diff options
| -rw-r--r-- | src/tilearea.cpp | 15 |
1 files changed, 11 insertions, 4 deletions
diff --git a/src/tilearea.cpp b/src/tilearea.cpp index 74f701315..c518fe8f1 100644 --- a/src/tilearea.cpp +++ b/src/tilearea.cpp @@ -139,15 +139,22 @@ TileIterator &DiagonalTileIterator::operator++() { assert(this->tile != INVALID_TILE); + bool new_line = false; do { /* Iterate using the rotated coordinates. */ if (this->a_max > 0) { - ++this->a_cur; + this->a_cur += 2; + new_line = this->a_cur >= this->a_max; } else { - --this->a_cur; + this->a_cur -= 2; + new_line = this->a_cur <= this->a_max; } - if (this->a_cur == this->a_max) { - this->a_cur = 0; + if (new_line) { + /* offset of initial a_cur: one tile in the same direction as a_max + * every second line. + */ + this->a_cur = abs(this->a_cur) % 2 ? 0 : (this->a_max > 0 ? 1 : -1); + if (this->b_max > 0) { ++this->b_cur; } else { |