V1.2 adds .VDB file support

Added OpenVDB .vdb file support
This requires runtime v1.2

Author: LinKayser

Examples/Ex_VdbIo.cs

@@ -0,0 +1,123 @@
+using PicoGK;
+
+namespace PicoGKExamples
+{
+    class OpenVdbExample
+    {
+        /// <summary>
+        /// his function comprehensively explains how to deal with OpenVDB
+        /// (.vdb) files. These files can contain many different fields and
+        /// each field be of a number of types.
+        ///
+        /// PicoGK Voxels are stored in GRID_LEVEL_SET data structures
+        /// PicoGK doesn't support any other data types at the moment.
+        ///
+        /// If you want to make sure you deal with all of these cases
+        /// this detailed function is for you
+        ///
+        /// If you have control over the files and just want to load/save
+        /// voxel data in PicoGK, you can use the helper functions
+        /// implemented in PicoGK_VoxelsIo.cs
+        ///
+        /// Basically you do:
+        ///
+        /// vox.SaveToVdbFile("Hello.vdb")
+        ///
+        /// and
+        ///
+        /// Voxels vox = Voxels.voxFromVdbFile("Hello.vdb")
+        ///
+        /// Check out the end of the function below, for an example
+        ///
+        /// </summary>
+        public static void Task()
+        {
+            // Create a mesh from an existing STL file
+            Mesh msh = Mesh.mshFromStlFile(
+                Path.Combine(   Utils.strPicoGKSourceCodeFolder(),
+                                "Examples/Testfiles/Teapot.stl"));
+
+            // Create Voxels from the mesh
+            Voxels vox = new Voxels(msh);
+
+            // Create an empty VDB file object
+            OpenVdbFile oFileCreated = new OpenVdbFile();
+
+            // Add the voxels to the VDB file object
+            // You can add multiple fields to an object
+            // The name is optional
+            oFileCreated.nAdd(vox, "Teapot");
+
+            // Let's add another field, Vdb supports multiple
+            oFileCreated.nAdd(vox, "Another One");
+
+            // Let's add a third field
+            oFileCreated.nAdd(vox, "Three");
+
+            // Let's add a fourth field with an auto generated name
+            oFileCreated.nAdd(vox);
+
+            // Note, internally copies are made of the voxel fields, so
+            // after you add a voxel field, any changes made to it are not
+            // reflected when you save it
+
+            // Filename to use
+            string strVdbFileName = Path.Combine(   Library.strLogFolder,
+                                                    "Teapot.vdb");
+
+            Library.Log($"In memory VdbFile object contains {oFileCreated.nFieldCount()} fields");
+
+            for (int nField = 0; nField < oFileCreated.nFieldCount(); nField++)
+            {
+                Library.Log($"-  Field {nField} has type {oFileCreated.strFieldType(nField)} and name '{oFileCreated.strFieldName(nField)}'");
+            }
+
+            // Save the VdbFile object to an actual file on disk
+            oFileCreated.SaveToFile(strVdbFileName);
+
+            // Load the saved VdbFile from disk
+            // If this fails, an exception is thrown
+            OpenVdbFile oFileLoad = new OpenVdbFile(strVdbFileName);
+
+            Library.Log($"Loaded VdbFile {strVdbFileName}");
+            Library.Log($"VdbFile contains {oFileLoad.nFieldCount()} fields");
+
+            for (int nField = 0; nField <oFileLoad.nFieldCount(); nField++)
+            {
+                Library.Log($"-  Field {nField} has type {oFileLoad.strFieldType(nField)} and name '{oFileLoad.strFieldName(nField)}'");
+            }
+
+            // Extract field number with the name Teapot (case insensitive)
+            // .vdb files support several fields of various types, which
+            // are unsupported in PicoGK.
+            // Also be aware that the order of which these fields are
+            // written to the file may often not be the same order that we
+            // added it to the object, so don't rely on the third added
+            // field to be the third field in the file
+            // The safest way to get exactly what you want is to search by
+            // name.
+            
+            Voxels voxRead = oFileLoad.voxGet("Teapot");
+
+            // Show what we loaded
+            Library.oViewer().Add(voxRead);
+
+            // Lastly, let's demonstrate the simple helper functions
+            // which you can use when you have full control over
+            // the origin VDB files (no surprises)
+
+            // Create a Voxel field from the first compatible field in a VDB
+            // file. If there are multiple fields, all others are ignored
+            // If no compatible field is found, an exception is thrown
+            Voxels voxReadSimple = Voxels.voxFromVdbFile(strVdbFileName);
+
+            // Now lets save the Voxels to a new file
+            voxReadSimple.SaveToVdbFile(Path.Combine(   Library.strLogFolder,
+                                                        "Simple.vdb"));
+
+            // This file now contains exactly one field,
+            // and uses an auto-generated field name
+        }
+    }
+}
+

PicoGK_Library.cs

@@ -48,8 +48,7 @@ public partial class Library
         /// <returns>The name of the dynamically loaded C++ library</returns>
         public static string strName()
         {
-            const int iLen = 255;
-            StringBuilder oBuilder = new StringBuilder(iLen);
+            StringBuilder oBuilder = new StringBuilder(Library.nStringLength);
             _GetName(oBuilder);
             return oBuilder.ToString();
         }
@@ -60,8 +59,7 @@ public static string strName()
         /// <returns>The library version of the C++ library</returns>
         public static string strVersion()
         {
-            const int iLen = 255;
-            StringBuilder oBuilder = new StringBuilder(iLen);
+            StringBuilder oBuilder = new StringBuilder(Library.nStringLength);
             _GetVersion(oBuilder);
             return oBuilder.ToString();
         }
@@ -73,8 +71,7 @@ public static string strVersion()
         /// <returns>Internal build info of the C++ library</returns>
         public static string strBuildInfo()
         {
-            const int iLen = 255;
-            StringBuilder oBuilder = new StringBuilder(iLen);
+            StringBuilder oBuilder = new StringBuilder(Library.nStringLength);
             _GetBuildInfo(oBuilder);
             return oBuilder.ToString();
         }