Give Data directory priority over CoreData. Give autoload paths priority over the default directories/packages. Fix the resource path/package add priority (index) having no effect, which would result in the editor not giving highest priority to the user's resource data directory. Closes #499.

Docs/Reference.dox

@@ -129,7 +129,7 @@ The full list of supported parameters, their datatypes and default values:
 - LogName (string) %Log filename. Default "Urho3D.log".
 - FrameLimiter (bool) Whether to cap maximum framerate to 200 (desktop) or 60 (Android/iOS.) Default true.
 - WorkerThreads (bool) Whether to create worker threads for the %WorkQueue subsystem according to available CPU cores. Default true.
-- ResourcePaths (string) A semicolon-separated list of resource paths to use. If corresponding packages (ie. Data.pak for Data directory) exist they will be used instead. Default "CoreData;Data".
+- ResourcePaths (string) A semicolon-separated list of resource paths to use. If corresponding packages (ie. Data.pak for Data directory) exist they will be used instead. Default "Data;CoreData".
 - ResourcePackages (string) A semicolon-separated list of resource packages to use. Default empty.
 - AutoloadPaths (string) A semicolon-separated list of autoload paths to use. Any resource packages and subdirectories inside an autoload path will be added to the resource system. Default "Extra".
 - ForceSM2 (bool) Whether to force %Shader %Model 2, effective in Direct3D9 mode only. Default false.

Source/Engine/Engine/Engine.cpp

@@ -196,7 +196,7 @@ bool Engine::Initialize(const VariantMap& parameters)
     FileSystem* fileSystem = GetSubsystem<FileSystem>();
     String exePath = fileSystem->GetProgramDir();
 
-    Vector<String> resourcePaths = GetParameter(parameters, "ResourcePaths", "CoreData;Data").GetString().Split(';');
+    Vector<String> resourcePaths = GetParameter(parameters, "ResourcePaths", "Data;CoreData").GetString().Split(';');
     Vector<String> resourcePackages = GetParameter(parameters, "ResourcePackages").GetString().Split(';');
     Vector<String> autoloadFolders = GetParameter(parameters, "AutoloadPaths", "Extra").GetString().Split(';');
 
@@ -262,7 +262,7 @@ bool Engine::Initialize(const VariantMap& parameters)
         }
     }
     
-    // Add auto load folders
+    // Add auto load folders. Prioritize these (if exist) before the default folders
     for (unsigned i = 0; i < autoloadFolders.Size(); ++i)
     {
         bool success = true;
@@ -279,7 +279,7 @@ bool Engine::Initialize(const VariantMap& parameters)
                     continue;
 
                 String autoResourceDir = exePath + autoloadFolder + "/" + folder;
-                success = cache->AddResourceDir(autoResourceDir);
+                success = cache->AddResourceDir(autoResourceDir, 0);
                 if (!success)
                 {
                     badResource = folder;
@@ -300,7 +300,7 @@ bool Engine::Initialize(const VariantMap& parameters)
                     String autoResourcePak = exePath + autoloadFolder + "/" + pak;
                     SharedPtr<PackageFile> package(new PackageFile(context_));
                     if (package->Open(autoResourcePak))
-                        cache->AddPackageFile(package);
+                        cache->AddPackageFile(package, 0);
                     else
                     {
                         badResource = autoResourcePak;

Source/Engine/Resource/ResourceCache.cpp

@@ -107,8 +107,7 @@ bool ResourceCache::AddResourceDir(const String& pathName, unsigned priority)
             return true;
     }
     
-    // If the priority isn't last or greater than size insert at position otherwise push.
-    if (priority > PRIORITY_LAST && priority < resourceDirs_.Size())
+    if (priority < resourceDirs_.Size())
         resourceDirs_.Insert(priority, fixedPath);
     else
         resourceDirs_.Push(fixedPath);
@@ -133,8 +132,7 @@ void ResourceCache::AddPackageFile(PackageFile* package, unsigned priority)
     if (!package || !package->GetNumFiles())
         return;
     
-    // If the priority isn't last or greater than size insert at position otherwise push.
-    if (priority > PRIORITY_LAST && priority < packages_.Size())
+    if (priority < packages_.Size())
         packages_.Insert(priority, SharedPtr<PackageFile>(package));
     else
         packages_.Push(SharedPtr<PackageFile>(package));