Revert "DrawFloor: Remove a redundant check"

This reverts commit a75f77b.

Revert the commit while we investigate the issue

Source/engine/render/scrollrt.cpp

@@ -576,12 +576,6 @@ void DrawCell(const Surface &out, Point tilePosition, Point targetBufferPosition
  */
 void DrawFloorTile(const Surface &out, Point tilePosition, Point targetBufferPosition)
 {
-	const uint16_t levelPieceId = dPiece[tilePosition.x][tilePosition.y];
-
-	// Floor tiles always come in pairs. If the left triangle (mt[0]) exists, so does the right one.
-	assert(DPieceMicros[levelPieceId].mt[0].hasValue() == DPieceMicros[levelPieceId].mt[1].hasValue());
-	if (!DPieceMicros[levelPieceId].mt[0].hasValue()) return;
-
 	const int lightTableIndex = dLight[tilePosition.x][tilePosition.y];
 
 	const uint8_t *tbl = LightTables[lightTableIndex].data();
@@ -590,10 +584,21 @@ void DrawFloorTile(const Surface &out, Point tilePosition, Point targetBufferPos
 		tbl = GetPauseTRN();
 #endif
 
-	RenderTileFrame(out, targetBufferPosition, TileType::LeftTriangle,
-	    GetDunFrame(DPieceMicros[levelPieceId].mt[0].frame()), DunFrameTriangleHeight, MaskType::Solid, tbl);
-	RenderTileFrame(out, targetBufferPosition + RightFrameDisplacement, TileType::RightTriangle,
-	    GetDunFrame(DPieceMicros[levelPieceId].mt[1].frame()), DunFrameTriangleHeight, MaskType::Solid, tbl);
+	const uint16_t levelPieceId = dPiece[tilePosition.x][tilePosition.y];
+	{
+		const LevelCelBlock levelCelBlock { DPieceMicros[levelPieceId].mt[0] };
+		if (levelCelBlock.hasValue()) {
+			RenderTileFrame(out, targetBufferPosition, TileType::LeftTriangle,
+			    GetDunFrame(levelCelBlock.frame()), DunFrameTriangleHeight, MaskType::Solid, tbl);
+		}
+	}
+	{
+		const LevelCelBlock levelCelBlock { DPieceMicros[levelPieceId].mt[1] };
+		if (levelCelBlock.hasValue()) {
+			RenderTileFrame(out, targetBufferPosition + RightFrameDisplacement, TileType::RightTriangle,
+			    GetDunFrame(levelCelBlock.frame()), DunFrameTriangleHeight, MaskType::Solid, tbl);
+		}
+	}
 }
 
 /**
@@ -840,8 +845,9 @@ void DrawFloor(const Surface &out, Point tilePosition, Point targetBufferPositio
 				world_draw_black_tile(out, targetBufferPosition.x, targetBufferPosition.y);
 				continue;
 			}
-			if (!IsFloor(tilePosition)) continue;
-			DrawFloorTile(out, tilePosition, targetBufferPosition);
+			if (IsFloor(tilePosition)) {
+				DrawFloorTile(out, tilePosition, targetBufferPosition);
+			}
 		}
 		// Return to start of row
 		tilePosition += Displacement(Direction::West) * columns;