Contact surface

[mayataka]

The current implementation assumes that the contact surface is just the ground, i.e., its normal vector is z-axis and the height is zero. The class

• [ ] ContactSurface

must be implemented, which contains information regarding the contact, .e.g, the normal vector and the height from the ground. Accordingly, PointContact, Robot, or FrictionCone must also be modified.

[mayataka]

Now ContactStatus and ImpulseStatus are included in arguments of the cost and constraints, we should focus on how to implement ContactSurface in ContactStatus and ImpulseStatus.