Program Listing for File ContactForce.h

↰ Return to documentation for file (include/Karana/Collision/ContactForce.h)

/*
 * Copyright (c) 2024-2026 Karana Dynamics Pty Ltd. All rights reserved.
 *
 * NOTICE TO USER:
 *
 * This source code and/or documentation (the "Licensed Materials") is
 * the confidential and proprietary information of Karana Dynamics Inc.
 * Use of these Licensed Materials is governed by the terms and conditions
 * of a separate software license agreement between Karana Dynamics and the
 * Licensee ("License Agreement"). Unless expressly permitted under that
 * agreement, any reproduction, modification, distribution, or disclosure
 * of the Licensed Materials, in whole or in part, to any third party
 * without the prior written consent of Karana Dynamics is strictly prohibited.
 *
 * THE LICENSED MATERIALS ARE PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND.
 * KARANA DYNAMICS DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
 * BUT NOT LIMITED TO WARRANTIES OF MERCHANTABILITY, NON-INFRINGEMENT, AND
 * FITNESS FOR A PARTICULAR PURPOSE.
 *
 * IN NO EVENT SHALL KARANA DYNAMICS BE LIABLE FOR ANY DAMAGES WHATSOEVER,
 * INCLUDING BUT NOT LIMITED TO LOSS OF PROFITS, DATA, OR USE, EVEN IF
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGES, WHETHER IN CONTRACT, TORT,
 * OR OTHERWISE ARISING OUT OF OR IN CONNECTION WITH THE LICENSED MATERIALS.
 *
 * U.S. Government End Users: The Licensed Materials are a "commercial item"
 * as defined at 48 C.F.R. 2.101, and are provided to the U.S. Government
 * only as a commercial end item under the terms of this license.
 *
 * Any use of the Licensed Materials in individual or commercial software must
 * include, in the user documentation and internal source code comments,
 * this Notice, Disclaimer, and U.S. Government Use Provision.
 */

/**
 * @file
 * @brief Defines ContactForceBase. The base class for all contact force models.
 */

#pragma once

#include "Karana/Collision/FrameCollider.h"
#include "Karana/SOADyn/Node.h"
#include "Karana/SOADyn/SubTree.h"

namespace Karana::Collision {

    namespace kc = Karana::Core;
    namespace km = Karana::Math;
    namespace kd = Karana::Dynamics;

    /**
     * @class ContactForceBase
     * @brief Base class for all contact force models.
     *
     * See \sref{collision_dynamics_sec} for more discussion on
     * contact and collision dynamics.
     */
    class ContactForceBase : public kc::Base {
      public:
        /* @brief ContactForceBase class constructor.
         *
         * @param name Name for the ContactForceBase.
         * @param container The container to add the Base too.
         *                  If none is specified, the default singleton container will be used.
         */
        using kc::Base::Base;

        /**
         * @brief Apply the contact force for the associated contact.
         *
         * This first calls computeForce to get the contact force. Then, it
         * applies it to frames if those frames belong to a body.
         *
         * @param contact The contact to apply the force for.
         * @param st The SubTree we are computing forces for.
         */
        virtual void applyForce(const FrameContact &contact,
                                const kc::ks_ptr<Karana::Dynamics::SubTree> &st);

        /**
         * @brief Compute the contact force for the associated contact.
         *
         * @param contact The contact to compute the force for.
         * @param nd_1 The contact node associated with object 1. This node is located at
         *             contact.location_1 and the frame of the node is that of frame_1.
         * @param nd_2 The contact node associated with object 2. This node is located at
         *             contact.location_2 and the frame of the node is that of frame_2.
         * @returns The contact force on the frame_1 object at location_1 expressed in frame_1
         * coordinates.
         */
        virtual km::SpatialVector computeForce(const FrameContact &contact,
                                               const kc::ks_ptr<kd::Node> &nd_1,
                                               const kc::ks_ptr<kd::Node> &nd_2) = 0;

        /// The pair of nodes used when computing the contact force
        using NodePair = std::pair<kc::ks_ptr<kd::Node>, kc::ks_ptr<kd::Node>>;

        /**
         * @brief Get the pair of nodes from the most recent contact.
         * @returns The node pair (may be null)
         */
        const NodePair &getLastNodePair() const;

        /**
         * @brief Reset the most recent contact node pair to nullptr
         */
        virtual void resetLastNodePair();

      protected:
        /// The last node pair used in contact force calculation
        NodePair _last_node_pair = {nullptr, nullptr};
    };
} // namespace Karana::Collision