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snake.js
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snake.js
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function Snake() {
this.x = 0;
this.y = 0;
this.xSpeed = scale * 1;
this.ySpeed = 0;
this.total = 0;
this.tail = [];
this.draw = () => {
ctx.fillStyle = '#FFFFFF';
// tail growth: draw the snake's tail
for(let i=0; i<this.tail.length; i++) {
ctx.fillRect(this.tail[i].x, this.tail[i].y, scale, scale);
}
ctx.fillRect(this.x, this.y, scale, scale);
}
this.update = () => {
// tail growth: move each pixel forward within the snake
for(let i=0; i<this.tail.length - 1; i++) {
this.tail[i] = this.tail[i+1];
}
// tail growth: update the head pixel to the current pixel
if (this.total > 0) {
this.tail[this.total - 1] = { x: this.x, y: this.y };
}
this.x += this.xSpeed;
this.y += this.ySpeed;
// If we hit the wall, come back from the other side
if (this.x > canvas.width) {
this.x = 0;
}
if (this.x < 0) {
this.x = canvas.width;
}
if (this.y > canvas.height) {
this.y = 0;
}
if (this.y < 0) {
this.y = canvas.height;
}
}
// controlling directions using arrow keys
this.changeDirection = (direction) => {
switch(direction) {
case 'Up':
this.xSpeed = 0;
this.ySpeed = -scale * 1;
break;
case 'Down':
this.xSpeed = 0;
this.ySpeed = scale * 1;
break;
case 'Left':
this.xSpeed = -scale * 1;
this.ySpeed = 0;
break;
case 'Right':
this.xSpeed = scale * 1;
this.ySpeed = 0;
break;
}
}
this.eat = (fruit) => {
// if snake coordinates matches with the fruit, return true (it means snake touched the fruit)
if (this.x === fruit.x && this.y === fruit.y) {
this.total++; // tail growth
return true;
}
return false;
}
}