From: Charles McGarvey <chazmcgarvey@brokenzipper.com>
Date: Wed, 13 Jul 2011 06:58:02 +0000 (-0600)
Subject: global gravity for rigid bodies
X-Git-Url: https://git.dogcows.com/gitweb?p=chaz%2Fyoink;a=commitdiff_plain;h=aa67fc8ab5691cad24b55d0e12aba2f6c3e58316

global gravity for rigid bodies
---

diff --git a/src/moof/rigid_body.cc b/src/moof/rigid_body.cc
new file mode 100644
index 0000000..ce409b4
--- /dev/null
+++ b/src/moof/rigid_body.cc
@@ -0,0 +1,20 @@
+
+/*]  Copyright (c) 2009-2011, Charles McGarvey  [*****************************
+**]  All rights reserved.
+*
+* Distributable under the terms and conditions of the 2-clause BSD license;
+* see the file COPYING for a complete text of the license.
+*
+*****************************************************************************/
+
+#include "math.hh"
+
+
+namespace moof {
+
+
+scalar global_acceleration;
+
+
+} // namespace moof
+
diff --git a/src/moof/rigid_body.hh b/src/moof/rigid_body.hh
index b8b9048..7ed0a88 100644
--- a/src/moof/rigid_body.hh
+++ b/src/moof/rigid_body.hh
@@ -27,7 +27,9 @@
 namespace moof {
 
 
-template <int D = 3>
+extern scalar global_acceleration;
+
+template <int D>
 struct linear_state
 {
 	typedef moof::vector< scalar, fixed<D> > vector;
@@ -56,22 +58,20 @@ struct linear_state
 
 	struct gravity_force
 	{
-		explicit gravity_force(scalar a = -9.8)
+		gravity_force()
 		{
 			force.zero();
-			acceleration = a;
 		}
 
 		const vector& operator () (const linear_state& state)
 		{
-			force[1] = state.mass * acceleration;
+			force[1] = state.mass * global_acceleration;
 			return force;
 		}
 
 	private:
 
-		vector force;
-		scalar acceleration;
+		vector	force;
 	};
 
 	void init()
@@ -85,7 +85,7 @@ struct linear_state
 		forces.clear();
 
 		mass = SCALAR(1.0);
-		inverse_mass = 1.0 / mass;
+		inverse_mass = SCALAR(1.0);
 	}
 
 	struct derivative
@@ -114,9 +114,10 @@ struct linear_state
 	{
 		vector f(force);
 
-		for (size_t i = 0; i < forces.size(); ++i)
+		typename std::vector<force_function>::const_iterator it;
+		for (it = forces.begin(); it != forces.end(); ++it)
 		{
-			f += forces[i](*this);
+			f += (*it)(*this);
 		}
 
 		return f;
@@ -143,7 +144,7 @@ struct rotational_state2
 	scalar		angular_momentum;
 
 	// secondary
-	scalar		angularVelocity;
+	scalar		angular_velocity;
 
 	// constant
 	scalar		inertia;
@@ -151,18 +152,18 @@ struct rotational_state2
 
 	void recalculate()
 	{
-		angularVelocity = angular_momentum * inertia;
+		angular_velocity = angular_momentum * inertia;
 	}
 
 	struct derivative
 	{
-		scalar	angularVelocity;
+		scalar	angular_velocity;
 		scalar	torque;
 	};
 
 	void step(const derivative& derivative, scalar dt)
 	{
-		orientation += dt * derivative.angularVelocity;
+		orientation += dt * derivative.angular_velocity;
 		angular_momentum += dt * derivative.torque;
 		recalculate();
 	}
@@ -176,7 +177,7 @@ struct rotational_state3
 
 	// secondary
 	quaternion	spin;
-	vector3		angularVelocity;
+	vector3		angular_velocity;
 
 	// constant
 	scalar		inertia;
@@ -184,7 +185,7 @@ struct rotational_state3
 
 	void recalculate()
 	{
-		angularVelocity = angular_momentum * inertia;
+		angular_velocity = angular_momentum * inertia;
 	}
 };
 
@@ -255,11 +256,6 @@ interpolate<state3>(const state3& a, const state3& b, scalar alpha)
 template <class T>
 class rigid_body : public entity
 {
-protected:
-
-	T	state_;
-	T	prev_state_;
-
 public:
 
 	virtual ~rigid_body() {}
@@ -284,6 +280,11 @@ public:
 	{
 		return prev_state_;
 	}
+
+protected:
+
+	T	state_;
+	T	prev_state_;
 };
 
 typedef rigid_body<state2> rigid_body2;