window.addEventListener("keydown", moveSnake, false);
var game_over = false;
var snake = new Array(4);
var snakeLen = 4;
var dir = "right";
var food = "";
var level = new Array();
var total_height = 640;
var total_width = 640;
var lvl_width = 20;
var lvl_height = 20;
var speed = 16;
snakeHeadImage = new Image();
snakeHeadImage.src = "resources/head.png";
snakeBodyImage = new Image();
snakeBodyImage.src = "resources/body.png";
snakeTailImage = new Image();
snakeTailImage.src = "resources/tail.png";
//food
foodImage = new Image();
foodImage.src = "resources/food.png";
create_snake();
create_food();
for(i = 0; i < lvl_width; i++)
{
level[i] = new Array(lvl_height);
for(var ii = 0; ii < lvl_height; ii++)
{
level[i][ii] = -1;
}
}
window.requestAnimFrame = (function(callback)
{
return window.requestAnimationFrame || window.webkitRequestAnimationFrame || window.mozRequestAnimationFrame || window.oRequestAnimationFrame || window.msRequestAnimationFrame ||
function(callback)
{
window.setTimeout(callback, 1000);
};
})();
var the_date = new Date();
var test1 = the_date.getTime();
var stamp = the_date.getTime() + 250;
function animate()
{
the_date = new Date();
test1 = the_date.getTime();
if(stamp <= test1)
{
move_snake();
the_date = new Date();
stamp = the_date.getTime() + 250;
}
if(game_over == false)
{
// clear
context.clearRect(0, 0, canvas.width, canvas.height);
displayText("Score: " + (snakeLen - 4));
display();
}
else
{
displayText("You so Sux.. Game Over homie");
}
//context.drawImage(aniblock, aniblock_x, aniblock_y);
// request new frame
requestAnimFrame(function()
{
animate();
});
}
function displayText(what)
{
context.font = "30px Arial";
context.fillText(what, 50, 50);
}
function checkSnakeCollide()
{
if( snake[0].xx == food.xx && snake[0].yy == food.yy )
{
create_food();
return true;
}
else
{
//if head moving right
if(dir == "right")
{
if(snake[0].xx > lvl_width - 1)
{
game_over = true;
}
}
else if(dir == "left")
{
if(snake[0].xx < 0)
{
game_over = true;
}
}
else if(dir == "up")
{
if(snake[0].yy <= -1)
{
game_over = true;
}
}
else if(dir = "down")
{
if(snake[0].yy >= lvl_height)
{
game_over = true;
}
}
for(i = 2; i < snakeLen; i++)
{
if( (snake[0].xx == snake[i].xx) && (snake[0].yy == snake[i].yy) )
{
game_over = true;
break;
}
}
return false;
}
}
setTimeout(function() {
animate();
}, 1000);
function moveSnake(e)
{
switch(e.keyCode)
{
case 37:
if(dir != "right")
{
dir = "left";
}
break;
case 38:
if(dir != "down")
{
dir = "up";
}
break;
case 39:
if(dir != "left")
{
dir = "right";
}
break;
case 40:
if(dir != "up")
{
dir = "down";
}
break;
}
}
function checkAllowMove(x, y)
{
if(x < 32)
{
var x_index = 0;
}
else
{
var x_index = Math.round(x / 32);
}
if(y < 32)
{
var y_index = 19;
}
else
{
var y_index = (total_height / 32) - Math.round(y / 32);
}
if(level[x_index][y_index] == -1)
{
return true;
}
else
{
return false;
}
}
function create_food()
{
var x = 0;
var y = 0;
var recreate = false;
do
{
recreate = false;
x = Math.floor((Math.random() * (lvl_width-1)));
y = Math.floor((Math.random() * (lvl_height-1)));
for(i = 0; i < snakeLen; i++)
