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-rw-r--r--src/texteff.cpp23
1 files changed, 19 insertions, 4 deletions
diff --git a/src/texteff.cpp b/src/texteff.cpp
index c376e42b4..f42a650e4 100644
--- a/src/texteff.cpp
+++ b/src/texteff.cpp
@@ -435,8 +435,11 @@ void DeleteAnimatedTile(TileIndex tile)
{
for (TileIndex *ti = _animated_tile_list; ti < _animated_tile_list + _animated_tile_count; ti++) {
if (tile == *ti) {
- /* Remove the hole */
- *ti = _animated_tile_list[_animated_tile_count - 1];
+ /* Remove the hole
+ * The order of the remaining elements must stay the same, otherwise the animation loop
+ * may miss a tile; that's why we must use memmove instead of just moving the last element.
+ */
+ memmove(ti, ti + 1, (_animated_tile_list + _animated_tile_count - (ti + 1)) * sizeof(*ti));
_animated_tile_count--;
MarkTileDirtyByTile(tile);
return;
@@ -472,8 +475,20 @@ void AddAnimatedTile(TileIndex tile)
*/
void AnimateAnimatedTiles()
{
- for (const TileIndex *ti = _animated_tile_list; ti < _animated_tile_list + _animated_tile_count; ti++) {
- AnimateTile(*ti);
+ const TileIndex *ti = _animated_tile_list;
+ while (ti < _animated_tile_list + _animated_tile_count) {
+ const TileIndex curr = *ti;
+ AnimateTile(curr);
+ /* During the AnimateTile call, DeleteAnimatedTile could have been called,
+ * deleting an element we've already processed and pushing the rest one
+ * slot to the left. We can detect this by checking whether the index
+ * in the current slot has changed - if it has, an element has been deleted,
+ * and we should process the current slot again instead of going forward.
+ * NOTE: this will still break if more than one animated tile is being
+ * deleted during the same AnimateTile call, but no code seems to
+ * be doing this anyway.
+ */
+ if (*ti == curr) ++ti;
}
}