diff options
| -rw-r--r-- | linetiler.c | 343 | ||||
| -rw-r--r-- | mkfile | 1 |
2 files changed, 344 insertions, 0 deletions
diff --git a/linetiler.c b/linetiler.c new file mode 100644 index 0000000..937bfbc --- /dev/null +++ b/linetiler.c @@ -0,0 +1,343 @@ +#include <u.h> +#include <libc.h> +#include <thread.h> +#include <draw.h> +#include <mouse.h> +#include <keyboard.h> +#include <geometry.h> + +#define CLAMP(n, min, max) ((n)<(min)?(min):(n)>(max)?(max):(n)) + +enum { + CLIPL = 1, + CLIPR = 2, + CLIPT = 4, + CLIPB = 8, +}; + +enum { + PCBg0, + PCBg1, + PCFg0, + PCFg1, + PCAux, + NCOLORS +}; + +typedef struct Line Line; + +struct Line +{ + Point2 pts[2]; +}; + +Rectangle UR = {0,0,1,1}; /* unit rectangle */ +RFrame worldrf; +Image *pal[NCOLORS]; +Rectangle *tiles; +int ntiles; +Line *lines; +int nlines; +Line theline; +Point2 thepoint; +Point2 pts[2]; +int npts; +uint paloff; +int thickness; +int showtheline; + +void resized(void); + +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); +} + +static void +swapi(int *a, int *b) +{ + int t; + + t = *a; + *a = *b; + *b = t; +} + +static void +swappt(Point *a, Point *b) +{ + Point t; + + t = *a; + *a = *b; + *b = t; +} + +static int +ptisinside(int code) +{ + return !code; +} + +static int +lineisinside(int code0, int code1) +{ + return !(code0|code1); +} + +static int +lineisoutside(int code0, int code1) +{ + return code0 & code1; +} + +static int +outcode(Point p, Rectangle r) +{ + int code; + + code = 0; + if(p.x < r.min.x) code |= CLIPL; + if(p.x > r.max.x) code |= CLIPR; + if(p.y < r.min.y) code |= CLIPT; + if(p.y > r.max.y) code |= CLIPB; + return code; +} + +/* + * Cohen-Sutherland rectangle-line clipping + */ +int +rectclipline(Rectangle r, Point *p0, Point *p1) +{ + int code0, code1; + int Δx, Δy; + double m; + + Δx = p1->x - p0->x; + Δy = p1->y - p0->y; + m = Δx == 0? 0: (double)Δy/Δx; + + for(;;){ + code0 = outcode(*p0, r); + code1 = outcode(*p1, r); + + if(lineisinside(code0, code1)) + return 0; + else if(lineisoutside(code0, code1)) + return -1; + + if(ptisinside(code0)){ + swappt(p0, p1); + swapi(&code0, &code1); + } + + if(code0 & CLIPL){ + p0->y += (r.min.x - p0->x)*m; + p0->x = r.min.x; + }else if(code0 & CLIPR){ + p0->y += (r.max.x - p0->x)*m; + p0->x = r.max.x; + }else if(code0 & CLIPT){ + if(p0->x != p1->x && m != 0) + p0->x += (r.min.y - p0->y)/m; + p0->y = r.min.y; + }else if(code0 & CLIPB){ + if(p0->x != p1->x && m != 0) + p0->x += (r.max.y - p0->y)/m; + p0->y = r.max.y; + } + } +} + +void +addline(Line l) +{ + lines = realloc(lines, ++nlines*sizeof(*lines)); + lines[nlines-1] = l; +} + +void +initpalette(void) +{ + pal[PCBg0] = allocimage(display, UR, screen->chan, 1, DWhite); + pal[PCBg1] = allocimage(display, UR, screen->chan, 1, 0x333333FF); + pal[PCFg0] = pal[PCBg1]; + pal[PCFg1] = pal[PCBg0]; + pal[PCAux] = allocimage(display, UR, screen->chan, 1, DRed); +} + +void +redraw(void) +{ + int i; + + lockdisplay(display); + for(i = 0; i < ntiles; i++) + draw(screen, rectaddpt(tiles[i], screen->r.min), pal[PCBg0+(i%2)], nil, ZP); + for(i = 0; i < nlines; i++) + line(screen, toscreen(lines[i].pts[0]), toscreen(lines[i].pts[1]), 0, 0, thickness, pal[PCFg0+(i+paloff)%2], ZP); + if(showtheline) + line(screen, toscreen(theline.pts[0]), toscreen(theline.pts[1]), 0, 0, 0, pal[PCAux], ZP); + fillellipse(screen, toscreen(thepoint), 2, 2, pal[PCAux], ZP); + flushimage(display, 1); + unlockdisplay(display); +} + +void +lmb(Mousectl *mc) +{ + Line l; + Point p0, p1; + int i; + + pts[npts] = thepoint = fromscreen(mc->xy); + if(++npts > 2-1){ + theline.pts[0] = pts[0]; + theline.pts[1] = pts[1]; + npts = 0; + + if(lines != nil){ + free(lines); + lines = nil; + nlines = 0; + } + + for(i = 0; i < ntiles; i++){ + p0 = Pt(theline.pts[0].x,theline.pts[0].y); + p1 = Pt(theline.pts[1].x,theline.pts[1].y); + if(ptinrect(p0, tiles[i])) + paloff = i; +//fprint(2, "%P, %P ∩ %R = ", p0, p1, tiles[i]); + if(rectclipline(tiles[i], &p0, &p1) < 0) + continue; +//fprint(2, "%P, %P\n", p0, p1); + l.pts[0] = Pt2(p0.x,p0.y,1); + l.pts[1] = Pt2(p1.x,p1.y,1); + addline(l); + } + } +} + +void +rmb(Mousectl *) +{ + showtheline ^= 1; +} + +void +mouse(Mousectl *mc) +{ + static Mouse om; + + if((om.buttons^mc->buttons) == 0) + return; + if((mc->buttons&1) != 0) + lmb(mc); + if((mc->buttons&4) != 0) + rmb(mc); + if((mc->buttons&8) != 0) + thickness = CLAMP(++thickness, 0, 10); + if((mc->buttons&16) != 0) + thickness = CLAMP(--thickness, 0, 10); + om = mc->Mouse; +} + +void +key(Rune r) +{ + switch(r){ + case Kdel: + case 'q': + threadexitsall(nil); + } +} + +void +usage(void) +{ + fprint(2, "usage: %s tiles\n", argv0); + exits("usage"); +} + +void +threadmain(int argc, char *argv[]) +{ + Mousectl *mc; + Keyboardctl *kc; + Rune r; + int i, Δx, Δy; + + ARGBEGIN{ + default: usage(); + }ARGEND; + if(argc != 1) + usage(); + + ntiles = strtoul(argv[0], nil, 10); + tiles = malloc(ntiles*sizeof(*tiles)); + + 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); + + Δx = Dx(screen->r); + Δy = Dy(screen->r)/ntiles; + for(i = 0; i < ntiles; i++) + tiles[i] = Rect(0,i*Δy,Δx,i == ntiles-1? Dy(screen->r): (i+1)*Δy); + + 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(); +} @@ -15,5 +15,6 @@ TARG=\ ptintriangle\ barycentric\ lineXcircle\ + linetiler\ </sys/src/cmd/mkmany |