OLPCities/The avatar
You can find avatares at our Inventory. The link is: Avatares. You can use one of them or create a nes . Remember to put it available for everybody. An avatar has some "frames" and some "animations". The size of one "cell" is 32 x 32 pixels.
At this lesson we will add an avatar to the Lot of the previous. We will use (take a look) elements of the Classes:
We will make some comentaries about the code of the page:
<html>
<head>
<script language="Javascript" src="http://www.dmu.com/olpc/gamelib_core.js"></script>
<script language="Javascript" src="http://www.dmu.com/olpc/gamelib_sprites.js"></script>
<script language="Javascript" src="http://www.dmu.com/olpc/gamelib_keyboard.js"></script>
<script language="Javascript">
function init(){
Sp_linuxcompatible=true;
Gl_preloader("floorW05N07.gif");
Gl_preloader("plaquehello.gif");
Gl_preloader("avat1.gif");
upkey=Kb_trapkey("UP");
downkey=Kb_trapkey("DOWN");
rightkey=Kb_trapkey("RIGHT");
leftkey=Kb_trapkey("LEFT");
av=new Sp_Sprite();
av.setImage("avat1.gif",32,32,4,2);
av.setXlimits(5,610);
av.setYlimits(5,385);
av.moveTo( 300,170);
av.setFrame(3);
av.setFrameByDirection(90,90,1,180,180,3,270,270,0,0,0,2);
av.setAnimation(0);
av.setZ(10);
av.collides=true;
av.useHitEvents(true);
av.setAnimationSpeed(3);
av.switchOn();
floor=new Sp_Sprite();
floor.setImage("floorW05N07.gif",614,390,1,1);
floor.setXlimits( 0,616);
floor.setYlimits( 0,390);
floor.setFrame(0);
floor.moveTo(0 , 0 );
floor.setZ(5);
floor.switchOn();
pl=new Sp_Sprite();
pl.setImage("plaquehello.gif",179,101,1,1);
pl.setXlimits( 0,614);
pl.setYlimits( 0,390);
pl.setFrame(0);
pl.moveTo(355 , 45 );
pl.setZ(12);
pl.makeHard();
pl.switchOn()
Gl_hook("timestep()");
Gl_start();
}
function timestep(){
av.setSpeed(0);
av.setAnimationRepeat(0);
if(rightkey.pressed){
av.setDir(1,0);
av.setAnimationRepeat(-1);
av.setSpeed(2);
}
else if(leftkey.pressed){
av.setDir(-1,0);
av.setAnimationRepeat(-1);
av.setSpeed(2);
}
else if(downkey.pressed){
av.setDir(0,1);
av.setAnimationRepeat(-1);
av.setSpeed(2);
}
else if(upkey.pressed){
av.setDir(0,-1);
av.setAnimationRepeat(-1);
av.setSpeed(2);
}
}//timestep
</script>
</head>
<title>TUTCITY </title>
<body bgcolor="black" onload="init()" >
</html>
We are pre-loading all the images. The OLPC browser wait the load of all the images to open the page/Lot.
We will use the arrow keys to move the avatar. The capture of the press of the key occurs inside a "timer loop".
The first frame of the avatar has the value 0 (zero). For the avatar going down we do: av.setFrame(3). setFrameByDirection Changing the direction of the movement of the avatar, the frame changes. We use the method: setFrameByDirection to define it. And we change the direction using the arrow keys and the method: setDir.