Creating the base

Now that we have walls, let's create our first GameObject class that will represent the base platform. When I say base platform, I mean the trampoline the clown will be trying relentlessly to jump off at the start of the game. We define the CreateBasePlatform function in GameWorld.cpp:

void GameWorld::CreateBasePlatform()
{
  // base platform will be a static body
  b2BodyDef platform_def;
  platform_def.position.Set(SCREEN_TO_WORLD(416), 
    SCREEN_TO_WORLD(172));
  b2Body* base_platform_body = world_->CreateBody(&platform_def);

  // create an edge slightly above the bottom of the screen
  b2EdgeShape base_platform_shape;
  base_platform_shape.Set(b2Vec2(SCREEN_TO_WORLD(-SCREEN_SIZE.width), 
    0.45f), b2Vec2(SCREEN_TO_WORLD(SCREEN_SIZE.width), 0.45f));
  b2FixtureDef base_platform_fixture_def;
  base_platform_fixture_def.shape = &base_platform_shape;
  // give the base platform perfectly elastic collision response
  base_platform_fixture_def.restitution ...