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$(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;
}
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