JS中实现A*算法寻路

提示：扫一扫查出行
【扫一扫了解最新限行尾号】
复制提示

<html><head><title>use A* to find path...</title></head>
<body style="margin:0px">
<script>
/*
written by hjjboy
email:tianmashuangyi@163.com
qq:156809986
*/
var closelist=new Array(),openlist=new Array();
var gw=10,gh=10,gwh=14;
var p_start=new Array(2),p_end=new Array(2);
var s_path,n_path="";
var num,bg,flag=0;
var w=30,h=20;
function GetRound(pos){
var a=new Array();
a[0]=(pos[0]+1)+","+(pos[1]-1);
a[1]=(pos[0]+1)+","+pos[1];
a[2]=(pos[0]+1)+","+(pos[1]+1);
a[3]=pos[0]+","+(pos[1]+1);
a[4]=(pos[0]-1)+","+(pos[1]+1);
a[5]=(pos[0]-1)+","+pos[1];
a[6]=(pos[0]-1)+","+(pos[1]-1);
a[7]=pos[0]+","+(pos[1]-1);
return a;
}
function GetF(arr){
var t,G,H,F;
for(var i=0;i<arr.length;i++){
t=arr[i].split(",");
t[0]=parseInt(t[0]);t[1]=parseInt(t[1]);
if(IsOutScreen([t[0],t[1]])||IsPass(arr[i])||InClose([t[0],t[1]])||IsStart([t[0],t[1]])||!IsInTurn([t[0],t[1]]))
continue;
if((t[0]-s_path[3][0])*(t[1]-s_path[3][1])!=0)
G=s_path[1]+gwh;
else
G=s_path[1]+gw;
if(InOpen([t[0],t[1]])){
if(G<openlist[num][1]){
openlist[num][0]=(G+openlist[num][2]);
openlist[num][1]=G;
openlist[num][4]=s_path[3];
}
else{G=openlist[num][1];}
}
else{
H=(Math.abs(p_end[0]-t[0])+Math.abs(p_end[1]-t[1]))*gw;
F=G+H;
arr[i]=new Array();
arr[i][0]=F;arr[i][1]=G;arr[i][2]=H;arr[i][3]=[t[0],t[1]];arr[i][4]=s_path[3];
openlist[openlist.length]=arr[i];
}
if(maptt.rows[t[1]].cells[t[0]].style.backgroundColor!="#cccccc"&&maptt.rows[t[1]].cells[t[0]].style.backgroundColor!="#0000ff"&&maptt.rows[t[1]].cells[t[0]].style.backgroundColor!="#ff0000"&&maptt.rows[t[1]].cells[t[0]].style.backgroundColor!="#00ff00")
{
maptt.rows[t[1]].cells[t[0]].style.backgroundColor="#FF00FF";
//maptt.rows[t[1]].cells[t[0]].innerHTML="<font color=white>"+G+"</font>";
}
}
}
function IsStart(arr){
if(arr[0]==p_start[0]&&arr[1]==p_start[1])
return true;
return false;
}
function IsInTurn(arr){
if(arr[0]>s_path[3][0]){
if(arr[1]>s_path[3][1]){
if(IsPass((arr[0]-1)+","+arr[1])||IsPass(arr[0]+","+(arr[1]-1)))
return false;
}
else if(arr[1]<s_path[3][1]){
if(IsPass((arr[0]-1)+","+arr[1])||IsPass(arr[0]+","+(arr[1]+1)))
return false;
}
}
else if(arr[0]<s_path[3][0]){
if(arr[1]>s_path[3][1]){
if(IsPass((arr[0]+1)+","+arr[1])||IsPass(arr[0]+","+(arr[1]-1)))
return false;
}
else if(arr[1]<s_path[3][1]){
if(IsPass((arr[0]+1)+","+arr[1])||IsPass(arr[0]+","+(arr[1]+1)))
return false;
}
}
return true;
}
function IsOutScreen(arr){
if(arr[0]<0||arr[1]<0||arr[0]>(w-1)||arr[1]>(h-1))
return true;
return false;
}
function InOpen(arr){
var bool=false;
for(var i=0;i<openlist.length;i++){
if(arr[0]==openlist[i][3][0]&&arr[1]==openlist[i][3][1]){
bool=true;num=i;break;}
}
return bool;
}
function InClose(arr){
var bool=false;
for(var i=0;i<closelist.length;i++){
if((arr[0]==closelist[i][3][0])&&(arr[1]==closelist[i][3][1])){
bool=true;break;}
}
return bool;
}
function IsPass(pos){
if((";"+n_path+";").indexOf(";"+pos+";")!=-1)
return true;
return false;
}
function Sort(arr){
var temp;
for(var i=0;i<arr.length;i++){
if(arr.length==1)break;
if(arr[i][0]<=arr[i+1][0]){
temp=arr[i];
arr[i]=arr[i+1];
arr[i+1]=temp;
}
if((i+1)==(arr.length-1))
break;
}
}
function main(){
GetF(GetRound(s_path[3]));
Sort(openlist);
s_path=openlist[openlist.length-1];
closelist[closelist.length]=s_path;
openlist[openlist.length-1]=null;
if(openlist.length==0){alert("找不到路径");return;}
openlist.length=openlist.length-1;
if((s_path[3][0]==p_end[0])&&(s_path[3][1]==p_end[1])){
getPath();
}
else{maptt.rows[s_path[3][1]].cells[s_path[3][0]].style.backgroundColor="#00ff00";setTimeout("main()",100);}
}
function getPath(){
var str="";
var t=closelist[closelist.length-1][4];
while(1){
str+=t.join(",")+";";
maptt.rows[t[1]].cells[t[0]].style.backgroundColor="#ffff00";
for(var i=0;i<closelist.length;i++){
if(closelist[i][3][0]==t[0]&&closelist[i][3][1]==t[1])
t=closelist[i][4];
}
if(t[0]==p_start[0]&&t[1]==p_start[1])
break;
}
alert(str);
}
function setPos(){
var h=(Math.abs(p_end[0]-p_start[0])+Math.abs(p_end[1]-p_start[1]))*gw;
s_path=[h,0,h,p_start,p_start];
}
function set(id,arr){
switch(id){
case 1:
p_start=arr;
maptt.rows[arr[1]].cells[arr[0]].style.backgroundColor="#ff0000";break;
case 2:
p_end=arr;maptt.rows[arr[1]].cells[arr[0]].style.backgroundColor="#0000ff";break;
case 3:
n_path+=arr.join(",")+";";maptt.rows[arr[1]].cells[arr[0]].style.backgroundColor="#cccccc";break;
default:
break;
}
}
function setflag(id){flag=id;}
</script>
<table id="maptt" cellspacing="1" cellpadding="0" border="0" bgcolor="#000000">
<script>
for(var i=0;i<h;i++){
document.write("<tr>");
for(var j=0;j<w;j++){
document.write('<td onclick="set(flag,['+j+','+i+']);" bgcolor="#ffffff" width="20" height="20"></td>');
}
document.write("</tr>");
}
</script>
</table>
<a href="javascript:setflag(1);">设置起点</a><br>
<a href='javascript:setflag(2);'>设置终点</a><br>
<a href='javascript:setflag(3);'>设置障碍点</a><br>
<input type="button" onclick="setPos();main();this.disabled=true;" value="find">
</body>
</html>