mirror of https://github.com/OpenTTD/OpenTTD.git
(svn r21499) -Add: diagonal tile iterator. Based on patch by fonsinchen
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@ -104,3 +104,64 @@ void TileArea::ClampToMap()
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this->h = min(this->h, MapSizeY() - TileY(this->tile));
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}
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DiagonalTileIterator::DiagonalTileIterator(TileIndex corner1, TileIndex corner2) : TileIterator(corner2), base_x(TileX(corner2)), base_y(TileY(corner2)), a_cur(0), b_cur(0)
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{
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assert(corner1 < MapSize());
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assert(corner2 < MapSize());
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int dist_x = TileX(corner1) - TileX(corner2);
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int dist_y = TileY(corner1) - TileY(corner2);
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this->a_max = dist_x + dist_y;
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this->b_max = dist_y - dist_x;
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/* Unfortunately we can't find a new base and make all a and b positive because
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* the new base might be a "flattened" corner where there actually is no single
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* tile. If we try anyway the result is either inaccurate ("one off" half of the
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* time) or the code gets much more complex;
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*
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* We also need to increment here to have equality as marker for the end of a row or
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* column. Like that it's shorter than having another if/else in operator++
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*/
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if (this->a_max > 0) {
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this->a_max++;
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} else {
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this->a_max--;
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}
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if (this->b_max > 0) {
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this->b_max++;
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} else {
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this->b_max--;
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}
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}
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TileIterator &DiagonalTileIterator::operator++()
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{
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assert(this->tile != INVALID_TILE);
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do {
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/* Iterate using the rotated coordinates. */
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if (this->a_max > 0) {
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++this->a_cur;
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} else {
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--this->a_cur;
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}
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if (this->a_cur == this->a_max) {
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this->a_cur = 0;
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if (this->b_max > 0) {
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++this->b_cur;
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} else {
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--this->b_cur;
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}
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}
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/* And convert the coordinates back once we've gone to the next tile. */
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uint x = this->base_x + (this->a_cur - this->b_cur) / 2;
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uint y = this->base_y + (this->b_cur + this->a_cur) / 2;
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/* Prevent wrapping around the map's borders. */
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this->tile = x >= MapSizeX() || y >= MapSizeY() ? INVALID_TILE : TileXY(x, y);
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} while (this->tile > MapSize() && this->b_max != this->b_cur);
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if (this->b_max == this->b_cur) this->tile = INVALID_TILE;
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return *this;
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}
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@ -73,11 +73,12 @@ protected:
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{
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}
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public:
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/** Some compilers really like this. */
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virtual ~TileIterator()
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{
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}
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public:
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/**
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* Get the tile we are currently at.
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* @return The tile we are at, or INVALID_TILE when we're done.
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@ -128,6 +129,27 @@ public:
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}
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};
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/** Iterator to iterate over a diagonal area of the map. */
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class DiagonalTileIterator : public TileIterator {
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private:
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uint base_x, base_y; ///< The base tile x and y coordinates from where the iterating happens.
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int a_cur, b_cur; ///< The current (rotated) x and y coordinates of the iteration.
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int a_max, b_max; ///< The (rotated) x and y coordinates of the end of the iteration.
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public:
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/**
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* Construct the iterator.
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* @param begin Tile from where to begin iterating.
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* @param end Tile where to end the iterating.
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*/
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DiagonalTileIterator(TileIndex begin, TileIndex end);
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/**
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* Move ourselves to the next tile in the rectange on the map.
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*/
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TileIterator& operator ++();
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};
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/**
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* A loop which iterates over the tiles of a TileArea.
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* @param var The name of the variable which contains the current tile.
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