Removing a body with box2D

Question

I need to remove a certain vector from my world bounds, for example only the left one. (box2d+cocos2d iphone)

This is how I set the bounds:

screenBorderShape.Set(lowerLeftCorner, lowerRightCorner);
screenBorderBody->CreateFixture(&screenBorderShape, 0);
screenBorderShape.Set(lowerRightCorner, upperRightCorner);
screenBorderBody->CreateFixture(&screenBorderShape, 0);
screenBorderShape.Set(upperRightCorner, upperLeftCorner);
screenBorderBody->CreateFixture(&screenBorderShape, 0);
screenBorderShape.Set(upperLeftCorner, lowerLeftCorner);
screenBorderBody->CreateFixture(&screenBorderShape, 0);

How can I remove the left one ONLY?

I know this :

screenBorderBody->DestroyFixture(b2Fixture *fixture)

But I need to do that later on, so can I reach that fixture (having the body pointer) without saving this specific one as a global?

Thanks.

Answer 1

screenBorderShape.Set(lowerRightCorner, upperRightCorner); screenBorderBody->CreateFixture(&screenBorderShape, 0);

Name this fixture as left fixture or left wall....

After this you can use screenBorderBody->DestroyFixture(<#b2Fixture *fixture#>)

...

The way is

groundBox.Set(b2Vec2(X1/PTM_RATIO,Y1/PTM_RATIO), b2Vec2(X2/PTM_RATIO, Y1/PTM_RATIO)); bottomFixture = groundBody->CreateFixture(&groundBoxDef);

and then remove bottom fixture (left in your case)

In caseyou just want to cancel the collisions do it by setting category or mask bits that way