forked from Whales/Cataclysm2
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geometry.cpp
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geometry.cpp
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#include <vector>
#include <stdlib.h>
#include "geometry.h"
#define SGN(a) (((a)<0) ? -1 : 1)
std::vector <point> line_to(int x0, int y0, int x1, int y1)
{
int t = 0;
std::vector<point> ret;
int dx = x1 - x0;
int dy = y1 - y0;
int ax = abs(dx)<<1;
int ay = abs(dy)<<1;
int sx = SGN(dx);
int sy = SGN(dy);
if (dy == 0) sy = 0;
if (dx == 0) sx = 0;
point cur;
cur.x = x0;
cur.y = y0;
int xmin = (x0 < x1 ? x0 : x1), ymin = (y0 < y1 ? y0 : y1),
xmax = (x0 > x1 ? x0 : x1), ymax = (y0 > y1 ? y0 : y1);
xmin -= abs(dx);
ymin -= abs(dy);
xmax += abs(dx);
ymax += abs(dy);
if (ax == ay) {
do {
cur.y += sy;
cur.x += sx;
ret.push_back(cur);
} while ((cur.x != x1 || cur.y != y1) &&
(cur.x >= xmin && cur.x <= xmax && cur.y >= ymin && cur.y <= ymax));
} else if (ax > ay) {
do {
if (t > 0) {
cur.y += sy;
t -= ax;
}
cur.x += sx;
t += ay;
ret.push_back(cur);
} while ((cur.x != x1 || cur.y != y1) &&
(cur.x >= xmin && cur.x <= xmax && cur.y >= ymin && cur.y <= ymax));
} else {
do {
if (t > 0) {
cur.x += sx;
t -= ay;
}
cur.y += sy;
t += ax;
ret.push_back(cur);
} while ((cur.x != x1 || cur.y != y1) &&
(cur.x >= xmin && cur.x <= xmax && cur.y >= ymin && cur.y <= ymax));
}
return ret;
}
int rl_dist(int x0, int y0, int x1, int y1)
{
int dx = (x0 > x1 ? x0 - x1 : x1 - x0), dy = (y0 > y1 ? y0 - y1 : y1 - y0);
return (dx > dy ? dx : dy);
}