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. Pay attentions that: to make the avatar collide against the plaque we have used: pl.makeHard(). The plaque is not one of the 3D objects. For "3D objects" the avatr has a more sophisticated behavior. You can make all the objects in the Lot to be 3D but you will have lots of work. The idea is to make 3D only objects in the "street" or inside "houses".
