How to cancel collision on pre solve

Comments

• ar2rsawseen Maintainer

  October 2012

  @bysreg
  what do you mean by canceling collision?
  1) do not call collision callback
  2) do not allow for objects to collide and let them pass through each other?

  http://appcodingeasy.com/Gideros-Mobile

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• bysreg Member

  October 2012

  what i mean is like in box2d,
  
  void PreSolve(b2Contact* contact, const b2Manifold* oldManifold)
  
  {
  
  b2WorldManifold worldManifold;
  
  contact->GetWorldManifold(&worldManifold);
  
  if (worldManifold.normal.y < -0.5f)
  
  {
  
  contact->SetEnabled(false);
  
  }
  
  }
  
  the "contact->SetEnabled(false)" will cancel the collision between that two fixture. so, originally, the two fixtures will collide but i want in some cases they dont collide

  Likes: Yan

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• ar2rsawseen Maintainer

  October 2012 edited October 2012 Accepted Answer

  Well contact object is not implemented in Gideros, but I think you could save reference to fixture and then simply set

  fixture:setSensor(true)

  to allow object to pass through and then change it back to false

  http://appcodingeasy.com/Gideros-Mobile

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• petec Member

  October 2012

  I've managed to turn collisions off and on (in this case an open lid of a box that I wanted a ball to pass by at launch but bounce off later in the game once the lid was closed) using:

  lidBody:setActive(false) lidBody:setActive(true)

  No idea if that's legitimate as box2d is mostly suck it and see for me, but it worked for what I wanted to do.

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• bysreg Member

  November 2012

  @ar2rawseen & petec
  yes, that solve the problem. what i do is set it to sensor when pre-solve, and set it to non-sensor in post-solve

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• willyda Member

  February 2013 edited February 2013

  local function onPreSolve(event)
  local contact = event.contact
  contact:setEnabled(false)
  end

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