Move source to src.

physics/force.cpp

@@ -1,94 +0,0 @@
-// -*- C++ -*-
-
-#include <stdio.h>
-#include <stdlib.h>
-
-#include "force.h"
-#include "particle.h"
-#include "vector.h"
-
-using namespace mbostock;
-
-static const float epsilon = 1E-20;
-
-void UnaryForce::apply(Particle& p) {
-  p.force += force(p);
-}
-
-void BinaryForce::apply(Particle& a, Particle& b) {
-  Vector f = force(a, b);
-  a.force += f;
-  b.force -= f;
-}
-
-RandomForce::RandomForce(float k)
-    : k_(k) {
-}
-
-Vector RandomForce::force(Particle& p) {
-  return Vector::randomVector(k_);
-}
-
-GravitationalForce::GravitationalForce(float g)
-    : g_(g) {
-}
-
-Vector GravitationalForce::force(const Particle& p) {
-  return Vector(0, -g_ / p.inverseMass, 0);
-}
-
-LinearDragForce::LinearDragForce(float kd)
-    : kd_(kd) {
-}
-
-Vector LinearDragForce::force(const Particle& p) {
-  return p.velocity() * -kd_;
-}
-
-QuadraticDragForce::QuadraticDragForce(float kd)
-    : kd_(kd) {
-}
-
-Vector QuadraticDragForce::force(const Particle& p) {
-  const Vector& v = p.velocity();
-  return v * v.length() * -kd_;
-}
-
-HookeForce::HookeForce(float r, float ks)
-    : r_(r), ks_(ks) {
-}
-
-Vector HookeForce::force(const Particle& a, const Particle& b) {
-  Vector l = a.position - b.position;
-  float ll = l.length();
-  if (ll == 0.f) {
-    l = Vector::randomVector(epsilon);
-    ll = epsilon;
-  }
-  return l * -ks_ * (ll - r_) / ll;
-}
-
-DampenedHookeForce::DampenedHookeForce(float r, float ks, float kd)
-    : r_(r), ks_(ks), kd_(kd) {
-}
-
-Vector DampenedHookeForce::force(const Particle& a, const Particle& b) {
-  Vector l = a.position - b.position;
-  Vector dl = a.velocity() - b.velocity();
-  float ll = l.length();
-  if (ll == 0.f) {
-    l = Vector::randomVector(epsilon);
-    ll = epsilon;
-  }
-  return l * -(ks_ * (ll - r_) + kd_ * dl.dot(l) / ll) / ll;
-}
-
-CoulombForce::CoulombForce(float e)
-    : e_(e) {
-}
-
-Vector CoulombForce::force(const Particle& a, const Particle& b) {
-  Vector l = a.position - b.position;
-  float ll = l.length();
-  return -l * e_ / (ll * ll * ll);
-}