Adobe Community: I need help

chiggy83 Calculating status...

Currently Being Moderated

I need help

May 28, 2012 9:48 AM

Hello,

I am currently learning how to use actionscript3.0. to design a space invader game which i need to carry our a study. I have manageg to maake the player shoot bullet upward. I have also populated my Aliens (50) on the screen and they can moove horizontally. Now my problem is how to make the aliens move downwards when they hit both sides of the screen. Any suggestions would be appreciated.

1066 Views 14 Replies Latest reply: chiggy83, Jun 5, 2012 10:41 AM

Replies

Currently Being Moderated

1. esdebon,

May 28, 2012 10:18 AM in reply to chiggy83

Report

Conditions could be using

I think there may be problems depending on how you group or not the aliens.

The basics would be that when any alien touched the edge of the screen some all aliens are increased in height and alien (with this would lower).

if (aliensGroup.x <0) {
     aliensGroup.x = 1;
     aliensGroup.y + = individualAlien.height;
}

if (aliensGroup.x> aliensGroup.width) {
     aliensGroup.x = aliensGroup.width-1;
     aliensGroup.y + = individualAlien.height;
}

* That if the registration point is top left.

But what if they destroy the entire first column of aliens?

You would have to move all the aliens on the left

But know what aliens are on stage?

Maybe you would have to take into an array references for each alien and remove this of the array when it is destroyed

|
Mark as:
Currently Being Moderated

2. chiggy83,

May 28, 2012 10:44 AM in reply to chiggy83

Report

Thanks for your response but I still need some clarification.
here is what I have at the moment

var alien_direction:Number = 1.5;
          var alienArray:Array = new Array();

var columns = 10;
                              var rows = 5;
                              var HspaceBetweenInvaders = 60;
                              var VspaceBetweenInvaders = 40;

                              for (var i:int=0; i<columns;i++)
                              {
                                   for (var j:int=0; j<rows;j++)
                                           {
                                                    var alien_mc:mcAlien = new mcAlien();
                                                    alien_mc.x = i * HspaceBetweenInvaders+ 55;
                                                    alien_mc.y = j* VspaceBetweenInvaders+150;
                                                    addChild(alien_mc);
                                                    alienArray.push(alien_mc);
                                           }
                              }

addEventListener(Event.ENTER_FRAME, onEnterFrame);

function onEnterFrame (event:Event): void
                    {

                              for (var i:int = 0; i< alienArray.length; i++)
                                        {
                                if (alienArray[i].x > stage.stageWidth ) {
                                                            alien_direction = -1.5;
                                                  }

                                                  else if (alienArray[i].x < 0 ) {
                                                            alien_direction = 1.5;
                                                  }

                                                  alienArray[i].x = alienArray[i].x + alien_direction; //move to the right
                                                  //alienArray[i].y = -alienArray[i].y


                                        }

                    }

|
Mark as:
Currently Being Moderated

3. esdebon,

May 28, 2012 11:05 AM in reply to chiggy83

Report

Try with this:

var alien_direction:Number = 1.5;
var alienArray:Array = new Array();

var columns = 10;
var rows = 5;
var HspaceBetweenInvaders = 60;
var VspaceBetweenInvaders = 40;

for (var i:int=0; i<columns; i++)
{
    for (var j:int=0; j<rows; j++)
    {
        var alien_mc:mcAlien = new mcAlien();
        alien_mc.x = i * HspaceBetweenInvaders + 55;
        alien_mc.y = j * VspaceBetweenInvaders + 150;
        addChild(alien_mc);
        alienArray.push(alien_mc);
    }
}

addEventListener(Event.ENTER_FRAME, onEnterFrame);

function onEnterFrame(event:Event):void
{
    for (var i:int = 0; i< alienArray.length; i++)
    {
        if (alienArray[i].x > stage.stageWidth)
        {
            alien_direction = -1.5;
             down();
        }
        else if (alienArray[i].x < 0 )
        {
            alien_direction = 1.5;
            down();
        }

        alienArray[i].x = alienArray[i].x + alien_direction;//move to the right
        //alienArray[i].y = -alienArray[i].y
    }

