From Box2D to Nape in CitrusEngine

Due the massive Garbage generated by Box2D creating memory fragmentation. I will be porting my shoot'em up game Beekyr (using CitrusEngine) from Box2D to Nape.


Firstly, I have changed these physics instance from:

var params:Object = new Object();
params.doSleep = false;
var box2D:Box2D = new Box2D("box2D",params);

box2D.gravity = new b2Vec2(0, 0);

box2D.touchable = false;
box2D.world.SetContinuousPhysics(false);
box2D.velocityIterations = 1;
add(box2D);

to Nape:

var params:Object = new Object();
var nape:Nape = new Nape("nape", params);
nape.gravity = new Vec2(0, 0);
nape.touchable = false;
add(nape);

I changed all my objects from extending Box2DPhysicsObject to NapePhysicsObject.
All my custom fixtures has been erased, and collision groups dissapeared.

_body.SetActive(true/false);

to Nape:

_body.space = null; //to disable
_body.space = _nape.space //to enable.

Updating rotation:
before, Box2D:

_body.setRotation(rads)

now, Nape, (I think this same code should work the box2D wrapper?):

_body.rotation = rads;

Updating velocity:
before, Box2D:

_body.SetLinearVelocity(new b2Vec2(_currentSpeed.x, _currentSpeed.y);

now, Nape, (I think this same code should work the box2D wrapper?):

_body.velocity = new Vec2(_currentSpeed.x, _currentSpeed.y);

But since the units change betweens engines, Im using pixels as unit and updating the position with my own engine:

x +=speed.x;
y +=speed.y;

This is uesful for shoot'em ups but I am very unsure what would happen if I was using real physics, with gravity, etc.

Updating collisions... they use now a different override, but the rest is the same:

before, Box2D:

override public function handleBeginContact(contact:b2Contact):void {
var collisionWith:* = Box2DUtils.CollisionGetOther(this, contact);

now, Nape:

override public function handleBeginContact(contact:InteractionCallback):void {
var collisionWith:* = NapeUtils.CollisionGetOther(this, contact);

now fixtures are not present as such so I needed to change the way I set up the filters and physics:

override protected function defineBody():void {
_bodyType = BodyType.KINEMATIC ;
}

override protected function createFilter():void {
super.createFilter();
_shape.sensorEnabled = true;
_shape.filter.sensorGroup = PhysicsCollisionCategories.Get("enemyBullet");
_shape.filter.sensorMask = PhysicsCollisionCategories.Get("player", "playerBullet");
}

I think I didn't have to change anything else...

Performance doubled on my smartphone, I went from 18-30FPS to constant 30FPS for the game.

Optimizing performance in CitrusEngine and Box2D

Performance tips.

I will explain my experience when I was building Beekyr game for AIR using CitrusEngine and Box2D....

This might be applied to other game engines.... but the way Box2D is used might be the same.

When I created first Beekyr stage prototype I had about 2000 objects moving smoothly in screen, Stage3D was just amazing. But I needed the sprites to collide between each other. Everyone recommended to use the physics engine Box2D, even it if was just for collisions (later on I replaced it for Nape engine (for AS3), which is at least twice as fast, click here to see how I converted from Box2D to Nape).

After adding the physics engine, I only was able to have about hundred of objects moving smooth and fast (still no code to make them react with each other).

I didn't realize that a physics engine would make things THAT slow, specially in smartphones, so I had to start optimizing everything:

I made everything to be classified as sensor:

_fixtureDef.isSensor = true;

That means that touching objects can overlap without having a bounce effect or something.

Enable only begin handle contact:

beginContactEnabled = true;

Objects will not react until I enabled at least one form of contact in Citurs Engine.

Then I want to create groups, that means groups with the same ID will not react to each other this is very good when you have loads of real bullets or lots of enemies, this will stop most collision functions to be triggered when the bullets or enemies overlap.
The way to do this is to edit the fixture filter, this is how enemy bodies are filtered:

    override protected function defineFixture():void {
           super.defineFixture();
           _fixtureDef.filter.groupIndex = GameVars.ENEMY_GROUP;
           _fixtureDef.isSensor = true;
        }

Don't ever use isBullet() unless is completelly necesary. This will add more calculations to the engine making it slower.

Fitting the game to in any screen resolution.

For my Beekyr Android game it all started as 720p as it would be a Flash game,  but then I realized that the game needed to work in 800x480  for my smartphone... After that, I realized I needed to make it work in more resolutions for the rest of all Android phones out there. I had to think a way to scale the game and assets.... Turned out that is wasn't that hard!
 
Basically, I had to work always with 720p in mind.

