/* $NoKeywords: $ */
/*
//
// Copyright (c) 1993-2012 Robert McNeel & Associates. All rights reserved.
// OpenNURBS, Rhinoceros, and Rhino3D are registered trademarks of Robert
// McNeel & Associates.
//
// THIS SOFTWARE IS PROVIDED "AS IS" WITHOUT EXPRESS OR IMPLIED WARRANTY.
// ALL IMPLIED WARRANTIES OF FITNESS FOR ANY PARTICULAR PURPOSE AND OF
// MERCHANTABILITY ARE HEREBY DISCLAIMED.
//				
// For complete openNURBS copyright information see <http://www.opennurbs.org>.
//
////////////////////////////////////////////////////////////////
*/

#if !defined(OPENNURBS_MATERIAL_INC_)
#define OPENNURBS_MATERIAL_INC_


///////////////////////////////////////////////////////////////////////////////
//
// Class ON_Material
// 
class ON_CLASS ON_Material : public ON_ModelComponent
{
  ON_OBJECT_DECLARE(ON_Material);

public:
  static const double MaxShine; // maximum value of shine exponent = 255.0

  static const ON_Material Unset;   // nil id


  static const ON_Material Default; // index = -1, persistent id

  // Default material for locked objects
  static const ON_Material DefaultLockedObject; // index = -2, persistent id

  /*
  Parameters:
    model_component_reference - [in]
    none_return_value - [in]
      value to return if ON_Material::Cast(model_component_ref.ModelComponent())
      is nullptr
  Returns:
    If ON_Material::Cast(model_component_ref.ModelComponent()) is not nullptr,
    that pointer is returned.  Otherwise, none_return_value is returned. 
  */
  static const ON_Material* FromModelComponentRef(
    const class ON_ModelComponentReference& model_component_reference,
    const ON_Material* none_return_value
    );

  // compare everything except Index() value.
  static int Compare( 
    const ON_Material& a,
    const ON_Material& b
    );

  // compare Id(), Name(), m_rdk_material_instance_id
  static int CompareNameAndIds( 
    const ON_Material& a,
    const ON_Material& b
    );

  // Compare all settings (color, reflection, texture, plug-in id) 
  // that effect the appearance.
  // Ignore Index(), Id(), Name(), m_rdk_material_instance_id.
  static int CompareAppearance( 
    const ON_Material& a,
    const ON_Material& b
    );

  static int CompareColorAttributes( 
    const ON_Material& a,
    const ON_Material& b
    );

  static int CompareReflectionAttributes( 
    const ON_Material& a,
    const ON_Material& b
    );

  static int CompareTextureAttributes(
    const ON_Material& a,
    const ON_Material& b
  );

  static int CompareTextureAttributesAppearance(
    const ON_Material& a,
    const ON_Material& b
  );



  /*
  Parameters:
    fresnel_index_of_refraction - [in]
      ON_Material::Material::Default.m_fresnel_index_of_refraction 
      is a good default
    N - [in]
      3d surface normal
    R - [in]
      3d reflection direction
  Returns:
    1.0: 
      The input values were not valid or the calculation failed due to 
      a divide by zero or some other numerical arithmetic failure.
    fresnel reflection coefficient
      1/2 * ((g-c)/(g+c))^2 * (1 + ( (c*(g+c) -1)/(c*(g+c) + 1) )^2)
      where
        c = N o (N-R); // c = 3d vector dot product of N and (N-R)
      and
        g = sqrt(fresnel_index_of_refraction*fresnel_index_of_refraction + c*c - 1.0).
  */
  static double FresnelReflectionCoefficient(
    double fresnel_index_of_refraction,
    const double N[3],
    const double R[3]
    );

public:
  ON_Material() ON_NOEXCEPT;
  ON_Material(const ON_Material& src);
  ~ON_Material() = default;
  ON_Material& operator=(const ON_Material& src) = default;

private:
  void Internal_CopyFrom(
    const ON_Material& src
    );

public:
  /////////////////////////////////////////////////////////////////
  // ON_Object overrides
  bool IsValid( class ON_TextLog* text_log = nullptr ) const override;

  void Dump(
    ON_TextLog& text_log
    ) const override;

  bool Write(
    ON_BinaryArchive& archive
    ) const override;

  bool Read(
    ON_BinaryArchive& archive
    ) override;