}

function down():void {
    for (var i:int = 0; i< alienArray.length; i++)
    {
        alienArray[i].y += 5    //VspaceBetweenInvaders + 150;
    }
}

|
Mark as:
Currently Being Moderated

4. esdebon,

May 28, 2012 11:22 AM in reply to esdebon

Report

Indeed the condition would be better this way

if (alienArray[i].x < 0 || alienArray[i].x > stage.stageWidth)
        {
            alien_direction * = -1;
             down();
        }

|
Mark as:
Currently Being Moderated

5. chiggy83,

May 28, 2012 3:12 PM in reply to esdebon

Report

It worked! Thanks I do appreciate

But there is an issue with the last column of my aliens. When the aliens hit the right hand side of the screen, they move towards the alien column before them (i.e. the 9th column) and over time their position becomes the same as the aliens in the 9th column

How can I make them to retain the column spacing while they move horizontally and vertically downwards?

|
Mark as:
Currently Being Moderated

6. esdebon,

May 28, 2012 3:18 PM in reply to chiggy83

Report

could you give me the size of the stage you use, and the size of your alien in order to reproduce the problem

|
Mark as:
Currently Being Moderated

7. esdebon,

May 28, 2012 3:42 PM in reply to chiggy83

Report

The last code works fine to me, buy maybe this solve your problem

var alien_direction:Number = 1.5;
var alienArray:Array = new Array();

var columns = 10;
var rows = 5;
var HspaceBetweenInvaders = 60;
var VspaceBetweenInvaders = 40;

for (var i:int=0; i<columns; i++)
{
    for (var j:int=0; j<rows; j++)
    {
        var alien_mc:mcAlien = new mcAlien();
        alien_mc.x = i * HspaceBetweenInvaders + 55;
        alien_mc.y = j * VspaceBetweenInvaders + 150;
        addChild(alien_mc);
        alienArray.push(alien_mc);
    }
}

addEventListener(Event.ENTER_FRAME, onEnterFrame);

function onEnterFrame(event:Event):void
{
    for (var i:int = 0; i< alienArray.length; i++){


        if (alienArray[i].x+alienArray[i].width > stage.stageWidth){
            alien_direction = -1.5;
            down();
        }

        else if (alienArray[i].x < 0 ){
            alien_direction = 1.5;
            down();
        }

        alienArray[i].x = alienArray[i].x + alien_direction;

    }
}

function down():void{
    removeEventListener(Event.ENTER_FRAME, onEnterFrame);
    for (var i:int = 0; i< alienArray.length; i++){
        alienArray[i].y += 5;//VspaceBetweenInvaders + 150;
    }
    addEventListener(Event.ENTER_FRAME, onEnterFrame);
}

|
Mark as:
Currently Being Moderated

8. chiggy83,

May 29, 2012 12:36 AM in reply to esdebon

Report

this is a great solution.
thanks

Now that I have my aliens moving properly, I want to make them shoot bullets randomly

I thought of creatng an arraay for the bombs and populating about 10 bombs. But how can i make the aliens shoot the bullets randomly at given times?

|
Mark as:
Currently Being Moderated

9. esdebon,

May 29, 2012 8:24 AM in reply to chiggy83

Report

function onEnterFrame(event:Event):void{
     for (var i:int = 0; i< alienArray.length; i++){

     (Math.random()*100<10)?shoot(i):null    // each frame 10% probability of shot

      // more code
}

function shoot(i):void{

     var shoot:Shoot=new Shoot(); // Object from the library
     shoot.x=alienArray[i].x
    shoot.y=alienArray[i].y

}

|
Mark as:
Currently Being Moderated

10. chiggy83,

Jun 5, 2012 2:03 AM in reply to esdebon

Report

I'm sorry for replying late. Have been away
Back to the discussion, I don't understand the second line of the code:

(Math.random()*100<10)?shoot(i):null

could you explain a little bit more?

why do you have a question mark before shoot?

