/// <seealso cref="Joint.getReactionForce(float, Vec2)"></seealso>
public override void getReactionForce(float inv_dt, Vec2 argOut)
{
argOut.set_Renamed(m_impulse.x, m_impulse.y);
argOut.mulLocal(inv_dt);
}
public void computeCentroidToOut(Vec2[] vs, int count, Vec2 out_Renamed)
{
Debug.Assert(count >= 3);
out_Renamed.set_Renamed(0.0f, 0.0f);
float area = 0.0f;
// pRef is the reference point for forming triangles.
// It's location doesn't change the result (except for rounding error).
Vec2 pRef = pool1;
pRef.setZero();
Vec2 e1 = pool2;
Vec2 e2 = pool3;
float inv3 = 1.0f / 3.0f;
for (int i = 0; i < count; ++i)
{
// Triangle vertices.
Vec2 p1 = pRef;
Vec2 p2 = vs[i];
Vec2 p3 = i + 1 < count ? vs[i + 1] : vs[0];
e1.set_Renamed(p2).subLocal(p1);
e2.set_Renamed(p3).subLocal(p1);
float D = Vec2.cross(e1, e2);
float triangleArea = 0.5f * D;
area += triangleArea;
// Area weighted centroid
e1.set_Renamed(p1).addLocal(p2).addLocal(p3).mulLocal(triangleArea * inv3);
out_Renamed.addLocal(e1);
}
// Centroid
Debug.Assert(area > Settings.EPSILON);
out_Renamed.mulLocal(1.0f / area);
}
