ref: 7df9940505915a1e57fd4daba9602e6466626c50
parent: 3bef1314a3ae1e5bdc3ffb771e32866e05072d48
author: rodri <rgl@antares-labs.eu>
date: Sun Jun 7 17:14:05 EDT 2020
new toy: chain.
--- /dev/null
+++ b/chain.c
@@ -1,0 +1,189 @@
+#include <u.h>
+#include <libc.h>
+#include <thread.h>
+#include <draw.h>
+#include <mouse.h>
+#include <keyboard.h>
+#include <geometry.h>
+
+enum {+ MAXMAGNITUDE = 40
+};
+
+enum {+ Cbg,
+ Cfg,
+ NCOLOR
+};
+
+typedef struct Strut Strut;
+
+struct Strut
+{+ Point2 v;
+ Strut *next;
+};
+
+RFrame worldrf;
+Image *pal[NCOLOR];
+Strut *struts;
+Point2 origin;
+
+Strut*
+newstrut(Point2 v)
+{+ Strut *s;
+
+ s = malloc(sizeof(Strut));
+ if(s == nil)
+ sysfatal("malloc: %r");+ setmalloctag(s, getcallerpc(&v));
+ s->v = v;
+ s->next = nil;
+ return s;
+}
+
+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[Cbg] = allocimage(display, Rect(0,0,1,1), screen->chan, 1, 0x000000ff);
+ pal[Cfg] = allocimage(display, Rect(0,0,1,1), screen->chan, 1, 0xffffffff);
+}
+
+void
+redraw(void)
+{+ Strut *s;
+ Point2 p0, p1;
+
+ p0 = origin;
+
+ lockdisplay(display);
+ draw(screen, screen->r, pal[Cbg], nil, ZP);
+ for(s = struts; s != nil; s = s->next){+ p1 = addpt2(p0, s->v);
+ line(screen, toscreen(p0), toscreen(p1), Endsquare, Endarrow, 0, pal[Cfg], ZP);
+ p0 = p1;
+ }
+ flushimage(display, 1);
+ unlockdisplay(display);
+}
+
+void
+resized(void)
+{+ lockdisplay(display);
+ if(getwindow(display, Refnone) < 0)
+ sysfatal("resize failed");+ unlockdisplay(display);
+ worldrf.p = Pt2(screen->r.min.x,screen->r.max.y,1);
+ origin = Pt2(Dx(screen->r)/2,Dy(screen->r)/2,1);
+ redraw();
+}
+
+void
+mouse(Mouse m)
+{+ Strut *s;
+ Point2 mpos, v;
+ double θ;
+
+ if((m.buttons & 1) != 0){+ mpos = subpt2(fromscreen(m.xy), origin);
+ θ = atan2(mpos.y, mpos.x);
+ //v = Vec2(cos(frand() * 2*PI),sin(frand() * 2*PI));
+ v = Vec2(cos(θ),sin(θ));
+ v = mulpt2(v, frand()*MAXMAGNITUDE);
+ s = newstrut(v);
+ if(struts == nil)
+ struts = s;
+ else{+ s->next = struts;
+ struts = s;
+ }
+ }
+}
+
+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.max.y,1);
+ worldrf.bx = Vec2(1, 0);
+ worldrf.by = Vec2(0,-1);
+ origin = Pt2(Dx(screen->r)/2,Dy(screen->r)/2,1);
+
+ 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->Mouse);
+ break;
+ case RESIZE:
+ resized();
+ break;
+ case KEYBOARD:
+ key(r);
+ break;
+ }
+
+ redraw();
+ }
+}
--- a/mkfile
+++ b/mkfile
@@ -8,6 +8,7 @@
grid\
isometric\
ptinline\
+ chain\
HFILES=\
libgeometry/geometry.h\
--- /dev/null
+++ b/readme.md
@@ -1,0 +1,9 @@
+# E-Toys
+
+A bunch of little computer programs for exploration and learning.
+
+## Notice
+
+The libgeometry used in these programs is not the stock one, but the
+one i wrote (some of you probably noticed from the mkfile). Clone it
+in the top dir and it will work.