When the game loads I need to work out a conversion rate for the resolution. So first lines of code executed, even before the engine :

        public static const ORIGINAL_X:int= 1280;
        public static const ORIGINAL_Y:int = 720;
        public static var SCREEN_X:int;
        public static var SCREEN_Y:int;
      
        public static var REDUCTION_RATIO:Number;
    

   private function getReductionRatio():void
        {
           &nbspSCREEN_X = Capabilities.screenResolutionX;
           &nbspSCREEN_Y = Capabilities.screenResolutionY;
            var ratioX:Number = SCREEN_X / ORIGINAL_X;
            var ratioY:Number = SCREEN_Y / ORIGINAL_Y;

            if (ratioX < ratioY) {
                REDUCTION_RATIO = ratioX;
            }else {
                REDUCTION_RATIO = ratioY;  
            }
        }

Then apply this REDUCTION_RATIO variable to every loaded asset, positions,speeds and basically everything that involved pixels.

Examples:

params.height = size.w*REDUCTION_RATIO;
params.width = size.h*REDUCTION_RATIO;
_bulletSpeed = 38*REDUCTION_RATIO;

If using AssetManager, all the stretching will be done for you if you initialize it like this:

assetsManager = new AssetManager (1 / GameVars.REDUCTION_RATIO, false);

But if you are converting textures manually then convert them like this:

Texture.fromBitmap(bitmap,false,true,1/GameVars.REDUCTION_RATIO);

This will still use same amounts of Texture Memory in 720 than 480 or 320. If you have troubles with that , load different assets that are smaller and change the REDUCTION RATIO.

In my case, load / unload assets between stages, works well too.
I never reached 128MB of VRAM (more or less, the minimum memory these days: ipad1).

It takes time and real concentration to make it work well but when is done it works flawlessly.

Enjoy.

Career Shift : from Flash websites to AIR apps

I have been developing websites since 2004, I immediately jumped into Flash when I knew about it. This plug-in let me do really amazing things when you compared it with the HTML3-4 limits...

I worked for years as Flash developer along with very few PHP jobs. But Flash was becoming stronger. It was a solid OOP language and very tested plug-in without hardly any flaws.... until Steve Jobbs told otherwise and everyone believed him, they didn't realize it was all a war between Apple and Adobe, and everybody lost. Only the apple man won his own personal fight.

With all of this in mind I tried to make a game in Flash 10. I wanted to add many graphics and effects but I couldn't get anything very complex working due the lack of GPU acceleration. So I left the game in a playable state, but it was too simple. I had to discard the idea of making complex flash games.

Meanwhile Adobe didn't know how to handle the fight with Apple. Nevertheless Adobe released the best update ever made for flash: molehill - Stage3D. It was the beginning of triple A games in Flash. But it was all obscured with the war.

I realized about this and knew I was finally able to make complex games in flash... but flash sites were starting to die, all iProducts didn't accept flash so the world had to adapt to this (instead of the other way).

I didn't see the GPU acceleration happening in mobile phones until very late 2012. By then market almost already shifted back to old HTML. I was sure that didn't like this backwards step. In fact it was a waste of time for me, I lost all interest in the web: coding with JavaScript (no OOP) is a total nightmare when you add browsers variety to the equation.
So I had no choice other than leaving the web scene and move into apps/games.

I wanted to make games, I didn't mind what language so I researched into some of them: coronaSDK, Unity3D, phoneGap. But a friend told me about CitrusEngine framework for flash Stage3D. So I started working heavily for a month or two to get a demo that looked and and was responsive in Flash at very high frame rates... I was impressed as that was exactly what I had in mind a year back...
Only then,  I decided to make a real game. I got in touch with two friends that were able to work with me: Diego Gangl (amazing artist) and Mete Burch (modern musician). I ended up leading a team making the awesome game I always wanted and playable in most Android phones:
Beekyr

I made it in adobe AIR to be able to get to android devices. It was a really good decision. In the other hand it was also difficult to make the app perform well in these low powered devices. I was used to powerful PCs but I had to work hard to optimize everything and learn some very interesting techniques to make it run smooth everywhere.

So now, in 2013, the history carries on as Indie Developer.
I hope I can manage it well and live from making good quality games!

TouchPad class for AS3 + Starling (Rev.2)

A month ago I shared a touch class that was pretty useful to play games in smart-phones but after some testing I realized that didn't work well when moving (with left thumb) + shooting (with right thumb) and pressing them alternatively.

After a bit of thinking, I have improved the class and now it will use always the left thumb to move and the right to shoot keeping the previous functionality. (But you can invert this easily, it have upgrade my class but it is still not public as I want to add more features before posting about it again!)

There is some tap functionality I need to implement, that will be in an future release: Ver.3....

