Added SampleDensityWhenMovingProperty to control LOD property of osgVolume.

examples/osgvolume/osgvolume.cpp

@@ -1576,6 +1576,7 @@ int main( int argc, char **argv )
 
         osgVolume::AlphaFuncProperty* ap = new osgVolume::AlphaFuncProperty(alphaFunc);
         osgVolume::SampleDensityProperty* sd = new osgVolume::SampleDensityProperty(0.005);
+        osgVolume::SampleDensityWhenMovingProperty* sdwm = new osgVolume::SampleDensityWhenMovingProperty(0.02);
         osgVolume::TransparencyProperty* tp = new osgVolume::TransparencyProperty(1.0);
         osgVolume::TransferFunctionProperty* tfp = transferFunction.valid() ? new osgVolume::TransferFunctionProperty(transferFunction.get()) : 0;
 
@@ -1584,6 +1585,7 @@ int main( int argc, char **argv )
             osgVolume::CompositeProperty* cp = new osgVolume::CompositeProperty;
             cp->addProperty(ap);
             cp->addProperty(sd);
+            cp->addProperty(sdwm);
             cp->addProperty(tp);
             if (tfp) cp->addProperty(tfp);
 

include/osgVolume/Property

@@ -35,6 +35,7 @@ class MaximumIntensityProjectionProperty;
 class LightingProperty;
 class AlphaFuncProperty;
 class SampleDensityProperty;
+class SampleDensityWhenMovingProperty;
 class TransparencyProperty;
 
 class OSGVOLUME_EXPORT PropertyVisitor
@@ -55,6 +56,7 @@ class OSGVOLUME_EXPORT PropertyVisitor
         virtual void apply(MaximumIntensityProjectionProperty&) {}
         virtual void apply(LightingProperty&) {}
         virtual void apply(SampleDensityProperty&) {}
+        virtual void apply(SampleDensityWhenMovingProperty&) {}
         virtual void apply(TransparencyProperty&) {}
 
         bool _traverseOnlyActiveChildren;
@@ -289,6 +291,7 @@ class OSGVOLUME_EXPORT LightingProperty : public Property
 };
 
 
+/** Sample density to use when the volume is static relative to the eye point or when moving if no SampleDensityWhenMovingProperty is assigned.*/
 class OSGVOLUME_EXPORT SampleDensityProperty : public ScalarProperty
 {
     public:
@@ -306,6 +309,24 @@ class OSGVOLUME_EXPORT SampleDensityProperty : public ScalarProperty
         virtual ~SampleDensityProperty() {}
 };
 
+/** Sample density to use when the volume is moving relative to the eye point.*/
+class OSGVOLUME_EXPORT SampleDensityWhenMovingProperty : public ScalarProperty
+{
+    public:
+
+        SampleDensityWhenMovingProperty(float value=1.0);
+
+        SampleDensityWhenMovingProperty(const SampleDensityWhenMovingProperty& isp,const osg::CopyOp& copyop=osg::CopyOp::SHALLOW_COPY);
+
+        META_Object(osgVolume, SampleDensityWhenMovingProperty);
+
+        virtual void accept(PropertyVisitor& pv) { pv.apply(*this); }
+
+    protected:
+
+        virtual ~SampleDensityWhenMovingProperty() {}
+};
+
 class OSGVOLUME_EXPORT TransparencyProperty : public ScalarProperty
 {
     public:
@@ -338,6 +359,7 @@ class OSGVOLUME_EXPORT CollectPropertiesVisitor : public osgVolume::PropertyVisi
         virtual void apply(MaximumIntensityProjectionProperty& mip);
         virtual void apply(LightingProperty& lp);
         virtual void apply(SampleDensityProperty& sdp);
+        virtual void apply(SampleDensityWhenMovingProperty& sdp);
         virtual void apply(TransparencyProperty& tp);
 
         osg::ref_ptr<TransferFunctionProperty>              _tfProperty;
@@ -346,6 +368,7 @@ class OSGVOLUME_EXPORT CollectPropertiesVisitor : public osgVolume::PropertyVisi
         osg::ref_ptr<MaximumIntensityProjectionProperty>    _mipProperty;
         osg::ref_ptr<LightingProperty>                      _lightingProperty;
         osg::ref_ptr<SampleDensityProperty>                 _sampleDensityProperty;
+        osg::ref_ptr<SampleDensityWhenMovingProperty>       _sampleDensityWhenMovingProperty;
         osg::ref_ptr<TransparencyProperty>                  _transparencyProperty;
 
