allow for float data, and prepare for 'quad edge flip', either re-use the first triangle vertex, or second (re-use index 00 or 01)

Demos/VehicleDemo/VehicleDemo.cpp

@@ -237,7 +237,10 @@ const float TRIANGLE_SIZE=20.f;
 
 	btScalar maxHeight = 20000.f;
 	
-	groundShape = new btHeightfieldTerrainShape(width,length,heightfieldData,maxHeight,upIndex);
+	bool useFloatDatam=false;
+	bool flipQuadEdges=false;
+
+	groundShape = new btHeightfieldTerrainShape(width,length,heightfieldData,maxHeight,upIndex,useFloatDatam,flipQuadEdges);
 	btVector3 localScaling(20,20,20);
 	localScaling[upIndex]=1.f;
 	groundShape->setLocalScaling(localScaling);