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/* $Id$ */
/*
* 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 begin Tile from where to begin iterating.
* @param end 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;
}
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