<!DOCTYPE html>
<html>
<head>
<script type="text/javascript">
var ctx = null;
var gameMap = [
0, 0, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 2, 4, 4, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 2, 2, 0,
0, 2, 3, 4, 4, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 2, 2, 0,
0, 2, 3, 1, 4, 4, 1, 1, 2, 2, 2, 2, 1, 1, 2, 2, 2, 2, 2, 0,
0, 2, 3, 1, 1, 4, 4, 1, 2, 3, 3, 2, 1, 1, 2, 1, 0, 0, 0, 0,
0, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 2, 2, 2, 2, 1, 1, 1, 1, 0,
0, 1, 1, 1, 1, 2, 4, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 0,
0, 1, 1, 1, 1, 2, 4, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 0,
0, 1, 1, 1, 1, 2, 4, 4, 4, 4, 4, 1, 1, 1, 2, 2, 2, 2, 1, 0,
0, 1, 1, 1, 1, 2, 3, 2, 1, 1, 4, 1, 1, 1, 1, 3, 3, 2, 1, 0,
0, 1, 2, 2, 2, 2, 1, 2, 1, 1, 4, 1, 1, 1, 1, 1, 3, 2, 1, 0,
0, 1, 2, 3, 3, 2, 1, 2, 1, 1, 4, 4, 4, 4, 4, 4, 4, 2, 4, 4,
0, 1, 2, 3, 3, 2, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 0,
0, 1, 2, 3, 4, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, 0, 1, 2, 1, 0,
0, 3, 2, 3, 4, 4, 1, 2, 2, 2, 2, 2, 2, 2, 1, 0, 1, 2, 1, 0,
0, 3, 2, 3, 4, 4, 3, 2, 1, 1, 1, 1, 1, 2, 1, 1, 1, 2, 3, 0,
0, 3, 2, 3, 4, 1, 3, 2, 1, 3, 1, 1, 1, 2, 1, 1, 1, 2, 3, 0,
0, 1, 2, 2, 2, 2, 2, 2, 3, 3, 3, 1, 1, 2, 2, 2, 2, 2, 3, 0,
0, 1, 1, 1, 1, 1, 1, 3, 3, 3, 3, 3, 1, 1, 1, 1, 1, 1, 4, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
];
var tileW = 40, tileH = 40;
var mapW = 20, mapH = 20;
var currentSecond = 0, frameCount = 0, framesLastSecond = 0, lastFrameTime = 0;
var floorTypes = {
solid : 0,
path : 1,
water : 2
};
var tileTypes = {
0 : { colour:"#685b48", floor:floorTypes.solid },
1 : { colour:"#5aa457", floor:floorTypes.path },
2 : { colour:"#e8bd7a", floor:floorTypes.path },
3 : { colour:"#286625", floor:floorTypes.solid },
4 : { colour:"#678fd9", floor:floorTypes.water }
};
var keysDown = {
37 : false,
38 : false,
39 : false,
40 : false
};
var viewport = {
screen : [0,0],
startTile : [0,0],
endTile : [0,0],
offset : [0,0],
update : function(px, py) {
this.offset[0] = Math.floor((this.screen[0]/2) - px);
this.offset[1] = Math.floor((this.screen[1]/2) - py);
var tile = [ Math.floor(px/tileW), Math.floor(py/tileH) ];
this.startTile[0] = tile[0] - 1 - Math.ceil((this.screen[0]/2) / tileW);
this.startTile[1] = tile[1] - 1 - Math.ceil((this.screen[1]/2) / tileH);
if(this.startTile[0] < 0) { this.startTile[0] = 0; }
if(this.startTile[1] < 0) { this.startTile[1] = 0; }
this.endTile[0] = tile[0] + 1 + Math.ceil((this.screen[0]/2) / tileW);
this.endTile[1] = tile[1] + 1 + Math.ceil((this.screen[1]/2) / tileH);
if(this.endTile[0] >= mapW) { this.endTile[0] = mapW-1; }
if(this.endTile[1] >= mapH) { this.endTile[1] = mapH-1; }
}
};
var player = new Character();
function Character()
{
this.tileFrom = [1,1];
this.tileTo = [1,1];
this.timeMoved = 0;
this.dimensions = [30,30];
this.position = [45,45];
this.delayMove = 700;
}
Character.prototype.placeAt = function(x, y)
{
this.tileFrom = [x,y];
this.tileTo = [x,y];
this.position = [((tileW*x)+((tileW-this.dimensions[0])/2)),
((tileH*y)+((tileH-this.dimensions[1])/2))];
};
Character.prototype.processMovement = function(t)
{
if(this.tileFrom[0]==this.tileTo[0] && this.tileFrom[1]==this.tileTo[1]) { return false; }
if((t-this.timeMoved)>=this.delayMove)
{
this.placeAt(this.tileTo[0], this.tileTo[1]);
}
else
{
this.position[0] = (this.tileFrom[0] * tileW) + ((tileW-this.dimensions[0])/2);
this.position[1] = (this.tileFrom[1] * tileH) + ((tileH-this.dimensions[1])/2);
if(this.tileTo[0] != this.tileFrom[0])
{
var diff = (tileW / this.delayMove) * (t-this.timeMoved);
this.position[0]+= (this.tileTo[0]<this.tileFrom[0] ? 0 - diff : diff);
}
