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include/framework/geometry/sat.h

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+/* -----------------------------------------------------------------------------
+	GSFramework
+	Copyright 2001-2013 Emmanuel Julien. All Rights Reserved.
+----------------------------------------------------------------------------- */
+
+
+#ifndef	__NSAT__
+#define	__NSAT__
+
+
+		#include <float.h>
+
+
+namespace GS {
+	namespace SAT {
+
+/// SAT overlap test results.
+enum	Overlap
+{
+	Outside		=	0,
+	Inside,		// B inside A
+	Clipped
+};
+
+/// Helper function to test overlap on a given axis.
+Overlap		TestOverlap(const Vector4 &axis, int ca, const Vector4 *a, int cb, const Vector4 *b)
+{
+	// A interval.
+	float a_mn = FLT_MAX, a_mx = -FLT_MAX;
+	for	(int n = 0; n < ca; ++n)
+	{
+		float d = axis.Dot(a[n]);
+		if	(d < a_mn)	a_mn = d;
+		if	(d > a_mx)	a_mx = d;
+	}
+
+	// B interval.
+	float b_mn = FLT_MAX, b_mx = -FLT_MAX;
+	for	(int n = 0; n < cb; ++n)
+	{
+		float d = axis.Dot(b[n]);
+		if	(d < b_mn)	b_mn = d;
+		if	(d > b_mx)	b_mx = d;
+	}
+
+	// Test overlap.
+	if	((a_mx < b_mn) || (a_mn > b_mx))
+		return Outside;
+	if	((b_mn > a_mn) && (b_mx < a_mx))
+		return Inside;
+
+	return Clipped;
+}
+
+	} // SAT
+} // GS
+
+
+#endif	// __NSAT__