Added preliminary ProxLayer and DataSetLayer in GDAL plugin to aid integration

of GDAL reading into osgTerrain.

src/osgPlugins/gdal/DataSetLayer.cpp

@@ -0,0 +1,49 @@
+/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2006 Robert Osfield 
+ *
+ * This library is open source and may be redistributed and/or modified under  
+ * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or 
+ * (at your option) any later version.  The full license is in LICENSE file
+ * included with this distribution, and on the openscenegraph.org website.
+ * 
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the 
+ * OpenSceneGraph Public License for more details.
+*/
+
+#include "DataSetLayer.h"
+
+using namespace GDALPlugin;
+
+DataSetLayer::DataSetLayer()
+{
+    _dataset = 0;
+}
+
+DataSetLayer::DataSetLayer(const std::string& fileName)
+{
+    setFileName(fileName);
+    _dataset = (GDALDataset*)GDALOpen(fileName.c_str(),GA_ReadOnly);
+}
+
+DataSetLayer::DataSetLayer(const DataSetLayer& dataSetLayer,const osg::CopyOp& copyop):
+    ProxyLayer(dataSetLayer)
+{
+    _dataset = (GDALDataset*)GDALOpen(getFileName().c_str(),GA_ReadOnly);
+}
+
+DataSetLayer::~DataSetLayer()
+{
+    if (_dataset) delete _dataset;
+}
+
+unsigned int DataSetLayer::getNumColumns() const
+{
+    return _dataset!=0 ? _dataset->GetRasterXSize() : 0;
+}
+
+unsigned int DataSetLayer::getNumRows() const
+{
+    return _dataset!=0 ? _dataset->GetRasterYSize() : 0;
+}
+