#include <u.h>
#include <libc.h>
#include <draw.h>
uchar canvas[256*192];
Warp warp = {{{1 << 11, 0, 0}, {0, 1 << 11, 0}, {0, 0, 1 << 13}}, WFintupscale};
double sinθ = 0.0, cosθ = 1.0;
double
sdf(double x, double y, double z){
	double t, d;
	t = x * cosθ - z * sinθ;
	d = sqrt(t * t + y * y) - 2.0;
	t = x * sinθ + z * cosθ;
	d = sqrt(d * d + t * t) - 0.2;
	t = -x;
	x = t * cosθ - z * sinθ;
	z = t * sinθ + z * cosθ;
	y += 0.5;
	t = sqrt(x * x + y * y) - 0.9;
	t = sqrt(t * t + z * z) - 0.2;
	if(t < d)
		d = t;
	y -= 0.5;
	t = x + 0.8;
	x = t * 0.923879532511 - y * 0.382683432365;
	y = t * 0.382683432365 + y * 0.923879532511;
	if(y > 1.5)
		y -= 1.5;
	else if(y > 0.0)
		y = 0.0;
	t = sqrt(x * x + y * y + z * z) - 0.2;
	return d < t ? d :  t;
}
uchar
march(double Δx, double Δy){
	double t, d, z, x, y, Δz;
	Δz = 1.0 / sqrt(Δx * Δx + Δy * Δy + 27648.0);
	Δx *= Δz;
	Δy *= Δz;
	Δz *= 166.276877527;
	t = x = y = z = 0.0;
	do{
		t += d = sdf(x, y, z - 5.0);
		x = t * Δx;
		y = t * Δy;
		z = t * Δz;
	}while(t < 8.0 && d > 0.05);
	if(t > 8.0)
		return 0;
	t = 255 - t * 35;
	return t < 0.0 ? 0 : t > 255.0 ? 255 : t;
};
void
main(int, char**){
	Rectangle r;
	Image *rowimg, *img;
	int i, j, fc;
	vlong ns;
	if(initdraw(nil, nil, nil) < 0)
		sysfatal("initdraw: %r");
	rowimg = allocimage(display, Rect(0, 0, 256 * 4, 1), GREY8, 1, DNofill);
	if(rowimg == nil)
		sysfatal("allocimage: %r");
	img = allocimage(display, Rect(0, 0, 256, 192), GREY8, 0, DNofill);
	if(img == nil)
		sysfatal("allocimage: %r");
	r.min.x = screen->r.min.x + screen->r.max.x - 4 * 256 >> 1;
	r.min.y = screen->r.min.y + screen->r.max.y - 4 * 192 >> 1;
	r.max.x = r.min.x + 4 * 256;
	r.max.y = r.min.y + 4 * 192;
	warp.m[0][2] = screen->r.min.x - r.min.x << 11;
	warp.m[1][2] = screen->r.min.y - r.min.y << 11;
	ns = uptime();
	for(fc = 0; fc < 200; fc++){
		for(j = 0; j < 192; j++)
			for(i = 0; i < 256; i++)
				canvas[j << 8 | i] = march(i - 128, j - 92);
		loadimage(img, img->r, canvas, sizeof canvas);
		affinewarp(screen, r, img, nil, ZP, &warp, 0);
		flushimage(display, 1);
		sinθ -= 0.1 * cosθ;
		cosθ += 0.1 * sinθ;
	}
	fprint(2, "affinewarp: %g frames per second\n", 200.0 / ((uptime() - ns) * 0.000000001));
	ns = uptime();
	for(fc = 0; fc < 200; fc++){
		for(j = 0; j < 192; j++){
			for(i = 0; i < 1024; i += 4)
				canvas[i] = canvas[i | 1] = 
				canvas[i | 2] = canvas[i | 3] = march((i >> 2) - 128, j - 92);
			loadimage(rowimg, rowimg->r, canvas, 1024);
			r.max.y = r.min.y + 4;
			draw(screen, r, rowimg, nil, ZP);
			r.min.y = r.max.y;
		}
		r.min.y -= 192 * 4;
		flushimage(display, 1);
		sinθ -= 0.1 * cosθ;
		cosθ += 0.1 * sinθ;
	}
	fprint(2, "repl trick: %g frames per second\n", 200.0 / ((uptime() - ns) * 0.000000001));
	exits(nil);
}