Support for DDS Texture Cache

- pass texture cache control properties to simgear
 - /sim/rendering/texture-cache/cache-enabled
 - /sim/rendering/texture-cache/compress-transparent
 - /sim/rendering/texture-cache/compress-solid
 - /sim/rendering/texture-cache/compress

- support --texture-cache-dir command line option
- set max reported supported texture size during splashscreen.

src/Main/globals.cxx

@@ -279,6 +279,12 @@ void FGGlobals::set_fg_home (const SGPath &home)
     fg_home = home.realpath();
 }
 
+void FGGlobals::set_texture_cache_dir(const SGPath &textureCache)
+{
+    texture_cache_dir = textureCache.realpath();
+}
+
+
 PathList FGGlobals::get_data_paths() const
 {
     PathList r(additional_data_paths);

src/Main/globals.hxx

@@ -103,6 +103,8 @@ private:
 
     // Users home directory for data
     SGPath fg_home;
+
+    SGPath texture_cache_dir;
     // Download directory
     SGPath download_dir;
     // Terrasync directory
@@ -199,7 +201,8 @@ public:
     inline void set_sim_time_sec (double t) { sim_time_sec = t; }
 
     const SGPath &get_fg_root () const { return fg_root; }
-    void set_fg_root (const SGPath&root);
+    void set_fg_root(const SGPath&root);
+    void set_texture_cache_dir(const SGPath&textureCache);
 
     /**
      * Get list of data locations. fg_root is always the final item in the
@@ -232,6 +235,8 @@ public:
     // place.
     void set_download_dir (const SGPath &path);
 
+    const SGPath &get_texture_cache_dir() const { return texture_cache_dir; }
+
     const SGPath &get_terrasync_dir () const { return terrasync_dir; }
     // The 'path' argument to set_terrasync_dir() must come from trustworthy
     // code, because the method grants read permissions to Nasal code for all

src/Main/options.cxx

@@ -1731,6 +1731,7 @@ struct OptionDesc {
     {"enable-terrasync",             false, OPTION_BOOL,   "/sim/terrasync/enabled", true, "", 0 },
     {"terrasync-dir",                true,  OPTION_IGNORE,   "", false, "", 0 },
     {"download-dir",                 true,  OPTION_IGNORE,   "", false, "", 0 },
+    {"texture-cache-dir",            true,  OPTION_IGNORE,   "", false, "", 0 },
     {"allow-nasal-read",             true,  OPTION_FUNC | OPTION_MULTI,   "", false, "", fgOptAllowNasalRead },
     {"geometry",                     true,  OPTION_FUNC,   "", false, "", fgOptGeometry },
     {"bpp",                          true,  OPTION_FUNC,   "", false, "", fgOptBpp },
@@ -2460,17 +2461,23 @@ SGPath defaultDownloadDir()
 {
 #if defined(SG_WINDOWS)
     SGPath p(SGPath::documents());
-	if (p.isNull()) {
-		SG_LOG(SG_IO, SG_ALERT, "Failed to locate user's Documents directory, will default to FG_HOME");
-		// fall through to standard get_fg_home codepath
-	} else {
-		return p / "FlightGear";
-	}
+    if (p.isNull()) {
+        SG_LOG(SG_IO, SG_ALERT, "Failed to locate user's Documents directory, will default to FG_HOME");
+        // fall through to standard get_fg_home codepath
+    }
+    else {
+        return p / "FlightGear";
+    }
 #endif
 
     return globals->get_fg_home();
 }
 
+SGPath defaultTextureCacheDir()
+{
+    return defaultDownloadDir() / "TextureCache";
+}
+
 OptionResult Options::processOptions()
 {
   // establish locale before showing help (this selects the default locale,
@@ -2553,6 +2560,29 @@ OptionResult Options::processOptions()
     // via a Nasal-writable place such as the property tree.
     globals->set_download_dir(downloadDir);
 
+    // Texture Cache directory handling
+    SGPath textureCacheDir = SGPath::fromLocal8Bit(
+        valueForOption("texture-cache-dir").c_str());
+    if (textureCacheDir.isNull()) {
+        textureCacheDir = defaultTextureCacheDir();
+        SG_LOG(SG_GENERAL, SG_INFO,
+            "Using default texture cache directory: " << textureCacheDir);
+    }
+    else {
+        SG_LOG(SG_GENERAL, SG_INFO,
+            "Using explicit texture cache directory: " << textureCacheDir);
+    }
+
+    simgear::Dir tcd(textureCacheDir);
+    if (!tcd.exists()) {
+        SG_LOG(SG_GENERAL, SG_INFO,
+            "Creating texture cache directory: " << textureCacheDir);
+        tcd.create(0755);
+    }
+
+    globals->set_texture_cache_dir(textureCacheDir);
+
+
     // TerraSync directory fixup
     SGPath terrasyncDir = SGPath::fromLocal8Bit(
       valueForOption("terrasync-dir").c_str());

src/Scenery/scenery.cxx

@@ -47,6 +47,7 @@
 #include <simgear/scene/util/SGSceneUserData.hxx>
 #include <simgear/scene/model/CheckSceneryVisitor.hxx>
 #include <simgear/scene/sky/sky.hxx>
+#include <simgear/scene/util/SGSceneFeatures.hxx>
 
