// Copyright (C) 2003 Dolphin Project.

// 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, version 2.0.

// 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 2.0 for more details.

// A copy of the GPL 2.0 should have been included with the program.
// If not, see http://www.gnu.org/licenses/

// Official SVN repository and contact information can be found at
// http://code.google.com/p/dolphin-emu/

#ifndef _OGL_FRAMEBUFFERMANAGER_H_
#define _OGL_FRAMEBUFFERMANAGER_H_

#include <list>

#include "OGL_GLUtil.h"

#include "../FramebufferManager.h"

namespace OGL
{

// On the GameCube, the game sends a request for the graphics processor to
// transfer its internal EFB (Embedded Framebuffer) to an area in GameCube RAM
// called the XFB (External Framebuffer). The size and location of the XFB is
// decided at the time of the copy, and the format is always YUYV. The video
// interface is given a pointer to the XFB, which will be decoded and
// displayed on the TV.
//
// There are two ways for Dolphin to emulate this:
//
// Real XFB mode:
//
// Dolphin will behave like the GameCube and encode the EFB to
// a portion of GameCube RAM. The emulated video interface will decode the data
// for output to the screen.
//
// Advantages: Behaves exactly like the GameCube.
// Disadvantages: Resolution will be limited.
//
// Virtual XFB mode:
//
// When a request is made to copy the EFB to an XFB, Dolphin
// will remember the RAM location and size of the XFB in a Virtual XFB list.
// The video interface will look up the XFB in the list and use the enhanced
// data stored there, if available.
//
// Advantages: Enables high resolution graphics, better than real hardware.
// Disadvantages: If the GameCube CPU writes directly to the XFB (which is
// possible but uncommon), the Virtual XFB will not capture this information.

// There may be multiple XFBs in GameCube RAM. This is the maximum number to
// virtualize.

inline bool addrRangesOverlap(u32 aLower, u32 aUpper, u32 bLower, u32 bUpper)
{
	return !((aLower >= bUpper) || (bLower >= aUpper));
}

struct XFBSource : XFBSourceBase
{
	XFBSource() : texture(0) {}

	void CopyEFB(const TargetRectangle& efbSource);

	GLuint texture;
	TargetRectangle sourceRc;
};

class FramebufferManager : public ::FramebufferManagerBase
{
	friend struct XFBSource;

public:
	FramebufferManager(int targetWidth, int targetHeight, int msaaSamples, int msaaCoverageSamples);
	~FramebufferManager();

	// To get the EFB in texture form, these functions may have to transfer
	// the EFB to a resolved texture first.
	static GLuint GetEFBColorTexture(const EFBRectangle& sourceRc);
	static GLuint GetEFBDepthTexture(const EFBRectangle& sourceRc);

	static GLuint GetEFBFramebuffer() { return m_efbFramebuffer; }

	// Resolved framebuffer is only used in MSAA mode.
	static GLuint GetResolvedFramebuffer() { return m_resolvedFramebuffer; }

	static void SetFramebuffer(GLuint fb);

	// If in MSAA mode, this will perform a resolve of the specified rectangle, and return the resolve target as a texture ID.
	// Thus, this call may be expensive. Don't repeat it unnecessarily.
	// If not in MSAA mode, will just return the render target texture ID.
	// After calling this, before you render anything else, you MUST bind the framebuffer you want to draw to.
	static GLuint ResolveAndGetRenderTarget(const EFBRectangle &rect);

	// Same as above but for the depth Target.
	// After calling this, before you render anything else, you MUST bind the framebuffer you want to draw to.
	static GLuint ResolveAndGetDepthTarget(const EFBRectangle &rect);

	XFBSourceBase* CreateXFBSource(unsigned int target_width, unsigned int target_height);

protected:
	static GLuint m_efbFramebuffer;
	static GLuint m_xfbFramebuffer; // Only used in MSAA mode

private:
	static void copyToRealXFB(u32 xfbAddr, u32 fbWidth, u32 fbHeight, const EFBRectangle& sourceRc);
	static const XFBSourceBase** getRealXFBSource(u32 xfbAddr, u32 fbWidth, u32 fbHeight, u32 &xfbCount);

	static int m_targetWidth;
	static int m_targetHeight;
	static int m_msaaSamples;
	static int m_msaaCoverageSamples;

	static GLuint m_efbColor; // Renderbuffer in MSAA mode; Texture otherwise
	static GLuint m_efbDepth; // Renderbuffer in MSAA mode; Texture otherwise

	// Only used in MSAA mode.
	static GLuint m_resolvedFramebuffer;
	static GLuint m_resolvedColorTexture;
	static GLuint m_resolvedDepthTexture;

	static XFBSource m_realXFBSource; // Only used in Real XFB mode
};

}

#endif