Here it is, enjoy (for AIR or AS3):
(feel free to contribute to the class commenting here or in Starling Forum).



Class: TouchPad.as

package beekyr.controllers
{
    import flash.geom.Point;
    import starling.display.Quad;
    import starling.events.Touch;
    import starling.events.TouchEvent;
    import starling.events.TouchPhase;
    public class TouchPad extends Quad
    {
    /**
     * ...
     * @author Jaime Dominguez for Beekyr (2013)
     * http://www.jaimedominguez.com
     */
       
        private var _moveVector:Point = new Point();
        private var _tapVector:Point = new Point();
        private var _latestVector:TouchData = new TouchData();
        private var _sensitivity:Number;
        private var _touching:Boolean;
        private var _dualTouching:Boolean;
        private const TAP_SENSITIVITY:Number = 2;
        private var _tap:Boolean;
        private var _justTapped:Boolean;
       
       
        public function TouchPad(width:int, height:int, sensitivity:Number = 1) {
           
            super(width,height,0xff0000);
            _latestVector = new TouchData();
            _moveVector = new Point();
            _sensitivity = sensitivity;
            _touching = false;
            alpha = 0.05;
            addEventListener(TouchEvent.TOUCH , _handleTouch);
        }
       
        public function getLatestMovement():TouchData     {
            _latestVector._vX = _moveVector.x * _sensitivity;
            _latestVector._vY = _moveVector.y * _sensitivity;
            _latestVector.touching = _touching;
            _latestVector.dualTouching = _dualTouching;
            _latestVector.tap = _tap;
            resetValues();
            return _latestVector;
        }
       
        private function resetValues():void
        {
            _moveVector.x = 0 ;
            _moveVector.y = 0 ;
           
            _tap = false;
        }
       
        public function setWidth(w:Number):void {
            width = w;
        }
       
        public function setHeight(h:Number):void {
            height = h;
        }
       
        public function updateSensitivity(s:Number):void {
            _sensitivity = s;
        }
       
        private function _handleTouch(e:TouchEvent):void {
            e.stopImmediatePropagation()
            var touchArray:Vector. = e.getTouches(this);
            //var _wasDualTouch:Boolean = _dualTouching;
           
            _dualTouching = false;
            dispatchEventWith(TouchPhase.BEGAN);
            if (touchArray.length>0){
                var touch:Touch = touchArray[0];
                if (touchArray.length>1){
                    _dualTouching = true;
                   //If you want to move with the right thumb then edit the next line.
                    if (touchArray[0].getLocation(this).x > touchArray[1].getLocation(this).x) {
                        touch = touchArray[1];
                    }
                }
               
                switch (touch.phase){
                    case TouchPhase.BEGAN:
                        _justTapped = true;
                        storeThisPos(touch);
                    break;
                   
                    case TouchPhase.ENDED:
                        //checkForTap();
                        //stopMovement();
                        _tap = _justTapped;
                        _touching = false;
                    break;
                   
                    case TouchPhase.MOVED:
                        _justTapped = false;
                        getMovementVector(touch);
                    break;
                }
           
               
            }
           
        }
   
               
        private function getMovementVector(touch:Touch):void
        {
            _moveVector = touch.getMovement(this);
       
        }
       
        private function storeThisPos(touch:Touch):void
        {
            _touching = true;
            _tapVector = touch.getMovement(this);
        }
   
    }

}

Class:  TouchData.as 

package beekyr.controllers
{
    /**
     * ...
     * @author Jaime Dominguez
     */
    public class TouchData
    {
        public var _vX:Number;
        public var _vY:Number;

        public var touching:Boolean;
        public var dualTouching:Boolean;
        public var tap:Boolean;
           
        public function TouchData()
        {
           
        }
       
    }

}

Used in Beekyr for Android.

TouchPad class for AS3+Starling.

When I started developing games for Android I had to work pretty hard to invent a good controller, It has been created to meet the needs of my shooter game Beekyr. But Im sure it will work in other kinds of games.

I couldn't find anything that was good enough so I made one that works very well...

UPDATE, VER2: Allows two fingers and works better than this version. VIEW UPDATE HERE!

