Use Hounsfield scale for transfer functions

Assets/Editor/TransferFunctionEditorWindow.cs

@@ -5,7 +5,7 @@ namespace UnityVolumeRendering
 {
     public class TransferFunctionEditorWindow : EditorWindow
     {
-        private TransferFunction tf = null;
+        private TransferFunctionInstance tfInstance = null;
 
         private VolumeRenderedObject volRendObject = null;
 
@@ -49,7 +49,8 @@ private void OnGUI()
             if (volRendObject == null)
                 return;
 
-            tf = volRendObject.transferFunction;
+            tfInstance = volRendObject.transferFunctionInstance;
+            TransferFunction tf = tfInstance.transferFunction;
 
             Event currentEvent = new Event(Event.current);
 
@@ -62,7 +63,7 @@ private void OnGUI()
             Rect outerRect = new Rect(0.0f, 0.0f, contentWidth, contentHeight);
             Rect tfEditorRect = new Rect(outerRect.x + 20.0f, outerRect.y + 20.0f, outerRect.width - 40.0f, outerRect.height - 50.0f);
 
-            tfEditor.SetVolumeObject(volRendObject);
+            tfEditor.SetTransferFunctionInstnace(tfInstance);
             tfEditor.DrawOnGUI(tfEditorRect);
 
             // Save TF
@@ -76,7 +77,7 @@ private void OnGUI()
             // Load TF
             if(GUI.Button(new Rect(tfEditorRect.x + 75.0f, tfEditorRect.y + tfEditorRect.height + 20.0f, 70.0f, 30.0f), "Load"))
             {
-                string filepath = EditorUtility.OpenFilePanel("Save transfer function", "", "tf");
+                string filepath = EditorUtility.OpenFilePanel("Load transfer function", "", "tf");
                 if(filepath != "")
                 {
                     TransferFunction newTF = TransferFunctionDatabase.LoadTransferFunction(filepath);
@@ -92,6 +93,7 @@ private void OnGUI()
             if(GUI.Button(new Rect(tfEditorRect.x + 150.0f, tfEditorRect.y + tfEditorRect.height + 20.0f, 70.0f, 30.0f), "Clear"))
             {
                 tf = ScriptableObject.CreateInstance<TransferFunction>();
+                tf.relativeScale = true;
                 tf.alphaControlPoints.Add(new TFAlphaControlPoint(0.2f, 0.0f));
                 tf.alphaControlPoints.Add(new TFAlphaControlPoint(0.8f, 1.0f));
                 tf.colourControlPoints.Add(new TFColourControlPoint(0.5f, new Color(0.469f, 0.354f, 0.223f, 1.0f)));

