| public Step ( float dt, int velocityIterations, int positionIteration ) : void | ||
| dt | float | The amount of time to simulate, this should not vary. |
| velocityIterations | int | |
| positionIteration | int | |
| return | void | |
public virtual void Step(Microsoft.Xna.Framework.GameTime gameTime, int velocityIterations, int positionIteration)
{
world.Step((float)gameTime.ElapsedGameTime.TotalSeconds, velocityIterations, positionIteration);
}
// This is a simple example of building and running a simulation
// using Box2DX. Here we create a large ground box and a small dynamic
// box.
static void Main(string[] args)
{
// Define the size of the world. Simulation will still work
// if bodies reach the end of the world, but it will be slower.
AABB worldAABB = new AABB();
worldAABB.LowerBound.Set(-100.0f);
worldAABB.UpperBound.Set(100.0f);
// Define the gravity vector.
Vec2 gravity = new Vec2(0.0f, -10.0f);
// Do we want to let bodies sleep?
bool doSleep = true;
// Construct a world object, which will hold and simulate the rigid bodies.
World world = new World(worldAABB, gravity, doSleep);
// Define the ground body.
BodyDef groundBodyDef = new BodyDef();
groundBodyDef.Position.Set(0.0f, -10.0f);
// Call the body factory which creates the ground box shape.
// The body is also added to the world.
Body groundBody = world.CreateBody(groundBodyDef);
// Define the ground box shape.
PolygonDef groundShapeDef = new PolygonDef();
// The extents are the half-widths of the box.
groundShapeDef.SetAsBox(50.0f, 10.0f);
// Add the ground shape to the ground body.
groundBody.CreateFixture(groundShapeDef);
// Define the dynamic body. We set its position and call the body factory.
BodyDef bodyDef = new BodyDef();
bodyDef.Position.Set(0.0f, 4.0f);
Body body = world.CreateBody(bodyDef);
// Define another box shape for our dynamic body.
PolygonDef shapeDef = new PolygonDef();
shapeDef.SetAsBox(1.0f, 1.0f);
// Set the box density to be non-zero, so it will be dynamic.
shapeDef.Density = 1.0f;
// Override the default friction.
shapeDef.Friction = 0.3f;
// Add the shape to the body.
body.CreateFixture(shapeDef);
// Now tell the dynamic body to compute it's mass properties base
// on its shape.
body.SetMassFromShapes();
// Prepare for simulation. Typically we use a time step of 1/60 of a
// second (60Hz) and 10 iterations. This provides a high quality simulation
// in most game scenarios.
float timeStep = 1.0f / 60.0f;
int velocityIterations = 8;
int positionIterations = 1;
// This is our little game loop.
for (int i = 0; i < 100; ++i)
{
// Instruct the world to perform a single step of simulation. It is
// generally best to keep the time step and iterations fixed.
world.Step(timeStep, velocityIterations, positionIterations);
// Now print the position and angle of the body.
Vec2 position = body.GetPosition();
float angle = body.GetAngle();
Console.WriteLine("Step: {3} - X: {0}, Y: {1}, Angle: {2}", new object[]{position.X.ToString(),position.Y.ToString(),angle.ToString(), i.ToString()});
}
// When the world destructor is called, all bodies and joints are freed. This can
// create orphaned pointers, so be careful about your world management.
Console.ReadLine();
}
