Initial commit.

physics/particle.h

@@ -0,0 +1,39 @@
+// -*- C++ -*-
+
+#ifndef MBOSTOCK_PARTICLE_H
+#define MBOSTOCK_PARTICLE_H
+
+#include "vector.h"
+
+namespace mbostock {
+
+  class Particle {
+  public:
+    Particle();
+
+    float inverseMass;
+    Vector position;
+    Vector previousPosition;
+    Vector force;
+
+    Vector velocity() const;
+  };
+
+  class ParticleSimulator {
+  public:
+    ParticleSimulator();
+    ParticleSimulator(float drag);
+
+    void step(Particle& p) const;
+
+    static float timeStep();
+
+  private:
+    static float timeStep_;
+    static float timeStepSquared_;
+    float drag_;
+  };
+
+}
+
+#endif