T3D 1.0.1 Barebones Dedicated Server Problems and Solutions

I finally started converting my TGEA game over to T3D and decided to start by splitting out the FPS example project into 3 projects: Client, Server and Common. This post is a quick reference for process, issues I ran into and solutions for those issues.

To get started I removed any client / gui related directories from the FPS example project:

• tools
• shaders
• core\fonts
• core\unifiedshell
• core\scripts\client\
• core\scripts\gui
• core\art\gui
• scripts\gui
• scripts\client

One of the first issues was a problem with SFXDescriptions. The SFXDescription datablocks on the server all inherit from SFXDescriptions declared on the client. To resolve this I simply moved the SFXDescription's from the client to the top of core\art\datablocks\audioDescription.cs

//-----------------------------------------------------------------------------
//    Channel assignments (channel 0 is unused in-game).
//-----------------------------------------------------------------------------

$GuiAudioType        = 1;  // Interface.
$SimAudioType        = 2;  // Game.
$MessageAudioType    = 3;  // Notifications.
$MusicAudioType      = 4;  // Music.

//-----------------------------------------------------------------------------
//    Master SFXDescriptions.
//-----------------------------------------------------------------------------

// Master description for interface audio.
new SFXDescription( AudioGui )
{
   volume         = 1.0;
   channel        = $GuiAudioType;
};

// Master description for game effects audio.
new SFXDescription(AudioSim)
{
   volume         = 1.0;
   channel        = $SimAudioType;
};

// Master description for audio in notifications.
new SFXDescription( AudioMessage )
{
   volume         = 1.0;
   channel        = $MessageAudioType;
};

// Master description for music.
new SFXDescription( AudioMusic )
{
   volume         = 1.0;
   channel        = $MusicAudioType;
};

With that resolved I deleted all exec statements and related function calls that tried to exec files in any client/ or gui/ directory. This was a simple process with Torsion: CTRL-SHIFT-F to "Find in Files" and then searching for client/ and gui/ respectively. Going through the list in the search results and removing all of the calls was quick and easy -- most were in main.cs.

With all of the client scripts out of the way it seemed like the dedicated server should just work but there were two additional issues I ran into that required slight modification to the engine.

First, when starting the dedicated server it would immediately crash on: exec("core/art/datablocks/datablockExec.cs");

Specifically in that file when trying to:
// LightFlareData and LightAnimData(s)
exec("./lights.cs");

I tracked this down to the declaration of LightFlareData datablocks that had a flareTexture specified (starting with datablock LightFlareData( SunFlareExample )).

After some debugging it appeared that a call to (engine\data\T3D\lightFlareData.cpp):
void GFXPrimitiveBufferHandle::set(GFXDevice *theDevice, U32 indexCount, U32 primitiveCount, GFXBufferType bufferType, String desc)

in LightFlareData::_preload was the culprit. The easy solution was simply to move all of the code in this method into the if ( !server ) block resulting in the method looking like:

bool LightFlareData::_preload( bool server, String &errorStr )
{
	if ( !server )
	{
		mElementCount = 0;
		for ( U32 i = 0; i < MAX_ELEMENTS; i++ )
		{
			if ( mElementDist[i] == -1 )
				break;
			mElementCount = i + 1;
		}   

		if ( mElementCount > 0 )
			_makePrimBuffer( &mFlarePrimBuffer, mElementCount );

		if ( mFlareTextureName.isNotEmpty() )      
			mFlareTexture.set( mFlareTextureName, &GFXDefaultStaticDiffuseProfile, "FlareTexture" );  
	}

	return true;
}

Once this was resolved there was still another engine-related issue that was crashing the dedicated server. This time in Engine\sceneGraph\reflector.cpp

The very last line of the constructor was causing the problem:

ReflectorBase::ReflectorBase()
{
   mEnabled = false;
   mOccluded = false;
   mIsRendering = false;
   mDesc = NULL;
   mObject = NULL;
   mOcclusionQuery = GFX->createOcclusionQuery(); //server doesn't like this
}

To get around this I reserved creating the occlusion query until calcScore was called rather than doing it in the constructor. Since this is only ever called on the client the server won't run into this call. This resulted in the constructor and two methods being changed.

The constructor became:

ReflectorBase::ReflectorBase()
{
   mEnabled = false;
   mOccluded = false;
   mIsRendering = false;
   mDesc = NULL;
   mObject = NULL;
   mOcclusionQuery = NULL;
}

The destructor became:

ReflectorBase::~ReflectorBase()
{
	if(mOcclusionQuery != NULL)
		delete mOcclusionQuery;
}

And I added the following two lines right to the start of
F32 ReflectorBase::calcScore( const ReflectParams &params )

if(mOcclusionQuery == NULL)
		mOcclusionQuery = GFX->createOcclusionQuery();

With these changes in place the same executable/dll works without a problem on both the client and server. The dedicated server runs without crashing as does the client which appears to be handling the flares without issue.

If anyone finds this useful, great. If anyone has any suggestions or comments regarding the engine modifications (including areas that I may have missed that should be addressed for a dedicated server) even better.