gistfile1.diff

diff --git a/src/tile.cpp b/src/tile.cpp
index f7f1779..eeddc4e 100644
--- a/src/tile.cpp
+++ b/src/tile.cpp
@@ -373,6 +373,18 @@ class TextureSource : public IWritableTextureSource
        // AtlasPointer based on it's texture id
        void updateAP(AtlasPointer &ap);
 
+       bool isKnownSourceImage(const std::string &name)
+       {
+               bool is_known = false;
+               bool cache_found = m_source_image_existence.get(name, &is_known);
+               if(cache_found)
+                       return is_known;
+               // Not found in cache; find out if a local file exists
+               is_known = (getTexturePath(name) != "");
+               m_source_image_existence.set(name, is_known);
+               return is_known;
+       }
+
        // Processes queued texture requests from other threads.
        // Shall be called from the main thread.
        void processQueue();
@@ -400,6 +412,9 @@ class TextureSource : public IWritableTextureSource
        // This should be only accessed from the main thread
        SourceImageCache m_sourcecache;
 
+       // Thread-safe cache of what source images are known (true = known)
+       MutexedMap<std::string, bool> m_source_image_existence;
+
        // A texture id is index in this array.
        // The first position contains a NULL texture.
        core::array<SourceAtlasPointer> m_atlaspointer_cache;
@@ -781,6 +796,7 @@ void TextureSource::insertSourceImage(const std::string &name, video::IImage *im
        assert(get_current_thread_id() == m_main_thread);
        
        m_sourcecache.insert(name, img, true, m_device->getVideoDriver());
+       m_source_image_existence.set(name, true);
 }
        
 void TextureSource::rebuildImagesAndTextures()
diff --git a/src/tile.h b/src/tile.h
index ae986e7..12c40c8 100644
--- a/src/tile.h
+++ b/src/tile.h
@@ -131,6 +131,7 @@ class ITextureSource
        virtual IrrlichtDevice* getDevice()
                {return NULL;}
        virtual void updateAP(AtlasPointer &ap){};
+       virtual bool isKnownSourceImage(const std::string &name)=0;
 };
 
 class IWritableTextureSource : public ITextureSource
@@ -149,6 +150,7 @@ class IWritableTextureSource : public ITextureSource
        virtual IrrlichtDevice* getDevice()
                {return NULL;}
        virtual void updateAP(AtlasPointer &ap){};
+       virtual bool isKnownSourceImage(const std::string &name)=0;
 
        virtual void processQueue()=0;
        virtual void insertSourceImage(const std::string &name, video::IImage *img)=0;