RandomBGEndsAtLastBeat metric.

Docs/Changelog_sm5.txt

@@ -11,6 +11,7 @@ ________________________________________________________________________________
   RandomBGStartBeat sets the beat of the music the first random bg occurs on.
   RandomBGChangeMeasures sets the number of measures between changes.
   RandomBGChangesWhenBPMChangesAtMeasureStart toggles the behavior in its name.
+  RandomBGEndsAtLastBeat toggles the behavior in its name.
 
 ================================================================================
 StepMania 5.0.9 | 20150520

Themes/_fallback/metrics.ini

@@ -242,6 +242,7 @@ BottomEdge=SCREEN_BOTTOM
 RandomBGStartBeat=-1000
 RandomBGChangeMeasures=4
 RandomBGChangesWhenBPMChangesAtMeasureStart=true
+RandomBGEndsAtLastBeat=false
 
 [Banner]
 # Scroll stuff when you roll over it, DDR Extreme style.

src/Background.cpp

@@ -34,6 +34,7 @@ static ThemeMetric<bool> USE_STATIC_BG		("Background","UseStaticBackground");
 static ThemeMetric<float> RAND_BG_START_BEAT("Background", "RandomBGStartBeat");
 static ThemeMetric<float> RAND_BG_CHANGE_MEASURES("Background", "RandomBGChangeMeasures");
 static ThemeMetric<bool> RAND_BG_CHANGES_WHEN_BPM_CHANGES("Background", "RandomBGChangesWhenBPMChangesAtMeasureStart");
+static ThemeMetric<bool> RAND_BG_ENDS_AT_LAST_BEAT("Background", "RandomBGEndsAtLastBeat");
 
 
 static Preference<bool>	g_bShowDanger( "ShowDanger", true );
@@ -613,12 +614,15 @@ void BackgroundImpl::LoadFromSong( const Song* pSong )
 
 		LoadFromRandom( firstBeat, lastBeat, BackgroundChange() );
 
+		if(RAND_BG_ENDS_AT_LAST_BEAT)
+		{
 			// end showing the static song background
 			BackgroundChange change;
 			change.m_def = m_StaticBackgroundDef;
 			change.m_fStartBeat = lastBeat;
 			layer.m_aBGChanges.push_back( change );
 		}
+	}
 
 	// sort segments
 	FOREACH_BackgroundLayer( i )