public CompoundShapes()
{
{
BodyDef bd = new BodyDef();
bd.position = new Vector2(0.0, 0.0);
Body body = _world.CreateBody(bd);
PolygonShape shape = new PolygonShape();
shape.SetAsEdge(new Vector2(50.0, 0.0), new Vector2(-50.0, 0.0));
body.CreateFixture(shape, 0.0);
}
{
CircleShape circle1 = new CircleShape();
circle1._radius = 0.5f;
circle1._p = new Vector2(-0.5f, 0.5f);
CircleShape circle2 = new CircleShape();
circle2._radius = 0.5f;
circle2._p = new Vector2(0.5f, 0.5f);
for (int i = 0; i < 10; ++i)
{
double x = Rand.RandomFloat(-0.1f, 0.1f);
BodyDef bd = new BodyDef();
bd.type = BodyType.Dynamic;
bd.position = new Vector2(x + 5.0f, 1.05f + 2.5f * i);
bd.angle = Rand.RandomFloat(-Alt.Box2D.Settings.b2_pi, Alt.Box2D.Settings.b2_pi);
Body body = _world.CreateBody(bd);
body.CreateFixture(circle1, 2.0f);
body.CreateFixture(circle2, 0.0f);
}
}
{
PolygonShape polygon1 = new PolygonShape();
polygon1.SetAsBox(0.25f, 0.5f);
PolygonShape polygon2 = new PolygonShape();
polygon2.SetAsBox(0.25f, 0.5f, new Vector2(0.0f, -0.5f), 0.5f * Alt.Box2D.Settings.b2_pi);
for (int i = 0; i < 10; ++i)
{
double x = Rand.RandomFloat(-0.1f, 0.1f);
BodyDef bd = new BodyDef();
bd.type = BodyType.Dynamic;
bd.position = new Vector2(x - 5.0f, 1.05f + 2.5f * i);
bd.angle = Rand.RandomFloat(-Alt.Box2D.Settings.b2_pi, Alt.Box2D.Settings.b2_pi);
Body body = _world.CreateBody(bd);
body.CreateFixture(polygon1, 2.0f);
body.CreateFixture(polygon2, 2.0f);
}
}
{
Alt.Box2D.Transform xf1 = new Alt.Box2D.Transform();
xf1.R.Set(0.3524f * Alt.Box2D.Settings.b2_pi);
xf1.Position = MathUtils.Multiply(ref xf1.R, new Vector2(1.0f, 0.0f));
Vector2[] vertices = new Vector2[3];
PolygonShape triangle1 = new PolygonShape();
vertices[0] = MathUtils.Multiply(ref xf1, new Vector2(-1.0f, 0.0f));
vertices[1] = MathUtils.Multiply(ref xf1, new Vector2(1.0f, 0.0f));
vertices[2] = MathUtils.Multiply(ref xf1, new Vector2(0.0f, 0.5f));
triangle1.Set(vertices, 3);
Alt.Box2D.Transform xf2 = new Alt.Box2D.Transform();
xf2.R.Set(-0.3524f * Alt.Box2D.Settings.b2_pi);
xf2.Position = MathUtils.Multiply(ref xf2.R, new Vector2(-1.0f, 0.0f));
PolygonShape triangle2 = new PolygonShape();
vertices[0] = MathUtils.Multiply(ref xf2, new Vector2(-1.0f, 0.0f));
vertices[1] = MathUtils.Multiply(ref xf2, new Vector2(1.0f, 0.0f));
vertices[2] = MathUtils.Multiply(ref xf2, new Vector2(0.0f, 0.5f));
triangle2.Set(vertices, 3);
for (int i = 0; i < 10; ++i)
{
double x = Rand.RandomFloat(-0.1f, 0.1f);
BodyDef bd = new BodyDef();
bd.type = BodyType.Dynamic;
bd.position = new Vector2(x, 2.05f + 2.5f * i);
bd.angle = 0.0f;
Body body = _world.CreateBody(bd);
body.CreateFixture(triangle1, 2.0f);
body.CreateFixture(triangle2, 2.0f);
}
}
{
PolygonShape bottom = new PolygonShape();
bottom.SetAsBox(1.5f, 0.15f);
PolygonShape left = new PolygonShape();
left.SetAsBox(0.15f, 2.7f, new Vector2(-1.45f, 2.35f), 0.2f);
PolygonShape right = new PolygonShape();
right.SetAsBox(0.15f, 2.7f, new Vector2(1.45f, 2.35f), -0.2f);
BodyDef bd = new BodyDef();
bd.type = BodyType.Dynamic;
bd.position = new Vector2(0.0f, 2.0f);
Body body = _world.CreateBody(bd);
