internal b2FrictionJoint(b2FrictionJointDef def) : base(def)
{
m_localAnchorA = def.localAnchorA;
m_localAnchorB = def.localAnchorB;
m_linearImpulse.SetZero();
m_angularImpulse = 0.0f;
m_maxForce = def.maxForce;
m_maxTorque = def.maxTorque;
}
public ApplyForce()
{
m_world.Gravity = new b2Vec2(0.0f, 0.0f);
float k_restitution = 0.4f;
b2Body ground;
{
b2BodyDef bd = new b2BodyDef();
bd.position = new b2Vec2(0.0f, 20.0f);
ground = m_world.CreateBody(bd);
b2EdgeShape shape = new b2EdgeShape();
b2FixtureDef sd = new b2FixtureDef();
sd.shape = shape;
sd.density = 0.0f;
sd.restitution = k_restitution;
// Left vertical
shape.Set(new b2Vec2(-20.0f, -20.0f), new b2Vec2(-20.0f, 20.0f));
ground.CreateFixture(sd);
// Right vertical
shape.Set(new b2Vec2(20.0f, -20.0f), new b2Vec2(20.0f, 20.0f));
ground.CreateFixture(sd);
// Top horizontal
shape.Set(new b2Vec2(-20.0f, 20.0f), new b2Vec2(20.0f, 20.0f));
ground.CreateFixture(sd);
// Bottom horizontal
shape.Set(new b2Vec2(-20.0f, -20.0f), new b2Vec2(20.0f, -20.0f));
ground.CreateFixture(sd);
}
{
b2Transform xf1;
xf1.q = new b2Rot(0.3524f * b2Settings.b2_pi);
xf1.p = xf1.q.GetXAxis();
b2Vec2[] vertices = new b2Vec2[3];
vertices[0] = b2Math.b2Mul(xf1, new b2Vec2(-1.0f, 0.0f));
vertices[1] = b2Math.b2Mul(xf1, new b2Vec2(1.0f, 0.0f));
vertices[2] = b2Math.b2Mul(xf1, new b2Vec2(0.0f, 0.5f));
b2PolygonShape poly1 = new b2PolygonShape();
poly1.Set(vertices, 3);
b2FixtureDef sd1 = new b2FixtureDef();
sd1.shape = poly1;
sd1.density = 4.0f;
b2Transform xf2 = new b2Transform();
xf2.q.Set(-0.3524f * b2Settings.b2_pi);
xf2.p = -xf2.q.GetXAxis();
vertices[0] = b2Math.b2Mul(xf2, new b2Vec2(-1.0f, 0.0f));
vertices[1] = b2Math.b2Mul(xf2, new b2Vec2(1.0f, 0.0f));
vertices[2] = b2Math.b2Mul(xf2, new b2Vec2(0.0f, 0.5f));
b2PolygonShape poly2 = new b2PolygonShape();
poly2.Set(vertices, 3);
b2FixtureDef sd2 = new b2FixtureDef();
sd2.shape = poly2;
sd2.density = 2.0f;
b2BodyDef bd = new b2BodyDef();
bd.type = b2BodyType.b2_dynamicBody;
bd.angularDamping = 5.0f;
bd.linearDamping = 0.1f;
bd.position.Set(0.0f, 2.0f);
bd.angle = b2Settings.b2_pi;
bd.allowSleep = false;
m_body = m_world.CreateBody(bd);
m_body.CreateFixture(sd1);
m_body.CreateFixture(sd2);
}
{
b2PolygonShape shape = new b2PolygonShape();
shape.SetAsBox(0.5f, 0.5f);
b2FixtureDef fd = new b2FixtureDef();
fd.shape = shape;
fd.density = 1.0f;
fd.friction = 0.3f;
for (int i = 0; i < 10; ++i)
{
b2BodyDef bd = new b2BodyDef();
bd.type = b2BodyType.b2_dynamicBody;
bd.position = new b2Vec2(0.0f, 5.0f + 1.54f * i);
b2Body body = m_world.CreateBody(bd);
body.CreateFixture(fd);
float gravity = 10.0f;
float I = body.Inertia;
float mass = body.Mass;
// For a circle: I = 0.5 * m * r * r ==> r = sqrt(2 * I / m)
float radius = b2Math.b2Sqrt(2.0f * I / mass);
b2FrictionJointDef jd = new b2FrictionJointDef();
jd.localAnchorA = b2Vec2.Zero;
jd.localAnchorB = b2Vec2.Zero;
jd.BodyA = ground;
jd.BodyB = body;
jd.CollideConnected = true;
jd.maxForce = mass * gravity;
jd.maxTorque = mass * radius * gravity;
m_world.CreateJoint(jd);
}
}
}
internal static global::System.Runtime.InteropServices.HandleRef getCPtr(b2FrictionJointDef obj)
{
return((obj == null) ? new global::System.Runtime.InteropServices.HandleRef(null, global::System.IntPtr.Zero) : obj.swigCPtr);
}