{
if( (snake[i].xx == x) && (snake[i].yy == y) )
{
recreate = true;
break;
}
}
}while(recreate == true);
food = {xx: x, yy: y};
}
function create_snake()
{
//var x = Math.floor((Math.random() * (lvl_width-1)));
//var y = Math.floor((Math.random() * (lvl_height-1)));
snake[0] = {xx: 4, yy: 1};
snake[1] = {xx: 3, yy: 1};
snake[2] = {xx: 2, yy: 1};
snake[3] = {xx: 1, yy: 1};
dir = "right";
}
function move_snake()
{
var temp_x = 0;
var temp_y = 0;
var temp_xx = 0;
var temp_yy = 0;
var swap = true;
//move snake forward
for(var ii = 0; ii < snakeLen; ii++)
{
if(ii == 0)
{
temp_x = snake[ii].xx;
temp_y = snake[ii].yy;
//if head moving right
if(dir == "right")
{
snake[0] = {xx: (snake[0].xx + 1), yy: snake[0].yy};
}
else if(dir == "left")
{
snake[0] = {xx: (snake[0].xx - 1), yy: snake[0].yy};
}
else if(dir == "up")
{
snake[0] = {xx: snake[0].xx, yy: (snake[0].yy - 1)};
}
else if(dir = "down")
{
snake[0] = {xx: snake[0].xx, yy: (snake[0].yy + 1)};
}
if(checkSnakeCollide())
{
snake.push({xx: snake[(snake.length-1)].xx, yy: snake[(snake.length-1)].yy});
snakeLen++;
}
}
else
{
if(swap == true)
{
temp_xx = snake[ii].xx;
temp_yy = snake[ii].yy;
snake[ii] = {xx: temp_x, yy: temp_y};
swap = false;
}
else
{
temp_x = snake[ii].xx;
temp_y = snake[ii].yy;
snake[ii] = {xx: temp_xx, yy: temp_yy};
swap = true;
}
}
}
}
function display()
{
for(var i = 0; i < snakeLen; i++)
{
if(i == 0)
{
switch (dir)
{
case "left":
context.drawImage(snakeHeadImage, (snake[i].xx * 32), (snake[i].yy * 32) );
break;
case "right":
drawRotatedImage(snakeHeadImage,(snake[i].xx * 32), (snake[i].yy * 32), 180);
break;
case "up":
drawRotatedImage(snakeHeadImage,(snake[i].xx * 32), (snake[i].yy * 32), 90);
break;
case "down":
drawRotatedImage(snakeHeadImage,(snake[i].xx * 32), (snake[i].yy * 32), 270);
break;
}
}
else if(i == (snakeLen - 1) )
{
//following left
if(snake[i].xx > snake[i-1].xx)
{
context.drawImage(snakeTailImage, (snake[i].xx * 32), (snake[i].yy * 32) );
}
//following right
else if(snake[i].xx < snake[i-1].xx)
{
drawRotatedImage(snakeTailImage,(snake[i].xx * 32), (snake[i].yy * 32), 180);
}
//following up
else if(snake[i].yy > snake[i-1].yy)
{
drawRotatedImage(snakeTailImage,(snake[i].xx * 32), (snake[i].yy * 32), 90);
}
//following down
else if(snake[i].yy < snake[i-1].yy)
{
drawRotatedImage(snakeTailImage,(snake[i].xx * 32), (snake[i].yy * 32), 270);
}
}
else
{
context.drawImage(snakeBodyImage, (snake[i].xx * 32), (snake[i].yy * 32) );
}
}
context.drawImage(foodImage, (food.xx * 32), (food.yy * 32) );
}
function drawRotatedImage(image, x, y, angle)
{
var TO_RADIANS = Math.PI/180;
// save the current co-ordinate system
// before we screw with it
context.save();
// move to the middle of where we want to draw our image
context.translate(x, y);
// rotate around that point, converting our
// angle from degrees to radians
context.rotate(angle * TO_RADIANS);
// draw it up and to the left by half the width
// and height of the image
context.drawImage(image, -(image.width/2), -(image.height/2));
// and restore the co-ords to how they were when we began
context.restore();
}
