internal FrictionJoint(FrictionJointDef def)
: base(def)
{
_localAnchor1 = def.localAnchorA;
_localAnchor2 = def.localAnchorB;
_maxForce = def.maxForce;
_maxTorque = def.maxTorque;
}
internal FrictionJoint(FrictionJointDef 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;
}
internal FrictionJoint(FrictionJointDef 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.SetGravity(new Vec2(0.0f, 0.0f));
const float k_restitution = 0.4f;
Body ground;
{
BodyDef bd = new BodyDef();
bd.Position.Set(0.0f, 20.0f);
ground = m_world.CreateBody(bd);
EdgeShape shape = new EdgeShape();
FixtureDef sd = new FixtureDef();
sd.shape = shape;
sd.Density = 0.0f;
sd.restitution = k_restitution;
// Left vertical
shape.Set(new Vec2(-20.0f, -20.0f), new Vec2(-20.0f, 20.0f));
ground.CreateFixture(sd);
// Right vertical
shape.Set(new Vec2(20.0f, -20.0f), new Vec2(20.0f, 20.0f));
ground.CreateFixture(sd);
// Top horizontal
shape.Set(new Vec2(-20.0f, 20.0f), new Vec2(20.0f, 20.0f));
ground.CreateFixture(sd);
// Bottom horizontal
shape.Set(new Vec2(-20.0f, -20.0f), new Vec2(20.0f, -20.0f));
ground.CreateFixture(sd);
}
{
Transform xf1 = new Transform();
xf1.q.Set(0.3524f * (float)Math.PI);
xf1.p = xf1.q.GetXAxis();
Vec2[] vertices = new Vec2[3];
vertices[0] = Utilities.Mul(xf1, new Vec2(-1.0f, 0.0f));
vertices[1] = Utilities.Mul(xf1, new Vec2(1.0f, 0.0f));
vertices[2] = Utilities.Mul(xf1, new Vec2(0.0f, 0.5f));
PolygonShape poly1 = new PolygonShape();
poly1.Set(vertices, 3);
FixtureDef sd1 = new FixtureDef();
sd1.shape = poly1;
sd1.Density = 4.0f;
Transform xf2 = new Transform();
xf2.q.Set(-0.3524f * (float)Math.PI);
xf2.p = -xf2.q.GetXAxis();
vertices[0] = Utilities.Mul(xf2, new Vec2(-1.0f, 0.0f));
vertices[1] = Utilities.Mul(xf2, new Vec2(1.0f, 0.0f));
vertices[2] = Utilities.Mul(xf2, new Vec2(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._dynamicBody;
bd.angularDamping = 5.0f;
bd.linearDamping = 0.1f;
bd.Position.Set(0.0f, 2.0f);
bd.angle = (float)Math.PI;
bd.allowSleep = false;
m_body = m_world.CreateBody(bd);
m_body.CreateFixture(sd1);
m_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._dynamicBody;
bd.Position.Set(0.0f, 5.0f + 1.54f * i);
Body body = m_world.CreateBody(bd);
body.CreateFixture(fd);
float gravity = 10.0f;
float I = body.GetInertia();
float mass = body.GetMass();
// For a circle: I = 0.5 * m * r * r ==> r = sqrt(2 * I / m)
float radius = (float)Math.Sqrt(2.0f * I / mass);
FrictionJointDef jd = new FrictionJointDef();
jd.localAnchorA.SetZero();
jd.localAnchorB.SetZero();
jd.bodyA = ground;
jd.bodyB = body;
jd.collideConnected = true;
jd.maxForce = mass * gravity;
jd.maxTorque = mass * radius * gravity;
m_world.CreateJoint(jd);
}
}
}