 };

include/osgVolume/RayTracedTechnique

@@ -52,7 +52,7 @@ class OSGVOLUME_EXPORT RayTracedTechnique : public VolumeTechnique
         OpenThreads::Mutex _mutex;
         ModelViewMatrixMap _modelViewMatrixMap;
 
-        osg::ref_ptr<osg::StateSet> _lodStateSet;
+        osg::ref_ptr<osg::StateSet> _whenMovingStateSet;
 };
 
 }

src/osgVolume/Property.cpp

@@ -179,6 +179,21 @@ SampleDensityProperty::SampleDensityProperty(const SampleDensityProperty& isp,co
 }
 
 
+/////////////////////////////////////////////////////////////////////////////
+//
+// SampleDensityWhenMovingProperty
+//
+SampleDensityWhenMovingProperty::SampleDensityWhenMovingProperty(float value):
+    ScalarProperty("SampleDensityValue",value)
+{
+}
+
+SampleDensityWhenMovingProperty::SampleDensityWhenMovingProperty(const SampleDensityWhenMovingProperty& isp,const osg::CopyOp& copyop):
+    ScalarProperty(isp, copyop)
+{
+}
+
+
 /////////////////////////////////////////////////////////////////////////////
 //
 // TransparencyProperty
@@ -246,6 +261,7 @@ void CollectPropertiesVisitor::apply(AlphaFuncProperty& af) { _afProperty = ⁡
 void CollectPropertiesVisitor::apply(MaximumIntensityProjectionProperty& mip) { _mipProperty = &mip; }
 void CollectPropertiesVisitor::apply(LightingProperty& lp) { _lightingProperty = &lp; }
 void CollectPropertiesVisitor::apply(SampleDensityProperty& sdp) { _sampleDensityProperty = &sdp; }
+void CollectPropertiesVisitor::apply(SampleDensityWhenMovingProperty& sdp) { _sampleDensityWhenMovingProperty = &sdp; }
 void CollectPropertiesVisitor::apply(TransparencyProperty& tp) { _transparencyProperty = &tp; }
 
 

src/osgVolume/RayTracedTechnique.cpp

@@ -534,9 +534,11 @@ void RayTracedTechnique::init()
 
     } 
 
-    _lodStateSet = new osg::StateSet;
+    if (cpv._sampleDensityWhenMovingProperty.valid())
-    _lodStateSet->addUniform(new osg::Uniform("SampleDensityValue",0.01f), osg::StateAttribute::OVERRIDE | osg::StateAttribute::ON);
+    {
-
+        _whenMovingStateSet = new osg::StateSet;
+        _whenMovingStateSet->addUniform(cpv._sampleDensityWhenMovingProperty->getUniform(), osg::StateAttribute::OVERRIDE | osg::StateAttribute::ON);
+    }
 }
 
 void RayTracedTechnique::update(osgUtil::UpdateVisitor* uv)
@@ -548,7 +550,7 @@ void RayTracedTechnique::cull(osgUtil::CullVisitor* cv)
 {
     if (!_transform.valid()) return;
 
-    if (_lodStateSet.valid())
+    if (_whenMovingStateSet.valid())
     {
         bool moving = false;
         {
@@ -570,7 +572,7 @@ void RayTracedTechnique::cull(osgUtil::CullVisitor* cv)
 
         if (moving)
         {
-            cv->pushStateSet(_lodStateSet.get());
+            cv->pushStateSet(_whenMovingStateSet.get());
             _transform->accept(*cv);
             cv->popStateSet();
         }