ref: a4ce29dba46f9d9b36a5fac40317432dfb19c815
dir: /ai.c/
#include <u.h>
#include <libc.h>
#include <draw.h>
#include "dat.h"
#include "fns.h"
Path *path;
int pathwidth, pathheight;
typedef struct Queue Queue;
struct Queue{
Path *pp;
Queue *q;
Queue *p;
};
static Queue q1 = {.q = &q1, .p = &q1}, *popen = &q1;
int
isblocked(Point *p, Mobj *mo)
{
int x, y;
Path *pp, *e;
if(mo->o->f & Fair)
return 0;
pp = path + p->y * pathwidth + p->x;
x = mo->o->w * (Tlwidth / Tlsubwidth);
y = mo->o->h * (Tlheight / Tlsubheight);
while(y-- > 0){
for(e=pp+x; pp<e; pp++)
if(pp->blk != nil && pp->blk != mo)
return 1;
pp += pathwidth - x;
}
return 0;
}
void
setblk(Mobj *mo, int clr)
{
int x, y;
Path *pp, *e;
Lobj *lo;
pp = path + mo->y * pathwidth + mo->x;
x = mo->o->w * (Tlwidth / Tlsubwidth);
y = mo->o->h * (Tlheight / Tlsubheight);
lo = mo->blk;
if(mo->x + x > pathwidth)
x = pathwidth - mo->x;
if(mo->y + y > pathheight)
y = pathheight - mo->y;
while(y-- > 0){
for(e=pp+x; pp<e; pp++)
if(clr){
if(pp->blk == mo)
pp->blk = nil;
lunlink(lo++);
}else{
if((mo->o->f & Fair) == 0)
pp->blk = mo;
llink(lo++, &pp->lo);
}
pp += pathwidth - x;
}
}
static Path *
poppath(Queue *r)
{
Path *p;
Queue *q;
q = r->q;
if(q == r)
return nil;
p = q->pp;
r->q = q->q;
free(q);
return p;
}
static void
pushpath(Queue *r, Path *pp)
{
Queue *q, *qp, *p;
for(qp=r, q=qp->q; q!=r && pp->g+pp->h > q->pp->g+q->pp->h; qp=q, q=q->q)
;
p = emalloc(sizeof *p);
p->pp = pp;
p->q = q;
qp->q = p;
}
static void
clearpath(void)
{
Queue *p, *q;
Path *pp;
/* FIXME: separate table(s)? */
for(pp=path; pp<path+pathwidth*pathheight; pp++){
pp->g = 0x7fffffff;
pp->h = 0x7fffffff;
pp->from = nil;
pp->closed = 0;
pp->open = 0;
}
for(p=popen->q; p!=popen; p=q){
q = p->q;
free(p);
}
popen->p = popen->q = popen;
}
static void
setpath(Path *e, Mobj *mo)
{
int n;
Point *p, *pe, x, p0, p1;
/* FIXME: probably better to just replace it with a static buffer;
* except for static buildings and air units, units are going to move
* and use pathfinding almost always */
pe = emalloc(Npath * sizeof *pe);
mo->path = pe;
p = pe + Npath - 1;
n = 0;
/* FIXME: drawing: spawn needs to center unit on path node, and
* drawing needs to offset sprite from path center */
for(; e!=nil; e=e->from){
x.x = ((e - path) % pathwidth) * Tlsubwidth + (Tlsubwidth >> 1);
x.y = ((e - path) / pathwidth) * Tlsubheight + (Tlsubheight >> 1);
if(n == 0){
x.x -= Tlsubwidth >> 1;
x.y -= Tlsubheight >> 1;
*p-- = x;
p0 = x;
n++;
}else if(n == 1){
p1 = x;
n++;
}else{
if(atan2(x.y - p0.y, x.x - p0.x)
!= atan2(p1.y - p0.y, p1.x - p0.x)){
if(p < pe){
memmove(pe+1, pe, (Npath - 1) * sizeof *pe);
*pe = p1;
}else
*p-- = p1;
p0 = p1;
n = 2;
}
p1 = x;
}
}
mo->pathp = p + 1;
mo->pathe = pe + Npath;
}
static double
dist(Path *p, Path *q)
{
int dx, dy;
dx = abs(p->x - q->x);
dy = abs(p->y - q->y);
return dx + dy;
//return 1 * (dx + dy) + (1 - 2 * 1) * (dx < dy ? dx : dy);
//return sqrt(dx * dx + dy * dy);
}
/* FIXME: air: ignore pathfinding? */
static Path **
trywalk(Path *pp, Mobj *mo)
{
int x, y;
Point p, *d, diff[] = {
{1,0}, {0,-1}, {-1,0}, {0,1},
{1,1}, {-1,1}, {-1,-1}, {1,-1},
};
Path **lp;
static Path *l[nelem(diff) + 1];
x = (pp - path) % pathwidth;
y = (pp - path) / pathwidth;
for(d=diff, lp=l; d<diff+nelem(diff); d++){
p.x = x + d->x;
p.y = y + d->y;
if(p.x < 0 || p.x > pathwidth
|| p.y < 0 || p.y > pathheight)
continue;
if(!isblocked(&p, mo))
*lp++ = path + p.y * pathwidth + p.x;
}
*lp = nil;
return l;
}
static int
a∗(Mobj *mo, Point *p2)
{
double g;
Path *s, *pp, *e, *q, **l;
clearpath();
s = path + pathwidth * mo->y + mo->x;
e = path + pathwidth * (p2->y / Tlsubheight) + p2->x / Tlsubwidth;
/* FIXME: don't return an error, just an empty path, or the same
* block as the source */
if(s == e){
werrstr("no.");
return -1;
}
s->g = 0;
s->h = dist(s, e);
pushpath(popen, s);
while((pp = poppath(popen)) != nil){
if(pp == e)
break;
pp->closed = 1;
pp->open = 0;
l = trywalk(pp, mo);
for(q=*l; q!=nil; q=*l++)
if(!q->closed){
g = pp->g + dist(pp, q);
if(!q->open){
q->from = pp;
q->g = g;
q->h = dist(q, e);
q->open = 1;
pushpath(popen, q);
}else if(g < q->g){
q->from = pp;
q->g = g;
}
}
}
/* FIXME: move towards target anyway */
if(e->from == nil && pp != e){
werrstr("NOPE");
return -1;
}
setpath(e, mo);
return 0;
}
int
findpath(Mobj *mo, Point *p2)
{
return a∗(mo, p2);
}
void
initpath(void)
{
int n, x, y;
Path *pp;
pathwidth = mapwidth * (Tlwidth / Tlsubwidth);
pathheight = mapheight * (Tlheight / Tlsubheight);
n = pathwidth * pathheight;
path = emalloc(n * sizeof *path);
for(y=0, pp=path; y<pathheight; y++)
for(x=0; x<pathwidth; x++, pp++){
pp->x = x;
pp->y = y;
pp->lo.lo = pp->lo.lp = &pp->lo;
}
}