From 660cb74877426cbfe24cc07d3d9364dfa3492d2b Mon Sep 17 00:00:00 2001
From: Michael PLATINGS <mplatings@pixelpower.com>
Date: Thu, 18 Mar 2010 19:02:12 +0000
Subject: [PATCH] Workaround for models with inverted transparency

---
 src/osgPlugins/fbx/ReaderWriterFBX.cpp        |  2 ++
 .../fbx/fbxMaterialToOsgStateSet.cpp          | 35 ++++++++++++++++++-
 src/osgPlugins/fbx/fbxMaterialToOsgStateSet.h |  2 ++
 3 files changed, 38 insertions(+), 1 deletion(-)

diff --git a/src/osgPlugins/fbx/ReaderWriterFBX.cpp b/src/osgPlugins/fbx/ReaderWriterFBX.cpp
index 955502449..3ae768207 100644
--- a/src/osgPlugins/fbx/ReaderWriterFBX.cpp
+++ b/src/osgPlugins/fbx/ReaderWriterFBX.cpp
@@ -270,6 +270,8 @@ ReaderWriterFBX::readNode(const std::string& filenameInit,
 
             if (res.success())
             {
+                fbxMaterialToOsgStateSet.checkInvertTransparency();
+
                 resolveBindMatrices(*res.getNode(), boneBindMatrices, nodeMap);
 
                 osg::Node* osgNode = res.getNode();
diff --git a/src/osgPlugins/fbx/fbxMaterialToOsgStateSet.cpp b/src/osgPlugins/fbx/fbxMaterialToOsgStateSet.cpp
index 053885328..9a1d2d83e 100644
--- a/src/osgPlugins/fbx/fbxMaterialToOsgStateSet.cpp
+++ b/src/osgPlugins/fbx/fbxMaterialToOsgStateSet.cpp
@@ -80,7 +80,9 @@ FbxMaterialToOsgStateSet::convert(const KFbxSurfaceMaterial* pFbxMat)
                 static_cast<float>(pFbxPhong->GetShininess().Get()));
         }
     }
-    return std::make_pair(pOsgMat.release(), pOsgTex.release());
+    StateSetContent result(pOsgMat.release(), pOsgTex.release());
+    _kFbxMaterialMap.insert(KFbxMaterialMap::value_type(pFbxMat, result));
+    return result;
 }
 
 osg::ref_ptr<osg::Texture2D>
@@ -109,3 +111,34 @@ FbxMaterialToOsgStateSet::fbxTextureToOsgTexture(const KFbxTexture* fbx)
         return NULL;
     }
 }
+
+void FbxMaterialToOsgStateSet::checkInvertTransparency()
+{
+    int zeroAlpha = 0, oneAlpha = 0;
+    for (KFbxMaterialMap::const_iterator it = _kFbxMaterialMap.begin(); it != _kFbxMaterialMap.end(); ++it)
+    {
+        const osg::Material* pMaterial = it->second.first;
+        float alpha = pMaterial->getDiffuse(osg::Material::FRONT).a();
+        if (alpha > 0.999f)
+        {
+            ++oneAlpha;
+        }
+        else if (alpha < 0.001f)
+        {
+            ++zeroAlpha;
+        }
+    }
+
+    if (zeroAlpha > oneAlpha)
+    {
+        //Transparency values seem to be back to front so invert them.
+
+        for (KFbxMaterialMap::const_iterator it = _kFbxMaterialMap.begin(); it != _kFbxMaterialMap.end(); ++it)
+        {
+            osg::Material* pMaterial = it->second.first;
+            osg::Vec4 diffuse = pMaterial->getDiffuse(osg::Material::FRONT);
+            diffuse.a() = 1.0f - diffuse.a();
+            pMaterial->setDiffuse(osg::Material::FRONT_AND_BACK, diffuse);
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/osgPlugins/fbx/fbxMaterialToOsgStateSet.h b/src/osgPlugins/fbx/fbxMaterialToOsgStateSet.h
index a9a4b83d6..7c7a157d7 100644
--- a/src/osgPlugins/fbx/fbxMaterialToOsgStateSet.h
+++ b/src/osgPlugins/fbx/fbxMaterialToOsgStateSet.h
@@ -33,6 +33,8 @@ public:
     FbxMaterialToOsgStateSet::FbxMaterialToOsgStateSet(const std::string& dir, const osgDB::Options* options) :
         _options(options),
         _dir(dir) {}
+
+    void checkInvertTransparency();
 private:
     //Convert a texture fbx to an osg texture.
     osg::ref_ptr<osg::Texture2D>