Member Avatar for lea_1

Hey, all! I'm trying to figure out how to add collision detection to the following code but I'm having trouble trying to figure out how to pull in the x and y coordinates of the different eggs that are falling randomly. Would you be able to tell me what I'm doing wrong? Thank you!

<html>
<style>
#playingArea {
    position: absolute;
    top: 1;
    left: 1;
    width: 750;
    height: 720;
    z-index: 2;
}
#basket {
    position: absolute;
    top: 650;
    left: 228;
    width: 100;
    height: 145;
}
</style>
<script type="text/javascript" language="Javascript">
    var basket;
    var basketLeft = 228;

    function keyListener(e) {
        document.getElementById("si"+i).style.top=eggsTop;
        document.getElementById("si"+i).style.left=eggsLeft;
        if (!e || (typeof(e)=="undefined")) { e = window.event; }
        if (e.keyCode==37 && basketLeft > 0) {
            basketLeft -= 8;
            basket.style.left = basketLeft + 'px' ;
        if (basket.style.left < eggsLeft + 65 &&
            basket.style.left + basket.style.width > eggsLeft &&
            basket.style.top < eggsTop + 84 &&
            basket.style.height + basket.style.top > eggsTop) {
                console.log("collision");
            }
        }
        if (e.keyCode==39 && basketLeft < 436){
            basketLeft += 8;
            basket.style.left = basketLeft + 'px' ;
        }
    }

    function init() {
        basket=document.getElementById('basket');
        document.onkeydown=keyListener;
        fall();
    }

    grphcs=new Array(5)
    Image0=new Image();
    Image0.src=grphcs[0]="egg.png";
    Image1=new Image();
    Image1.src=grphcs[1]="egg_2.png";
    Image2=new Image();
    Image2.src=grphcs[2]="egg_3.png";
    Image3=new Image();
    Image3.src=grphcs[3]="egg_4.png";
    Image4=new Image();
    Image4.src=grphcs[4]="egg_5.png";

    Amount=5;
    Ypos=new Array();
    Xpos=new Array();
    Speed=new Array();
    Step=new Array();
    Cstep=new Array();
    var Stop=false;

    for(i=0;i<Amount;i++) {
        var P=Math.floor(Math.random()*grphcs.length);
        rndPic=grphcs[P];
        document.write('<img id="si'+i+'" src="'+rndPic+'"style="position:absolute;top:0px;left:0px">');
    }

    WinHeight=document.body.clientHeight;
    WinWidth=document.body.clientWidth;

    for(i=0;i<Amount;i++) {
        Ypos[i]=Math.round(Math.random()*WinHeight);
        Xpos[i]=Math.round(Math.random()*WinWidth);
        Speed[i]=Math.random()*5+3;
        Cstep[i]=0;
        Step[i]=Math.random()*0.1+0.05;
    }

    function fall() {
        if(Stop)
        {clear();
        return;
    }

    var WinHeight=document.body.clientHeight-100;
    var WinWidth=document.body.clientWidth-500;

    for(i=0;i<Amount;i++) {
        sy=Speed[i]*Math.sin(90*Math.PI/180);
        sx=Speed[i]*Math.cos(Cstep[i]);
        Ypos[i]+=sy;
        Xpos[i]+=sx;
        if(Ypos[i]>WinHeight) {
            Ypos[i]=60;
            Xpos[i]=Math.round(Math.random()*WinWidth);
            Speed[i]=Math.random()*5+3;
        }

        else
        {
            document.getElementById("si"+i).style.left=Math.min(WinWidth,Xpos[i])-200;
            document.getElementById("si"+i).style.top=Ypos[i];
        }

        Cstep[i]+=Step[i];
    }

    setTimeout('fall()',20);
    }

    setTimeout("Stop=true",30000);

    function clear() {
        for(i=0;i<Amount;i++)
        document.getElementById("si"+i).style.display='none';
    }

</script>
<body onload="init()";>

    <div id= "basket">
        <img src= "bottle.png">
    </div>

    <div id= "playingArea">

    </div>

</body>
</html>
  • 3 Contributors
  • 4 Replies
  • 857 Views
  • 1 Day Discussion Span
  • Latest Post Latest Post by janissantony

Recommended Answers

All 4 Replies

Member Avatar for janissantony

If just rectable collision detection, just test the for corders if inside the rect.

boolean collide(int x1, int y1, int w1, int h1, 
int x2, int y2, int w2, int h2) {
return 
collide(x1, y1, w1, h1, x2, y2) || 
collide(x1, y1, w1, h1, x2+w2, y2) || 
collide(x1, y1, w1, h1, x2, y2+h2) || 
collide(x1, y1, w1, h1, x2+w2, y2+h2);

}

boolean collide(int x1, int y1, int w, int h, 
int x2, int y2) {
return x2>=x1 && x2 <= x1+w
&& y2>=y1 && y2 <= y1+h;
}
Member Avatar for lea_1

That's what I'm attempting to do but how can I obtain the x, y, width, and height values of the images? Also, would this go inside or after the keyListener?

Member Avatar for Airshow

Try jQuery-turtle, "a jQuery plugin for turtle graphics".

I've not used this plugin but assume that its "accurate collision-testing of turtles with arbitrary convex hulls" can be used for collision detection of turtles with each other, ie. turtlize each of your eggs.

You would need to more-or-less restart your coding from scratch but would benefit from many hours of good work put in by the plugin's author.

Member Avatar for janissantony

perhaps try simpler subset of your problem first. maybe change mechanics a bit.

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