Qt: Fix crash in sprite view for partially out-of-bounds sprites (fixes #2165)

CHANGES

@@ -14,6 +14,7 @@ Other fixes:
  - GBA: Fix out of bounds ROM accesses on patched ROMs smaller than 32 MiB
  - Qt: Fix infrequent deadlock when using sync to video
  - Qt: Fix applying savetype-only overrides
+ - Qt: Fix crash in sprite view for partially out-of-bounds sprites (fixes mgba.io/i/2165)
  - Util: Fix loading UPS patches that affect the last byte of the file
 Misc:
  - Core: Suspend runloop when a core crashes

src/platform/qt/ObjView.cpp

@@ -131,16 +131,20 @@ void ObjView::updateTilesGBA(bool force) {
 	m_objInfo = newInfo;
 	m_tileOffset = newInfo.tile;
 	mTileCache* tileCache = mTileCacheSetGetPointer(&m_cacheSet->tiles, newInfo.paletteSet);
-
+	unsigned maxTiles = mTileCacheSystemInfoGetMaxTiles(tileCache->sysConfig);
 	int i = 0;
 	for (unsigned y = 0; y < newInfo.height; ++y) {
 		for (unsigned x = 0; x < newInfo.width; ++x, ++i, ++tile, ++tileBase) {
+			if (tile < maxTiles) {
 				const color_t* data = mTileCacheGetTileIfDirty(tileCache, &m_tileStatus[16 * tileBase], tile, newInfo.paletteId);
 				if (data) {
 					m_ui.tiles->setTile(i, data);
 				} else if (force) {
 					m_ui.tiles->setTile(i, mTileCacheGetTile(tileCache, tile, newInfo.paletteId));
 				}
+			} else {
+				m_ui.tiles->clearTile(i);
+			}
 		}
 		tile += newInfo.stride - newInfo.width;
 		tileBase += newInfo.stride - newInfo.width;

src/platform/qt/TilePainter.cpp

@@ -44,6 +44,16 @@ void TilePainter::mousePressEvent(QMouseEvent* event) {
 	emit indexPressed(y * (width() / m_size) + x);
 }
 
+void TilePainter::clearTile(int index) {
+	QPainter painter(&m_backing);
+	int w = width() / m_size;
+	int x = index % w;
+	int y = index / w;
+	QRect r(x * m_size, y * m_size, m_size, m_size);
+	painter.eraseRect(r);
+	update(r);
+}
+
 void TilePainter::setTile(int index, const color_t* data) {
 	QPainter painter(&m_backing);
 	int w = width() / m_size;

src/platform/qt/TilePainter.h

@@ -22,6 +22,7 @@ public:
 	QPixmap backing() const { return m_backing; }
 
 public slots:
+	void clearTile(int index);
 	void setTile(int index, const color_t*);
 	void setTileCount(int tiles);
 	void setTileMagnification(int mag);