From efb52dfab9d52f5921d97ea9db41452cf7aa176d Mon Sep 17 00:00:00 2001
From: Robert Osfield <robert@openscenegraph.com>
Date: Mon, 30 Apr 2007 09:47:35 +0000
Subject: [PATCH] Added TerrainNode::setColorFilter(layerNum,Filter) to allow
 developers to set what type of texture filter to use, either LINEAER and
 NEAREST.

---
 examples/osgterrain/osgterrain.cpp   | 23 ++++++++++++++++++++
 include/osgTerrain/TerrainNode       | 32 +++++++++++++++++++++++++++-
 src/osgTerrain/GeometryTechnique.cpp |  3 +++
 src/osgTerrain/TerrainNode.cpp       |  7 ++++++
 4 files changed, 64 insertions(+), 1 deletion(-)

diff --git a/examples/osgterrain/osgterrain.cpp b/examples/osgterrain/osgterrain.cpp
index 4647c6d3b..b8e0d0363 100644
--- a/examples/osgterrain/osgterrain.cpp
+++ b/examples/osgterrain/osgterrain.cpp
@@ -84,6 +84,8 @@ int main(int argc, char** argv)
 
     unsigned int layerNum = 0;
 
+    std::string filterName;
+
     bool readParameter = false;
     float minValue, maxValue;
     int pos = 1;
@@ -174,6 +176,27 @@ int main(int argc, char** argv)
             }
         }
 
+        else if (arguments.read(pos, "--filter",filterName))
+        {
+            readParameter = true;
+            
+            if (filterName=="NEAREST")
+            {
+                osg::notify(osg::NOTICE)<<"--filter "<<filterName<<std::endl;
+                terrain->setColorFilter(layerNum, osgTerrain::TerrainNode::NEAREST);
+            }
+            else if (filterName=="LINEAER") 
+            {
+                osg::notify(osg::NOTICE)<<"--filter "<<filterName<<std::endl;
+                terrain->setColorFilter(layerNum, osgTerrain::TerrainNode::LINEAR);
+            }
+            else
+            {
+                osg::notify(osg::NOTICE)<<"--filter "<<filterName<<" unrecognized filter name, please use LINEAER or NEAREST."<<std::endl;
+            }            
+            
+        }
+
         else if (arguments.read(pos, "--tf",minValue, maxValue))
         {
             readParameter = true;
diff --git a/include/osgTerrain/TerrainNode b/include/osgTerrain/TerrainNode
index d920deeef..d77c639a1 100644
--- a/include/osgTerrain/TerrainNode
+++ b/include/osgTerrain/TerrainNode
@@ -88,6 +88,20 @@ class OSGTERRAIN_EXPORT TerrainNode : public osg::Group
         /** Get const color transfer function with specified layer number.*/
         const osg::TransferFunction* getColorTransferFunction(unsigned int i) const { return i<_colorLayers.size() ? _colorLayers[i].transferFunction.get() : 0; }
 
+        enum Filter
+        {
+            NEAREST,
+            LINEAR
+        };
+
+        /** Set a color filter with specified layer number.*/
+        void setColorFilter(unsigned int i, Filter filter);
+
+        /** Set const color filter with specified layer number.*/
+        Filter getColorFilter(unsigned int i) const { return i<_colorLayers.size() ? _colorLayers[i].filter : LINEAR; }
+
+
+        /** Get the number of colour layers.*/
         unsigned int getNumColorLayers() const { return _colorLayers.size(); }
 
 
@@ -107,7 +121,23 @@ class OSGTERRAIN_EXPORT TerrainNode : public osg::Group
 
         struct LayerData
         {
-            osg::ref_ptr<Layer> layer;
+            LayerData():
+                filter(LINEAR) {}
+        
+            LayerData(const LayerData& rhs):
+                filter(rhs.filter),
+                layer(rhs.layer),
+                transferFunction(rhs.transferFunction) {}
+
+            LayerData& operator = (const LayerData& rhs)
+            {
+                filter = rhs.filter;
+                layer = rhs.layer;
+                transferFunction = rhs.transferFunction;
+            }
+
+            Filter                              filter;
+            osg::ref_ptr<Layer>                 layer;
             osg::ref_ptr<osg::TransferFunction> transferFunction;
         };
 
diff --git a/src/osgTerrain/GeometryTechnique.cpp b/src/osgTerrain/GeometryTechnique.cpp
index f8182a918..ff4b9621c 100644
--- a/src/osgTerrain/GeometryTechnique.cpp
+++ b/src/osgTerrain/GeometryTechnique.cpp
@@ -49,6 +49,7 @@ void GeometryTechnique::init()
     osgTerrain::Layer* elevationLayer = _terrainNode->getElevationLayer();
     osgTerrain::Layer* colorLayer = _terrainNode->getColorLayer(0);
     osg::TransferFunction* colorTF = _terrainNode->getColorTransferFunction(0);
+    osgTerrain::TerrainNode::Filter filter = _terrainNode->getColorFilter(0);
 
     // if the elevationLayer and colorLayer are the same, and there is colorTF then
     // simply assing as a texture coordinate.
@@ -286,6 +287,8 @@ void GeometryTechnique::init()
             texture2D->setResizeNonPowerOfTwoHint(false);
             stateset->setTextureAttributeAndModes(color_index, texture2D, osg::StateAttribute::ON);
 
+            texture2D->setFilter(osg::Texture::MAG_FILTER, filter==TerrainNode::LINEAR ? osg::Texture::LINEAR :  osg::Texture::NEAREST);
+
             if (tf)
             {
                 // up the precision of hte internal texture format to its maximum.
diff --git a/src/osgTerrain/TerrainNode.cpp b/src/osgTerrain/TerrainNode.cpp
index 6fb8c2690..cd22b5634 100644
--- a/src/osgTerrain/TerrainNode.cpp
+++ b/src/osgTerrain/TerrainNode.cpp
@@ -81,6 +81,13 @@ void TerrainNode::setColorTransferFunction(unsigned int i, osg::TransferFunction
     _colorLayers[i].transferFunction = tf;
 }
 
+void TerrainNode::setColorFilter(unsigned int i, Filter filter)
+{
+    if (_colorLayers.size() <= i) _colorLayers.resize(i+1);
+    
+    _colorLayers[i].filter = filter;
+}
+
 osg::BoundingSphere TerrainNode::computeBound() const
 {
     osg::BoundingSphere bs;