Re: [simspark-devel] [Sserver-three-d] Offside Bug Report

[Hesham <hes...@gm...>]

Hi Joschka and Junqing Wang,

Sorry for the long delay. I couldn't answer earlier, that's a long story.
Anyway,  Junqing Wang, thank you so much for your report. I'm afraid, I
didn't understand some parts of the report. Actually,
    if (mGameState->GetTime() != time)
    {
             return false;
    }
isn't necessary. That was there to be sure when a new collision doesn't
occur it doesn't go through the offside code. To get rid of it, there is a
simple solution, please take a look at the attached file.

So far as I noticed for the next version there is no offside. In December I
was working on refactoring the offside code (I promised Joschka to finish it
before January but I couldn't). Since it was my first code for the server I
mad a big mistake in its design and that caused a lot of problems in
debugging. Anyway, I got rid of my problems and have more free time. Since
working on the offside doesn't make sense, I wonder if there is something
that I can work on for the new server. (I'm following the discussion
regarding multi-thread)

With kind regards,
Hesham

On 12/21/06, w jq <wj...@ho...> wrote:
>
>                               Offside Bug Report
>
> As all we known that the offside rule in simulator was not perfect. Today
> I
> don`t want to
>
> complain about it, but to solve the problem.
>
> I have watched many many matches . Some team took the advantage of this
> bug:Shooting the
>
> goal when they were offside.
>
> how could they do this ?how could some team can`t do this?
>
> The truth is that this team`s players don`t HIT the ball when they are
> attacking.they just
>
> kick the ball.
>
> so I thought there must be something wrong with "Last kick agent".
>
>
> Thus, I refered to the  function
> void
> Ball::PrePhysicsUpdateInternal(float deltaTime) in ball.cpp
>
> The agent who kicked the ball is recorded , everything seems to be OK.
>
> Then ,I refered to the  function
> bool
> SoccerRuleAspect::CheckOffside()
>
> Add some print code.
> /*****************************************/
>     if (mGameState->GetTime() != time)
>     {
>         GetLog()->Error()
>             << "ERROR: (SoccerRuleAspect) "<<mGameState->GetTime()<< " "
> <<
> time <<endl;
>         return false;
>     }
> /******************************************/
> Then ,when my player was dribbling. I thought the statement
> (mGameState->GetTime() != time)
> shall be FALSE sometimes,but things turned out to be not the same as  I
> thought.
>
> ....
> ERROR: (SoccerRuleAspect) 13.017 13.007
> ERROR: (SoccerRuleAspect) 13.027 13.017
> ERROR: (SoccerRuleAspect) 13.037 13.027
> ....
> After I refered to the function
> void SimulationServer::Step() in Simulationserver.cpp
> , I found the bug.
> /*****************************************/
>                     mSceneServer->Update(mSimStep);
>                     mGameControlServer->Update(mSimStep);
> /*****************************************/
> After Update the Physics(UpdateLastCollidingAgent),
> the sim time will add one sim step.
>
> As a result , if there is a agent kick the ball, the record time will
> aways
> be 0.01
> earlier than current time.
>
>
>
> One of the possible solutions:
>
> Add a bool member "mRecordTimeForKick"to class BallStateAspect
>
> Modify:
> void
> BallStateAspect::UpdateLastCollidingAgent(boost::shared_ptr<AgentAspect>
> agent)
> {
>     mLastCollidingAgent = agent;
>     mLastAgentCollisionTime = mGameState->GetTime();
> }
> ->
> void
> BallStateAspect::UpdateLastCollidingAgent(boost::shared_ptr<AgentAspect>
> agent)
> {
>     mLastCollidingAgent = agent;
>     mRecordTimeForKick = true;
> }
>
> Add "mRecordTimeForKick = false;" to
> BallStateAspect::BallStateAspect() : SoccerControlAspect()
>
> Add "
>     if(mRecordTimeForKick)
>     {
>         mLastAgentCollisionTime = mGameState->GetTime();
>         mRecordTimeForKick      = false;
>      }
>     " to the end of the function --
> void BallStateAspect::UpdateLastCollidingAgent()
>
>
>
>
> /****************************End of
> report*****************************************/
>
> Author:Junqing Wang
> Team:  Apollo3D ,  Nanjing University of Posts & Telecommunications, China
>
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