(svn r10343) -Cleanup: Add documentation of functions and code-style fix.

Thanks of 45 degree patch for bringing it up

src/viewport.cpp

@@ -649,6 +649,10 @@ static const int _AutorailType[6][2] = {
 
 #include "table/autorail.h"
 
+/**
+ * Checks if the specified tile is selected and if so draws selection using correct selectionstyle.
+ * @param *ti TileInfo Tile that is being drawn
+ */
 static void DrawTileSelection(const TileInfo *ti)
 {
 	SpriteID image;
@@ -1930,7 +1934,14 @@ static byte GetAutorailHT(int x, int y)
 	return HT_RAIL | _AutorailPiece[x & 0xF][y & 0xF];
 }
 
-/** called regular to update tile highlighting in all cases */
+/**
+ * Updates tile highlighting for all cases.
+ * Uses _thd.selstart and _thd.selend and _thd.place_mode (set elsewhere) to determine _thd.pos and _thd.size
+ * Also drawstyle is determined. Uses _thd.new.* as a buffer and calls SetSelectionTilesDirty() twice,
+ * Once for the old and once for the new selection.
+ * _thd is TileHighlightData, found in viewport.h
+ * Called by MouseLoop() in windows.cpp
+ */
 void UpdateTileSelection()
 {
 	int x1;