From 929601f0702dc4ad60b018328809d1ed8ad2ddfe Mon Sep 17 00:00:00 2001
From: Robert Osfield <robert@openscenegraph.com>
Date: Wed, 9 Mar 2005 20:40:31 +0000
Subject: [PATCH] Improvements to MultiTextureControl and texture layer
 handling in osgTerrain::DataSet.

---
 src/osgFX/MultiTextureControl.cpp | 29 +++++++++++++++++++-----
 src/osgTerrain/DataSet.cpp        | 37 ++++++++++++++++++++++++-------
 2 files changed, 53 insertions(+), 13 deletions(-)

diff --git a/src/osgFX/MultiTextureControl.cpp b/src/osgFX/MultiTextureControl.cpp
index fca15e345..fb273043e 100644
--- a/src/osgFX/MultiTextureControl.cpp
+++ b/src/osgFX/MultiTextureControl.cpp
@@ -46,12 +46,31 @@ void MultiTextureControl::updateStateSet()
     
     stateset->clear();
     
-    if (_textureWeightList.size()==1) 
+    unsigned int numTextureUnitsOn = 0;
+    unsigned int unit;
+    for(unit=0;unit<_textureWeightList.size();++unit)
     {
-        osg::TexEnv* texenv = new osg::TexEnv(osg::TexEnv::MODULATE);
-        stateset->setTextureAttribute(0, texenv);
+        if (_textureWeightList[unit]>0.0f) ++numTextureUnitsOn;
     }
-    if (_textureWeightList.size()==2)
+    
+    if (numTextureUnitsOn<=1)
+    {
+        for(unit=0;unit<_textureWeightList.size();++unit)
+        {
+            if (_textureWeightList[unit]>0.0f) 
+            {
+                osg::TexEnv* texenv = new osg::TexEnv(osg::TexEnv::MODULATE);
+                stateset->setTextureAttribute(unit, texenv);
+                stateset->setTextureMode(unit, GL_TEXTURE_2D, osg::StateAttribute::ON);
+            }
+            else
+            {
+                stateset->setTextureMode(unit, GL_TEXTURE_2D, osg::StateAttribute::OFF | osg::StateAttribute::OVERRIDE);
+            }
+        }
+
+    }
+    else if (_textureWeightList.size()==2)
     {
         {
             osg::TexEnvCombine* texenv = new osg::TexEnvCombine;
@@ -80,7 +99,7 @@ void MultiTextureControl::updateStateSet()
             stateset->setTextureAttribute(1, texenv);
         }
     } 
-    if (_textureWeightList.size()==3)
+    else if (_textureWeightList.size()==3)
     {
         float b = (_textureWeightList[0]+_textureWeightList[1])/(_textureWeightList[0]+_textureWeightList[1]+_textureWeightList[2]);
         float a = _textureWeightList[0]/(_textureWeightList[0]+_textureWeightList[1]);
diff --git a/src/osgTerrain/DataSet.cpp b/src/osgTerrain/DataSet.cpp
index 551a12cdb..15105496f 100644
--- a/src/osgTerrain/DataSet.cpp
+++ b/src/osgTerrain/DataSet.cpp
@@ -2833,19 +2833,40 @@ void DataSet::DestinationTile::readFrom(CompositeSource* sourceGraph)
     {
     
         Source* source = itr->get();
-        if (source && _level>=source->getMinLevel() && _level<=source->getMaxLevel()) 
+        if (source && 
+            _level>=source->getMinLevel() && _level<=source->getMaxLevel() && 
+            (*itr)->getSourceData()) 
         {
-            unsigned int layerNum = source->getLayer();
+            my_notify(osg::INFO)<<"DataSet::DestinationTile::readFrom -> SourceData::read() "<<std::endl;
+            my_notify(osg::INFO)<<"    destination._level="<<_level<<"\t"<<source->getMinLevel()<<"\t"<<source->getMaxLevel()<<std::endl;
+
             SourceData* data = (*itr)->getSourceData();
-            if (data)
+            if (source->getType()==DataSet::Source::IMAGE)
             {
-                my_notify(osg::INFO)<<"DataSet::DestinationTile::readFrom -> SourceData::read() "<<std::endl;
-                my_notify(osg::INFO)<<"    destination._level="<<_level<<"\t"<<source->getMinLevel()<<"\t"<<source->getMaxLevel()<<std::endl;
-                if (layerNum<_imagery.size() &&
-                    _imagery[layerNum]._imagery.valid())
+                unsigned int layerNum = source->getLayer();
+                
+                if (layerNum==0)
                 {
-                    data->read(*(_imagery[layerNum]._imagery));
+                    // copy the base layer 0 into layer 0 and all subsequent layers to provide a backdrop.
+                    for(unsigned int i=0;i<_imagery.size();++i)
+                    {
+                        if (_imagery[i]._imagery.valid())
+                        {
+                            data->read(*(_imagery[i]._imagery));
+                        }
+                    }
                 }
+                else
+                {
+                    // copy specific layer.
+                    if (layerNum<_imagery.size() && _imagery[layerNum]._imagery.valid())
+                    {
+                        data->read(*(_imagery[layerNum]._imagery));
+                    }
+                }
+            }
+            else
+            {
                 if (_terrain.valid()) data->read(*_terrain);
             }
         }