HTML5 Snake Game
Snake game and javascript source code
This is my modification of the HTML5 snake game seen in thecodeplayer.com. You can change all the start parameters using the input form below, just remember to hit r to reload so that the new values take effect. It is very customizable, try it!
p - pause game r - restart game
Options
Below is the javascript code, if you need it. You can also get it here. Of course you’ll need jQuery and some form input fields to get the initial values from in your html page, but this is not difficult to work out at all.
$(document).ready(
function() {
// GLOBAL VARIABLES
// Canvas stuff
canvas = $("#snakecanvas")[0];
ctx = canvas.getContext("2d");
// LOCAL VARIABLES
var d, pause = false;
var food;
var score;
var shape;
// Snake array
var snake_array;
// Initialization function
function init(interval) {
d = "right";
updateCanvasSize();
// block size
cw = parseInt($('#snakeoptions input:text[name="size"]').val());
// block shape
shape = $('#snakeoptions input:radio[name="shape"]:checked').val();
bgcol = $('#snakeoptions input:text[name="bgcol"]').val();
snakecol = $('#snakeoptions input:text[name="snakecol"]').val();
foodcol = $('#snakeoptions input:text[name="foodcol"]').val();
create_snake();
create_food();
score = 0;
if (typeof game_loop != "undefined")
clearInterval(game_loop);
game_loop = setInterval(paint, interval);
}
init(parseInt($('#snakeoptions input:text[name="velocity"]').val()));
function create_snake() {
var length = 4; // Initial length of the snake
snake_array = [];
for ( var i = length - 1; i >= 0; i--) {
// Create snake starting from top left
snake_array.push({
x : i,
y : 0
});
}
}
function create_food() {
food = {
x : Math.round(Math.random() * (w - cw) / cw),
y : Math.round(Math.random() * (h - cw) / cw),
};
}
// Paint the snake
function paint() {
if (pause){
writeText("Game paused", "white", 5, h-5, "15pt")
return;
}
ctx.fillStyle = bgcol;
ctx.fillRect(0, 0, w, h);
ctx.strokeStyle = "black";
ctx.strokeRect(0, 0, w, h);
var nx = snake_array[0].x;
var ny = snake_array[0].y;
if (d == "right")
nx++;
else if (d == "left")
nx--;
else if (d == "up")
ny--;
else if (d == "down")
ny++;
// Lets add the game over clauses now
if (nx == -1 || nx == w / cw || ny == -1 || ny == h / cw
|| check_collision(nx, ny, snake_array)) {
// restart game
init(parseInt($('#snakeoptions input:text[name="velocity"]').val()));
return;
}
// Lets write the code to make the snake eat the food
if (nx == food.x && ny == food.y) {
var tail = {
x : nx,
y : ny
};
score+=10;
create_food();
} else {
var tail = snake_array.pop();
tail.x = nx;
tail.y = ny;
}
snake_array.unshift(tail);
for ( var i = 0; i < snake_array.length; i++) {
var c = snake_array[i];
// Lets paint 10px wide cells
paint_cell(c.x, c.y, snakecol);
}
// Lets paint the food
paint_cell(food.x, food.y, foodcol);
// Lets paint the score
var score_text = "Score: " + score;
writeText(score_text, "black", w-80, h-5, "10pt");
}
function writeText(text, color, px, py, fontSize){
ctx.fillStyle = color;
ctx.font = fontSize + " Calibri";
ctx.fillText(text, px, py);
}
// Lets first create a generic function to paint cells
function paint_cell(x, y, color, shp) {
strokeStyle = "black"
if (shape == "square") {
ctx.fillStyle = color;
ctx.fillRect(x * cw, y * cw, cw, cw);
ctx.strokeStyle = strokeStyle;
ctx.strokeRect(x * cw, y * cw, cw, cw);
} else if (shape == "circle") {
ctx.beginPath();
ctx.arc(x * cw + cw / 2, y * cw + cw / 2, cw / 2, 0,
2 * Math.PI, false);
ctx.fillStyle = color;
ctx.strokeStyle = strokeStyle;
ctx.fill();
ctx.stroke();
}
}
function check_collision(x, y, array) {
for ( var i = 0; i < array.length; i++) {
if (array[i].x == x && array[i].y == y)
return true;
}
return false;
}
// Lets add the keyboard controls now
$(document).keydown(function(e) {
var key = e.which;
// We will add another clause to prevent reverse gear
if (key == "37" && d != "right")
d = "left";
else if (key == "38" && d != "down")
d = "up";
else if (key == "39" && d != "left")
d = "right";
else if (key == "40" && d != "up")
d = "down";
// Key -> p - toggle pause
if (key == "80")
pause = !pause;
// Key -> r - restart
if(key == "82")
init(parseInt($('#snakeoptions input:text[name="velocity"]').val()));
})
});
function updateCanvasSize(){
w = parseInt($('#snakeoptions input:text[name="canvaswidth"]').val()) * parseInt($('#snakeoptions input:text[name="size"]').val());
h = parseInt($('#snakeoptions input:text[name="canvasheight"]').val()) * parseInt($('#snakeoptions input:text[name="size"]').val());
canvas.width = w;
canvas.height = h;
}