and would like the game to select a random one each time the game begins.

 

I'm a complete newbie to Phaser and any help/tutorials would be hugely appreciated!

 

Can link code if needed.

 

Thanks!

 

[WitheringTreant]

I usually make randomized generation like this:

 

// this rolls either value 1, 2 or 3

var roll = game.rnd.integerInRange(1, 3);

 

// make separate if-statements for each value of roll

// (i dont know what kind of background item youre using, i use images like this, but add them to display groups)

if (roll === 1) {backgroundimage =  game.add.image(0, 0, 'image1');};

if (roll === 2) {backgroundimage =  game.add.image(0, 0, 'image2');};

if (roll === 3) {backgroundimage =  game.add.image(0, 0, 'image3');};

 

 

// Its basically just rolling a dice and telling the code what to do depending on the number it rolls

[clarkitect]

A simplification of WitheringTreant's answer looks like this:

backgroundimage = game.add.image(0, 0, 'image' + game.rnd.integerInRange(1,3));

[mattstyles]

I'd do something similar but I'd use an array of images to keep things DRY-er

var images = [  'foo.png',  'baz.png',  'bar.jpg']backgroundImage = game.add.image( 0, 0 images[ game.rnd.integerInRange( 0, images.length - 1 ) ] )

This also makes it a little easier to dynamically load the images array should that ever be necessary.

[WitheringTreant]

I like your answer, mattstyles. I've been a bit annoyed with that repetition. Might try your way next time.

Although I currently often use this, since it allows me to adjust rolls more accurately.

chanceRoll(4) means it has 4/100 chance of being true.

 

// ROLL: OBJECT

        var object = null;

        while (object === null) 

            {

            if (game.math.chanceRoll(1)) {object = 'star1'};

            if (game.math.chanceRoll(4)) {object = 'star2'};

            if (game.math.chanceRoll(1)) {object = 'nebula1'};

            if (game.math.chanceRoll(5)) {object = 'anomaly1'};

            }

[mattstyles]

Yeah, but, in your example you don't have a 1/25 chance of hitting `star2` because even if that succeeds you still have a chance of hitting either `nebula1` or `anomaly1`, unless I'm misreading it? (I just read the phaser docs, I dont use phaser currently).

 

Infact, I'm not exactly sure what happens practically with that code snippet. I'd guess its fairly random with a skew towards `anomaly1` and a slight skew favouring `star2` over the others, which I guess is what you're after, but why make that many chance rolls?

 

Why not roll once and use fuzzy logic to get your result:

function fuzzy( roll ) {  if ( roll >= 0 && roll < 4 ) {    return 'star1'  }  if ( roll >= 4 && roll < 9 ) {    return 'anomaly1'  }  // etc etc, perhaps with some better smarts to create the 'chance' table}object = fuzzy( random( 0, 11 ) ) // I just counted up all your chances 

That is hacked together, there's plenty of tidying and optimising that can be done.