At the moment only allows one finger, if you want to extend this class feel free to do so!

package beekyr.controllers
{
    import flash.geom.Point;
    import starling.display.Quad;
    import starling.events.Touch;
    import starling.events.TouchEvent;
    import starling.events.TouchPhase;
    public class TouchPad extends Quad
    {
    /**
     * ...
     * @author Jaime Dominguez for Beekyr : 2013
     * http://www.jaimedominguez.com
     */
       
        private var _moveVector:Point = new Point();
        private var _latestVector:Object = new Object();
        private var _sensitivity:Number;
        private var _touching:Boolean;
       
        public function TouchPad(width:int, height:int, sensitivity:Number = 1) {
            super(width,height,0xff0000);

            _moveVector = new Point();
            _sensitivity = sensitivity;
            _touching = false;
            alpha = 0;
            addEventListener(TouchEvent.TOUCH , _handleTouch);
        }
       
        public function getLatestMovement():Object     {
            _latestVector._vX = _moveVector.x * _sensitivity;
            _latestVector._vY = _moveVector.y * _sensitivity;
            _latestVector.touching = _touching;
            _moveVector.x = 0 ;
            _moveVector.y = 0 ;
            return _latestVector;
   
        }
       
        public function setWidth(w:Number):void {
            width = w;
        }
       
        public function setHeight(h:Number):void {
            height = h;
        }
       
        public function updateSensitivity(s:Number):void {
            _sensitivity = s;
        }
       
        private function _handleTouch(e:TouchEvent):void {
            e.stopImmediatePropagation()
            var touchArray:Vector. = e.getTouches(this);
           
            if (touchArray.length>0){
           
                var touch:Touch = touchArray[0];

                    switch (touch.phase)
                    {
                        case TouchPhase.BEGAN:
                            storeThisPos(touch);
                        break;
                       
                        case TouchPhase.ENDED:
                            stopMovement();
                        break;
                       
                        case TouchPhase.MOVED:
                            getMovementVector(touch);
                        break;
                       
                    }
               
            };
           
        }
       
        private function stopMovement():void
        {
             _moveVector = new Point();
             _moveVector.x = 0;
             _moveVector.y = 0;
             _touching = false;
        }
       
        private function stopMovementVector():void {
            _moveVector = new Point(0, 0);
        }
               
        private function getMovementVector(touch:Touch):void
        {
            _moveVector = touch.getMovement(this);
        }
       
        private function storeThisPos(touch:Touch):void
        {
            _touching = true;
        }
   
    }

}

With this class initialized at start of the game. Then you need to collect the values in each loop of the game with:

_speed = _game._touchPad.getLatestMovement();

IT will return a vector of the lastest movement.

You can adjust the sensitivity too with:

public function updateSensitivity(s:Number):void {
            _sensitivity = s;
        }

 

PHP security.

I recently discovered a blog post that I had written back in 2008 but it is still relevant today So I have decided to release it now in 2013.

This was the original post:


I have been recently reading a book about security. And I thought it was good to share all this new knowledge with the rest of the world.

There may be lots of practices that I'll miss but this text intends to be tips to be considered while programming any PHP app. :


Filter all the data you manage:

Golden rule:
All data you receive on your PHP scripts is invalid until is filtered and validated.



Use SSL every time you send sensitive data. Such login details or credit card data.


Differentiate your variables between verified and unverified. Create an empty array where you can copy all clean variables. This way will be a good thing to do verify that you are using the correct valid variables:

$cleanVars = array();

//if a variable is validated successfully you copy the value into the new array:

switch ($_POST['colorEyes']){

case 'brown':
case 'blue':
case 'green':

$cleanVar['colorEyes'] = $_POST['colorEyes']

}

Once you have filtered all the data:

Use htmlentities() to escape HTML code and html_entity_decode() to decode it.

To send strings into SQL queries use: mysql_real_escape_string().

Ask for re-login some times for specially delicate movements such password reset or contact details among others.

To check if a string is alphanumeric use: ctype_alnum()

When receiving a file name link as string you don't want the hackers to be using relative or full paths, you want just file names and deal with the directories on the script. Erase all possibility of path edition on the variables using the function basename()



Include files:
Set the includes outside root directory.
They can be anywhere and make sure that only the server and only your internal user is able to access them no one else need them. Use .htacess for this matter.

Credentials such password and username for databases should be stored in a file named db.inc
Make sure that inc is treated like a php file and if u want to deny all access to INC files u can configure Apache htaccess to deny all requests to that file extension by normal users:

<Files ~ "\.inc(.php)?$">
Order allow,deny
Deny from all
Satisfy All
</Files>


Dangerous functions:

Try to avoid using the next functions:
eval , exec, shell exec, passthru, system, popen, preg_replace, proc_open, file_get_contents, readfile, file, ini_restore, symlink, fsockopen, escapeshellcmd

Then disable them on Apache with disable_functions. If some of the functions above has to be used then be very careful how you use them...


Apache security:

Have a look at the php.ini and have a look at these apache directives:

allow_url_fopen
disable_functions
display_errors
enable_dl
error_reporting
file_uploads
log_errors
magic_quotes_gpc
memory_limit
open_basedir
register_globals
safe_mode (not used anymore?)

They are all gathered in this php.net page, (you have to scroll down, it is not very well structured)...