}

	void _onResize() {
		int scale = min(window.innerWidth~/width, window.innerHeight~/height);
		_canvas.width = width*scale;
		_canvas.height = height*scale;
		_canvas.context2D.scale(scale,scale);

		var left = (window.innerWidth-_canvas.width) ~/ 2;
		var top = (window.innerHeight-_canvas.height) ~/ 2;
		_canvas.style.left = left.toString() + 'px';
		_canvas.style.top = top.toString() + 'px';
		_canvas.context2D.imageSmoothingEnabled = false;
	}

	void _step(num timestamp) {
		if(!_preloaded && _load.loaded == 0) {
			_preloaded = true;
			_last_timestamp = timestamp;
			onLoad();

import 'dart:html';

// l + 2*ul + 4*u
// nah, l, ul, l+ul, u, u+l, u+ul, u+ul+l
//const int _autotile_a = [0, 12, 0, 12, 8, 4, 8, 16];
int _autotile_a = [
[0.0,0.0],[3.0,0.0],[0.0,0.0],[3.0,0.0],[2.0,0.0],[1.0,0.0],[2.0,0.0],[4.0,0.0]
];

// u + 2*ur + 4*r
// nah, u, ur, u+ur, r, u+r, ur+r, u+ur+r
//const int _autotile_b = [1, 9, 1, 9, 13, 5, 13, 17];
int _autotile_b = [
[0.5,0.0],[2.5,0.0],[0.5,0.0],[2.5,0.0],[3.5,0.0],[1.5,0.0],[3.5,0.0],[4.5,0.0]
];

// d + 2*dl + 4*l
// nah, d, dl, d+dl, l, d+l, dl+l, d+dl+l
//const int _autotile_c = [2, 10, 2, 10, 14, 6, 14, 18];
int _autotile_c = [
[0.0,0.5],[2.0,0.5],[0.0,0.5],[2.0,0.5],[3.0,0.5],[1.0,0.5],[3.0,0.5],[4.0,0.5]
];

// r + 2*dr + 4*d
// nah, r, dr, r+dr, d, r+d, dr+d, r+dr+d
//const int _autotile_d = [3, 15, 3, 15, 11, 7, 11, 19];
int _autotile_d = [
[0.5,0.5],[3.5,0.5],[0.5,0.5],[3.5,0.5],[2.5,0.5],[1.5,0.5],[2.5,0.5],[4.5,0.5]
];


class Tileset {
	ImageElement _img;
	int _tileW, _tileH, _spacing;
	Tileset(this._img, this._tileW, this._tileH, this._spacing) {
		
	}
	
	int tileCountX() {
		return ((_img.width+_spacing) / (_tileW+_spacing)).floor();
	}
}

class AutoTileset {
	ImageElement _img;
	int _tileW, _tileH;
	AutoTileset(this._img, this._tileW, this._tileH) {
		
	}
}

class Context {
	CanvasRenderingContext2D _ctx;
	Context(this._ctx);
	void draw(ImageElement img, int x, int y) {
		_ctx.drawImage(img, x, y);
	}

	void rect(int x, int y, int w, int h) {
		_ctx.fillRect(x, y, w, h);
	}

	void drawTile(Tileset tileset, int tile, int x, int y) {
		int tcx = tileset.tileCountX();
		int tx = tile % tcx;
		int ty = tile ~/ tcx;
		int posx = tx*(tileset._tileW+tileset._spacing);
		int posy = ty*(tileset._tileH+tileset._spacing);
		var src = new Rectangle(posx, posy, tileset._tileW, tileset._tileH);
		var dst = new Rectangle(x, y, tileset._tileW, tileset._tileH);
		_ctx.drawImageToRect(tileset._img, dst, sourceRect: src);
	}

	void drawAutoTile(AutoTileset tileset, int tile, int x, int y,
		bool ul, bool u, bool ur, bool r, bool dr, bool d, bool dl, bool l)
	{
		var tile_a = _autotile_a[(l?1:0) + (ul?2:0) + (u?4:0)];
		var tile_b = _autotile_b[(u?1:0) + (ur?2:0) + (r?4:0)];
		var tile_c = _autotile_c[(d?1:0) + (dl?2:0) + (l?4:0)];
		var tile_d = _autotile_d[(r?1:0) + (dr?2:0) + (d?4:0)];
		int tw2 = tileset._tileW/2;
		int th2 = tileset._tileH/2;
		
		var srcA = new Rectangle(
			tile_a[0] * tileset._tileW, (tile_a[1]+tile) * tileset._tileW, 
			tileset._tileW/2, tileset._tileH/2);
		var dstA = new Rectangle(x,y,tileset._tileW/2,tileset._tileH/2);

		var srcB = new Rectangle(
			tile_b[0] * tileset._tileW, (tile_b[1]+tile) * tileset._tileW, 
			tileset._tileW/2, tileset._tileH/2);
		var dstB = new Rectangle(x+tw2,y,tileset._tileW/2,tileset._tileH/2);

		var srcC = new Rectangle(
			tile_c[0] * tileset._tileW, (tile_c[1]+tile) * tileset._tileW, 
			tileset._tileW/2, tileset._tileH/2);
		var dstC = new Rectangle(x,y+th2,tileset._tileW/2,tileset._tileH/2);

		var srcD = new Rectangle(
			tile_d[0] * tileset._tileW, (tile_d[1]+tile) * tileset._tileW, 
			tileset._tileW/2, tileset._tileH/2);
		var dstD = new Rectangle(x+tw2,y+th2,tileset._tileW/2,tileset._tileH/2);

		_ctx.drawImageToRect(tileset._img, dstA, sourceRect: srcA);
		_ctx.drawImageToRect(tileset._img, dstB, sourceRect: srcB);
		_ctx.drawImageToRect(tileset._img, dstC, sourceRect: srcC);
		_ctx.drawImageToRect(tileset._img, dstD, sourceRect: srcD);
	}
}

class Loader {
	int loaded = 0;
	ImageElement image(String url) {
		var img = new ImageElement(src: url);
		loaded -= 1;
		img.onLoad.listen((e) => loaded += 1);
		return img;
	}

	Tileset tileset(String url, int tileWidth, int tileHeight,
	                {int spacing = 0}) {
		return new Tileset(image(url), tileWidth, tileHeight, spacing);
	}

	AutoTileset autoTileset(String url, int tileWidth, int tileHeight) {
		return new AutoTileset(image(url), tileWidth, tileHeight);
	}
}

import 'dart:html';
import 'package:playtypus/playtypus.dart';

class MyGame extends Game {
	ImageElement img;
	Tileset tileset;
	AutoTileset auto;
	int tick = 0;
	MyGame() : super(320,180) {}
	
	void onPreload(Loader load) {
		img = load.image("tileset.png");
		tileset = load.tileset("tileset.png", 16, 16, spacing: 1);
		auto = load.autoTileset("tileset_a1.png", 16, 16);
	}
	
	void onLoad() {
	}
	
	void onRender(Context ctx) {
		ctx.rect(0,0,500,600);
		//ctx.draw(img, 0, 0);
		int tile = (tick ~/ 10);
		for(int x = 0; x < 20; ++x)
			for(int y = 0; y < 11; ++y)
				ctx.drawAutoTile(auto, 1, x*16, y*16, false, false, false, false, false, false, false, false);
				//ctx.drawTile(tileset, tile+x+y*20, x*16, y*16);
	}
	void onTick() {
		tick += 1;
	}
		
}