// NeL - MMORPG Framework <http://dev.ryzom.com/projects/nel/>
// Copyright (C) 2010  Winch Gate Property Limited
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as
// published by the Free Software Foundation, either version 3 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 Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

#ifndef NL_BLOOM_EFFECT_H
#define NL_BLOOM_EFFECT_H

// Misc
#include "nel/misc/singleton.h"
#include "nel/misc/vector_2f.h"
#include "nel/misc/geom_ext.h"

// 3D
#include "nel/3d/u_material.h"
#include "nel/3d/texture.h"

namespace NL3D
{

class UDriver;
class UScene;
class CTextureUser;

//-----------------------------------------------------------------------------------------------------------
//---------------------------------------- CBloomEffect -----------------------------------------------------
//-----------------------------------------------------------------------------------------------------------
// CBloomEffect class apply a bloom effect on the whole scene. The whole scene is rendered in a
// render target (a Frame Buffer Object on OpengL, the normal back buffer in Direct3D) which is stretched
// in a 256*256 another render target.
// We apply a horizontal blur on this 256*256 render target, then a vertical blur on the result of this first pass.
// The final blurred render target is blend with the initial render target of scene, with a dest + src - dest*src
// blend operation.
//-----------------------------------------------------------------------------------------------------------
class CBloomEffect : public NLMISC::CSingleton<CBloomEffect>
{
public:

	/// Constructor
	CBloomEffect();

	// Destructor
	~CBloomEffect();

	// Called after the Driver initialization.
	void init();

	// must be called before init
	void setDriver(UDriver *driver) { _Driver = driver; }
	UDriver* getDriver() const { return _Driver; }

	// must be called before applyBloom
	void setScene(UScene *scene) { _Scene = scene; }
	UScene* getScene() const { return _Scene; }

	// enable or disable square bloom
	void setSquareBloom(bool squareBloom) { _SquareBloom = squareBloom; }
	bool getSquareBloom() const { return _SquareBloom; }

	// set bloom density
	void setDensityBloom(uint8 densityBloom) { _DensityBloom = densityBloom; }
	uint8 getDensityBloom() const { return _DensityBloom; }

	// Applies bloom to the current render target
	void applyBloom();

	// Called at the beginning of renderAll method in the main loop, if window has been resized,
	// reinitialize bloom textures according to new window size.
	// The bloom texture (_InitText attribute) which is used as render target during scene render
	// is reinitialized with window dimensions.
	// If window size exceeds 256*256 the textures used to apply blur are reinitialized with
	// 256*256 size. If a dimension is less than 256, the texture is initialized with the nearer
	// power of 2, lower than this window dimension.
	// void initBloom();

	// Called at the end of renderAll method in the main loop, recover stretched texture, apply
	// both blur passes, and the blending operation between initial render target and the blured one.
	// void endBloom();

	// In OpenGL, the use of FBO implies that Z buffer values of scene render have been stored in
	// a depth render target. Then, to display 3D interfaces, we must display them in the same FBO,
	// to keep Z tests correct.
	// This method is called at the end of interfaces display in the main loop, to display final render target
	// (with added interfaces) in the color frame buffer.
	// NB : In Direct3D, the final render target is displayed at the end of endBloom call.
	// void endInterfacesDisplayBloom();

private:

	// Initialize a bloom texture with new dimensions.
	// void initTexture(NLMISC::CSmartPtr<NL3D::ITexture> & tex, bool isMode2D, uint32 width, uint32 height);

	// Called in endBloom method to build a blurred texture. Two passes (then two calls)
	// are necessary : horizontal and vertical.
	// For the first pass, blur is applied horizontally to stretched texture _BlurFinalTex and recover in
	// _BlurHorizontalTex render target texture.
	// For the second pass, blur is applied vertically to precedent _BlurHorizontalTex texture and recover
	// in _BlurFinalTex render target texture.
	// For each pass, thanks to a vertex program, first texture is displayed with several little decals
	// in order to obtain in the render target texture a mix of color of a texel and its neighboured texels
	// on the axis of the pass.
	void doBlur(bool horizontalBlur);

	// Called in endBloom method after the both doBlur passes. Apply blend operation between initial render target
	// texture _InitText of scene and the blurred texture _BlurFinalTex.
	void applyBlur();

	// the driver to use
	UDriver*	_Driver;
	// the scene to use
	UScene*		_Scene;

	// use square bloom
	bool		_SquareBloom;
	// density of bloom
	uint8		_DensityBloom;

/*
	// render target textures
	// used to display scene
	NLMISC::CSmartPtr<NL3D::ITexture>  _InitText;
	// used as stretched texture from _InitText, as displayed texture in first blur pass,
	// and as render target in second blur pass.
	NLMISC::CSmartPtr<NL3D::ITexture>  _BlurFinalTex;
	// used as render target in first blur pass, and as displayed texture on second blur pass.
	NLMISC::CSmartPtr<NL3D::ITexture>  _BlurHorizontalTex;
	// original render target
	NLMISC::CSmartPtr<NL3D::ITexture>  _OriginalRenderTarget;
*/


	// materials
	// used to display first texture in doBlur passes.
	NL3D::UMaterial		_BlurMat;
	// used to blend initial scene render target texture and blur texture according to a
	// dest+src - dest*src blend operation.
	NL3D::UMaterial		_DisplayBlurMat;
	// used to blend initial scene render target texture and blur texture according to a
	// dest+src - dest*src blend operation, with a square stage operation.
	NL3D::UMaterial		_DisplaySquareBlurMat;

	// quads
	NLMISC::CQuadUV		_BlurQuad;

	// textures and materials already initialized?
	bool				_Init;

	// current window dimensions
	/*uint32				_WndWidth;
	uint32				_WndHeight;*/

	// Temporary variables used during applyBloom(...) ->
	// current blur texture dimensions
	uint32				_BlurWidth;
	uint32				_BlurHeight;
	// used as stretched texture from _InitText, as displayed texture in first blur pass,
	// and as render target in second blur pass.
	CTextureUser		*_BlurFinalTex;
	// used as render target in first blur pass, and as displayed texture on second blur pass.
	CTextureUser		*_BlurHorizontalTex;
	// <-
};

} // NL3D

#endif // NL_BLOOM_EFFECT_H

/* End of bloom_effect.h */