comparison examples/10-Instruments/airharp/MassSpringDamper.cpp @ 464:8fcfbfb32aa0 prerelease

Examples reorder with subdirectories. Added header to each project. Moved Doxygen to bottom of render.cpp.

+/*
+ *
+ * Simple 1-Dimensional Mass Spring Damper
+ *
+ * Christian Heinrichs 04/2015
+ *
+ */
+
+#include "MassSpringDamper.h"
+
+MassSpringDamper::MassSpringDamper(float mass, float spring, float damp)	{
+
+	_dt = 1.0/44100.0;
+	_mass = mass;
+	_spring = spring;
+	_damp = damp;
+	_position = 0;
+	_velocity = 0;
+
+}
+
+void MassSpringDamper::setup()	{
+
+}
+
+double MassSpringDamper::update(float inForce)	{
+
+	// 1. calculate spring/damper forces using current position and velocity
+
+	double out = (_position * (double)_spring * -1) + (_velocity * (double)_damp * -1);
+
+	// 2. apply external force
+
+	out += inForce;
+
+	// 3. derive acceleration (a = f/m)
+
+	out /= (double)_mass;
+
+	// 4. derive velocity (v = a*dt)
+
+	out *= _dt;
+
+	// 5. apply previous velocity
+
+	out += _velocity;
+
+	// 6. save current velocity state for next iteration
+
+	_velocity = out;
+
+	// 7. derive new position (x[n] = x[n-1] + v[n]) and save for next iteration
+
+	out += _position;
+	_position = out;
+
+	return out;
+
+}