/*
^echo w; window -r 0 0 699 699 -cd src rci '''mk 6.brush && 6.brush'''
*/
#include <u.h>
#include <libc.h>
#include <draw.h>
Image *px;
uchar abgr[4] = {30, 30, 20, 30};
Point o[65];
void
spray(Point c, int rad, int n){
	int x, y, r;
	double θ;
	while(n--){
		r = sqrt(frand()) * rad;
		θ = frand() * 2.0 * PI;
		x = c.x + r * cos(θ);
		y = c.y + r * sin(θ);
		draw(screen, Rect(x, y, x + 1, y + 1), px, nil, ZP);
	}
}
void
stroke(Point from, Point to){
	int steps;
	steps = 8;
	while(steps){
		spray(from, 16, 200);
		from.x += (to.x - from.x) / steps;
		from.y += (to.y - from.y) / steps;
		--steps;
	}
}
void
chaikin(int n){
	Point p, ¼;
	int i;
	p = o[0];
	for(i = n; i < 64; i += n + n){
		¼ = divpt(subpt(o[i + n], p), 4);
		o[i] = addpt(p, ¼);
		p = o[i + n];
		o[i + n] = subpt(p, ¼);
	}
}
void
main(int, char**){
	int i, r;
	double θ;
	i = truerand();
	print("%d", i);
	srand(i);
	if(initdraw(nil, nil, nil) < 0)
		sysfatal("initdraw: %r");
	px = allocimage(display, Rect(0, 0, 1, 1), RGBA32, 1, DNofill);
	if(px == nil)
		sysfatal("allocimage: %r");
	draw(screen, screen->r, display->black, nil, ZP);
	loadimage(px, px->r, abgr, 4);
	r = 196;
	o[0] = Pt(screen->r.min.x + screen->r.max.x >> 1, screen->r.min.y + screen->r.max.y >> 1);
	θ = 0.0;
	while(9){
		for(i = 8; i <= 64; i += 8){
			θ += PIO2 + frand() * PIO2 - PIO2 / 2;
			o[i] = addpt(o[i - 8], Pt(r * cos(θ), r * sin(θ)));
	//		o[i].x = o[i - 8].x + r;
	//		o[i].y = o[0].y + nrand(r) - r / 2;
		}
		chaikin(4);
		chaikin(2);
		chaikin(1);
		for(i = 0; i < 64; i++){
			stroke(o[i], o[i + 1]);
			flushimage(display, 1);
//			sleep(10);
		}
		o[0] = o[64];
		if(o[0].x < screen->r.min.x)
			o[0].x = screen->r.max.x;
		if(o[0].y < screen->r.min.y)
			o[0].y = screen->r.max.y;
		if(o[0].x >= screen->r.max.x)
			o[0].x = screen->r.min.x;
		if(o[0].y >= screen->r.max.y)
			o[0].y = screen->r.min.y;
	}
}