<!doctype html>
<html>
<head>
<meta charset="utf-8">
<style>
body {
background-color: black;
}
canvas {
display: block;
margin: 30px auto 0px auto;
border: solid 1px white;
border-radius: 10px;
}
</style>
</head>
<body>
<canvas id="canvas"></canvas>
<script type="application/javascript">
var svg = function() {
"use strict";
var svgImages = [];
var areImagesLoaded = true;
var isPageLoaded = false;
addEventListener("load",function() { isPageLoaded = true; isFinished(); });
var exports = {
onload: function() {},
request: null,
get: null
};
function isFinished() {
if (isPageLoaded && areImagesLoaded) {
exports.onload();
}
}
function onSvgError() {
this.isDone = true;
console.warn("SVG " + this.src + " failed to load.");
}
function onSvgLoaded() {
this.isDone = true;
for (var id in svgImages) {
if (!svgImages[id].isDone) {
return;
}
}
areImagesLoaded = true;
isFinished();
}
function request(id,path) {
if (svgImages[id]) {
return;
}
areImagesLoaded = false;
var img = document.createElement("img");
img.onerror = onSvgError;
img.onload = onSvgLoaded;
img.isDone = false;
img.id = id;
img.src = path;
svgImages[id] = img;
}
function get(id) {
return svgImages[id];
}
exports.request = request;
exports.get = get;
return exports;
}();
var board = function() {
"use strict";
var canvasWidth = 0;
var canvasHeight = 0;
var canvas = null;
var ctx = null;
var frameRequested = false;
var tileWidth = 0;
var tileHeight = 0;
var tileTypes = [];
var boardWidth = 0;
var boardHeight = 0;
var board = [];
var hasInitialized = false;
var camera = {
x: 0.0,
y: 0.0,
zoom: 1.0
};
function mapToBoard(x,y) {
var invZoom = 1.0 / camera.zoom;
return [
(x - (canvasWidth >> 1)) * invZoom - camera.x,
(y - (canvasHeight >> 1)) * invZoom - camera.y
];
}
var isMouseDragging = false;
var mouseStartX = 0;
var mouseStartY = 0;
var mouseLastX = 0;
var mouseLastY = 0;
var tileEvent = {
background: "",
foreground: "",
x: 0,
y: 0
};
function onTileSelected(e) {
}
function onMouseDown(e) {
isMouseDragging = true;
var bounds = canvas.getBoundingClientRect();
mouseStartX = mouseLastX = e.clientX - bounds.left;
mouseStartY = mouseLastY = e.clientY - bounds.top;
}
function onMouseUp(e) {
isMouseDragging = false;
var bounds = canvas.getBoundingClientRect()
var x = e.clientX - bounds.left - mouseStartX;
var y = e.clientY - bounds.top - mouseStartY;
var l = Math.sqrt(x * x + y * y);
if (l < 2.0) {
[x,y] = mapToBoard(e.clientX - bounds.left,e.clientY - bounds.top);
if (x > 0 && y > 0 && x < boardWidth * tileWidth && y < boardHeight * tileHeight) {
x = (x / tileWidth) | 0;
y = (y / tileHeight) | 0;
var tile = board[x + y * boardWidth];
tileEvent.background = tile.background;
tileEvent.foreground = tile.foreground;
tileEvent.x = x;
tileEvent.y = y;
} else {
tileEvent.background = "";
tileEvent.foreground = "";
tileEvent.x = -1;
tileEvent.y = -1;
}
onTileSelected(tileEvent);
}
}
function onMouseMove(e) {
if (hasInitialized && isMouseDragging) {
var bounds = canvas.getBoundingClientRect();
var x = e.clientX - bounds.left;
var y = e.clientY - bounds.top;
camera.x += (x - mouseLastX) / camera.zoom;
camera.y += (y - mouseLastY) / camera.zoom;
mouseLastX = x;
mouseLastY = y;
requestDraw();
}
}
function onWheel(e) {
if (Math.sign(e.deltaY) === -1) {
camera.zoom *= 1.1;
} else {
camera.zoom *= 0.9;
}
requestDraw();
}
function draw() {
ctx.fillStyle = "gray";
ctx.fillRect(-canvasWidth >> 1,-canvasHeight >> 1,canvasWidth,canvasHeight);
