var nodeWH = 10
var direction = 'right'
var timer = null
var nodes=[]
var food = null
var context = wx.createContext()
var lastPoint = null
var isGameOver = false
var that
var score = 0
function Node(x,y){
this.x = x;
this.y = y;
}
function createSnake(){
nodes.splice(0, nodes.length)
for (var i = 4; i >= 0; i--) {
var node = new Node(nodeWH * (i + 0.5), nodeWH * 0.5)
nodes.push(node);
}
}
function createFood(){
var x = parseInt(Math.random() * 24) * nodeWH + nodeWH * 0.5
var y = parseInt(Math.random() * 34) * nodeWH + nodeWH * 0.5
//如果食物的坐标在蛇身上，则重新创建
for (var i = 0; i < nodes.length; i++) {
var node = nodes[i]
if (node.x == x && node.y == y) {
createFood()
return
}
}
food = new Node(x,y)
}
//绘制蛇与食物
function draw(){
for (var i = 0; i < nodes.length; i++) {
var node = nodes[i]
if (i == 0) {
context.setFillStyle('#ff0000')
} else {
context.setFillStyle('#000000')
}
context.beginPath()
context.rect(node.x, node.y, nodeWH, nodeWH)
context.closePath()
context.fill()
}
context.setFillStyle('#0000ff')
context.beginPath()
context.rect(food.x, food.y, nodeWH, nodeWH)
context.closePath()
context.fill()
wx.drawCanvas({
canvasId: 'snakeCanvas',
actions: context.getActions()
})
}
//游戏结束
function gameOver(){
isGameOver = true
clearInterval(timer)
wx.showModal({
title:'Game Over',
content:'总得分：'+ score +'，不服再来?',
confirmText:'不服',
success:function(e){
if (e.confirm == true) {
startGame()
} else {
console.log('cancel')
that.setData({
btnTitle:'开始'
})
}
}
})
}
//是否吃到食物
function isEatedFood(){
var head = nodes[0]
if (head.x == food.x && head.y == food.y) {
score++
nodes.push(lastPoint)
createFood()
}
}
//是否撞到墙壁或者撞到自己的身体
function isDestroy(){
var head = nodes[0]
for (var i = 1; i < nodes.length; i++) {
var node = nodes[i]
if (head.x == node.x && head.y == node.y) {
gameOver()
}
}
if (head.x < 5 || head.x > 245) {
gameOver()
}
if (head.y < 5 || head.y > 345) {
gameOver()
}
}
function moveEnd(){
isEatedFood()
isDestroy()
draw()
}
function move(){
lastPoint = nodes[nodes.length - 1]
var node = nodes[0]
var newNode = {x: node.x, y: node.y}
switch (direction) {
case 'up':
newNode.y -= nodeWH;
break;
case 'left':
newNode.x -= nodeWH;
break;
case 'right':
newNode.x += nodeWH;
break;
case 'down':
newNode.y += nodeWH;
break;
}
nodes.pop()
nodes.unshift(newNode)
moveEnd()
}
function startGame() {
if (isGameOver) {
direction = 'right'
createSnake()
createFood()
score = 0
isGameOver = false
}
timer = setInterval(move,300)
}
Page({
data:{
btnTitle:'开始'
},
onLoad:function(){
that = this
createSnake()
createFood()
draw()
},
changeDirection:function(e){
if ('开始' == this.data.btnTitle) return
var title = e.target.id
if (title == 'down' || title == 'up') {
if (direction == 'up' || direction == 'down') return
} else if (direction == 'left' || direction == 'right') return
direction = title;
},
startGame:function() {
var title = this.data.btnTitle
if (title == '暂停') {
clearInterval(timer)
this.setData({
btnTitle : '开始'
})
} else {
startGame()
this.setData({
btnTitle : '暂停'
})
}
}
})
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