Use std::shared_ptr for editor resources, fix crashes with brush

Simplify memory management of groups, layers, images, sounds and envelopes by using `std::shared_ptr` for all of them.

Clear brush when creating a new map to prevent crash due to unloaded textures being used in tile layer. Closes ddnet#6935.

Also fix crash when restoring a saved brush after removing an image that is being used by it.

src/game/editor/layer_game.cpp

@@ -30,7 +30,7 @@ void CLayerGame::SetTile(int x, int y, CTile Tile)
 	{
 		if(!m_pEditor->m_Map.m_pFrontLayer)
 		{
-			CLayer *pLayerFront = new CLayerFront(m_Width, m_Height);
+			std::shared_ptr<CLayer> pLayerFront = std::make_shared<CLayerFront>(m_Width, m_Height);
 			m_pEditor->m_Map.MakeFrontLayer(pLayerFront);
 			m_pEditor->m_Map.m_pGameGroup->AddLayer(pLayerFront);
 		}

src/game/editor/layer_quads.cpp

@@ -107,10 +107,10 @@ void CLayerQuads::BrushSelecting(CUIRect Rect)
 	Graphics()->LinesEnd();
 }
 
-int CLayerQuads::BrushGrab(CLayerGroup *pBrush, CUIRect Rect)
+int CLayerQuads::BrushGrab(std::shared_ptr<CLayerGroup> pBrush, CUIRect Rect)
 {
 	// create new layers
-	CLayerQuads *pGrabbed = new CLayerQuads();
+	std::shared_ptr<CLayerQuads> pGrabbed = std::make_shared<CLayerQuads>();
 	pGrabbed->m_pEditor = m_pEditor;
 	pGrabbed->m_Image = m_Image;
 	pBrush->AddLayer(pGrabbed);
@@ -138,9 +138,9 @@ int CLayerQuads::BrushGrab(CLayerGroup *pBrush, CUIRect Rect)
 	return pGrabbed->m_vQuads.empty() ? 0 : 1;
 }
 
-void CLayerQuads::BrushPlace(CLayer *pBrush, float wx, float wy)
+void CLayerQuads::BrushPlace(std::shared_ptr<CLayer> pBrush, float wx, float wy)
 {
-	CLayerQuads *pQuadLayer = (CLayerQuads *)pBrush;
+	std::shared_ptr<CLayerQuads> pQuadLayer = std::static_pointer_cast<CLayerQuads>(pBrush);
 	for(const auto &Quad : pQuadLayer->m_vQuads)
 	{
 		CQuad n = Quad;
@@ -264,9 +264,9 @@ void CLayerQuads::ModifyEnvelopeIndex(FIndexModifyFunction Func)
 	}
 }
 
-CLayer *CLayerQuads::Duplicate() const
+std::shared_ptr<CLayer> CLayerQuads::Duplicate() const
 {
-	return new CLayerQuads(*this);
+	return std::make_shared<CLayerQuads>(*this);
 }
 
 int CLayerQuads::SwapQuads(int Index0, int Index1)

src/game/editor/layer_sounds.cpp

@@ -140,10 +140,10 @@ void CLayerSounds::BrushSelecting(CUIRect Rect)
 	Graphics()->LinesEnd();
 }
 
-int CLayerSounds::BrushGrab(CLayerGroup *pBrush, CUIRect Rect)
+int CLayerSounds::BrushGrab(std::shared_ptr<CLayerGroup> pBrush, CUIRect Rect)
 {
 	// create new layer
-	CLayerSounds *pGrabbed = new CLayerSounds();
+	std::shared_ptr<CLayerSounds> pGrabbed = std::make_shared<CLayerSounds>();
 	pGrabbed->m_pEditor = m_pEditor;
 	pGrabbed->m_Sound = m_Sound;
 	pBrush->AddLayer(pGrabbed);
@@ -167,9 +167,9 @@ int CLayerSounds::BrushGrab(CLayerGroup *pBrush, CUIRect Rect)
 	return pGrabbed->m_vSources.empty() ? 0 : 1;
 }
 
-void CLayerSounds::BrushPlace(CLayer *pBrush, float wx, float wy)
+void CLayerSounds::BrushPlace(std::shared_ptr<CLayer> pBrush, float wx, float wy)
 {
-	CLayerSounds *pSoundLayer = (CLayerSounds *)pBrush;
+	std::shared_ptr<CLayerSounds> pSoundLayer = std::static_pointer_cast<CLayerSounds>(pBrush);
 	for(const auto &Source : pSoundLayer->m_vSources)
 	{
 		CSoundSource n = Source;
@@ -228,7 +228,7 @@ void CLayerSounds::ModifyEnvelopeIndex(FIndexModifyFunction Func)
 	}
 }
 
-CLayer *CLayerSounds::Duplicate() const
+std::shared_ptr<CLayer> CLayerSounds::Duplicate() const
 {
-	return new CLayerSounds(*this);
+	return std::make_shared<CLayerSounds>(*this);
 }