Merge branch 'master' into MultiLayerTileDatabase

Author: robertosfield

include/vsg/app/ViewMatrix.h

@@ -33,7 +33,7 @@ namespace vsg
 
         /// origin value provides a means of translating the view matrix relative to the origin of any CoordinateFrame subgraphs
         /// to maximize the precision when moving around the CoordinateFrame subgraph.  This is helpful for astronmically large
-        /// scenes where standrd double precision is insufficient for avoiding visually significant numerical errors.
+        /// scenes where standard double precision is insufficient for avoiding visually significant numerical errors.
         dvec3 origin;
 
         virtual dmat4 transform(const dvec3& offset = {}) const = 0;

src/vsg/app/ViewMatrix.cpp

@@ -20,14 +20,18 @@ void ViewMatrix::read(Input& input)
 {
     Object::read(input);
 
-    input.read("origin", origin);
+    if (input.version_greater_equal(1, 1, 8))
+        input.read("origin", origin);
+    else
+        origin = {};
 }
 
 void ViewMatrix::write(Output& output) const
 {
     Object::write(output);
 
-    output.write("origin", origin);
+    if (output.version_greater_equal(1, 1, 8))
+        output.write("origin", origin);
 }
 
 void LookAt::read(Input& input)