moved SAT code into collision module

include/bounce/collision/sat/sat.h

@@ -52,4 +52,57 @@ float32 b3Project(const b3Vec3& P1, const b3Vec3& E1, const b3Vec3& P2, const b3
 b3EdgeQuery b3QueryEdgeSeparation(const b3Transform& xf1, const b3Hull* hull1,
 	const b3Transform& xf2, const b3Hull* hull2);
 
+
+///////////////////////////////////////////////////////////////////////////////////////////////////
+
+enum b3SATCacheType
+{
+	e_separation,
+	e_overlap,
+	e_empty,
+};
+
+enum b3SATFeatureType
+{
+	e_edge1, // an edge on hull 1 and an edge on hull 2
+	e_face1, // a face on hull 1 and a vertex/edge/face on hull 2
+	e_face2, // a face on hull 2 and a vertex/edge/face on hull 1
+};
+
+// A cached feature pair is used to improve the performance 
+// of the SAT when called more than once. 
+struct b3SATFeaturePair
+{
+	b3SATCacheType state; // sat result
+	b3SATFeatureType type; // feature pair type
+	u32 index1; // feature index on hull 1
+	u32 index2; // feature index on hull 2
+};
+
+inline b3SATFeaturePair b3MakeFeaturePair(b3SATCacheType state, b3SATFeatureType type, u32 index1, u32 index2)
+{
+	b3SATFeaturePair pair;
+	pair.state = state;
+	pair.type = type;
+	pair.index1 = index1;
+	pair.index2 = index2;
+	return pair;
+}
+
+struct b3FeatureCache
+{
+	// Read the current state of the cache.
+	// Return e_unkown if neither a separation or penetration was detected.
+	b3SATCacheType ReadState(const b3Transform& xf1, const b3Hull* hull1,
+		const b3Transform& xf2, const b3Hull* hull2, float32 totalRadius);
+
+	b3SATCacheType ReadEdge(const b3Transform& xf1, const b3Hull* hull1,
+		const b3Transform& xf2, const b3Hull* hull2, float32 totalRadius);
+
+	b3SATCacheType ReadFace(const b3Transform& xf1, const b3Hull* hull1,
+		const b3Transform& xf2, const b3Hull* hull2, float32 totalRadius);
+	
+	b3SATFeaturePair m_featurePair;
+};
+
 #endif