From e35b0796d6ee5c8191cecf3c8ef3ea31df3ee139 Mon Sep 17 00:00:00 2001
From: Robert Osfield <robert@openscenegraph.com>
Date: Mon, 15 Sep 2014 17:53:44 +0000
Subject: [PATCH] Added .tf & .tf-255 plugin for reading ascii 1D transfer
 functon files in support for volume rendering.

git-svn-id: http://svn.openscenegraph.org/osg/OpenSceneGraph/trunk@14448 16af8721-9629-0410-8352-f15c8da7e697
---
 src/osgDB/Registry.cpp               |   3 +
 src/osgPlugins/CMakeLists.txt        |   1 +
 src/osgPlugins/tf/CMakeLists.txt     |   3 +
 src/osgPlugins/tf/ReaderWriterTF.cpp | 137 +++++++++++++++++++++++++++
 4 files changed, 144 insertions(+)
 create mode 100644 src/osgPlugins/tf/CMakeLists.txt
 create mode 100644 src/osgPlugins/tf/ReaderWriterTF.cpp

diff --git a/src/osgDB/Registry.cpp b/src/osgDB/Registry.cpp
index e759ff4b2..6e9858c09 100644
--- a/src/osgDB/Registry.cpp
+++ b/src/osgDB/Registry.cpp
@@ -424,6 +424,9 @@ Registry::Registry()
     // addFileExtensionAlias("pfa",   "freetype");  // type2 ascii
 
 
+    // TransferFunction head
+    addFileExtensionAlias("tf-255", "tf");
+
     // portable bitmap, greyscale and colour/pixmap image formats
     addFileExtensionAlias("pbm", "pnm");
     addFileExtensionAlias("pgm", "pnm");
diff --git a/src/osgPlugins/CMakeLists.txt b/src/osgPlugins/CMakeLists.txt
index 1a6c4a381..66c3f055c 100644
--- a/src/osgPlugins/CMakeLists.txt
+++ b/src/osgPlugins/CMakeLists.txt
@@ -257,6 +257,7 @@ ADD_SUBDIRECTORY(pvr)
 
 ADD_SUBDIRECTORY(osc)
 ADD_SUBDIRECTORY(trk)
+ADD_SUBDIRECTORY(tf)
 
 
 ####################################################
diff --git a/src/osgPlugins/tf/CMakeLists.txt b/src/osgPlugins/tf/CMakeLists.txt
new file mode 100644
index 000000000..f968c8b84
--- /dev/null
+++ b/src/osgPlugins/tf/CMakeLists.txt
@@ -0,0 +1,3 @@
+SET(TARGET_SRC ReaderWriterTF.cpp )
+#### end var setup  ###
+SETUP_PLUGIN(tf)
diff --git a/src/osgPlugins/tf/ReaderWriterTF.cpp b/src/osgPlugins/tf/ReaderWriterTF.cpp
new file mode 100644
index 000000000..46d53c62c
--- /dev/null
+++ b/src/osgPlugins/tf/ReaderWriterTF.cpp
@@ -0,0 +1,137 @@
+// Released under the OSGPL license, as part of the OpenSceneGraph distribution.
+//
+// Implementation of a native TransferFunction ascii file format.
+//
+#include <osg/Notify>
+
+#include <osg/TransferFunction>
+
+#include <osgDB/FileNameUtils>
+#include <osgDB/FileUtils>
+#include <osgDB/Registry>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+class ReaderWriterTF : public osgDB::ReaderWriter
+{
+    public:
+
+        ReaderWriterTF()
+        {
+            supportsExtension("tf","TransferFunction format");
+            supportsExtension("tf-255","TransferFunction format");
+        }
+
+        virtual const char* className() const { return "TransferFunction Reader/Writer"; }
+
+        ReadResult readTransferFunction(std::istream& fin, float colorScale) const
+        {
+            osg::TransferFunction1D::ColorMap colorMap;
+            while(fin)
+            {
+                float value, red, green, blue, alpha;
+                fin >> value >> red >> green >> blue >> alpha;
+                if (fin)
+                {
+                    std::cout<<"value = "<<value<<" ("<<red<<", "<<green<<", "<<blue<<", "<<alpha<<")"<<std::endl;
+                    colorMap[value] = osg::Vec4(red,green,blue,alpha);
+                }
+            }
+
+            if (colorMap.empty())
+            {
+                return ReadResult::ERROR_IN_READING_FILE;
+            }
+
+            // colorMap[value] = osg::Vec4(red*colorScale,green*colorScale,blue*colorScale,alpha*colorScale);
+
+            if (colorScale==0.0f)
+            {
+                float maxValue = 0.0f;
+                for(osg::TransferFunction1D::ColorMap::iterator itr = colorMap.begin();
+                    itr != colorMap.end();
+                    ++itr)
+                {
+                    const osg::Vec4& c = itr->second;
+                    if (c.r()>maxValue) maxValue = c.r();
+                    if (c.g()>maxValue) maxValue = c.g();
+                    if (c.b()>maxValue) maxValue = c.b();
+                    if (c.a()>maxValue) maxValue = c.a();
+                }
+
+                if (maxValue>=2.0f)
+                {
+                    colorScale = 1.0f/255.0f;
+                }
+            }
+
+            if (colorScale!=0.0)
+            {
+                OSG_NOTICE<<"Rescaling ColorMap by "<<colorScale<<std::endl;
+                for(osg::TransferFunction1D::ColorMap::iterator itr = colorMap.begin();
+                    itr != colorMap.end();
+                    ++itr)
+                {
+                    osg::Vec4& c = itr->second;
+                    c.r() *= colorScale;
+                    c.g() *= colorScale;
+                    c.b() *= colorScale;
+                    c.a() *= colorScale;
+                }
+            }
+
+            osg::TransferFunction1D* tf = new osg::TransferFunction1D;
+            tf->assign(colorMap);
+
+            return tf;
+        }
+
+        bool readColorScale(const osgDB::ReaderWriter::Options* options, float& colorScale) const
+        {
+            if (options && options->getOptionString().find("tf-255")!=std::string::npos)
+            {
+                colorScale = 1.0/255.0f;
+                return true;
+            }
+            else
+            {
+                return false;
+            }
+
+        }
+
+        virtual ReadResult readObject(std::istream& fin,const osgDB::ReaderWriter::Options* options =NULL) const
+        {
+            float colorScale = 0.0f; // default auto-detect scale
+
+            readColorScale(options, colorScale);
+
+            return readTransferFunction(fin, colorScale);
+        }
+
+        virtual ReadResult readObject(const std::string& file, const osgDB::ReaderWriter::Options* options) const
+        {
+            std::string ext = osgDB::getLowerCaseFileExtension(file);
+            if (!acceptsExtension(ext)) return ReadResult::FILE_NOT_HANDLED;
+
+            std::string fileName = osgDB::findDataFile( file, options );
+            if (fileName.empty()) return ReadResult::FILE_NOT_FOUND;
+
+            float colorScale = 0.0f; // default auto-detect scale
+            if (ext=="tf-255") colorScale = 1.0f/255.0f;
+
+            readColorScale(options, colorScale);
+
+            osgDB::ifstream fin(fileName.c_str(), std::ios::in | std::ios::binary);
+
+            if (fin) return readTransferFunction( fin, colorScale);
+            else return ReadResult::ERROR_IN_READING_FILE;
+        }
+
+};
+
+// now register with Registry to instantiate the above
+// reader/writer.
+REGISTER_OSGPLUGIN(tf, ReaderWriterTF)