|
Mark as:
Currently Being Moderated

11. esdebon,

Jun 5, 2012 7:57 AM in reply to chiggy83

Report

this line

(Math.random()*100<10)?shoot(i):null

is same to:

if(Math.random()*100<10){
shoot(); // you need create this function
}

where Math.random()*100 is a number between 0 and 100

then each frame have a 10% of probability of shoot

|
Mark as:
Currently Being Moderated

12. chiggy83,

Jun 5, 2012 8:38 AM in reply to esdebon

Report

I have the code below but it still wouldnt work when i test it

// make aliens drop bombs randomly
                              for (var bombNumber:int = 0; bombNumber< alienArray.length; bombNumber++)
                                        {
                                                       var random:Number = Math.random();

                                             if(Math.random()*100<10)
                                                            {
                                                                 shoot(); // you need create this function
            }
                                        }

function shoot():void
                                {

                                   // create bombs and put them in array
                                             var bomb_mc:mcBomb = new mcBomb();
                                             var bombArray:Array = new Array();
                                             bomb_mc.x = alienArray[i].x;
                                             bomb_mc.y = alienArray[i].y
                                             bombArray.push(bomb_mc);

                              for (var i:int = 0; i< alienArray.length; i++)
       {
                                                            bombArray[i].y += 10;
                                             }

}

|
Mark as:
Currently Being Moderated

13. esdebon,

Jun 5, 2012 8:46 AM in reply to chiggy83

Report

// make aliens drop bombs randomly
                              for (var bombNumber:int = 0; bombNumber< alienArray.length; bombNumber++)
                                        {
                                                       var random:Number = Math.random();

                                             if(Math.random()*100<10)
                                                            {
                                                                 shoot(); // you need create this function
            }
                                        }

var bombArray:Array = new Array();

function shoot():void
                                {

                                   // create bombs and put them in array
                                             var bomb_mc:mcBomb = new mcBomb();
                                          addChild(bomb_mc)
                                             bomb_mc.x = alienArray[i].x;
                                             bomb_mc.y = alienArray[i].y
                                             bombArray.push(bomb_mc);

}

addEventListener(Event.ENTER_FRAME,moveBombs)
function moveBombs(e:Event):void{
          for (var i:int = 0; i< alienArray.length; i++){
                    bombArray[i].y += 10;
       }
}

|
Mark as:
Currently Being Moderated

14. chiggy83,

Jun 5, 2012 10:41 AM in reply to esdebon

Report

the code above seemed not to work so i modified it as follows

function onEnterFrame (event:Event): void
                    {

     // make aliens drop bombs randomly
       for (var bombNumber:int = 0; bombNumber< alienArray.length; bombNumber++)
                                                  {
                                                                 var random:Number = Math.random();

                                                  if(Math.random()*100<10)
                                                                      {
                                                                      shoot();

                                                                 }

                                                  }

function shoot():void
                                {
                                         var random:Number = Math.random();
                                   // create bombs and put them in array
                                        var bomb_mc:mcBomb = new mcBomb();
                                        addChild(bomb_mc);
                                        bomb_mc.x = Math.random()*1280;
                                        bomb_mc.y = Math.random()*800;
                                        bombArray.push(bomb_mc);

                              for (var i:int = 0; i< alienArray.length; i++)
                                        {
                                                  bombArray[i].y += 10;
                                        }

                        }

}

However, I still have issues with the aliens droping the bombs.
at the moment bombs are randomly displayed on the screen. I tried replacing this section

bomb_mc.x = Math.random()*1280;
bomb_mc.y = Math.random()*800;

with
bomb_mc.x = Math.random()*alienArray[i].x;
bomb_mc.y = Math.random()*alienArray[i].y;

but it still wouldnt work.

i really want the aliens to drop about 5 bombs randomly and then delay for few seconds before droping more.

|
Mark as:

Forum guidelines

Answers + Points = Status

10 points awarded for Correct Answers
5 points awarded for Helpful Answers
10,000+ points
1,001-10,000 points
501-1,000 points
5-500 points

ActionScript 3

I need help

May 28, 2012 9:48 AM

More Like This

Bookmarked By (0)

Answers + Points = Status