Added support for shader packs with a top-level parent directory

Signed-off-by: SwitchAxe <sofiacerasuoli@gmail.com>

launcher/minecraft/mod/tasks/LocalShaderPackParseTask.cpp

@@ -61,11 +61,32 @@ bool processZIP(ShaderPack& pack, ProcessingLevel level)
     Q_ASSERT(pack.type() == ResourceType::ZIPFILE);
 
     MMCZip::ArchiveReader zip(pack.fileinfo().filePath());
-    if (!zip.collectFiles())
+    if (!zip.collectFiles(false))
         return false;  // can't open zip file
 
     if (!zip.exists("/shaders")) {
-        return false;  // assets dir does not exists at zip root
+      // assets dir does not exists at zip root, but shader packs
+      // will sometimes be a zip file containing a folder with the
+      // actual contents in it. This happens
+      // e.g. when the shader pack is downloaded as code
+      // from Github. so other than "/shaders", we
+      // could also check for a "shaders" folder one level deep.
+
+      QStringList files = zip.getFiles();
+
+      // the assumption here is that there is just one
+      // folder with the "shader" subfolder. In case
+      // there are multiple, the first one is picked.
+      bool isShaderPresent = false;
+      for (QString f: files) {
+	if (zip.exists(f + "/shaders"))
+	  isShaderPresent = true;
+      }
+      
+      if (!isShaderPresent)
+	// assets dir does not exist.
+	return false;
+      
     }
     pack.setPackFormat(ShaderPackFormat::VALID);