[Feature] Make it so music doesn't pre assign on new scenes

[davidrenne]

Everyone removes imaginopolis song and others on each scene. This was a mistake in the design I believe. Maybe someone can fix that.

[willbr]

There's a struct called BDS for Background Default Sound

3DMMForever/inc/bkgd.h

Lines 84 to 91 in 79b3010

	struct BDS
	{
	short bo;
	short osk;
	long vlm;
	bool fLoop;
	TAG tagSnd;
	};

Maybe we can edit the background file BKGDS.3cn?

If I edit the BDS quad ID=11 and set the bds.tagSnd.sid field to -1, it's removed from the black background scene.

Or we could patch it out here?

3DMMForever/src/engine/scene.cpp

Lines 3403 to 3424 in 79b3010

	// Add the default sound for the new background, if any
	_pbkgd->GetDefaultSound(&tag, &vlm, &fLoop);
	if (tag.sid != ksidInvalid) // new background sound
	{
	// Note: since FSetBkgdCore is only called at edit time,
	// it's okay to call FCacheTag. The background default
	// sound is not an intrinsic part of the BKGD...it's more
	// of a "serving suggestion" that the user can remove
	// once the background is added.
	Assert(!_pmvie->FPlaying(), "Shouldn't cache tags if movie is playing!");
	if (vptagm->FCacheTagToHD(&tag))
	{
	pmsnd = (PMSND)vptagm->PbacoFetch(&tag, MSND::FReadMsnd);
	if (pvNil != pmsnd)
	{
	sty = pmsnd->Sty();
	ReleasePpo(&pmsnd);
	// non-destructive if we fail
	FAddSndCore(fLoop, fFalse, vlm, sty, 1, &tag);
	}
	}
	}