LodGenerator now properly shift short indexes so that there is no negative value when assigned to an int and used as an index in an array

git-svn-id: https://jmonkeyengine.googlecode.com/svn/trunk@10783 75d07b2b-3a1a-0410-a2c5-0572b91ccdca

engine/src/tools/jme3tools/optimize/LodGenerator.java

@@ -331,7 +331,9 @@ public class LodGenerator {
                 if (b instanceof IntBuffer) {
                     tri.vertexId[i] = ((IntBuffer) b).get();
                 } else {
-                    tri.vertexId[i] = ((ShortBuffer) b).get();
+                    //bit shift to avoid negative values due to conversion form short to int.
+                    //we need an unsigned int here.
+                    tri.vertexId[i] = ((ShortBuffer) b).get()& 0xffff;
                 }
                // assert (tri.vertexId[i] < vertexLookup.size());
                 tri.vertex[i] = vertexLookup.get(tri.vertexId[i]);