From 3572251a9139bf95f2217c2e9957668b6c82ccdc Mon Sep 17 00:00:00 2001
From: Don Bright <hugh.m.bright@gmail.com>
Date: Sat, 24 Dec 2011 07:50:24 -0600
Subject: commit Marius' linalg.cc


diff --git a/src/linalg.cc b/src/linalg.cc
new file mode 100644
index 0000000..30f23af
--- /dev/null
+++ b/src/linalg.cc
@@ -0,0 +1,27 @@
+#include "linalg.h"
+
+// FIXME: We can achieve better pruning by either:
+// o Recalculate the box based on the transformed object
+// o Store boxes are oriented bounding boxes and implement oriented
+//   bbox intersection
+
+// FIXME: This function can be generalized, but we don't need it atm.
+
+/*!
+	Transforms the given bounding box by transforming each of its 8 vertices.
+	Returns a new bounding box.
+*/
+BoundingBox operator*(const Transform3d &m, const BoundingBox &box)
+{
+	BoundingBox newbox;
+	Vector3d boxvec[2] = { box.min(), box.max() };
+	for (int k=0;k<2;k++) {
+		for (int j=0;j<2;j++) {
+			for (int i=0;i<2;i++) {
+				newbox.extend(m * Vector3d(boxvec[i][0], boxvec[j][1], boxvec[k][2]));
+			}
+		}
+	}
+	return newbox;
+}
+
-- 
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