#include <u.h>
#include <libc.h>
#include <draw.h>
uchar canvas[512 * 512];
Rectangle rect;
Image *img;
int t;
typedef struct Vec Vec; struct Vec{float x, y, z;};
Vec add(Vec a, Vec b){return (Vec){a.x+b.x, a.y+b.y, a.z+b.z};}
Vec sub(Vec a, Vec b){return (Vec){a.x-b.x, a.y-b.y, a.z-b.z};}
Vec mul(Vec p, float s){return (Vec){p.x*s, p.y*s, p.z*s};}
Vec vabs(Vec p){if(p.x<0)p.x=-p.x; if(p.y<0)p.y=-p.y; if(p.z<0)p.z=-p.z; return p;}
float dot(Vec a, Vec b){return a.x*b.x + a.y*b.y + a.z*b.z;}
float mag(Vec v){return sqrt(dot(v, v));}
Vec norm(Vec v){
	float len;
	len = mag(v);
	return len == 0 ? (Vec){0,0,0} : (Vec){v.x/len, v.y/len, v.z/len};
}
Vec cross(Vec a, Vec b){
	return (Vec){
		a.y*b.z - a.z*b.y,
		a.z*b.x - a.x*b.z,
		a.x*b.y - a.y*b.x,
	};
}
struct{Vec pos, right, up, fwd;}camera;
void
mvcam(float x0, float y0, float z0, float x1, float y1, float z1){
	camera.pos = (Vec){x0, y0, z0};
	camera.fwd = norm((Vec){x1 - x0, y1 - y0, z1 - z0});
	camera.right = cross((Vec){0.0, 1.0, 0.0}, camera.fwd);
	camera.up = cross(camera.fwd, camera.right);
}
float
dist(Vec p){
//	p = vabs(p);
//	return (p.x + p.y + p.z - 3.3) * 0.57735027;
//	return mag(p) - 0.2 + sin(t / 10.0) - 1.0;
	float x, y;
	x = sqrt(p.x * p.x + p.z * p.z) - 1.0;
	return sqrt(x * x + p.y * p.y) - 0.8;
}
void
march(){
	Vec p, n, lux;
	float d, tot;
	int x, y, i;
	uchar *out;
	out = canvas + 64 + 1;
	for(y = -32; y < 32; y++){
		for(x = -32; x < 32; x++){
			p = add(camera.fwd, mul(camera.right, x / 32.0));
			p = add(p, mul(camera.up, y / 32.0));
			n = norm(p);
			p = camera.pos;
			for(i = tot = 0.0; i < 50; i++){
				tot += d = dist(p);
				if(tot >= 80.0 || d < 0.05f)
					break;
				p = add(p, mul(n, d));
			}
			lux = norm(sub(camera.pos, p));
			n.x = (dist((Vec){p.x + 0.05f, p.y, p.z}) - d) / 0.05f;
			n.y = (dist((Vec){p.x, p.y + 0.05f, p.z}) - d) / 0.05f;
			n.z = (dist((Vec){p.x, p.y, p.z + 0.05f}) - d) / 0.05f;
			d = dot(lux, n) * 255;
			*out++ = d < 0.0 ? 0 : d > 255.0 ? 255 : d;
		}
		out += 2;
	}
}
void
marchrow(uchar *out, int y){
	Vec p, n, lux;
	float d, tot;
	int x, i;
	for(x = -32; x < 32; x++){
		p = add(camera.fwd, mul(camera.right, x / 32.0));
		p = add(p, mul(camera.up, y / 32.0));
		n = norm(p);
		p = camera.pos;
		for(i = tot = 0.0; i < 50; i++){
			tot += d = dist(p);
			if(tot >= 80.0 || d < 0.05f)
				break;
			p = add(p, mul(n, d));
		}
		lux = norm(sub(camera.pos, p));
		n.x = (dist((Vec){p.x + 0.05f, p.y, p.z}) - d) / 0.05f;
		n.y = (dist((Vec){p.x, p.y + 0.05f, p.z}) - d) / 0.05f;
		n.z = (dist((Vec){p.x, p.y, p.z + 0.05f}) - d) / 0.05f;
		d = dot(lux, n) * 255;
		*out++ = d < 0.0 ? 0 : d > 255.0 ? 255 : d;
	}
}
uchar bayer[8][8] = {
	{0, 128, 32, 160, 8, 136, 40, 168},
	{192, 64, 224, 96, 200, 72, 232, 104},
	{48, 176, 16, 144, 56, 184, 24, 152},
	{240, 112, 208, 80, 248, 120, 216, 88},
	{12, 140, 44, 172, 4, 132, 36, 164},
	{204, 76, 236, 108, 196, 68, 228, 100},
	{60, 188, 28, 156, 52, 180, 20, 148},
	{252, 124, 220, 92, 244, 116, 212, 84}
};
void
dither(void){
	int i;
