Revert "Don't force DDS file usage (fixes #1392)"

This reverts commit 90f3ff2da4.

components/misc/resourcehelpers.cpp

@@ -63,16 +63,28 @@ std::string Misc::ResourceHelpers::correctResourcePath(const std::string &topLev
 
     std::string origExt = correctedPath;
 
-    if (vfs->exists(origExt)
-     || (changeExtensionToDds(correctedPath) && vfs->exists(correctedPath)))
+    // since we know all (GOTY edition or less) textures end
+    // in .dds, we change the extension
+    bool changedToDds = changeExtensionToDds(correctedPath);
+    if (vfs->exists(correctedPath))
         return correctedPath;
+    // if it turns out that the above wasn't true in all cases (not for vanilla, but maybe mods)
+    // verify, and revert if false (this call succeeds quickly, but fails slowly)
+    if (changedToDds && vfs->exists(origExt))
+        return origExt;
 
     // fall back to a resource in the top level directory if it exists
-    std::string fallback = topLevelDirectory + "\\" + getBasename(origExt);
-    if (vfs->exists(fallback)
-     || (changeExtensionToDds(fallback) && vfs->exists(fallback)))
+    std::string fallback = topLevelDirectory + "\\" + getBasename(correctedPath);
+    if (vfs->exists(fallback))
         return fallback;
 
+    if (changedToDds)
+    {
+        fallback = topLevelDirectory + "\\" + getBasename(origExt);
+        if (vfs->exists(fallback))
+            return fallback;
+    }
+
     return correctedPath;
 }