diff options
Diffstat (limited to 'ptinpoly.c')
| -rw-r--r-- | ptinpoly.c | 237 |
1 files changed, 237 insertions, 0 deletions
diff --git a/ptinpoly.c b/ptinpoly.c new file mode 100644 index 0000000..7f60f1c --- /dev/null +++ b/ptinpoly.c @@ -0,0 +1,237 @@ +#include <u.h> +#include <libc.h> +#include <thread.h> +#include <draw.h> +#include <mouse.h> +#include <keyboard.h> +#include <geometry.h> + +enum { + PCBg, + PCFg, + PCPoly, + PCPolydark, + PCAux, + NCOLORS +}; + +typedef struct Polygon Polygon; + +struct Polygon +{ + Point2 *pts; + Point *scrpts; + int npts; + + void (*push)(Polygon*, Point2); +}; + +Rectangle UR = {0,0,1,1}; /* unit rectangle */ +RFrame worldrf; +Image *pal[NCOLORS]; +Polygon *thepoly; +Point2 thepoint; +int isinside; + +void resized(void); +Point toscreen(Point2); + +void +polygonpush(Polygon *poly, Point2 p) +{ + poly->pts = realloc(poly->pts, ++poly->npts*sizeof(Point2)); + poly->pts[poly->npts-1] = p; + poly->scrpts = realloc(poly->scrpts, poly->npts*sizeof(Point)); + poly->scrpts[poly->npts-1] = toscreen(p); +} + +Polygon* +newpolygon(Point2 *pts, int npts) +{ + Polygon *poly; + int i; + + poly = malloc(sizeof(Polygon)); + if(pts == nil){ + poly->pts = nil; + poly->scrpts = nil; + poly->npts = 0; + }else{ + poly->pts = pts; + poly->scrpts = malloc(npts*sizeof(Point)); + for(i = 0; i < npts; i++) + poly->scrpts[i] = toscreen(poly->pts[i]); + poly->npts = npts; + } + poly->push = polygonpush; + return poly; +} + +int +ptinpoly(Point2 p, Polygon poly) +{ + int i, j, c; + + for(i = c = 0, j = poly.npts-1; i < poly.npts; j = i++) + if(p.y < poly.pts[i].y != p.y < poly.pts[j].y && + p.x < (poly.pts[j].x - poly.pts[i].x) * (p.y - poly.pts[i].y)/(poly.pts[j].y - poly.pts[i].y) + poly.pts[i].x) + c ^= 1; + return c; +} + +Point +toscreen(Point2 p) +{ + p = invrframexform(p, worldrf); + return Pt(p.x,p.y); +} + +Point2 +fromscreen(Point p) +{ + return rframexform(Pt2(p.x,p.y,1), worldrf); +} + +void +initpalette(void) +{ + pal[PCBg] = allocimage(display, UR, screen->chan, 1, DWhite); + pal[PCFg] = allocimage(display, UR, screen->chan, 1, DBlack); + pal[PCPoly] = allocimage(display, UR, screen->chan, 1, DPaleblue); + pal[PCPolydark] = allocimage(display, UR, screen->chan, 1, DDarkblue); + pal[PCAux] = allocimage(display, UR, screen->chan, 1, DRed); +} + +void +drawbanner(void) +{ + static char *msgs[] = { + "THE POINT IS OUTSIDE", + "THE POINT IS INSIDE" + }, *s; + + s = msgs[isinside]; + string(screen, toscreen(Pt2(Dx(screen->r)/2 - strlen(s)/2*font->width,10,1)), pal[PCFg], ZP, font, s); +} + +void +redraw(void) +{ + int i; + + lockdisplay(display); + draw(screen, screen->r, pal[PCBg], nil, ZP); + fillpoly(screen, thepoly->scrpts, thepoly->npts, 1, pal[PCPoly], ZP); + poly(screen, thepoly->scrpts, thepoly->npts, Enddisc, Enddisc, 1, pal[PCPolydark], ZP); + for(i = 0; i < thepoly->npts; i++) + fillellipse(screen, thepoly->scrpts[i], 2, 2, pal[PCPolydark], ZP); + fillellipse(screen, toscreen(thepoint), 2, 2, pal[PCAux], ZP); + drawbanner(); + flushimage(display, 1); + unlockdisplay(display); +} + +void +rmb(Mousectl *mc) +{ + thepoint = fromscreen(mc->xy); + isinside = ptinpoly(thepoint, *thepoly); +} + +void +lmb(Mousectl *mc) +{ + thepoly->push(thepoly, fromscreen(mc->xy)); +} + +void +mouse(Mousectl *mc) +{ + if((mc->buttons&1) != 0) + lmb(mc); + if((mc->buttons&4) != 0) + rmb(mc); +} + +void +key(Rune r) +{ + switch(r){ + case Kdel: + case 'q': + threadexitsall(nil); + } +} + +void +usage(void) +{ + fprint(2, "usage: %s\n", argv0); + exits("usage"); +} + +void +threadmain(int argc, char *argv[]) +{ + Mousectl *mc; + Keyboardctl *kc; + Rune r; + + ARGBEGIN{ + default: usage(); + }ARGEND; + if(argc > 0) + usage(); + + if(initdraw(nil, nil, nil) < 0) + sysfatal("initdraw: %r"); + if((mc = initmouse(nil, screen)) == nil) + sysfatal("initmouse: %r"); + if((kc = initkeyboard(nil)) == nil) + sysfatal("initkeyboard: %r"); + initpalette(); + + worldrf.p = Pt2(screen->r.min.x,screen->r.min.y,1); + worldrf.bx = Vec2(1,0); + worldrf.by = Vec2(0,1); + thepoly = newpolygon(nil, 0); + + display->locking = 1; + unlockdisplay(display); + redraw(); + + for(;;){ + enum { MOUSE, RESIZE, KEYBOARD }; + Alt a[] = { + {mc->c, &mc->Mouse, CHANRCV}, + {mc->resizec, nil, CHANRCV}, + {kc->c, &r, CHANRCV}, + {nil, nil, CHANEND} + }; + + switch(alt(a)){ + case MOUSE: + mouse(mc); + break; + case RESIZE: + resized(); + break; + case KEYBOARD: + key(r); + break; + } + + redraw(); + } +} + +void +resized(void) +{ + lockdisplay(display); + if(getwindow(display, Refnone) < 0) + sysfatal("couldn't resize"); + unlockdisplay(display); + worldrf.p = Pt2(screen->r.min.x,screen->r.min.y,1); + redraw(); +} |