////  Physics.cpp//  interface/src////  Copyright 2013 High Fidelity, Inc.////  Distributed under the Apache License, Version 2.0.//  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html// #include <glm/glm.hpp>#include <SharedUtil.h> #include "Util.h"#include "world.h"#include "Physics.h" ////  Applies static friction:  maxVelocity is the largest velocity for which there//  there is friction, and strength is the amount of friction force applied to reduce//  velocity. // void applyStaticFriction(float deltaTime, glm::vec3& velocity, float maxVelocity, float strength) {    float v = glm::length(velocity);    if (v < maxVelocity) {        velocity *= glm::clamp((1.0f - deltaTime * strength * (1.0f - v / maxVelocity)), 0.0f, 1.0f);    }} ////  Applies velocity damping, with a strength value for linear and squared velocity damping// void applyDamping(float deltaTime, glm::vec3& velocity, float linearStrength, float squaredStrength) {    if (squaredStrength == 0.0f) {        velocity *= glm::clamp(1.0f - deltaTime * linearStrength, 0.0f, 1.0f);    } else {        velocity *= glm::clamp(1.0f - deltaTime * (linearStrength + glm::length(velocity) * squaredStrength), 0.0f, 1.0f);    }} void applyDampedSpring(float deltaTime, glm::vec3& velocity, glm::vec3& position, glm::vec3& targetPosition, float k, float damping) {    }