body.CreateFixture(bottom, 4.0f);
body.CreateFixture(left, 4.0f);
body.CreateFixture(right, 4.0f);
}
}
public ApplyForce()
{
_world.Gravity = new Vector2(0.0, 0.0);
const double k_restitution = 0.4;
Body ground;
{
BodyDef bd = new BodyDef();
bd.position = new Vector2(0.0f, 20.0f);
ground = _world.CreateBody(bd);
PolygonShape shape = new PolygonShape();
FixtureDef sd = new FixtureDef();
sd.shape = shape;
sd.density = 0.0f;
sd.restitution = k_restitution;
// Left vertical
shape.SetAsEdge(new Vector2(-20.0f, -20.0f), new Vector2(-20.0f, 20.0f));
ground.CreateFixture(sd);
// Right vertical
shape.SetAsEdge(new Vector2(20.0f, -20.0f), new Vector2(20.0f, 20.0f));
ground.CreateFixture(sd);
// Top horizontal
shape.SetAsEdge(new Vector2(-20.0f, 20.0f), new Vector2(20.0f, 20.0f));
ground.CreateFixture(sd);
// Bottom horizontal
shape.SetAsEdge(new Vector2(-20.0f, -20.0f), new Vector2(20.0f, -20.0f));
ground.CreateFixture(sd);
}
{
Alt.Box2D.Transform xf1 = new Alt.Box2D.Transform();
xf1.R.Set(0.3524 * Alt.Box2D.Settings.b2_pi);
xf1.Position = MathUtils.Multiply(ref xf1.R, new Vector2(1.0f, 0.0f));
Vector2[] vertices = new Vector2[3];
vertices[0] = MathUtils.Multiply(ref xf1, new Vector2(-1.0f, 0.0f));
vertices[1] = MathUtils.Multiply(ref xf1, new Vector2(1.0f, 0.0f));
vertices[2] = MathUtils.Multiply(ref xf1, new Vector2(0.0f, 0.5f));
PolygonShape poly1 = new PolygonShape();
poly1.Set(vertices, 3);
FixtureDef sd1 = new FixtureDef();
sd1.shape = poly1;
sd1.density = 4.0f;
Alt.Box2D.Transform xf2 = new Alt.Box2D.Transform();
xf2.R.Set(-0.3524 * Alt.Box2D.Settings.b2_pi);
xf2.Position = MathUtils.Multiply(ref xf2.R, new Vector2(-1.0f, 0.0f));
vertices[0] = MathUtils.Multiply(ref xf2, new Vector2(-1.0f, 0.0f));
vertices[1] = MathUtils.Multiply(ref xf2, new Vector2(1.0f, 0.0f));
vertices[2] = MathUtils.Multiply(ref xf2, new Vector2(0.0f, 0.5f));
PolygonShape poly2 = new PolygonShape();
poly2.Set(vertices, 3);
FixtureDef sd2 = new FixtureDef();
sd2.shape = poly2;
sd2.density = 2.0f;
BodyDef bd = new BodyDef();
bd.type = BodyType.Dynamic;
bd.angularDamping = 5.0f;
bd.linearDamping = 0.1f;
bd.position = new Vector2(0.0f, 2.0f);
bd.angle = Alt.Box2D.Settings.b2_pi;
bd.allowSleep = false;
_body = _world.CreateBody(bd);
_body.CreateFixture(sd1);
_body.CreateFixture(sd2);
}
{
PolygonShape shape = new PolygonShape();
shape.SetAsBox(0.5f, 0.5f);
FixtureDef fd = new FixtureDef();
fd.shape = shape;
fd.density = 1.0f;
fd.friction = 0.3f;
for (int i = 0; i < 10; ++i)
{
BodyDef bd = new BodyDef();
bd.type = BodyType.Dynamic;
bd.position = new Vector2(0.0f, 5.0f + 1.54f * i);
Body body = _world.CreateBody(bd);
body.CreateFixture(fd);
double gravity = 10.0f;
double I = body.GetInertia();
double mass = body.GetMass();
// For a circle: I = 0.5 * m * r * r ==> r = sqrt(2 * I / m)
double radius = (double)Math.Sqrt(2.0 * (double)(I / mass));
FrictionJointDef jd = new FrictionJointDef();
jd.localAnchorA = Vector2.Zero;
jd.localAnchorB = Vector2.Zero;
jd.bodyA = ground;
jd.bodyB = body;
jd.collideConnected = true;
jd.maxForce = mass * gravity;
jd.maxTorque = mass * radius * gravity;
_world.CreateJoint(jd);
}
}
}