Assets/Editor/TransferFunctionUpgraderWindow.cs

@@ -0,0 +1,145 @@
+using System.IO;
+using UnityEditor;
+using UnityEngine;
+
+namespace UnityVolumeRendering
+{
+    public class TransferFunctionUpgraderWindow : EditorWindow
+    {
+        private enum TFConversionState
+        {
+            ReadyToImport,
+            ReadyToConvert,
+            ReadyToSave
+        }
+
+        private TransferFunction transferFunction = null;
+        private VolumeRenderedObject targetObject = null;
+        private string infoText = "";
+        private string errorText = "";
+        private string tfFilePath = "";
+
+        private TFConversionState state = TFConversionState.ReadyToImport;
+
+        public static void ShowWindow()
+        {
+            TransferFunctionUpgraderWindow wnd = new TransferFunctionUpgraderWindow();
+            wnd.Show();
+        }
+
+        private void OnGUI()
+        {
+            if (state == TFConversionState.ReadyToImport)
+            {
+                targetObject = null;
+                transferFunction = null;
+            }
+
+            GUIStyle headerStyle = new GUIStyle(EditorStyles.label);
+            headerStyle.fontSize = 20;
+
+            GUIStyle groupHeaderStyle = new GUIStyle(EditorStyles.label);
+            groupHeaderStyle.fontSize = 16;
+            groupHeaderStyle.fontStyle = FontStyle.Bold;
+
+            GUIStyle errorStyle = new GUIStyle(EditorStyles.label);
+            errorStyle.normal.textColor = Color.red;
+
+            GUIStyle infoStyle = new GUIStyle(EditorStyles.label);
+            infoStyle.wordWrap = true;
+
+            EditorGUILayout.LabelField("Transfer function upgrader tool", headerStyle);
+
+            EditorGUILayout.Space();
+
+            if (infoText != "")
+            {
+                EditorGUILayout.LabelField(infoText);
+                EditorGUILayout.Space();
+            }
+
+            if (errorText != "")
+            {
+                EditorGUILayout.LabelField(errorText, errorStyle);
+                EditorGUILayout.Space();
+            }
+
+            GUILayout.Label("Import", groupHeaderStyle);
+            if (GUILayout.Button("Load transfer function"))
+            {
+                tfFilePath = EditorUtility.OpenFilePanel("Load transfer function", "", "tf");
+                transferFunction = TransferFunctionDatabase.LoadTransferFunction(tfFilePath);
+                if (transferFunction == null)
+                    errorText = "Invalid transfer function";
+                else
+                {
+                    if (transferFunction.relativeScale)
+                    {
+                        infoText = "Old transfer function with relative scale detected. Please convert it.";
+                        state = TFConversionState.ReadyToConvert;
+                    }
+                    else
+                    {
+                        infoText = "Transfer function already up-to-date. Nothing was done.";
+                    }
+                }
+            }
+            EditorGUILayout.Space();
+
+            if (state == TFConversionState.ReadyToConvert || state == TFConversionState.ReadyToSave)
+            {
+                GUILayout.Label("Select target object (dataset)", groupHeaderStyle);
+                targetObject = EditorGUILayout.ObjectField("Target object", targetObject, typeof(VolumeRenderedObject), true) as VolumeRenderedObject;
+                if (targetObject != null && targetObject.dataset != null)
+                {
+                    ConvertToAbsoluteTF(transferFunction, targetObject.dataset);
+                    infoText = "The transfer function has been converted. Please save it.";
+                    state = TFConversionState.ReadyToSave;
+                }
+                GUILayout.Label("Since the transfer function was using data values relative to a dataset," +
+                    "we need a reference to this dataset in order to convert the values to Hounsfield scale, which is now the default.", infoStyle);
+                EditorGUILayout.Space();
+            }
+
+            if (state == TFConversionState.ReadyToSave)
+            {
+                GUILayout.Label("Save converted dataset", groupHeaderStyle);
+                if (targetObject == null || transferFunction == null)
+                {
+                    state = TFConversionState.ReadyToImport;
+                    return;
+                }
+
+                if (GUILayout.Button("Save transfer function"))
+                {
+                    string filepath = EditorUtility.SaveFilePanel("Save transfer function", Path.GetDirectoryName(tfFilePath), Path.GetFileName(tfFilePath), "tf");
+                    TransferFunctionDatabase.SaveTransferFunction(transferFunction, filepath);
+                    infoText = "Transfer function saved. You can now import a new one.";
+                    state = TFConversionState.ReadyToImport;
+                }
+            }
+        }
+
+        private void ConvertToAbsoluteTF(TransferFunction transferFunction, VolumeDataset dataset)
+        {
+            if (transferFunction.relativeScale)
+            {
+                float minValue = dataset.GetMinDataValue();
+                float maxValue = dataset.GetMaxDataValue();
+                for (int i = 0; i < transferFunction.colourControlPoints.Count; i++)
+                {
+                    TFColourControlPoint point = transferFunction.colourControlPoints[i];
+                    point.dataValue = Mathf.Lerp(minValue, maxValue, point.dataValue);
+                    transferFunction.colourControlPoints[i] = point;
+                }
+                for (int i = 0; i < transferFunction.alphaControlPoints.Count; i++)
+                {
+                    TFAlphaControlPoint point = transferFunction.alphaControlPoints[i];
+                    point.dataValue = Mathf.Lerp(minValue, maxValue, point.dataValue);
+                    transferFunction.alphaControlPoints[i] = point;
+                }
+                transferFunction.relativeScale = false;
+            }
+        }
+    }
+}

Assets/Editor/VolumeRendererEditorFunctions.cs

@@ -372,7 +372,13 @@ private static void SpawnCutoutSphere()
                 VolumeObjectFactory.SpawnCutoutSphere(objects[0]);
         }
 
-        [MenuItem("Volume Rendering/1D Transfer Function")]
+        [MenuItem("Volume Rendering/Transfer Function/Transfer function upgrader tool")]
+        private static void ShowTFUpgraderWindow()
+        {
+            TransferFunctionUpgraderWindow.ShowWindow();
+        }
+
+        [MenuItem("Volume Rendering/Transfer Function/1D Transfer Function editor")]
         private static void Show1DTFWindow()
         {
             VolumeRenderedObject volRendObj = SelectionHelper.GetSelectedVolumeObject();
@@ -387,7 +393,7 @@ private static void Show1DTFWindow()
             }
         }
 
