do only invalid hashes instead of all textures on loading

this is a hack, but only the gpu thread is allowed to call ogl commands
suggestion: create an unused texture cache, so we can move all textures there

Source/Core/VideoCommon/Src/MainBase.cpp

@@ -203,7 +203,7 @@ void VideoBackendHardware::DoState(PointerWrap& p)
 
 		// Clear all caches that touch RAM
 		// (? these don't appear to touch any emulation state that gets saved. moved to on load only.)
-		TextureCache::Invalidate();
+		TextureCache::InvalidateHashes();
 		VertexLoaderManager::MarkAllDirty();
 	}
 }

Source/Core/VideoCommon/Src/TextureCacheBase.cpp

@@ -72,6 +72,18 @@ void TextureCache::Invalidate()
 	textures.clear();
 }
 
+// this function is dirty hack to work around a OGL bug.
+// it is only used on loading states. It will work for normal textures,
+// but for efb2ram, it wouldn't be checked. So there may be glitches on loading
+void TextureCache::InvalidateHashes()
+{
+	TexCache::iterator
+		iter = textures.begin(),
+		tcend = textures.end();
+	for (; iter != tcend; ++iter)
+		iter->second->hash = TEXHASH_INVALID;
+}
+
 TextureCache::~TextureCache()
 {
 	Invalidate();

Source/Core/VideoCommon/Src/TextureCacheBase.h

@@ -106,6 +106,7 @@ public:
 	static void Cleanup();
 
 	static void Invalidate();
+	static void InvalidateHashes();
 	static void InvalidateRange(u32 start_address, u32 size);
 	static void MakeRangeDynamic(u32 start_address, u32 size);
 	static void ClearRenderTargets();	// currently only used by OGL