[ADD] - Volume Renderer now allows the direct usage of pre-calculated gradient...

[ADD] - Volume Renderer now allows the direct usage of pre-calculated gradient fields for lighting. This speeds up rendering since gradients do not need to be created on the fly. It is still possible to use it without the gradient field.

src/modules/directVolumeRendering/WMDirectVolumeRendering.cpp

@@ -85,12 +85,10 @@ const std::string WMDirectVolumeRendering::getDescription() const
 void WMDirectVolumeRendering::connectors()
 {
     // DVR needs one input: the scalar dataset
-    m_input = boost::shared_ptr< WModuleInputData < WDataSetScalar  > >(
-        new WModuleInputData< WDataSetScalar >( shared_from_this(), "in", "The scalar dataset shown using isosurface." )
-    );
+    m_input = WModuleInputData< WDataSetScalar >::createAndAdd( shared_from_this(), "in", "The scalar dataset." );
 
-    // As properties, every connector needs to be added to the list of connectors.
-    addConnector( m_input );
+    // Optional: the gradient field
+    m_gradients = WModuleInputData< WDataSetVector >::createAndAdd( shared_from_this(), "gradients", "The gradient field of the dataset to display" );
 
     // call WModules initialization
     WModule::connectors();
@@ -102,9 +100,9 @@ void WMDirectVolumeRendering::properties()
     m_propCondition = boost::shared_ptr< WCondition >( new WCondition() );
 
     m_stepCount     = m_properties->addProperty( "Step count",       "The number of steps to walk along the ray during raycasting. A low value "
-                                                                      "may cause artifacts whilst a high value slows down rendering.", 250 );
+                                                                      "may cause artifacts whilst a high value slows down rendering.", 512 );
     m_stepCount->setMin( 1 );
-    m_stepCount->setMax( 1000 );
+    m_stepCount->setMax( 5000 );
 
     // illumination model
     m_localIlluminationSelections = boost::shared_ptr< WItemSelection >( new WItemSelection() );
@@ -138,6 +136,7 @@ void WMDirectVolumeRendering::moduleMain()
     // let the main loop awake if the data changes or the properties changed.
     m_moduleState.setResetable( true, true );
     m_moduleState.add( m_input->getDataChangedCondition() );
+    m_moduleState.add( m_gradients->getDataChangedCondition() );
     m_moduleState.add( m_propCondition );
 
     // Signal ready state.
@@ -164,7 +163,7 @@ void WMDirectVolumeRendering::moduleMain()
         }
 
         // was there an update?
-        bool dataUpdated = m_input->updated();
+        bool dataUpdated = m_input->updated() || m_gradients->updated();
         boost::shared_ptr< WDataSetScalar > dataSet = m_input->getData();
         bool dataValid   = ( dataSet );
         bool propUpdated = m_localIlluminationAlgo->changed() || m_tfLoaderEnabled || m_tfLoaderFile->changed() || m_tfLoaderTrigger->changed();
@@ -204,7 +203,7 @@ void WMDirectVolumeRendering::moduleMain()
             rootState->setMode( GL_BLEND, osg::StateAttribute::ON );
 
             ////////////////////////////////////////////////////////////////////////////////////////////////////
-            // setup defines (illumination)
+            // setup illumination
             ////////////////////////////////////////////////////////////////////////////////////////////////////
 
             size_t localIlluminationAlgo = m_localIlluminationAlgo->get( true ).getItemIndexOfSelected( 0 );
@@ -218,6 +217,19 @@ void WMDirectVolumeRendering::moduleMain()
                     break;
             }
 
+            // if there is a gradient field available -> apply as texture too
+            boost::shared_ptr< WDataSetVector > gradients = m_gradients->getData();
+            if ( gradients )
+            {
+                debugLog() << "Uploading specified gradient field.";
+
+                // bind the texture to the node
+                rootState->setTextureAttributeAndModes( 1, gradients->getTexture()->getTexture(), osg::StateAttribute::ON );
+                rootState->addUniform( new osg::Uniform( "tex1", 1 ) );
+                m_shader->setDefine( "GRADIENTTEXTURE_SAMPLER", "tex1" );
+                m_shader->setDefine( "GRADIENTTEXTURE_ENABLED" );
+            }
+
             ////////////////////////////////////////////////////////////////////////////////////////////////////
             // load transfer function
             ////////////////////////////////////////////////////////////////////////////////////////////////////
@@ -233,9 +245,9 @@ void WMDirectVolumeRendering::moduleMain()
                     tfTexture->setImage( tfImg );
 
                     // apply it
-                    rootState->setTextureAttributeAndModes( 1, tfTexture, osg::StateAttribute::ON );
-                    rootState->addUniform( new osg::Uniform( "tex1", 1 ) );
-                    m_shader->setDefine( "TRANSFERFUNCTION_SAMPLER", "tex1" );
+                    rootState->setTextureAttributeAndModes( 2, tfTexture, osg::StateAttribute::ON );
+                    rootState->addUniform( new osg::Uniform( "tex2", 2 ) );
+                    m_shader->setDefine( "TRANSFERFUNCTION_SAMPLER", "tex2" );
                     m_shader->setDefine( "TRANSFERFUNCTION_ENABLED" );
                 }
                 else
@@ -263,7 +275,6 @@ void WMDirectVolumeRendering::moduleMain()
             // build spatial search structure
             ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-
             // update node
             debugLog() << "Adding new rendering.";
             rootNode->clear();

src/modules/directVolumeRendering/WMDirectVolumeRendering.h

@@ -31,6 +31,8 @@
 #include <osg/Uniform>
 
 #include "../../graphicsEngine/WShader.h"
+#include "../../dataHandler/WDataSetScalar.h"
+#include "../../dataHandler/WDataSetVector.h"
 #include "../../kernel/WModule.h"
 #include "../../kernel/WModuleInputData.h"
 #include "../../kernel/WModuleOutputData.h"
@@ -108,6 +110,11 @@ private:
      */
     boost::shared_ptr< WModuleInputData< WDataSetScalar > > m_input;
 
+    /**
+     * The gradient field input
+     */
+    boost::shared_ptr< WModuleInputData< WDataSetVector > > m_gradients;
+
     /**
      * The number of steps to walk along the ray.
      */

src/modules/directVolumeRendering/shaders/WMDirectVolumeRendering-fragment.glsl

@@ -43,6 +43,7 @@
 // texture containing the data
 uniform sampler3D tex0;
 uniform sampler1D TRANSFERFUNCTION_SAMPLER;
+uniform sampler3D GRADIENTTEXTURE_SAMPLER;
 
 /////////////////////////////////////////////////////////////////////////////
 // Attributes
@@ -95,6 +96,9 @@ vec3 findRayEnd( out float d )
  */
 vec3 getGradient( in vec3 position )
 {
+#ifdef GRADIENTTEXTURE_ENABLED
+    return ( 2.0 * texture3D( GRADIENTTEXTURE_SAMPLER, position ).rgb ) + vec3( -1.0 );
+#else
     float s = 0.01;
     float valueXP = texture3D( tex0, position + vec3( s, 0.0, 0.0 ) ).r;
     float valueXM = texture3D( tex0, position - vec3( s, 0.0, 0.0 ) ).r;
@@ -104,6 +108,7 @@ vec3 getGradient( in vec3 position )
     float valueZM = texture3D( tex0, position - vec3( 0.0, 0.0, s ) ).r;
 
     return vec3( valueXP - valueXM, valueYP - valueYM, valueZP - valueZM );
+#endif
 }
 
 /**