Need help with Joystick implementation

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Need help with Joystick implementation

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Started 2 years ago by RedshirtRich
Latest reply from sfj

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RedshirtRich
Member

Hello All!

Being an uber-noob with cocos2d and Obj-C in general, I'm having a problem getting a joystick control to work for me.

After throwing some of my own franken-code around for a while, I did find slipter216's joystick code from Splat laying around and tried to implement that.

( http://www.mailinglistarchive.com/cocos2d-iphone-discuss@googlegroups.com/msg01054.html )

I'm sure I'm just being an idiot, but the overall framework of WHERE to implement all of this is driving me a little nuts. I've been trying to just add my player sprite and joystick object to the game Scene in a similar manner to what was shown in the TouchesTest Pong-type example found in the Cocos2d 0.8 folder.

WHERE to put the actual Touch event handling is confusing me. The Joystick class (along with slipsters Vector class) handles the base logic of the touch handling, but translating and passing those calculations to the player sprite has been my hangup.

Should this be added to EACH game Scene (which seems wasteful), or passed somehow into the player class?

Thanks in advance!

Posted 2 years ago #
RedshirtRich
Member

Okay, I don't know if I've have an epiphany or a brain-fart, but here's what's making sense to me at the moment:

The Player (actor, ship, whatever) and Joystick are added to the Game Layer

The game layer receives and forwards the actual touches via the joystick area to the Joystick class.

the Joystick class (using Vector class) translates the touch movements into calculation variables and then passes those to the Player class.

The Player class then turns those variables into actual actions and movements, which the actor/ship instantiation on the Game Layer will reflect.

...

I'll try this angle for now, and wait for greater minds than mine to correct me ;)

Posted 2 years ago #
slipster216
Moderator

Yep, that's basically how to do it. I need to post the new version of that class which doesn't rely on that vector class, as the functions used in that class are now in Cocos classes. Hmm, perhaps I should add it to the extra section in the svn repository?

Anyway, here's how I do things in splat. In my game layer, I forward the touch events to my joysticks (there are two in splat):

-(BOOL)ccTouchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
[mStickLeft touchesBegan:touches withEvent:event];
[mStickRight touchesBegan:touches withEvent:event];
return kEventHandled;
}

-(BOOL)ccTouchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
[mStickLeft touchesMoved:touches withEvent:event];
[mStickRight touchesMoved:touches withEvent:event];
return kEventHandled;
}

-(BOOL)ccTouchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
[mStickLeft touchesEnded:touches withEvent:event];
[mStickRight touchesEnded:touches withEvent:event];
return kEventHandled;
}

Note that you don't need to filter them based on the joystick areas, the joysticks will do that themselves.

Then, in my update function (called every frame), I update the player's velocity from the joystick like so:

CGPoint velocity = [mStickLeft getCurrentVelocity];
mPlayer->mVelocityX = velocity.x * 5;
mPlayer->mVelocityY = velocity.y * 5;
[mPlayer updatePosition:delta];

I prefer to store 'velocity' on the object rather than moving it directly, as I derive everything from a common GameObject class which has a shared function for updating positions based on velocity (and a bunch of other stuff).

Posted 2 years ago #
RedshirtRich
Member

I've added the ccTouches methods to the game Layer (AFTER, not IN the init), and added some NSLog lines to register back to the console that the touches have in fact been registered, but I get nothing.

How do you init your mStick? I've tried throwing it into the game Layer init, following the addChild style, but that just freaks the simulator out and crashes it.

So, I may not even be getting the joystick even initialized. And I don't seem to be getting any touches registered.

Posted 2 years ago #
slipster216
Moderator

Are you sure your initializing your layer correctly and calling the super's init function? Did you set isTouchEnabled to YES?

Posted 2 years ago #
RedshirtRich
Member

Yeah, I had forgotten the isTouchEnabled for a while, but I got it put in a little while ago. Big 'Duh' on my part.

The layer is initailizing... my player kart is showing up, and I DO have touches at least registering now, but I'm still unclear on the actual Joystick object.

I've added it into the Layer's init with:

mStick = [[[Joystick alloc] init:0 y:0 w:480 h:320] retain];

but if I try to implement with:

[self addChild:mStick];

I get "warning: passing argument 1 of 'addChild:' from distinct Objective-C type" as a warning from xcode, and the simulator crashes when the scene tries to load.
This gives me
"*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[Joystick tag]: unrecognized selector sent to instance 0xe21a20'"
in the Debugger Console

Posted 2 years ago #
RedshirtRich
Member

ARGGHHH! && OMG!

The whole stupid problem was in the deprecated device orientation code between Cocos2d 0.7 (or older) and 0.8!

The Joystick called if ([[Director sharedDirector] landscape]) to set the location of the x,y,h,w of the joysticks 'hit area'

This was deprecated, which I figured out to fix by replacing with
if([[Director sharedDirector] deviceOrientation] == CCDeviceOrientationLandscapeLeft || [[Director sharedDirector] deviceOrientation] == CCDeviceOrientationLandscapeRight)

So no more deprecated code. No problem. Right? WRONG

I was trying to do my Game in LandscapeRight, which was still messing it up.

