#include <CtrlLib/CtrlLib.h>

using namespace Upp;

#define LDUMP(x)
#define LLOG(x);
#define LTIMING(x) RTIMING(x)

class AABuffer {
	struct RGBAi {
		dword r;
		dword g;
		dword b;
		dword a;
	
		void Write(RGBA& t) {
			t.r = byte(r >> 4);
			t.g = byte(g >> 4);
			t.b = byte(b >> 4);
			t.a = byte(a >> 4);
		}
	
		void Put(const RGBA& s) {
			r += s.r;
			g += s.g;
			b += s.b;
			a += s.a;
		}
		
		RGBAi() { r = g = b = a = 0; }
	};
	
	#define COMPLEX *(RGBA *)(
	
	struct P16 {
		RGBA  simple;
		RGBA *complex;
		
		bool  IsComplex() const         { return simple.b == 255 && simple.a == 0; }
	};
	
	Buffer< Buffer<P16> > line;

	int cx, gx, cy;

	void  Free();
	
	static bool MakeComplexIf(P16 *p, RGBA color)
	{
		if(!p->IsComplex()) {
			if(p->simple == color)
				return false;
			RGBA h = p->simple;
			p->complex = new RGBA[16];
			p->complex[0] = h; p->complex[1] = h; p->complex[2] = h; p->complex[3] = h;
			p->complex[4] = h; p->complex[5] = h; p->complex[6] = h; p->complex[7] = h;
			p->complex[8] = h; p->complex[9] = h; p->complex[10] = h; p->complex[11] = h;
			p->complex[12] = h; p->complex[13] = h; p->complex[14] = h; p->complex[15] = h;
			p->simple.b = 255;
			p->simple.a = 0;
		}
		return true;
	}

public:
	void Fill(int x, int y, int n, RGBA color);
	
	void  Create(int cx, int cy);
	Image Downsample();
	
	~AABuffer();
};

void AABuffer::Fill(int x, int y, int n, RGBA color)
{
	if(n <= 0)
		return;
	P16 *p = line[y];
	int j = x >> 4;
	int a = x & 15;
	if(a || n < 16) {
		int c = min(n, 16 - a);
		if(MakeComplexIf(p, color))
			UPP::Fill(p->complex + a, color, c);
		n -= c;
		p++;
	}
	while(n > 16) {
		if(p->IsComplex())
			delete[] p->complex;
		p->simple = color;
		n -= 16;
		p++;
	}
	if(n && MakeComplexIf(p, color))
		UPP::Fill(p->complex, color, n);
}

void AABuffer::Create(int _cx, int _cy)
{
	cx = _cx << 2;
	cy = _cy << 2;
	gx = (cx + 15) >> 4;
	line.Alloc(cy);
	for(int i = 0; i < cy; i++) {
		line[i].Alloc(gx);
		memset(line[i], 0, cx * sizeof(P16));
	}
}

Image AABuffer::Downsample()
{
	LTIMING("Downscale");
	Size tsz = Size(cx >> 2, cy >> 2);
	ImageBuffer tb(tsz);
	RGBA *t = tb;
	for(int y = 0; y < tsz.cy; y++) {
		P16 *p[4];
		p[0] = line[4 * y + 0];
		p[1] = line[4 * y + 1];
		p[2] = line[4 * y + 2];
		p[3] = line[4 * y + 3];
		int x = 0;
		for(int i = 0; i < gx; i++) {
			RGBA c = p[1]->simple;
			if(c == p[2]->simple && c == p[3]->simple && c == p[4]->simple) {
				if(x + 4 < tsz.cx) {
					t[0] = c;
					t[1] = c;
					t[2] = c;
					t[3] = c;
					t += 4;
				}
				else
					while(x < tsz.cx)
						*t++ = c;
			}
			else {
				RGBAi m[4];
				for(int j = 0; j < 4; j++) {
					if(*p[j].IsSimple()) {
						for(int k = 0; k < 4; k++)
							m[k].Put4(*p[j]->simple);
					}
					else {
						for(int k = 0; k < 4; k++) {
							m[0].Put(p[j].complex[0]);
							m[0].Put(p[j].complex[1]);
							m[0].Put(p[j].complex[2]);
							m[0].Put(p[j].complex[3]);
						}
					}
				}
			}
			p[0]++;
			p[1]++;
			p[2]++;
			p[3]++;
		}
	return tb;
}

struct PolygonRenderer {
	Buffer< Vector<int> > ln;
	int y0, ymax, lnc;

	void AddPoint(int x, int y)
	{
		LDUMP(Point(x, y));
		if(y >= y0 && y <= ymax) {
			Vector<int>& v = ln[y - y0];
			int i;
			for(i = 0; i < v.GetCount(); i++)
				if(x < v[i])
					break;
			v.Insert(i, x);
		}
	}