	for(i = 0; i < sizeof canvas; i++)
		canvas[i] = 255 + (canvas[i] < bayer[i & 7][i >> 9 & 7]);
}
void
fill(void){
	int i, j;
	uchar *u;
	u = canvas;
	for(j = 0; j < 127; j++){
		for(i = 0; i < 128; i++){
			u[513 + 513] = *u + u[513 + 513 + 513 + 513] >> 1;
			u[513] = *u + u[513 + 513] >> 1;
			u[513 + 513 + 513] = u[513 + 513] + u[513 + 513 + 513 + 513] >> 1;
			u += 4;
		}
		u += 3 * 512;
	}
}
Image *scanline;
Rectangle scanlinerect;
void
quadruple(uchar *p, uchar *a, uchar *b, uchar *c, uchar *d){
	uchar out[512 * 2], *o;
	int i;
	o = out;
	for(i = 0; i < 64; i++){
//		o[0] = o[1] = o[2] = o[3] = c[i] == a[i] && c[i] != d[i] && a[i] != b[i] ? a[i] : p[i];
//		o[4] = o[5] = o[6] = o[7] = a[i] == b[i] && a[i] != c[i] && b[i] != d[i] ? b[i] : p[i];
//		o[512] = o[513] = o[514] = o[515] = d[i] == c[i] && d[i] != b[i] && c[i] != a[i] ? c[i] : p[i];
//		o[516] = o[517] = o[518] = o[519] = b[i] == d[i] && b[i] != a[i] && d[i] != c[i] ? d[i] : p[i];
		o[0] = o[1] = o[2] = o[3] = c[i] + a[i] + p[i] + p[i] >> 2;
		o[4] = o[5] = o[6] = o[7] = a[i] + b[i] + p[i] + p[i] >> 2;
		o[512] = o[513] = o[514] = o[515] = c[i] + d[i] + p[i] + p[i] >> 2;
		o[516] = o[517] = o[518] = o[519] = d[i] + b[i] + p[i] + p[i] >> 2;
		o += 8;
	}
	scanlinerect.max.y = scanlinerect.min.y + 4;
	loadimage(scanline, scanline->r, out, 512);
	draw(screen, scanlinerect, scanline, nil, ZP);
	scanlinerect.min.y = scanlinerect.max.y;
	scanlinerect.max.y = scanlinerect.min.y + 4;
	loadimage(scanline, scanline->r, o, 512);
	draw(screen, scanlinerect, scanline, nil, ZP);
	scanlinerect.min.y = scanlinerect.max.y;
}
void
nuscan(void){
	uchar *a, *d, *p, *t;
	uchar buf[(64 + 2) * 3];
	Rectangle r;
	int i, j;
	scanlinerect.min.x = screen->r.min.x + screen->r.max.x - 512 >> 1;
	scanlinerect.max.x = scanlinerect.min.x + 512;
	scanlinerect.min.y = screen->r.min.y + screen->r.max.y - 512 >> 1;
	memset(buf, 0, sizeof buf);
	a = buf + 1;
	p = a + 64 + 2;
	d = p + 64 + 2;
	marchrow(p, -32);
	for(i = 1; i < 64; i++){
		marchrow(d, i - 32);
		quadruple(p, a, p + 1, p - 1, d);
		t = a;
		a = p;
		p = d;
		d = t;
	}
	memset(d, 0, 64);
	quadruple(p, a, p + 1, p - 1, d);
	flushimage(display, 1);
}
void
main(int, char**){
	int i, j;
	if(initdraw(nil, nil, "③") < 0)
		sysfatal("initdraw: %r");
	img = allocimage(display, Rect(0, 0, 512, 512), GREY8, 1, DNofill);
	if(img == nil)
		sysfatal("allocimage: %r");
	scanline = allocimage(display, Rect(0, 0, 512, 1), GREY8, 1, DNofill);
	if(img == nil)
		sysfatal("allocimage: %r");
	i = open("/dev/wctl", OWRITE);
	if(i < 0)
		sysfatal("open: %r");
	write(i, "resize -r 0 0 9999 9999", 23);
	getwindow(display, Refnone);
	rect.min.x = screen->r.min.x + screen->r.max.x - 512 >> 1;
	rect.min.y = screen->r.min.y + screen->r.max.y - 512 >> 1;
	rect.max.x = rect.min.x + 512;
	rect.max.y = rect.min.y + 512;
	draw(screen, screen->r, display->black, nil, ZP);
	for(t = 0; t < 1200; t++){
		mvcam(2.0, -5.5 * sin(t * 2.0 * PI / 120.0), -5.5 * cos(t * 2.0 * PI / 120.0), 0, 0, 0);
		nuscan();
		sleep(50);
	}
	exits(nil);
}