In the 0.8 Director, there are DIFFERENT methods for convertCoordinate , which was giving me BAD touch locations, because it was still trying to convert for LandscapeLeft.

Once I realized THAT, I just switched my initial deviceOrientation, and BINGO.

I'm going to go write SEPARATE methods for the Joystick now, taking ALL deviceOrientations into account.

Hope this can at least help someone else having similar issues!

I'll keep you POSTED

Posted 2 years ago #
slipster216
Moderator

You also don't need to add the joystick to the scene - you just forward it touches.

Also, my new version of this class just converts the coordinates in the joystick class, like so:

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
if (mActive)
return;
NSArray *allTouches = [touches allObjects];
for (UITouch* t in allTouches)
{
CGPoint location = [[Director sharedDirector] convertCoordinate:[t locationInView:[t view]]];
if (CGRectContainsPoint(mBounds, location))
{
mActive = YES;
touchAddress = (int)t;
if (!mStaticCenter)
mCenter = CGPointMake(location.x, location.y);
mCurPosition = CGPointMake(location.x, location.y);
break;
}
}
}

Posted 2 years ago #
RedshirtRich
Member

just curious...

Where is your touchAddress getting used?

I'm getting your older Joystick to do all I need it to, so THANKS!

Please let us know when you do post your newer code to the SVN... I'd love to look at it.

Thanks AGAIN!

Posted 2 years ago #
RedshirtRich
Member

Weird!

I've been trying your CGPoint conversion, and looking at what work and what doesn't in ALL orientations.

I've actually got the thing working in ALL orientations just by eliminating the conversion in the init. I had the conversions in both the init AND the touchEvents, which was going wacky.

Posted 2 years ago #
slipster216
Moderator

I had to go back to the code and see why I was storing off the touch address; it looks like I'm using it to prevent other touches from becoming the new joystick touch in a multi-touch environment. So basically, if you have multiple joysticks in the scene (like I do in Splat), then you need to make sure it always uses the same touch each time, otherwise another finger crossing the bounds could possibly cause the joystick to go the wrong way.

In regards to adding this to the repository, I'm not sure where I should put it. I actually have a lot of useful code I'm willing to share that's not directly cocos-related, such as this joystick class. Perhaps we should have an 'extras' section in the repository? Also, my primary hang up with submitting this stuff is having to write demo's for it all; I barely have enough time to finish the apps I'm working on, let alone write demo's.

Another class which would be quite useful to other cocos developers is my proximity manager. It's based off the one Grant Skinner wrote for AS3 (http://gskinner.com/blog/archives/2008/01/proximitymanage.html), but it has some extra goodness like support for spanning more than neighboring cells, and doing a fine grain pass as well (for exact, non-grid based distance checks).

Oh, I also have an interesting late-stage optimization class which takes a list of game objects and draws them as a single particle system. I use it for bullets, which might as well be particles in the rendering sense, but needed more state than a simple particle system would allow.

Posted 2 years ago #
RedshirtRich
Member

Okay, I've got some new issues (surprise, surprise).

The joystick I have implemented uses the constructor (and a lot of other goodies) from Slipsters code, which basically returns a square space to act as the joystick targeting area.

Slippy's Joystick works very much like an Analog thumbstick, returning a higher velocity the farther out you go from the stick's center.

The problem then is that as I am calling the difference between the joystick position (mCurrentPosition) and the center of the joystick base, or point of origin (mCenter) as my player velocity, I am getting much more speed as I go out 45 degrees from my point-of-origin than I would if I drag my stick out up/down or left/right, because I am out further from the center of the joystick. (on that square)

So, is there a way to limit my touch area, or even just the stick's movement, to a ROUND touch object? That way I can only go out as far as the RADIUS of the circle from the center, and thereby have a consistent top speed, regardless of the direction it's going.

Posted 2 years ago #
slipster216
Moderator

just clamp the value to the maximum of the smaller distance and you'll have the equivalent of a circular area.

Posted 2 years ago #
RedshirtRich
Member

?

Posted 2 years ago #

adunsmoor
Member

Here's some code I'm using for my *very* simple joystick implementation. The joystick has a single public property - the velocity - which has x and y values that are intended to go from -1.0 to 1.0.

The joystick is implemented as a Layer. I have a circular area in the bottom left that accepts touches. It is centered at CENTER,CENTER on the screen. The radius of touchable area constrains the velocity.

#define CENTER (64.0+5.0)
#define JOYSTICK_RADIUS 64.0

- (void)updateVelocity:(CGPoint)point {
	// calculate distance and angle from the center
	float dx = point.x - CENTER;
	float dy = point.y - CENTER;

	float distance = sqrt(dx * dx + dy * dy);
	float angle = atan2(dy, dx); // in radians

	// Velocity goes from -1.0 to 1.0.
	// BE CAREFUL: don't just cap each direction at 1.0 since that
	// doesn't preserve the proportions.
	if (distance > JOYSTICK_RADIUS) {
		dx = cos(angle)*JOYSTICK_RADIUS;
		dy = sin(angle)*JOYSTICK_RADIUS;
	}

	velocity = CGPointMake(dx/JOYSTICK_RADIUS, dy/JOYSTICK_RADIUS);
}

Posted 2 years ago #

adunsmoor
Member

Turns out there is a slightly simpler way to do this (there always is).

