//========= Copyright © 1996-2005, Valve Corporation, All rights reserved. ============//
//
// Purpose: 
//
// $NoKeywords: $
//
//=============================================================================//

#ifndef ISHADER_H
#define ISHADER_H

#ifdef _WIN32
#pragma once
#endif


#include "materialsystem/imaterialsystem.h"
#include "materialsystem/ishaderapi.h"


//-----------------------------------------------------------------------------
// forward declarations
//-----------------------------------------------------------------------------
class IMaterialVar;
class IShaderShadow;
class IShaderDynamicAPI;
class IShaderInit;
class CBasePerMaterialContextData;

//-----------------------------------------------------------------------------
// Shader flags
//-----------------------------------------------------------------------------
enum ShaderFlags_t
{
	SHADER_NOT_EDITABLE = 0x1
};


//-----------------------------------------------------------------------------
// Shader parameter flags
//-----------------------------------------------------------------------------
enum ShaderParamFlags_t
{
	SHADER_PARAM_NOT_EDITABLE = 0x1
};


//-----------------------------------------------------------------------------
// Information about each shader parameter
//-----------------------------------------------------------------------------
struct ShaderParamInfo_t
{
	const char *m_pName;
	const char *m_pHelp;
	ShaderParamType_t m_Type;
	const char *m_pDefaultValue;
	int m_nFlags;
};


//-----------------------------------------------------------------------------
// Standard vertex shader constants
//-----------------------------------------------------------------------------
enum
{
	// Standard vertex shader constants
	VERTEX_SHADER_MATH_CONSTANTS0 = 0,
	VERTEX_SHADER_MATH_CONSTANTS1 = 1,
	VERTEX_SHADER_CAMERA_POS = 2,
	VERTEX_SHADER_LIGHT_INDEX = 3,
	VERTEX_SHADER_MODELVIEWPROJ = 4,
	VERTEX_SHADER_VIEWPROJ = 8,
	VERTEX_SHADER_UNUSED = 12,
	VERTEX_SHADER_FLEXSCALE = 13,
	VERTEX_SHADER_SHADER_SPECIFIC_CONST_10 = 14,
	VERTEX_SHADER_SHADER_SPECIFIC_CONST_11 = 15,
	VERTEX_SHADER_FOG_PARAMS = 16,
	VERTEX_SHADER_VIEWMODEL = 17,
	VERTEX_SHADER_AMBIENT_LIGHT = 21,
	VERTEX_SHADER_LIGHTS = 27,
	VERTEX_SHADER_LIGHT0_POSITION = 29,
	VERTEX_SHADER_MODULATION_COLOR = 47,
	VERTEX_SHADER_SHADER_SPECIFIC_CONST_0 = 48,
	VERTEX_SHADER_SHADER_SPECIFIC_CONST_1 = 49,
	VERTEX_SHADER_SHADER_SPECIFIC_CONST_2 = 50,
	VERTEX_SHADER_SHADER_SPECIFIC_CONST_3 = 51,
	VERTEX_SHADER_SHADER_SPECIFIC_CONST_4 = 52,
	VERTEX_SHADER_SHADER_SPECIFIC_CONST_5 = 53,
	VERTEX_SHADER_SHADER_SPECIFIC_CONST_6 = 54,
	VERTEX_SHADER_SHADER_SPECIFIC_CONST_7 = 55,
	VERTEX_SHADER_SHADER_SPECIFIC_CONST_8 = 56,
	VERTEX_SHADER_SHADER_SPECIFIC_CONST_9 = 57,
	VERTEX_SHADER_MODEL = 58,

	VERTEX_SHADER_FLEX_WEIGHTS = 1024,
	VERTEX_SHADER_MAX_FLEX_WEIGHT_COUNT = 512,
};


//-----------------------------------------------------------------------------
// Standard vertex shader constants
//-----------------------------------------------------------------------------
enum
{
	// Standard vertex shader constants
	VERTEX_SHADER_LIGHT_ENABLE_BOOL_CONST = 0,
	VERTEX_SHADER_LIGHT_ENABLE_BOOL_CONST_COUNT = 4,

	VERTEX_SHADER_SHADER_SPECIFIC_BOOL_CONST_0 = 4,
	VERTEX_SHADER_SHADER_SPECIFIC_BOOL_CONST_1 = 5,
	VERTEX_SHADER_SHADER_SPECIFIC_BOOL_CONST_2 = 6,
	VERTEX_SHADER_SHADER_SPECIFIC_BOOL_CONST_3 = 7,
	VERTEX_SHADER_SHADER_SPECIFIC_BOOL_CONST_4 = 8,
	VERTEX_SHADER_SHADER_SPECIFIC_BOOL_CONST_5 = 9,
	VERTEX_SHADER_SHADER_SPECIFIC_BOOL_CONST_6 = 10,
	VERTEX_SHADER_SHADER_SPECIFIC_BOOL_CONST_7 = 11,
};
// The public methods exposed by each shader
//-----------------------------------------------------------------------------
abstract_class IShader
{
public:
	// Returns the shader name
	virtual char const* GetName( ) const = 0;

	// returns the shader fallbacks
	virtual char const* GetFallbackShader( IMaterialVar** params ) const = 0;

	// Shader parameters
	virtual int GetNumParams( ) const = 0;

	// These functions must be implemented by the shader
	virtual void InitShaderParams( IMaterialVar** ppParams, const char *pMaterialName ) = 0;
	virtual void InitShaderInstance( IMaterialVar** ppParams, IShaderInit *pShaderInit, const char *pMaterialName, const char *pTextureGroupName ) = 0;
	virtual void DrawElements( IMaterialVar **params, int nModulationFlags,
		IShaderShadow* pShaderShadow, IShaderDynamicAPI* pShaderAPI, VertexCompressionType_t vertexCompression, CBasePerMaterialContextData **pContextDataPtr ) = 0;

	virtual char const* GetParamName( int paramIndex ) const = 0;
	virtual char const* GetParamHelp( int paramIndex ) const = 0;
	virtual ShaderParamType_t GetParamType( int paramIndex ) const = 0;
	virtual char const* GetParamDefault( int paramIndex ) const = 0;

	// FIXME: Figure out a better way to do this?
	virtual int ComputeModulationFlags( IMaterialVar** params, IShaderDynamicAPI* pShaderAPI ) = 0;
	virtual bool NeedsPowerOfTwoFrameBufferTexture( IMaterialVar **params, bool bCheckSpecificToThisFrame = true ) const = 0;
	virtual bool NeedsFullFrameBufferTexture( IMaterialVar **params, bool bCheckSpecificToThisFrame ) const = 0;
	virtual bool IsTranslucent( IMaterialVar **params ) const = 0;

	virtual int GetParamFlags( int paramIndex ) const = 0;

	virtual int GetFlags() const = 0;

	// FIXME: Remove GetParamName, etc. above
//	virtual const ShaderParamInfo_t& GetParamInfo( int paramIndex ) const = 0;
};


//-----------------------------------------------------------------------------
// Shader dictionaries defined in DLLs
//-----------------------------------------------------------------------------
enum PrecompiledShaderType_t
{
	PRECOMPILED_VERTEX_SHADER = 0,
	PRECOMPILED_PIXEL_SHADER,

	PRECOMPILED_SHADER_TYPE_COUNT,
};


//-----------------------------------------------------------------------------
// Flags field of PrecompiledShader_t
//-----------------------------------------------------------------------------
enum
{
	// runtime flags
	SHADER_DYNAMIC_COMPILE_IS_HLSL = 0x1,
	SHADER_FAILED_LOAD = 0x2,
};

#endif // ISHADER_H