HTML and CSS Reference
In-Depth Information
Creating Balls
Creatingtheballsthatwillfallandbouncearoundinourdemoisverysimilartocreatingwalls
in Box2D. For this exercise, we will create 50 balls with random locations and sizes. The loc-
ations and sizes are (again) in MTS units. The only real difference from creating the walls is
that we set the fixture shape property to
b2CircleShape(size)
, where size is a random size
in MTS units.
var
var
numBalls
=
50
;
var
var
balls
=
new
new
Array
();
for
for
(
var
var
i
=
0
;
i
<
numBalls
;
i
++
) {
var
var
ballDef
=
new
new
b2BodyDef
;
ballDef
.
type
=
b2Body
.
b2_dynamicBody
;
var
var
ypos
=
(
Math
.
random
()
*
8
)
+
1
;
var
var
xpos
=
(
Math
.
random
()
*
14
)
+
1
;
var
var
size
=
(
Math
.
random
()
*
.
4
)
+
0.2
;
ballDef
.
position
.
Set
(
xpos
,
ypos
);
var
var
ballFixture
=
new
new
b2FixtureDef
;
ballFixture
.
density
=
10.0
;
ballFixture
.
friction
=
0.5
;
ballFixture
.
restitution
=
1
;
ballFixture
.
shape
=
new
b2CircleShape
(
size
);
var
var
newBall
=
world
.
CreateBody
(
ballDef
)
newBall
.
CreateFixture
(
ballFixture
);
balls
.
push
(
newBall
);
}
