Math, Physics, and Animation - HTML5 Canvas - page 344

function function render () {

var

var ball ;
context . fillStyle = "#000000" ;
for for ( var var i = 0 ; i < balls . length ; i ++ ) {

ball = balls [ i ];
ball . x = ball . nextx ;
ball . y = ball . nexty ;

context . beginPath ();
context . arc ( ball . x , ball . y , ball . radius , 0 , Math . PI * 2 , true

true );

context . closePath ();
context . fill ();

}

}

function function collide () {

var var ball ;

var var testBall ;

for

for ( var var i = 0 ; i < balls . length ; i ++ ) {

ball = balls [ i ];
for

for ( var var j = i + 1 ; j < balls . length ; j ++ ) {

testBall = balls [ j ];
iif ( hitTestCircle ( ball , testBall )) {
collideBalls ( ball , testBall );

}

}

}

}

function function hitTestCircle ( ball1 , ball2 ) {

var var retval = false false ;

var var dx = ball1 . nextx - ball2 . nextx ;

var var dy = ball1 . nexty - ball2 . nexty ;

var var distance = ( dx * dx + dy * dy );

iif ( distance <= ( ball1 . radius + ball2 . radius ) *
( ball1 . radius + ball2 . radius ) )

{

retval = true true ;

}
return return retval ;

}

function function collideBalls ( ball1 , ball2 ) {