cocos2d for iPhone

A fast, easy to use, free, and community supported 2D game engine

1. 

   ashmira
   Member

   i had the problem with the body. i want to set the body isSensor true and false at runtime. how to do it?
   This is my code:

   - (void) addSensor{
   	CGSize winSize = [CCDirector sharedDirector].winSize;
       float32 sensorWidth = winSize.width * 0.03;
       float32 sensorHeight = winSize.height;
       float32 sensorOffset = winSize.width * 0.15;
   
       b2BodyDef bodyDef;
       bodyDef.type = b2_staticBody;
       bodyDef.position.Set(
                            400/PTM_RATIO + sensorOffset/PTM_RATIO
                            + sensorWidth/2/PTM_RATIO,
                            sensorHeight/2/PTM_RATIO);
       screenSensorBody = world->CreateBody(&bodyDef);
   
       b2PolygonShape shape;
       shape.SetAsBox(sensorWidth/2/PTM_RATIO, sensorHeight/2/PTM_RATIO);
   
       b2FixtureDef fixtureDef;
       fixtureDef.shape = &shape;
       fixtureDef.isSensor = true;
       fixtureDef.density = 0.0;
   
       screenSensorBody->CreateFixture(&fixtureDef);
   }
   - (void) setSensorBody:(BOOL)Sensor{
   	if (Sensor) {
   		// Set Sensor TRUE;
   	}else{
                // Set Sensor FALSE;
           }
   }

   Posted 5 months ago #
2. 

   pimms
   Member

   You can't, you have to delete the old fixture and recreate it with the new property.

   - (void) addSensor:(BOOL)isSensor {
       if (screenSensorBody)
           world->DestroyBody(screenSensorBody);
   
   	CGSize winSize = [CCDirector sharedDirector].winSize;
       float32 sensorWidth = winSize.width * 0.03;
       float32 sensorHeight = winSize.height;
       float32 sensorOffset = winSize.width * 0.15;
   
       b2BodyDef bodyDef;
       bodyDef.type = b2_staticBody;
       bodyDef.position.Set(
                            400/PTM_RATIO + sensorOffset/PTM_RATIO
                            + sensorWidth/2/PTM_RATIO,
                            sensorHeight/2/PTM_RATIO);
       screenSensorBody = world->CreateBody(&bodyDef);
   
       b2PolygonShape shape;
       shape.SetAsBox(sensorWidth/2/PTM_RATIO, sensorHeight/2/PTM_RATIO);
   
       b2FixtureDef fixtureDef;
       fixtureDef.shape = &shape;
       fixtureDef.isSensor = isSensor;
       fixtureDef.density = 0.0;
   
       screenSensorBody->CreateFixture(&fixtureDef);
   }
   - (void) setSensorBody:(BOOL)Sensor{
   	[self setSensor:Sensor];
   }

   Posted 5 months ago #
3. 

   ashmira
   Member

   oh.i didn't know about this. Thanks for the info.

   Posted 5 months ago #
4. 

   aeroplane
   Member

   You can change the sensor at runtime. @pimms you don't necessarily have to delete the body.

   You can do:
   

   for (b2Fixture* f = screenSensorBody->GetFixtureList(); f; f = f->GetNext()){
            f->SetSensor(false);
            }

   Posted 5 months ago #
5. 

   pimms
   Member

   Oh! I'm sorry for stating false information, thanks for claring this up! :-)

   Posted 5 months ago #
6. 

   ashmira
   Member

   Thanks aeroplane :).

   Posted 5 months ago #

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