// Copyright (C) 2002-2012 Nikolaus Gebhardt
// This file is part of the "Irrlicht Engine".
// For conditions of distribution and use, see copyright notice in irrlicht.h

#ifndef IRR_I_MATERIAL_RENDERER_SERVICES_H_INCLUDED
#define IRR_I_MATERIAL_RENDERER_SERVICES_H_INCLUDED

#include "SMaterial.h"
#include "S3DVertex.h"

namespace irr
{
namespace video
{

class IVideoDriver;


//! Interface providing some methods for changing advanced, internal states of a IVideoDriver.
class IMaterialRendererServices
{
public:

	//! Destructor
	virtual ~IMaterialRendererServices() {}

	//! Return an index constant for the vertex shader based on a name.
	virtual s32 getVertexShaderConstantID(const c8* name) = 0;

	//! Call when you set shader constants outside of IShaderConstantSetCallBack
	/** Only for high-level shader functions, aka those using an index instead of 
	an register. Shader constants are attached to shader programs, so if you want 
	to set them you have to make sure the correct shader program is in use.
	IShaderConstantSetCallBack functions like OnSetConstants do that for you,
	but if you want to set shader constants outside of those (usually for performance
	reasons) call startUseProgram() before doing so and stopUseProgram() afterwards.
	Note: Currently only necessary in OpenGL, but no real calling costs on other drivers.
	*/
	virtual void startUseProgram() {}

	//! Call this when you are done setting shader constants outside of OnCreate or OnSetConstants 
	virtual void stopUseProgram() {}

	//! Sets a constant for the vertex shader based on a name.
	/** This can be used if you used a high level shader language like GLSL
	or HLSL to create a shader. Example: If you created a shader which has
	variables named 'mWorldViewProj' (containing the WorldViewProjection
	matrix) and another one named 'fTime' containing one float, you can set
	them in your IShaderConstantSetCallBack derived class like this:
	\code
	virtual void OnSetConstants(video::IMaterialRendererServices* services, s32 userData)
	{
		video::IVideoDriver* driver = services->getVideoDriver();

		f32 time = (f32)os::Timer::getTime()/100000.0f;
		services->setVertexShaderConstant("fTime", &time, 1);

		core::matrix4 worldViewProj(driver->getTransform(video::ETS_PROJECTION));
		worldViewProj *= driver->getTransform(video::ETS_VIEW);
		worldViewProj *= driver->getTransform(video::ETS_WORLD);
		services->setVertexShaderConstant("mWorldViewProj", worldViewProj.M, 16);
	}
	\endcode
	\param index Index of the variable
	\param floats Pointer to array of floats
	\param count Amount of floats in array.
	\return True if successful.
	*/
	virtual bool setVertexShaderConstant(s32 index, const f32* floats, int count) = 0;

	//! Int interface for the above.
	virtual bool setVertexShaderConstant(s32 index, const s32* ints, int count) = 0;

	//! Uint interface for the above.
	/* NOTE: UINT only works with GLSL, not supported for other shaders.
	         Also GLES drivers in Irrlicht do not support it as this needs at least GLES 3.0.
	*/
	virtual bool setVertexShaderConstant(s32 index, const u32* ints, int count) = 0;

	//! Sets a vertex shader constant.
	/** Can be used if you created a shader using pixel/vertex shader
	assembler or ARB_fragment_program or ARB_vertex_program.
	\param data: Data to be set in the constants
	\param startRegister: First register to be set
	\param constantAmount: Amount of registers to be set. One register consists of 4 floats. */
	virtual void setVertexShaderConstant(const f32* data, s32 startRegister, s32 constantAmount=1) = 0;

	//! Return an index constant for the pixel shader based on a name.
	virtual s32 getPixelShaderConstantID(const c8* name) = 0;

	//! Sets a constant for the pixel shader based on a name.
	/** This can be used if you used a high level shader language like GLSL
	or HLSL to create a shader. See setVertexShaderConstant() for an
	example on how to use this.
	\param index Index of the variable
	\param floats Pointer to array of floats
	\param count Amount of floats in array.
	\return True if successful. */
	virtual bool setPixelShaderConstant(s32 index, const f32* floats, int count) = 0;

	//! Int interface for the above.
	virtual bool setPixelShaderConstant(s32 index, const s32* ints, int count) = 0;

	//! Uint interface for the above.
	/* NOTE: UINT only works with GLSL, not supported for other shaders.
	         Also GLES drivers in Irrlicht do not support it as this needs at least GLES 3.0.
	*/
	virtual bool setPixelShaderConstant(s32 index, const u32* ints, int count) = 0;

	//! Sets a pixel shader constant.
	/** Can be used if you created a shader using pixel/vertex shader
	assembler or ARB_fragment_program or ARB_vertex_program.
	\param data Data to be set in the constants
	\param startRegister First register to be set.
	\param constantAmount Amount of registers to be set. One register consists of 4 floats. */
	virtual void setPixelShaderConstant(const f32* data, s32 startRegister, s32 constantAmount=1) = 0;

	//! \deprecated. This method may be removed by Irrlicht 2.0
	IRR_DEPRECATED bool setVertexShaderConstant(const c8* name, const f32* floats, int count)
	{
		return setVertexShaderConstant(getVertexShaderConstantID(name), floats, count);
	}

	//! \deprecated. This method may be removed by Irrlicht 2.0
	IRR_DEPRECATED bool setVertexShaderConstant(const c8* name, const s32* ints, int count)
	{
		return setVertexShaderConstant(getVertexShaderConstantID(name), ints, count);
	}

	//! \deprecated. This method may be removed by Irrlicht 2.0
	IRR_DEPRECATED bool setPixelShaderConstant(const c8* name, const f32* floats, int count)
	{
		return setPixelShaderConstant(getPixelShaderConstantID(name), floats, count);
	}

	//! \deprecated. This method may be removed by Irrlicht 2.0
	IRR_DEPRECATED bool setPixelShaderConstant(const c8* name, const s32* ints, int count)
	{
		return setPixelShaderConstant(getPixelShaderConstantID(name), ints, count);
	}

	//! Get pointer to the IVideoDriver interface
	/** \return Pointer to the IVideoDriver interface */
	virtual IVideoDriver* getVideoDriver() = 0;
};

} // end namespace video
} // end namespace irr

#endif