Split theora::VideoStream into OggDemuxer and TheoraVideoStream

This makes the internal API more modular, but the split also forces a cleaner
implementation. It also means the OggDemuxer is now responsible for the
ogg-specific stuff like seeking and (ogg-specific) type detection.

Backported from the love.video-vpx branch of love-experiments

--HG--
branch : minor

src/modules/video/theora/TheoraVideoStream.h

@@ -0,0 +1,96 @@
+/**
+ * Copyright (c) 2006-2017 LOVE Development Team
+ *
+ * This software is provided 'as-is', without any express or implied
+ * warranty.  In no event will the authors be held liable for any damages
+ * arising from the use of this software.
+ *
+ * Permission is granted to anyone to use this software for any purpose,
+ * including commercial applications, and to alter it and redistribute it
+ * freely, subject to the following restrictions:
+ *
+ * 1. The origin of this software must not be misrepresented; you must not
+ *    claim that you wrote the original software. If you use this software
+ *    in a product, an acknowledgment in the product documentation would be
+ *    appreciated but is not required.
+ * 2. Altered source versions must be plainly marked as such, and must not be
+ *    misrepresented as being the original software.
+ * 3. This notice may not be removed or altered from any source distribution.
+ **/
+
+#ifndef LOVE_VIDEO_THEORA_VIDEOSTREAM_H
+#define LOVE_VIDEO_THEORA_VIDEOSTREAM_H
+
+#include "video/VideoStream.h"
+
+// LOVE
+#include "common/int.h"
+#include "filesystem/File.h"
+#include "thread/threads.h"
+#include "OggDemuxer.h"
+
+// OGG/Theora
+#include <ogg/ogg.h>
+#include <theora/codec.h>
+#include <theora/theoradec.h>
+
+namespace love
+{
+namespace video
+{
+namespace theora
+{
+
+class TheoraVideoStream : public love::video::VideoStream
+{
+public:
+	TheoraVideoStream(love::filesystem::File *file);
+	~TheoraVideoStream();
+
+	const void *getFrontBuffer() const;
+	size_t getSize() const;
+	void fillBackBuffer();
+	bool swapBuffers();
+
+	int getWidth() const;
+	int getHeight() const;
+	const std::string &getFilename() const;
+	void setSync(FrameSync *frameSync);
+
+	bool isPlaying() const;
+
+	void threadedFillBackBuffer(double dt);
+
+private:
+	OggDemuxer demuxer;
+
+	bool headerParsed;
+
+	ogg_packet packet;
+
+	th_info videoInfo;
+	th_dec_ctx *decoder;
+
+	Frame *frontBuffer;
+	Frame *backBuffer;
+	unsigned int yPlaneXOffset;
+	unsigned int cPlaneXOffset;
+	unsigned int yPlaneYOffset;
+	unsigned int cPlaneYOffset;
+
+	love::thread::MutexRef bufferMutex;
+	bool frameReady;
+
+	double lastFrame;
+	double nextFrame;
+	unsigned int lagCounter;
+
+	void parseHeader();
+	void seekDecoder(double target);
+}; // TheoraVideoStream
+
+} // theora
+} // video
+} // love
+
+#endif // LOVE_VIDEO_THEORA_VIDEOSTREAM_H