/*
   Copyright (C) 1999-2006 Id Software, Inc. and contributors.
   For a list of contributors, see the accompanying CONTRIBUTORS file.

   This file is part of GtkRadiant.

   GtkRadiant 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.

   GtkRadiant 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 GtkRadiant; if not, write to the Free Software
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

#if !defined( INCLUDED_ISHADERS_H )
#define INCLUDED_ISHADERS_H

#include "generic/constant.h"
#include "generic/callback.h"

enum
{
	QER_TRANS = 1 << 0,
	QER_NOCARVE = 1 << 1,
	QER_NODRAW = 1 << 2,
	QER_NONSOLID = 1 << 3,
	QER_WATER = 1 << 4,
	QER_LAVA = 1 << 5,
	QER_FOG = 1 << 6,
	QER_ALPHATEST = 1 << 7,
	QER_CULL = 1 << 8,
	QER_AREAPORTAL = 1 << 9,
	QER_CLIP = 1 << 10,
	QER_BOTCLIP = 1 << 11,
	QER_POLYOFS = 1 << 12,
};

struct qtexture_t;

template<typename Element> class BasicVector3;
typedef BasicVector3<float> Vector3;
typedef Vector3 Colour3;

typedef unsigned char BlendFactor;
const BlendFactor BLEND_ZERO = 0;
const BlendFactor BLEND_ONE = 1;
const BlendFactor BLEND_SRC_COLOUR = 2;
const BlendFactor BLEND_ONE_MINUS_SRC_COLOUR = 3;
const BlendFactor BLEND_SRC_ALPHA = 4;
const BlendFactor BLEND_ONE_MINUS_SRC_ALPHA = 5;
const BlendFactor BLEND_DST_COLOUR = 6;
const BlendFactor BLEND_ONE_MINUS_DST_COLOUR = 7;
const BlendFactor BLEND_DST_ALPHA = 8;
const BlendFactor BLEND_ONE_MINUS_DST_ALPHA = 9;
const BlendFactor BLEND_SRC_ALPHA_SATURATE = 10;

class BlendFunc
{
public:
BlendFunc( BlendFactor src, BlendFactor dst ) : m_src( src ), m_dst( dst ){
}
BlendFactor m_src;
BlendFactor m_dst;
};

class ShaderLayer
{
public:
virtual qtexture_t* texture() const = 0;
virtual BlendFunc blendFunc() const = 0;
virtual bool clampToBorder() const = 0;
virtual float alphaTest() const = 0;
};

typedef Callback<void (const ShaderLayer&)> ShaderLayerCallback;


class IShader
{
public:
enum EAlphaFunc
{
	eAlways,
	eEqual,
	eLess,
	eGreater,
	eLEqual,
	eGEqual,
};
enum ECull
{
	eCullNone,
	eCullBack,
};
// Increment the number of references to this object
virtual void IncRef() = 0;
// Decrement the reference count
virtual void DecRef() = 0;
// get/set the qtexture_t* Radiant uses to represent this shader object
virtual qtexture_t* getTexture() const = 0;
virtual qtexture_t* getDiffuse() const = 0;
virtual qtexture_t* getBump() const = 0;
virtual qtexture_t* getSpecular() const = 0;
// get shader name
virtual const char* getName() const = 0;
virtual bool IsInUse() const = 0;
virtual void SetInUse( bool bInUse ) = 0;
// get the editor flags (QER_NOCARVE QER_TRANS)
virtual int getFlags() const = 0;
// get the transparency value
virtual float getTrans() const = 0;
virtual int getPolygonOffset() const = 0;
// test if it's a true shader, or a default shader created to wrap around a texture
virtual bool IsDefault() const = 0;
// get the alphaFunc
virtual void getAlphaFunc( EAlphaFunc *func, float *ref ) = 0;
virtual BlendFunc getBlendFunc() const = 0;
// get the cull type
virtual ECull getCull() = 0;
// get shader file name (ie the file where this one is defined)
virtual const char* getShaderFileName() const = 0;

virtual const ShaderLayer* firstLayer() const = 0;
virtual void forEachLayer( const ShaderLayerCallback& layer ) const = 0;

virtual qtexture_t* lightFalloffImage() const = 0;
};

typedef struct _GSList GSList;
typedef Callback<void (const char*)> ShaderNameCallback;

class ModuleObserver;

class ShaderSystem
{
public:
INTEGER_CONSTANT( Version, 1 );
STRING_CONSTANT( Name, "shaders" );
// NOTE: shader and texture names used must be full path.
// Shaders usable as textures have prefix equal to getTexturePrefix()

virtual void realise() = 0;
virtual void unrealise() = 0;
virtual void refresh() = 0;
// activate the shader for a given name and return it
// will return the default shader if name is not found
virtual IShader* getShaderForName( const char* name ) = 0;

virtual void foreachShaderName( const ShaderNameCallback& callback ) = 0;

// iterate over the list of active shaders
virtual void beginActiveShadersIterator() = 0;
virtual bool endActiveShadersIterator() = 0;
virtual IShader* dereferenceActiveShadersIterator() = 0;
virtual void incrementActiveShadersIterator() = 0;

virtual void setActiveShadersChangedNotify( const Callback<void()>& notify ) = 0;

virtual void attach( ModuleObserver& observer ) = 0;
virtual void detach( ModuleObserver& observer ) = 0;

virtual void setLightingEnabled( bool enabled ) = 0;

virtual const char* getTexturePrefix() const = 0;
};

#include "modulesystem.h"

template<typename Type>
class GlobalModule;
typedef GlobalModule<ShaderSystem> GlobalShadersModule;

template<typename Type>
class GlobalModuleRef;
typedef GlobalModuleRef<ShaderSystem> GlobalShadersModuleRef;

inline ShaderSystem& GlobalShaderSystem(){
	return GlobalShadersModule::getTable();
}


#define QERApp_Shader_ForName GlobalShaderSystem().getShaderForName
#define QERApp_ActiveShaders_IteratorBegin GlobalShaderSystem().beginActiveShadersIterator
#define QERApp_ActiveShaders_IteratorAtEnd GlobalShaderSystem().endActiveShadersIterator
#define QERApp_ActiveShaders_IteratorCurrent GlobalShaderSystem().dereferenceActiveShadersIterator
#define QERApp_ActiveShaders_IteratorIncrement GlobalShaderSystem().incrementActiveShadersIterator

#endif