From df541170776dc4ac4f241ca480812bd70bcb6eca Mon Sep 17 00:00:00 2001
From: Charles McGarvey <chazmcgarvey@brokenzipper.com>
Date: Sun, 20 Sep 2009 10:36:42 -0600
Subject: [PATCH] spring experiments

---
 src/Character.cc | 19 ++++++++++++++++++-
 src/Character.hh |  2 +-
 src/Moof/RK4.hh  |  9 +++++++++
 3 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/src/Character.cc b/src/Character.cc
index c7de260..4ce1105 100644
--- a/src/Character.cc
+++ b/src/Character.cc
@@ -40,7 +40,7 @@ Character::Character(const std::string& name) :
 	current.inverseMass = 1.0 / current.mass;
 
 	// gravity
-	current.force = Mf::Vector2(0.0, -120.0);
+	//current.force = Mf::Vector2(0.0, -120.0);
 
 	// starting position
 	current.position = Mf::Vector2(64.0, 64.0);
@@ -56,6 +56,23 @@ Character::Character(const std::string& name) :
 void Character::update(Mf::Scalar t, Mf::Scalar dt)
 {
 	previous = current;
+
+	Mf::Scalar epsilon = 100.0;
+
+	//current.momentum = Mf::Vector2(0.0, -120.0);
+	current.momentum = -5 * (current.position - Mf::Vector2(500.0, 200.0))
+		- 2.0 * current.velocity;
+	current.recalculate();
+	std::cout << "force: " << current.momentum << std::endl;
+
+	//if (std::abs(current.force[0]) < epsilon && std::abs(current.force[1]) < epsilon &&
+		//std::abs(current.velocity[0]) < epsilon && std::abs(current.velocity[1]) < epsilon)
+	//{
+		//current.force = Mf::Vector2(0.0, 0.0);
+		//current.velocity = Mf::Vector2(0.0, 0.0);
+		//current.momentum = Mf::Vector2(0.0, 0.0);
+	//}
+
 	Mf::integrate<State,Derivative>(current, t, dt);
 
 	animation_.update(t, dt);
diff --git a/src/Character.hh b/src/Character.hh
index 96ac499..00e5a4b 100644
--- a/src/Character.hh
+++ b/src/Character.hh
@@ -123,7 +123,7 @@ struct Character : public Mf::Entity
 			return state;
 		}
 
-		State operator+(State state) const
+		State operator+(const State& state) const
 		{
 			State newState = *this;
 			newState.position +=  state.position;
diff --git a/src/Moof/RK4.hh b/src/Moof/RK4.hh
index a2e0f1c..00c0b64 100644
--- a/src/Moof/RK4.hh
+++ b/src/Moof/RK4.hh
@@ -75,6 +75,15 @@ inline void integrate(S& state, Scalar t, Scalar dt)
 }
 
 
+//template<typename T>
+//inline T spring(Scalar k, Scalar b)
+//{
+	//current.force = -15 * (current.position - Mf::Vector2(200.0, 200.0))
+		//- 15.0 * current.velocity;
+	//return 
+//}
+
+
 } // namespace Mf
 
 #endif // _MOOF_RK4_HH_
-- 
2.45.2