add openGL based framebuffer implementation for testing on PC

this is based on Carsten Juttner's previous work, but without
any video decoding.


Origin commit data
------------------
Commit: e0c80399d6
Author: Stefan Seyfried <seife@tuxbox-git.slipkontur.de>
Date: 2012-10-08 (Mon, 08 Oct 2012)

src/driver/glthread.h

@@ -0,0 +1,103 @@
+/*
+	Neutrino-GUI  -   DBoxII-Project
+
+	Copyright 2010 Carsten Juttner <carjay@gmx.net>
+	Copyright 2012 Stefan Seyfried <seife@tuxboxcvs.slipkontur.de>
+
+	License: GPL
+
+	This program is free software; you can redistribute it and/or modify
+	it under the terms of the GNU General Public License as published by
+	the Free Software Foundation; either version 2 of the License, or
+	(at your option) any later version.
+
+	This program 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 General Public License for more details.
+
+	You should have received a copy of the GNU General Public License
+	along with this program; if not, write to the Free Software
+	Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+*/
+
+#ifndef __glthread__
+#define __glthread__
+#include <OpenThreads/Thread>
+//#include <OpenThreads/Condition>
+#include <vector>
+#include <GL/glew.h>
+#include <GL/freeglut.h>
+#include <GL/gl.h>
+
+//class SWDecoder;
+
+/* TODO: some stuff is probably not needed without the SW decoder... */
+class GLThreadObj : public OpenThreads::Thread
+{
+public:
+	GLThreadObj(int x, int y);
+	~GLThreadObj();
+	// GLThreadObj(GLThreadObj &rhs);
+	// GLThreadObj const &operator= (GLThreadObj const &rhs);
+	// void operator()();
+
+	void run();
+	void Start() { OpenThreads::Thread::start(); }
+	void waitInit();			/* wait until things are set up */
+	void shutDown() { mShutDown = true; }	/* shut down event loop (causes thread to exit) */
+	void join() { OpenThreads::Thread::join(); }
+	unsigned char *getOSDBuffer() { return &mOSDBuffer[0]; } /* gets pointer to OSD bounce buffer */
+
+	int getOSDWidth() { return mState.width; }
+	int getOSDHeight() { return mState.height; }
+
+	void clear();
+
+private:
+	int mX;				/* window size */
+	int mY;
+	bool mReInit;			/* setup things for GL */
+	bool mShutDown;			/* if set main loop is left */
+	bool mInitDone;			/* condition predicate */
+	// OpenThreads::Condition mInitCond;	/* condition variable for init */
+	// mutable OpenThreads::Mutex mMutex;	/* lock our data */
+
+	std::vector<unsigned char> mOSDBuffer; /* silly bounce buffer */
+
+	std::map<unsigned char, neutrino_msg_t> mKeyMap;
+	std::map<int, neutrino_msg_t> mSpecialMap;
+
+	void checkReinit();		/* e.g. in case window was resized */
+	static void rendercb();		/* callback for GLUT */
+	void render();			/* actual render function */
+	static void keyboardcb(unsigned char key, int x, int y);
+	static void specialcb(int key, int x, int y);
+
+	void initKeys();		/* setup key bindings for window */
+	void setupCtx();		/* create the window and make the context current */
+	void setupOSDBuffer();		/* create the OSD buffer */
+	void setupGLObjects();		/* PBOs, textures and stuff */
+	void releaseGLObjects();
+	void eventLoop();		/* enter the GL window event loop */
+	void drawCube(float size);	/* cubes are the building blocks of our society */
+	void drawSquare(float size);	/* do not be square */
+	void initDone();		/* "things are now set up", called by this */
+
+	struct {
+		int width;		/* width and height, fixed for a framebuffer instance */
+		int height;
+		GLuint osdtex;		/* holds the OSD texture */
+		GLuint pbo;		/* PBO we use for transfer to texture */
+		// GLuint displaytex;	/* holds the display texture */
+		// GLuint displaypbo;
+		int go3d;
+	} mState;
+
+	// boost::shared_ptr<SWDecoder>mpSWDecoder; /* our Decoder-Object that runs in its own thread */
+	// boost::thread mSWDecoderThread; /* thread running the decoder */
+
+	void bltOSDBuffer();
+	// void bltDisplayBuffer();
+};
+#endif