Game crashes when i try to utilize the features of a b2Body in my NSObject class, why

NorthCode · 05-15-2011, 09:16 AM

My app crashes when i try to use the features of b2Body from within my NSObject class.

Here is the interface of my class:

Code:

#import <Foundation/Foundation.h>

#import "Box2D.h"
#import "GLES-Render.h"
#import "cocos2d.h"
#import "HelloWorldScene.h"


@interface Magnet : NSObject {


b2Body* body;

}
@property (readwrite,assign) b2Body* body;
@end

And here is how i declare it in HelloWorldScene.h:

Code:

#import "cocos2d.h"
#import "Box2D.h"
#import "GLES-Render.h"
#import <UIKit/UIKit.h>
#import "Magnet.h"

@class Magnet;

@interface HelloWorld : CCLayer
{
b2World* world;
GLESDebugDraw *m_debugDraw;



 Magnet *magnet;

}

And here is how i access the b2Body in magnet, in HelloWorldScene.mm:

Code:

b2BodyDef bodyDef2;
bodyDef2.type = b2_staticBody;

bodyDef2.position.Set(300/PTM_RATIO, 150/PTM_RATIO);
bodyDef2.userData = sprite2;
magnet.body = world->CreateBody(&bodyDef2);

// Define another box shape for our dynamic body.
//b2PolygonShape dynamicBox;
b2CircleShape dynamicBox2;

//dynamicBox.SetAsBox(1.0f, 1.0f);//These are mid points for our 1m box
dynamicBox2.m_radius = 0.49;
// Define the dynamic body fixture.
b2FixtureDef fixtureDef2;

fixtureDef2.shape = &dynamicBox2;   


fixtureDef2.density = 1.3f;
fixtureDef2.friction = 1.0f;


magnet.body->CreateFixture(&fixtureDef2);

Is there any problem with my code?

Im receiving a SIGABRT in the Box2D sourcefiles in the CreateFixture() function... What should I do?

NorthCode · 05-15-2011, 04:57 PM

I have been struggling with this for a while, it works when i use a regular b2Body (outside the class), but the second it becomes a property of "Magnet" it doesnt work. I cant see whats different between the two, do I have to init it within the class or something? Please help.

NorthCode · 05-16-2011, 06:32 PM

Has anyone done this? (creating class with b2Body), Box2D being C++ gets really confusing when using Objective-C classes..

anorak · 06-01-2011, 02:41 PM

Have you tried creating the body separately, then setting "magnet.body = <body created separately>"?