Adding bounding box computation.

Change-Id: I682609312519d9474176556ade7a208c7d0a1323

rsMesh.h

diff --git a/rsMesh.h b/rsMesh.h
index 765a971..ed01c38 100644
--- a/rsMesh.h
+++ b/rsMesh.h
@@ -61,6 +61,11 @@
     virtual RsA3DClassID getClassId() const { return RS_A3D_CLASS_ID_MESH; }
     static Mesh *createFromStream(Context *rsc, IStream *stream);
 
+    // Bounding volumes
+    float mBBoxMin[3];
+    float mBBoxMax[3];
+    void computeBBox();
+
 protected:
 };