-        [MenuItem("Volume Rendering/2D Transfer Function")]
+        [MenuItem("Volume Rendering/Transfer Function/2D Transfer Function editor")]
         private static void Show2DTFWindow()
         {
             TransferFunction2DEditorWindow.ShowWindow();

Assets/Scripts/GUI/Components/DistanceMeasureTool.cs

@@ -94,31 +94,5 @@ private void UpdateWindow(int windowID)
 
             GUILayout.EndVertical();
         }
-
-        private void OnLoadTransferFunction(RuntimeFileBrowser.DialogResult result)
-        {
-            if(!result.cancelled)
-            {
-                string extension = Path.GetExtension(result.path);
-                if(extension == ".tf")
-                {
-                    TransferFunction tf = TransferFunctionDatabase.LoadTransferFunction(result.path);
-                    if (tf != null)
-                    {
-                        targetObject.transferFunction = tf;
-                        targetObject.SetTransferFunctionMode(TFRenderMode.TF1D);
-                    }
-                }
-                if (extension == ".tf2d")
-                {
-                    TransferFunction2D tf = TransferFunctionDatabase.LoadTransferFunction2D(result.path);
-                    if (tf != null)
-                    {
-                        targetObject.transferFunction2D = tf;
-                        targetObject.SetTransferFunctionMode(TFRenderMode.TF2D);
-                    }
-                }
-            }
-        }
     }
 }

Assets/Scripts/GUI/Components/EditVolumeGUI.cs

@@ -116,7 +116,7 @@ private void OnLoadTransferFunction(RuntimeFileBrowser.DialogResult result)
                     TransferFunction tf = TransferFunctionDatabase.LoadTransferFunction(result.path);
                     if (tf != null)
                     {
-                        targetObject.transferFunction = tf;
+                        targetObject.SetTransferFunction(tf);
                         targetObject.SetTransferFunctionMode(TFRenderMode.TF1D);
                     }
                 }

Assets/Scripts/GUI/Components/RuntimeTransferFunctionEditor.cs

@@ -5,7 +5,7 @@ namespace UnityVolumeRendering
     public class RuntimeTransferFunctionEditor : MonoBehaviour
     {
         private static RuntimeTransferFunctionEditor instance = null;
-        private TransferFunction tf = null;
+        private TransferFunctionInstance tfInstance = null;
         private VolumeRenderedObject volRendObject = null;
 
         private int windowID;
@@ -60,15 +60,16 @@ private void UpdateWindow(int windowID)
             if (volRendObject == null)
                 return;
 
-            tf = volRendObject.transferFunction;
+            tfInstance = volRendObject.transferFunctionInstance;
+            TransferFunction tf = tfInstance.transferFunction;
 
             float contentWidth = Mathf.Min(WINDOW_WIDTH, (WINDOW_HEIGHT - 100.0f) * 2.0f);
             float contentHeight = contentWidth * 0.5f;
 
             Rect outerRect = new Rect(0.0f, 0.0f, contentWidth, contentHeight);
             Rect tfEditorRect = new Rect(outerRect.x + 20.0f, outerRect.y + 20.0f, outerRect.width - 40.0f, outerRect.height - 50.0f);
 
-            tfEditor.SetVolumeObject(volRendObject);
+            tfEditor.SetTransferFunctionInstnace(tfInstance);
             tfEditor.DrawOnGUI(tfEditorRect);
 
             // Save TF
@@ -136,6 +137,7 @@ private void UpdateWindow(int windowID)
         /// <param name="maxDistance">Threshold for maximum distance. Points further away than this won't get picked.</param>
         private int PickColourControlPoint(float position, float maxDistance = 0.03f)
         {
+            TransferFunction tf = tfInstance.transferFunction;
             int nearestPointIndex = -1;
             float nearestDist = 1000.0f;
             for (int i = 0; i < tf.colourControlPoints.Count; i++)
@@ -157,6 +159,7 @@ private int PickColourControlPoint(float position, float maxDistance = 0.03f)
         /// <param name="maxDistance">Threshold for maximum distance. Points further away than this won't get picked.</param>
         private int PickAlphaControlPoint(Vector2 position, float maxDistance = 0.05f)
         {
+            TransferFunction tf = tfInstance.transferFunction;
             int nearestPointIndex = -1;
             float nearestDist = 1000.0f;
             for (int i = 0; i < tf.alphaControlPoints.Count; i++)