var _tileWidth = tileWidth * camera.zoom;
var _tileHeight = tileHeight * camera.zoom;
var _ox = camera.x * camera.zoom;
var _oy = camera.y * camera.zoom;
var _x = _ox;
var _y = _oy;
for (var x = 0; x <boardWidth; ++x) {
for (var y = 0; y < boardHeight; ++y) {
var index = x + y * boardWidth;
var tile = board[index];
var background = tileTypes[tile.background];
var foreground = tileTypes[tile.foreground];
if (background) {
ctx.drawImage(
background,
_x,
_y,
_tileWidth,
_tileHeight
);
}
if (foreground) {
ctx.drawImage(
foreground,
_x,
_y,
_tileWidth,
_tileHeight
);
}
_y += _tileHeight;
}
_y = _oy;
_x += _tileWidth;
}
frameRequested = false;
}
function requestDraw() {
if (!frameRequested) {
frameRequested = true;
requestAnimationFrame(draw);
}
}
return {
BACKGROUND: 0,
FOREGROUND: 1,
set canvas(canvasID) {
if (!hasInitialized) {
canvas = document.getElementById(canvasID);
canvas.onmousedown = onMouseDown;
canvas.onmouseup = onMouseUp;
canvas.onmousemove = onMouseMove;
canvas.onwheel = onWheel;
ctx = canvas.getContext("2d");
}
},
set canvasWidth(w) {
if (!hasInitialized && canvas) {
canvasWidth = canvas.width = w;
}
},
set canvasHeight(h) {
if (!hasInitialized && canvas) {
canvasHeight = canvas.height = h;
}
},
set tileWidth(w) {
if (!hasInitialized) {
tileWidth = w;
}
},
set tileHeight(h) {
if (!hasInitialized) {
tileHeight = h;
}
},
set width(w) {
if (!hasInitialized) {
boardWidth = w;
}
},
set height(h) {
if (!hasInitialized) {
boardHeight = h;
}
},
set onTileSelected(callback) {
onTileSelected = callback;
},
get width() {
return boardWidth;
},
get height() {
return boardHeight;
},
get onTileSelected() {
return onTileSelected;
},
defineTileTypes: function(types) {
if (types.length % 2 !== 0) {
return;
}
for (var i = 0; i < types.length; i += 2) {
var id = types[i];
var img = types[i + 1];
tileTypes[id] = img;
}
},
init: function() {
camera.x = -(boardWidth >> 1) * tileWidth;
camera.y = -(boardHeight >> 1) * tileHeight;
ctx.translate(canvasWidth >> 1,canvasHeight >> 1);
board.length = boardWidth * boardHeight;
for (var i = 0; i < board.length; ++i) {
board[i] = {
background: "",
foreground: ""
};
}
hasInitialized = true;
requestAnimationFrame(draw);
},
set: function(type,id,x,y) {
if (hasInitialized
&& tileTypes[id]
&& x > -1
&& x < boardWidth
&& y > -1
&& y < boardHeight) {
var index = x + y * boardWidth;
if (type === this.BACKGROUND) {
board[index].background = id;
} else {
board[index].foreground = id;
}
requestDraw();
}
}
};
}();
void function() {
"use strict";
svg.request("grass","https://i.stack.imgur.com/CkvU7.png");
svg.request("water","https://i.stack.imgur.com/an6a5.png");
svg.onload = function() {
board.canvas = "canvas";
board.canvasWidth = 180;
board.canvasHeight = 160;
board.tileWidth = 25;
board.tileHeight = 25;
board.width = 20;
board.height = 20;
board.defineTileTypes([
"GRASS",svg.get("grass"),
"WATER",svg.get("water")
]);
board.init();
for (var x = 0; x < board.width; ++x) {
for (var y = 0; y < board.height; ++y) {
board.set(board.BACKGROUND,"WATER",x,y);
if (Math.random() > 0.2) {
board.set(board.BACKGROUND,"GRASS",x,y);
} else {
board.set(board.BACKGROUND,"WATER",x,y);
}
}
}
}
board.onTileSelected = function(e) {
if (e.background === "GRASS") {
board.set(board.BACKGROUND,"WATER",e.x,e.y);
} else {
board.set(board.BACKGROUND,"GRASS",e.x,e.y);
}
}
}();
</script>
</body>
</html>