generalized object render caches so they can be used for any object types

app/render/backend/rendercache.h

@@ -0,0 +1,22 @@
+#ifndef RENDERCACHE_H
+#define RENDERCACHE_H
+
+#include <QMap>
+
+template<class K, class V>
+class RenderCache
+{
+public:
+  RenderCache() = default;
+
+  void Clear(){values_.clear();}
+
+  void Add(K stream, V shader){values_.insert(stream, shader);}
+
+  V Get(K stream){return values_.value(stream);}
+
+private:
+  QMap<K, V> values_;
+};
+
+#endif // RENDERCACHE_H