Adding Bodies to the World - Box2D for Flash Games - page 23

addChild(debugSprite);
debugDraw.SetSprite(debugSprite);
debugDraw.SetDrawScale(worldScale);
debugDraw.SetFlags(b2DebugDraw.e_shapeBit);
debugDraw.SetFillAlpha(0.5);
world.SetDebugDraw(debugDraw);
}

2. Then, as we need to create a lot of bricks, a function to create a brick

starting from its position and size is strongly recommended, so here is a
brick function with its arguments: brick horizontal and vertical origin,
width, and height.
private function brick(pX:int,pY:int,w:Number,h:Number):void {
var bodyDef:b2BodyDef=new b2BodyDef();
bodyDef.position.Set(pX/worldScale,pY/worldScale);
// bodyDef.type=b2Body.b2_dynamicBody;
var polygonShape:b2PolygonShape=new b2PolygonShape();
polygonShape.SetAsBox(w/2/worldScale,h/2/worldScale);
var fixtureDef:b2FixtureDef=new b2FixtureDef();
fixtureDef.shape=polygonShape;
fixtureDef.density=2;
fixtureDef.restitution=0.4;
fixtureDef.friction=0.5;
var theBrick:b2Body=world.CreateBody(bodyDef);
theBrick.CreateFixture(fixtureDef);
}

Obviously, if you want you can also pass as arguments the density,
friction, and restitution.

If you look at the code, there's nothing new, but I want you to have a look at
the highlighted lines:

° First, the line that sets the type attribute is commented, so at the
moment we will create static bodies. When you are designing a level,
it is better to start with static bodies, and once you are satisfied, turn
them into dynamic bodies. Static bodies will help you to see the exact
location of each body, avoiding overlapping or other design mistakes.
° Second, in the SetAsBox attributes, the width and the height of the
brick are divided by two before they get divided by worldScale too.
I am doing this because I want to call the brick function with real
width and height in pixels, no matter if the SetAsBox method wants
the half-width and the half-height as you already know.