 #include <simgear/bvh/BVHNode.hxx>
 #include <simgear/bvh/BVHLineSegmentVisitor.hxx>
@@ -224,6 +225,49 @@ private:
     const simgear::BVHMaterial* _material;
     bool _haveHit;
 };
+class FGScenery::TextureCacheListener : public SGPropertyChangeListener
+{
+protected:
+    const char* root_node_path = "/sim/rendering/texture-cache";
+public:
+    TextureCacheListener()
+    {
+        SGPropertyNode_ptr textureCacheNode = fgGetNode(root_node_path, true);
+        setupPropertyListener(textureCacheNode, "cache-enabled");
+        setupPropertyListener(textureCacheNode, "compress-transparent");
+        setupPropertyListener(textureCacheNode, "compress-solid");
+        setupPropertyListener(textureCacheNode, "compress");
+    }
+
+    ~TextureCacheListener()
+    {
+        SGPropertyNode_ptr maskNode = fgGetNode(root_node_path);
+        for (int i = 0; i < maskNode->nChildren(); ++i) {
+            maskNode->getChild(i)->removeChangeListener(this);
+        }
+    }
+
+    void setupPropertyListener(SGPropertyNode_ptr textureCacheNode, const char *node)
+    {
+        textureCacheNode->getChild(node, 0, true)->addChangeListener(this, true);
+    }
+
+    virtual void valueChanged(SGPropertyNode * node)
+    {
+        bool b = node->getBoolValue();
+        std::string name(node->getNameString());
+
+        if (name == "cache-enabled") {
+            SGSceneFeatures::instance()->setTextureCacheActive(b);
+        }
+        else if (name == "compress-transparent" || name == "compress") {
+            SGSceneFeatures::instance()->setTextureCacheCompressionActiveTransparent(b);
+        }
+        else if (name == "compress-solid" || name == "compress") {
+            SGSceneFeatures::instance()->setTextureCacheCompressionActive(b);
+        }
+    }
+};
 
 class FGScenery::ScenerySwitchListener : public SGPropertyChangeListener
 {
@@ -285,7 +329,7 @@ private:
 
 // Scenery Management system
 FGScenery::FGScenery() :
-    _listener(NULL)
+    _listener(nullptr), _textureCacheListener(nullptr)
 {
     // keep reference to pager singleton, so it cannot be destroyed while FGScenery lives
     _pager = FGScenery::getPagerSingleton();
@@ -297,6 +341,7 @@ FGScenery::FGScenery() :
 FGScenery::~FGScenery()
 {
     delete _listener;
+    delete _textureCacheListener;
 }
 
 
@@ -364,7 +409,7 @@ void FGScenery::init() {
     _terrain->init( terrain_branch.get() );
 
     _listener = new ScenerySwitchListener(this);
-
+    _textureCacheListener = new TextureCacheListener();
     // Toggle the setup flag.
     _inited = true;
 }

src/Scenery/scenery.hxx

@@ -65,6 +65,9 @@ class FGScenery : public SGSubsystem
     osg::ref_ptr<flightgear::SceneryPager> _pager;
     ScenerySwitchListener* _listener;
 
+    class TextureCacheListener;
+    friend class TextureCacheListener;
+    TextureCacheListener* _textureCacheListener;
 public:
     FGScenery();
     ~FGScenery();

src/Viewer/renderer.cxx

@@ -547,8 +547,8 @@ FGRenderer::init( void )
         SG_LOG(SG_VIEW, SG_WARN, "Unknown texture compression setting!");
       }
     }
-    
-// create sky, but can't build until setupView, since we depend
+    SGSceneFeatures::instance()->setTextureCompressionPath(globals->get_texture_cache_dir());
+    // create sky, but can't build until setupView, since we depend
 // on other subsystems to be inited, eg Ephemeris    
     _sky = new SGSky;
     
@@ -1554,6 +1554,14 @@ FGRenderer::update( ) {
     if (!_position_finalized || !_scenery_loaded->getBoolValue())
     {
         _splash_alpha->setDoubleValue(1.0);
+
+        GLint max_texture_size;
+        glGetIntegerv(GL_MAX_TEXTURE_SIZE, &max_texture_size);
+        // abritrary range change as sometimes during init the device reports somewhat dubious values, so 
+        // we know that the size must be greater than size and that probably 9999999 is unreasonably large
+        if (max_texture_size > 0 && max_texture_size < 9999999)
+            SGSceneFeatures::instance()->setMaxTextureSize(max_texture_size);
+
         return;
     }
     osgViewer::Viewer* viewer = globals->get_renderer()->getViewer();

utils/fgviewer/fgviewer.cxx

@@ -207,6 +207,9 @@ main(int argc, char** argv)
     options->setPluginStringData("SimGear::FG_ROOT", fg_root.local8BitStr());
     // Omit building bounding volume trees, as the viewer will not run a simulation
     options->setPluginStringData("SimGear::BOUNDINGVOLUMES", "OFF");
+    GLint max_texture_size;
+    glGetIntegerv(GL_MAX_TEXTURE_SIZE, &max_texture_size);
+    options->setPluginStringData("SimGear::MAXTEXTURESIZE", std::to_string(max_texture_size? max_texture_size:8192));
     viewer.setReaderWriterOptions(options.get());
 
     // Here, all arguments are processed