Separated OpenGL specific code into its own "compilation unit"

include/Rendering/PNG.h

@@ -0,0 +1,44 @@
+/*
+	This file is part of Daydream Engine.
+	Copyright 2014 Adam Byléhn, Tobias Dahl, Simon Holmberg, Viktor Ljung
+	
+	Daydream Engine is free software: you can redistribute it and/or modify
+	it under the terms of the GNU Lesser General Public License as published by
+	the Free Software Foundation, either version 3 of the License, or
+	(at your option) any later version.
+	
+	Daydream Engine is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU Lesser General Public License for more details.
+	
+	You should have received a copy of the GNU Lesser General Public License
+	along with Daydream Engine.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef PNG_h_
+#define PNG_h_
+
+#include <stdexcept>
+
+#include <png.h>
+
+#include "Image.h"
+
+namespace dd
+{
+
+class PNG : public Image
+{
+public:
+	PNG(std::string path);
+	~PNG();
+
+private:
+	static void pngErrorFunction(png_structp png_ptr, png_const_charp error_msg);
+	static void pngWarningFunction(png_structp png_ptr, png_const_charp warning_msg);
+};
+
+}
+
+#endif