Enable old-style texture compression

Thanks to Dany for tracking this down!

simgear/scene/model/ModelRegistry.cxx

@@ -113,9 +113,6 @@ protected:
     }
 };
 
-// disabling old-syle texture compression in favour of the 
-// texture-cache
-#if 0
 class SGTexCompressionVisitor : public SGTextureStateAttributeVisitor {
 public:
   virtual void apply(int, StateSet::RefAttributePair& refAttr)
@@ -146,7 +143,6 @@ public:
     }
   }
 };
-#endif
 
 class SGTexDataVarianceVisitor : public SGTextureStateAttributeVisitor {
 public:
@@ -644,12 +640,8 @@ osg::Node* OptimizeModelPolicy::optimize(osg::Node* node,
     SGTexDataVarianceVisitor dataVarianceVisitor;
     node->accept(dataVarianceVisitor);
 
-// disabling old-syle texture compression in favour of the 
-// texture-cache
-#if 0
     SGTexCompressionVisitor texComp;
     node->accept(texComp);
-#endif
     return node;
 }
 

simgear/scene/util/SGSceneFeatures.cxx

@@ -69,11 +69,11 @@ SGSceneFeatures::instance()
 void
 SGSceneFeatures::applyTextureCompression(osg::Texture* texture) const
 {
-  // disable older texture-compression, since it interacts confusingly
-  // with the the runtime texture-cache. We always want to use 
-  // 'USE_IMAGE_DATA_FORMAT' when the texture-cache is active, since we
-  // decided whether to compress (or not) prior to this point.
-#if 0
+    // if the texture cache is active, always use the file data format
+    if (_TextureCacheCompressionActive) {
+        texture->setInternalFormatMode(osg::Texture::USE_IMAGE_DATA_FORMAT);
+    } else {
+        // keep the older texture compression working, some people need it
         switch (_textureCompression) {
         case UseARBCompression:
           texture->setInternalFormatMode(osg::Texture::USE_ARB_COMPRESSION);
@@ -91,7 +91,7 @@ SGSceneFeatures::applyTextureCompression(osg::Texture* texture) const
           texture->setInternalFormatMode(osg::Texture::USE_IMAGE_DATA_FORMAT);
           break;
         }
-#endif
+    }
 }
 
 bool