/* $Id$ */ /* * This file is part of OpenTTD. * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2. * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>. */ /** @file tilearea.cpp Handling of tile areas. */ #include "stdafx.h" #include "tilearea_type.h" /** * Construct this tile area based on two points. * @param start the start of the area * @param end the end of the area */ TileArea::TileArea(TileIndex start, TileIndex end) { uint sx = TileX(start); uint sy = TileY(start); uint ex = TileX(end); uint ey = TileY(end); if (sx > ex) Swap(sx, ex); if (sy > ey) Swap(sy, ey); this->tile = TileXY(sx, sy); this->w = ex - sx + 1; this->h = ey - sy + 1; } /** * Add a single tile to a tile area; enlarge if needed. * @param to_add The tile to add */ void TileArea::Add(TileIndex to_add) { if (this->tile == INVALID_TILE) { this->tile = to_add; this->w = 1; this->h = 1; return; } uint sx = TileX(this->tile); uint sy = TileY(this->tile); uint ex = sx + this->w - 1; uint ey = sy + this->h - 1; uint ax = TileX(to_add); uint ay = TileY(to_add); sx = min(ax, sx); sy = min(ay, sy); ex = max(ax, ex); ey = max(ay, ey); this->tile = TileXY(sx, sy); this->w = ex - sx + 1; this->h = ey - sy + 1; } /** * Does this tile area intersect with another? * @param ta the other tile area to check against. * @return true if they intersect. */ bool TileArea::Intersects(const TileArea &ta) const { if (ta.w == 0 || this->w == 0) return false; assert(ta.w != 0 && ta.h != 0 && this->w != 0 && this->h != 0); uint left1 = TileX(this->tile); uint top1 = TileY(this->tile); uint right1 = left1 + this->w - 1; uint bottom1 = top1 + this->h - 1; uint left2 = TileX(ta.tile); uint top2 = TileY(ta.tile); uint right2 = left2 + ta.w - 1; uint bottom2 = top2 + ta.h - 1; return !( left2 > right1 || right2 < left1 || top2 > bottom1 || bottom2 < top1 ); } /** * Clamp the tile area to map borders. */ void TileArea::ClampToMap() { assert(this->tile < MapSize()); this->w = min(this->w, MapSizeX() - TileX(this->tile)); this->h = min(this->h, MapSizeY() - TileY(this->tile)); } /** * Construct the iterator. * @param corner1 Tile from where to begin iterating. * @param corner2 Tile where to end the iterating. */ DiagonalTileIterator::DiagonalTileIterator(TileIndex corner1, TileIndex corner2) : TileIterator(corner2), base_x(TileX(corner2)), base_y(TileY(corner2)), a_cur(0), b_cur(0) { assert(corner1 < MapSize()); assert(corner2 < MapSize()); int dist_x = TileX(corner1) - TileX(corner2); int dist_y = TileY(corner1) - TileY(corner2); this->a_max = dist_x + dist_y; this->b_max = dist_y - dist_x; /* Unfortunately we can't find a new base and make all a and b positive because * the new base might be a "flattened" corner where there actually is no single * tile. If we try anyway the result is either inaccurate ("one off" half of the * time) or the code gets much more complex; * * We also need to increment here to have equality as marker for the end of a row or * column. Like that it's shorter than having another if/else in operator++ */ if (this->a_max > 0) { this->a_max++; } else { this->a_max--; } if (this->b_max > 0) { this->b_max++; } else { this->b_max--; } } /** * Move ourselves to the next tile in the rectange on the map. */ TileIterator &DiagonalTileIterator::operator++() { assert(this->tile != INVALID_TILE); /* Determine the next tile, while clipping at map borders */ bool new_line = false; do { /* Iterate using the rotated coordinates. */ if (this->a_max == 1 || this->a_max == -1) { /* Special case: Every second column has zero length, skip them completely */ this->a_cur = 0; if (this->b_max > 0) { this->b_cur = min(this->b_cur + 2, this->b_max); } else { this->b_cur = max(this->b_cur - 2, this->b_max); } } else { /* Every column has at least one tile to process */ if (this->a_max > 0) { this->a_cur += 2; new_line = this->a_cur >= this->a_max; } else { this->a_cur -= 2; new_line = this->a_cur <= this->a_max; } 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 { --this->b_cur; } } } /* And convert the coordinates back once we've gone to the next tile. */ uint x = this->base_x + (this->a_cur - this->b_cur) / 2; uint y = this->base_y + (this->b_cur + this->a_cur) / 2; /* Prevent wrapping around the map's borders. */ this->tile = x >= MapSizeX() || y >= MapSizeY() ? INVALID_TILE : TileXY(x, y); } while (this->tile > MapSize() && this->b_max != this->b_cur); if (this->b_max == this->b_cur) this->tile = INVALID_TILE; return *this; }