/*
Minetest
Copyright (C) 2013 celeron55, Perttu Ahola <celeron55@gmail.com>
Copyright (C) 2013 Kahrl <kahrl@gmx.net>

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/

#ifndef SHADER_HEADER
#define SHADER_HEADER

#include "irrlichttypes_extrabloated.h"
#include "threads.h"
#include <string>

class IGameDef;

/*
	shader.{h,cpp}: Shader handling stuff.
*/

/*
	Gets the path to a shader by first checking if the file
	  name_of_shader/filename
	exists in shader_path and if not, using the data path.

	If not found, returns "".

	Utilizes a thread-safe cache.
*/
std::string getShaderPath(const std::string &name_of_shader,
		const std::string &filename);

struct ShaderInfo
{
	std::string name;
	video::E_MATERIAL_TYPE material;

	ShaderInfo(): name(""), material(video::EMT_SOLID) {}
	virtual ~ShaderInfo() {}
};

/*
	Setter of constants for shaders
*/

namespace irr { namespace video {
	class IMaterialRendererServices;
} }

class IShaderConstantSetter
{
public:
	virtual ~IShaderConstantSetter(){};
	virtual void onSetConstants(video::IMaterialRendererServices *services,
			bool is_highlevel) = 0;
};

/*
	ShaderSource creates and caches shaders.
*/

class IShaderSource
{
public:
	IShaderSource(){}
	virtual ~IShaderSource(){}
	virtual u32 getShaderId(const std::string &name){return 0;}
	virtual u32 getShaderIdDirect(const std::string &name){return 0;}
	virtual std::string getShaderName(u32 id){return "";}
	virtual ShaderInfo getShader(u32 id){return ShaderInfo();}
	virtual ShaderInfo getShader(const std::string &name){return ShaderInfo();}
};

class IWritableShaderSource : public IShaderSource
{
public:
	IWritableShaderSource(){}
	virtual ~IWritableShaderSource(){}
	virtual u32 getShaderId(const std::string &name){return 0;}
	virtual u32 getShaderIdDirect(const std::string &name){return 0;}
	virtual std::string getShaderName(u32 id){return "";}
	virtual ShaderInfo getShader(u32 id){return ShaderInfo();}
	virtual ShaderInfo getShader(const std::string &name){return ShaderInfo();}

	virtual void processQueue()=0;
	virtual void insertSourceShader(const std::string &name_of_shader,
		const std::string &filename, const std::string &program)=0;
	virtual void rebuildShaders()=0;
	virtual void addGlobalConstantSetter(IShaderConstantSetter *setter)=0;
};

IWritableShaderSource* createShaderSource(IrrlichtDevice *device);

#endif