~aleteoryx/9c

ref: 2a08c37c3db23b27b963442fe273097915bc30ea 9c/spiral.c -rw-r--r-- 2.7 KiB
2a08c37c — glenda spirals! 37 years ago 
                                                                                
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#include <u.h>
#include <libc.h>
#include <draw.h>
#include <event.h>

#define RAD (PI * 2)
#define DEG (PI / 180.0)

Image *bg,*fg;

int frametime;
double spr;
int wings;
double wingrads;
double eccen;

vlong starttime;

void
usage(void)
{
	fprint(2,"usage: %s [-f framerate] [-r rpm] [-w wings] [-e deg]\n", argv0);
	exits("usage");
}

Point
SPt(int x, int y)
{
	return addpt(Pt(x, y), screen->r.min);
}

Rectangle
SRect(int x0, int y0, int x1, int y1)
{
	return rectaddpt(Rect(x0, y0, x1, y1), screen->r.min);
}

Point
imagecenter(Image* img)
{
	return divpt(addpt(img->r.min, img->r.max), 2);
}

double
imageradius(Image* img)
{
	Point dims;
	dims = divpt(subpt(img->r.max, img->r.min), 2);
	return 1.4 + sqrt(dims.x*dims.x + dims.y*dims.y);
}

Point
vecpt(double radians, double radius)
{
	double x,y;
	x = sin(radians) * radius;
	y = cos(radians) * radius;

	return Pt(x + 1, y + 1);
}

void
drawframe(double ts)
{
	double radians, radius;
	Point center;
	Point wingpoints[6];

	radians = fmod(ts / spr, spr) * RAD;
	radius = imageradius(screen) * 1.4;
	center = imagecenter(screen);
	wingpoints[0] = center;
	wingpoints[5] = addpt(center, Pt(1, 1));

	draw(screen, screen->r, bg, nil, SPt(0, 0));

	for(int i = 0; i < wings; i++)
	{
		wingpoints[1] = addpt(center, vecpt(radians + eccen, radius / 3));
		wingpoints[2] = addpt(center, vecpt(radians, radius));
		radians += wingrads;
		wingpoints[3] = addpt(center, vecpt(radians, radius));
		wingpoints[4] = addpt(center, vecpt(radians + eccen, radius / 3));
		radians += wingrads;

		fillbezspline(screen, wingpoints, 6, ~0, fg, Pt(0, 0));
	}
}

double
ftime(void)
{
	return ((double)(nsec() - starttime)) / 1000000000.0;
}

void
eresized(int new)
{
	if(new && getwindow(display, Refnone) < 0)
		fprint(2,"can't reattach to window\n");
	drawframe(ftime());
}

void
main(int argc, char* argv[])
{
	int timer,etype;
	Event e;

	frametime = 1.0 / 30.0 * 1000;
	wings = 3;
	spr = 2;
	eccen = RAD / 6;

	ARGBEGIN{
	case 'f':
		frametime = 1.0 / atof(EARGF(usage())) * 1000;
		break;
	case 'r':
		spr = 1.0 / (atof(EARGF(usage())) / 60.0);
		break;
	case 'w':
		wings = atoi(EARGF(usage()));
		break;
	case 'e':
		eccen = DEG * atof(EARGF(usage()));
		break;
	default:
		usage();
	} ARGEND

	if(wings < 1) wings = 1;
	wingrads = PI / (double) wings;

	if(initdraw(nil, nil, "spiral") < 0)
		sysfatal("initdraw: %r");

	fg = allocimage(display, Rect(0,0, 1,1), GREY1, 1, DBlack);
	if(!fg)
		sysfatal("couldn't allocimage!");

	bg = allocimage(display, Rect(0,0, 1,1), GREY1, 1, DWhite);
	if(!bg)
		sysfatal("couldn't allocimage!");

	starttime = nsec();

	einit(Emouse);
	timer = etimer(0, frametime);

	for(;;)
	{
		etype = event(&e);

		if (etype == timer)
			drawframe(ftime());
	}
}