	void RenderPolygon(ImageBuffer& b, const Vector<Point>& p, RGBA color)
	{
		LTIMING("RenderPolygon");
		if(p.GetCount() < 2)
			return;
		ymax = y0 = p[0].y;
		for(int i = 0; i < p.GetCount(); i++) {
			int y = p[i].y;
			y0 = min(y0, y);
			ymax = max(ymax, y);
		}
		y0 = minmax(y0, 0, b.GetHeight() - 1);
		ymax = minmax(ymax, 0, b.GetHeight() - 1);
		int lines = ymax - y0 + 1;
		ln.Alloc(lines);
		for(int i = 0; i < p.GetCount(); i++) {
			Point p1 = p[i];
			Point p2 = p[i > 0 ? i - 1 : p.GetCount() - 1];
			LLOG(p1 << " - " << p2);
			if(p1.y > p2.y)
				Swap(p1, p2);
			int delta = ((p2.x - p1.x) << 16) / (p2.y - p1.y + 1);
			int x = p1.x << 16;
			AddPoint(p1.x, p1.y);
			for(int y = p1.y; y < p2.y; y++) {
				x += delta;
				AddPoint(x >> 16, y);
			}
			AddPoint(p2.x, p2.y);
		}
		RGBA *t = b[y0];
		int cx = b.GetWidth();
		for(int i = 0; i < lines; i++) {
			LDUMP(y0 + i);
			Vector<int>& v = ln[i];
			int j = 0;
			while(j < v.GetCount() - 1) {
				LLOG(v[j] << ' ' << v[j + 1]);
				if(v[j] < cx && v[j + 1] >= 0) {
					int x1 = max(v[j], 0);
					int x2 = min(v[j + 1], cx - 1);
					Fill(t + x1, color, x2 - x1 + 1);
				}
				j += 2;
			}
			t += cx;
		}
	}
};

void RenderPolygon(ImageBuffer& b, const Vector<Point>& p, RGBA color)
{
	PolygonRenderer r;
	r.RenderPolygon(b, p, color);
}

struct RGBAi {
	dword r;
	dword g;
	dword b;
	dword a;

	void Get(RGBA& t) {
		t.r = r >> 4;
		t.g = g >> 4;
		t.b = b >> 4;
		t.a = a >> 4;
	}

	void Put(const RGBA& s) {
		r += s.r;
		g += s.g;
		b += s.b;
		a += s.a;
	}
	
	RGBAi() { r = g = b = a = 0; }
};

Image Downscale(const ImageBuffer& b)
{
	LTIMING("Downscale");
	Size tsz = b.GetSize() / 4;
	ImageBuffer tb(tsz);
	int cx = b.GetWidth();
	const RGBA *bs = ~b;
	RGBA *t = tb;
	for(int y = 0; y < tsz.cy; y++) {
		const RGBA *q = bs;
		for(int x = 0; x < tsz.cx; x++) {
			RGBAi m;
			const RGBA *s = q;
			m.Put(s[0]); m.Put(s[1]); m.Put(s[2]); m.Put(s[3]);
			s += cx;
			m.Put(s[0]); m.Put(s[1]); m.Put(s[2]); m.Put(s[3]);
			s += cx;
			m.Put(s[0]); m.Put(s[1]); m.Put(s[2]); m.Put(s[3]);
			s += cx;
			m.Put(s[0]); m.Put(s[1]); m.Put(s[2]); m.Put(s[3]);
			q += 4;
			m.Get(*t++);
		}
		bs += 4 * cx;
	}
	return tb;
}

struct App : TopWindow {
	Vector<Point> p;

	virtual void LeftDown(Point, dword) {
		Size sz = GetSize() * 4;
		int n = Random(10) + 3;
		p.SetCount(n);
		for(int i = 0; i < n; i++)
			p[i] = Point(Random(sz.cx), Random(sz.cy));
//			p[i] = Point(Random(sz.cx + 30) - 15, Random(sz.cy + 30) - 15);
		Refresh();
	}

	void Plot(ImageBuffer& b, int x, int y) {
		if(Rect(b.GetSize()).Contains(Point(x, y)))
			b[y][x] = Yellow();
	}

	virtual void Paint(Draw& w) {
		ImageBuffer b(GetSize() * 4);
		Fill(b, LtGray(), b.GetLength());
		Image m;
		for(int i = 0; i < 10; i++) {
			RenderPolygon(b, p, Red());
			for(int i = 0; i < p.GetCount(); i++) {
				Point q = p[i];
				Plot(b, q.x, q.y);
				Plot(b, q.x - 1, q.y);
				Plot(b, q.x + 1, q.y);
				Plot(b, q.x, q.y + 1);
				Plot(b, q.x, q.y - 1);
			}
			m = Downscale(b);
		}
		w.DrawImage(0, 0, m);
	}
	
	App() {
		p << Point(20, 20) << Point(200, 20) << Point(230, 150) << Point(120, 200);
	}
};

GUI_APP_MAIN
{
	App().Run();
}