if(this.tileTo[1] != this.tileFrom[1])
{
var diff = (tileH / this.delayMove) * (t-this.timeMoved);
this.position[1]+= (this.tileTo[1]<this.tileFrom[1] ? 0 - diff : diff);
}
this.position[0] = Math.round(this.position[0]);
this.position[1] = Math.round(this.position[1]);
}
return true;
}
Character.prototype.canMoveTo = function(x, y)
{
if(x < 0 || x >= mapW || y < 0 || y >= mapH) { return false; }
if(tileTypes[gameMap[toIndex(x,y)]].floor!=floorTypes.path) { return false; }
return true;
};
Character.prototype.canMoveUp = function() { return this.canMoveTo(this.tileFrom[0], this.tileFrom[1]-1); };
Character.prototype.canMoveDown = function() { return this.canMoveTo(this.tileFrom[0], this.tileFrom[1]+1); };
Character.prototype.canMoveLeft = function() { return this.canMoveTo(this.tileFrom[0]-1, this.tileFrom[1]); };
Character.prototype.canMoveRight = function() { return this.canMoveTo(this.tileFrom[0]+1, this.tileFrom[1]); };
Character.prototype.moveLeft = function(t) { this.tileTo[0]-=1; this.timeMoved = t; };
Character.prototype.moveRight = function(t) { this.tileTo[0]+=1; this.timeMoved = t; };
Character.prototype.moveUp = function(t) { this.tileTo[1]-=1; this.timeMoved = t; };
Character.prototype.moveDown = function(t) { this.tileTo[1]+=1; this.timeMoved = t; };
function toIndex(x, y)
{
return((y * mapW) + x);
}
window.onload = function()
{
ctx = document.getElementById('game').getContext("2d");
requestAnimationFrame(drawGame);
ctx.font = "bold 10pt sans-serif";
window.addEventListener("keydown", function(e) {
if(e.keyCode>=37 && e.keyCode<=40) { keysDown[e.keyCode] = true; }
});
window.addEventListener("keyup", function(e) {
if(e.keyCode>=37 && e.keyCode<=40) { keysDown[e.keyCode] = false; }
});
viewport.screen = [document.getElementById('game').width,
document.getElementById('game').height];
};
function drawGame()
{
if(ctx==null) { return; }
var currentFrameTime = Date.now();
var timeElapsed = currentFrameTime - lastFrameTime;
var sec = Math.floor(Date.now()/1000);
if(sec!=currentSecond)
{
currentSecond = sec;
framesLastSecond = frameCount;
frameCount = 1;
}
else { frameCount++; }
if(!player.processMovement(currentFrameTime))
{
if(keysDown[38] && player.canMoveUp()) { player.moveUp(currentFrameTime); }
else if(keysDown[40] && player.canMoveDown()) { player.moveDown(currentFrameTime); }
else if(keysDown[37] && player.canMoveLeft()) { player.moveLeft(currentFrameTime); }
else if(keysDown[39] && player.canMoveRight()) { player.moveRight(currentFrameTime); }
}
viewport.update(player.position[0] + (player.dimensions[0]/2),
player.position[1] + (player.dimensions[1]/2));
ctx.fillStyle = "#000000";
ctx.fillRect(0, 0, viewport.screen[0], viewport.screen[1]);
for(var y = viewport.startTile[1]; y <= viewport.endTile[1]; ++y)
{
for(var x = viewport.startTile[0]; x <= viewport.endTile[0]; ++x)
{
ctx.fillStyle = tileTypes[gameMap[toIndex(x,y)]].colour;
ctx.fillRect( viewport.offset[0] + (x*tileW), viewport.offset[1] + (y*tileH),
tileW, tileH);
}
}
ctx.fillStyle = "#0000ff";
ctx.fillRect(viewport.offset[0] + player.position[0], viewport.offset[1] + player.position[1],
player.dimensions[0], player.dimensions[1]);
ctx.fillStyle = "#ff0000";
ctx.fillText("FPS: " + framesLastSecond, 10, 20);
lastFrameTime = currentFrameTime;
requestAnimationFrame(drawGame);
}
</script>
</head>
<body>
<canvas id="game" width="400" height="400"></canvas>
</body>
</html>
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1More Tile types and Character movement methods2Code showing modifications3More Tile types and Character movement source codeWatch Video
Point in Circle
Intermediate
A simple method for testing if a 2D coordinate falls inside the area of a given circle.
