Allow NoteField sharing. The semantics of this is simple. In game play, everything but note data is handled by the shared NoteField. Only the NoteData for the field is drawn but it is drawn using the shared NoteField.

stepmania/src/NoteField.cpp

@@ -23,6 +23,7 @@
 NoteField::NoteField()
 {	
 	m_pNoteData = NULL;
+	m_pSharedNoteField = NULL;
 	m_pCurDisplay = NULL;
 
 	m_textMeasureNumber.LoadFromFont( THEME->GetPathF("Common","normal") );
@@ -52,6 +53,7 @@ void NoteField::Unload()
 		delete it->second;
 	m_NoteDisplays.clear();
 	m_pCurDisplay = NULL;
+	m_pSharedNoteField = NULL;
 	memset( m_pDisplays, 0, sizeof(m_pDisplays) );
 }
 
@@ -214,6 +216,8 @@ float NoteField::GetWidth() const
 
 void NoteField::DrawBeatBar( const float fBeat )
 {
+	if( m_pSharedNoteField )
+		return;
 	bool bIsMeasure = fmodf( fBeat, (float)BEATS_PER_MEASURE ) == 0;
 	int iMeasureIndex = (int)fBeat / BEATS_PER_MEASURE;
 	int iMeasureNoDisplay = iMeasureIndex+1;
@@ -269,6 +273,8 @@ void NoteField::DrawBeatBar( const float fBeat )
 
 void NoteField::DrawMarkerBar( int iBeat )
 {
+	if( m_pSharedNoteField )
+		return;
 	float fBeat = NoteRowToBeat( iBeat );
 	const float fYOffset	= ArrowEffects::GetYOffset( m_pPlayerState, 0, fBeat );
 	const float fYPos	= ArrowEffects::GetYPos(    m_pPlayerState, 0, fYOffset, m_fYReverseOffsetPixels );
@@ -452,9 +458,11 @@ void NoteField::DrawPrimitives()
 	ArrowEffects::Update();
 
 	NoteDisplayCols *cur = m_pCurDisplay;
-	cur->m_ReceptorArrowRow.Draw();
+	if( !m_pSharedNoteField )
+		cur->m_ReceptorArrowRow.Draw(); // This will be handled by the shared NoteField
+	const NoteField &nf = m_pSharedNoteField ? *m_pSharedNoteField : *this;
 
-	const PlayerOptions &current_po = m_pPlayerState->m_CurrentPlayerOptions;
+	const PlayerOptions &current_po = nf.m_pPlayerState->m_CurrentPlayerOptions;
 
 	//
 	// Adjust draw range depending on some effects
@@ -712,7 +720,7 @@ void NoteField::DrawPrimitives()
 				if( m_iBeginMarker!=-1 && m_iEndMarker!=-1 )
 					bIsInSelectionRange = (m_iBeginMarker <= iStartRow && iEndRow < m_iEndMarker);
 				
-				NoteDisplayCols *displayCols = tn.pn == PLAYER_INVALID ? m_pCurDisplay : m_pDisplays[tn.pn];
+				NoteDisplayCols *displayCols = tn.pn == PLAYER_INVALID ? nf.m_pCurDisplay : nf.m_pDisplays[tn.pn];
 				displayCols->display[c].DrawHold( tn, c, iStartRow, bIsHoldingNote, bIsActive, Result, bIsInSelectionRange ? fSelectedRangeGlow : m_fPercentFadeToFail, false, m_fYReverseOffsetPixels, (float) iFirstPixelToDraw, (float) iLastPixelToDraw );
 			}
 
@@ -773,7 +781,7 @@ void NoteField::DrawPrimitives()
 			bool bIsAddition = (tn.source == TapNote::addition);
 			bool bIsMine = (tn.type == TapNote::mine);
 			bool bIsAttack = (tn.type == TapNote::attack);
-			NoteDisplayCols *displayCols = tn.pn == PLAYER_INVALID ? m_pCurDisplay : m_pDisplays[tn.pn];
+			NoteDisplayCols *displayCols = tn.pn == PLAYER_INVALID ? nf.m_pCurDisplay : nf.m_pDisplays[tn.pn];
 			
 			if( bIsAttack )
 			{
@@ -789,7 +797,8 @@ void NoteField::DrawPrimitives()
 		}
 	}
 
-	cur->m_GhostArrowRow.Draw();
+	if( !m_pSharedNoteField )
+		cur->m_GhostArrowRow.Draw();
 }
 
 void NoteField::FadeToFail()
@@ -797,12 +806,12 @@ void NoteField::FadeToFail()
 	m_fPercentFadeToFail = max( 0.0f, m_fPercentFadeToFail );	// this will slowly increase every Update()
 		// don't fade all over again if this is called twice
 }
-
-void NoteField::Step( int iCol, TapNoteScore score ) { m_pCurDisplay->m_ReceptorArrowRow.Step( iCol, score ); }
-void NoteField::SetPressed( int iCol ) { m_pCurDisplay->m_ReceptorArrowRow.SetPressed( iCol ); }
-void NoteField::DidTapNote( int iCol, TapNoteScore score, bool bBright ) { m_pCurDisplay->m_GhostArrowRow.DidTapNote( iCol, score, bBright ); }
-void NoteField::DidHoldNote( int iCol, HoldNoteScore score, bool bBright ) { m_pCurDisplay->m_GhostArrowRow.DidHoldNote( iCol, score, bBright ); }
-
+#define nf (m_pSharedNoteField ? *m_pSharedNoteField : *this)
+void NoteField::Step( int iCol, TapNoteScore score ) { nf.m_pCurDisplay->m_ReceptorArrowRow.Step( iCol, score ); }
+void NoteField::SetPressed( int iCol ) { nf.m_pCurDisplay->m_ReceptorArrowRow.SetPressed( iCol ); }
+void NoteField::DidTapNote( int iCol, TapNoteScore score, bool bBright ) { nf.m_pCurDisplay->m_GhostArrowRow.DidTapNote( iCol, score, bBright ); }
+void NoteField::DidHoldNote( int iCol, HoldNoteScore score, bool bBright ) { nf.m_pCurDisplay->m_GhostArrowRow.DidHoldNote( iCol, score, bBright ); }
+#undef nf
 /*
  * (c) 2001-2004 Chris Danford
  * All rights reserved.

stepmania/src/NoteField.h

@@ -39,6 +39,7 @@ public:
 	void DidHoldNote( int iCol, HoldNoteScore score, bool bBright );
 
 	const PlayerState *GetPlayerState() const { return m_pPlayerState; }
+	void SetSharedNoteField( NoteField *nf ) { m_pSharedNoteField = nf; }
 
 	int				m_iBeginMarker, m_iEndMarker;	// only used with MODE_EDIT
 
@@ -58,6 +59,7 @@ protected:
 	float GetWidth() const;
 
 	const NoteData *m_pNoteData;
+	const NoteField *m_pSharedNoteField;
 
 	float				m_fPercentFadeToFail;	// -1 if not fading to fail