Google "similar triangles" for the a more detailed explanation. Basically the idea is that the triangle created from the center to your touch is proportional to a triangle that expresses your velocity.

#define CENTER (64.0+5.0)
#define JOYSTICK_RADIUS 64.0

- (void)updateVelocity:(CGPoint)point {

    // Calculate the distance from the center.
    // Change the scale of dx and dy so that 1.0 is the edge of the circle.
    float dx = (point.x - CENTER) / JOYSTICK_RADIUS;
    float dy = (point.y - CENTER) / JOYSTICK_RADIUS;

    // If the point was outside of the circle then pick the largest distance
    // and change it to 1.0.  The smaller distance should be scaled down
    // proportionally.
    if (dx > 1.0 || dy > 1.0) {
        if (dx > dy) {
            dy = dy / dx;
            dx = 1.0;
        } else {
            dx = dx / dy;
            dy = 1.0;
        }
    }

    velocity = CGPointMake(dx, dy);
}

Posted 2 years ago #

natanavra
Member
You could check for collisions between the two circles.
Basically if you have a circle inside a circle then you could do this simple calc:
```
//Assuming you have 2 objects, one for joystick and one for joystick base.

float x1 = joystick.position.x;
float x2 = joystickBase.position.x;
float y1 = joystick.position.y;
float y2 = joystickBase.position.y;

float xdif = x1 - x2;
float ydif = y1 - y2;

float distance = sqrt( xdif * xdif + ydif * ydif);
float radDist = joystick.radius - joystickBase.radius;

if(distance >= radDist) {
     NSLog(@"Joystick is out of bounds");
     //Do stuff...
}
```
I guess you could use that to limit your joystick to just a circle instead of a rect.

BTW: I think slipster meant you should create a constant that is the maximum speed for the shortest length (up, down) and whenever the joystick distance from the center is bigger then the shortest length, you just equalize it to the constant... something like:
```
#define maxSpeed (yourNum)
#define maxDist (calculate the distance (up, down))
........
float distance = sqrt(pow(joystick.position.x - joystickBase.poisiton.x, 2) + pow(joystick.position.y - joystickBase.position.y, 2));
if(distance > maxDist)
    [player setSpeed:maxSpeed];
```
I suppose, sorry if something here isn't correct - it's dirty unchecked code, coming straight from my mind.

EDIT: Didn't see the posts above me, I posted as soon as the my connection came back online - as I was planning to post a few hours ago... sorry...
Posted 2 years ago #
adunsmoor
Member

That "simpler" method I posted earlier was a little too simple. It doesn't keep the position within a fixed radius from the center. I can't seem to edit that post to fix it so, for now, just ignore that 2nd method and look at the first (the one with the angle and sqrt, etc. ) That's also very similar to what natanavra suggested too.

Hope this helps.

Posted 2 years ago #
slipster216
Moderator

Hmm, my version of this class allows you to get the joystick data expressed as either an X,Y value, or as an angle and velocity value. The version posted might be older though.. I'm going to add the code to an extra's folder in svn tonight, hopefully riq won't mind..

Posted 2 years ago #
vieko
Member

Hey slipster216 - just wondering if you manage to post the updated class to the SVN... I'm trying something similar to what was suggested by adunsmoor but would love to give your class a try as well

Posted 2 years ago #
slipster216
Moderator

no, I was waiting for Riq to chime in on where we should put that kind of stuff.. I can email you the latest version if you need it sooner..

Posted 2 years ago #
natanavra
Member

I'd like to take a peek at the code, please e-mail me to: natanavra@gmail.com
Thanks in advance.

Posted 2 years ago #
vieko
Member

That would be great if you don't mind - please send it to: vieko@me.com - thank you!

Posted 2 years ago #
bradparks
Member

I as well would love to see it!

bradparks@bradparks.com

Thanks...

Brad

Posted 2 years ago #
slipster216
Moderator

sent..

Posted 2 years ago #
vieko
Member

Thank you slipster - much appreciated. I will play with it tomorrow and let you know how it works!

Posted 2 years ago #
Sama7
Member

I would greatly appreciate a copy to work with as well

vestrit at gmail dOt com

Posted 2 years ago #
RedshirtRich
Member

Sign me up as well ,I suppose.

redshirtrich AT gmail DOT com

Thanks for all the help!

Posted 2 years ago #
iphoneDev
Member

I as well would love to see it!

satman88@gmail.com

Thanks...

Posted 2 years ago #
Dakiu
Member

can you add me ? too
I am very interested in the joystick

dakiu8@hotmail.com

Posted 2 years ago #

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