  ON::object_type ObjectType() const override;
  
  /////////////////////////////////////////////////////////////////
  // Interface 

  ON_Color Ambient() const;
  ON_Color Diffuse() const;
  ON_Color Emission() const;
  ON_Color Specular() const;

  void SetAmbient(  ON_Color );
  void SetDiffuse(  ON_Color );
  void SetEmission( ON_Color );
  void SetSpecular( ON_Color );

  // Shine values are in range 0.0 to ON_Material::MaxShine
  double Shine() const;
  void SetShine( double );         // 0 to ON_Material::MaxShine

  // Transparency values are in range 0.0 = opaque to 1.0 = transparent
  double Transparency() const;
  void SetTransparency( double );  // 0.0 = opaque, 1.0 = transparent

  // Transparency values are in range 0.0 = opaque to 1.0 = transparent
  double Reflectivity() const;
  void SetReflectivity( double );  // 0.0 = opaque, 1.0 = transparent

  // ID of the last plug-in to modify this material
  ON_UUID MaterialPlugInId() const;
  void SetMaterialPlugInId( 
    ON_UUID plugin_id
    );

public:
  /*
  Description:
    Get the RDK material id.
  Returns:
    The RDK material id for this material.
  Remarks:
    The RDK material id identifies a material definition managed by
    the RDK (rendering development kit).  Multiple materials in
    a Rhino or opennurbs model can reference the same RDK material.
  */
  ON_UUID RdkMaterialInstanceId() const;

  /*
  Description:
    Set this material's RDK material id.
  Parameters:
    rdk_material_id - [in]
      RDK material id value.
  Remarks:
    The RDK material id identifies a material definition managed by
    the RDK (rendering development kit).  Multiple materials in
    a Rhino or opennurbs model can reference the same RDK material.
  */
  void SetRdkMaterialInstanceId(
    ON_UUID rdk_material_instance_id
    );

  bool RdkMaterialInstanceIdIsNotNil() const;
  bool RdkMaterialInstanceIdIsNil() const;

  /*
  Returns:
    True if the material can be shared.
  Remarks:
    If true, when an object using this material is copied,
    the copy references the same material.
  */
  bool Shareable() const;
  void SetShareable(
    bool bShareable
    );

  /*
  Returns:
    True if lighting is disabled.
  Remarks:
    True means render this object without
    applying any modulation based on lights.
    Basically, the diffuse, ambient, specular and
    emissive channels get combined additively, clamped,
    and then get treated as an emissive channel.
    Another way to think about it is when
    m_bDisableLighting is true, render the same way
    OpenGL does when ::glDisable( GL_LIGHTING ) is called.
  */
  bool DisableLighting() const;

  void SetDisableLighting(
    bool bDisableLighting
    );
  
  //If m_bUseDiffuseTextureAlphaForObjectTransparencyTexture is true, the alpha channel
  //of the texture in m_textures with m_type=bitmap_texture is used in addition to any
  //textures with m_type=transparency_texture.
  bool UseDiffuseTextureAlphaForObjectTransparencyTexture() const;
  void SetUseDiffuseTextureAlphaForObjectTransparencyTexture(
    bool bUseDiffuseTextureAlphaForObjectTransparencyTexture
    );
  
  //////////////////////////////////////////////////////////////
  //
  // Reflection and Refraction settings
  //

  // The bool m_bFresnelReflections enables fresnel scaling
  // of reflection contributions to the diffuse color.
  // True:
  //   The fresnel term is used to scale the reflection contribution
  //   before addition to the diffuse component.
  // False:
  //   The reflection contribution is simply added to the diffuse component.
  bool FresnelReflections() const;
  void SetFresnelReflections(
    bool bFresnelReflections
    );

  //Returns a color that can be used as a simple preview of the material in GUIs.  This is
  //the function that the layer manager uses to color the little material swatch, for example.
  ON_Color PreviewColor() const;

private:
  // The value of m_rdk_material_id idetifies an RDK (rendering development kit)
  // material. Multiple materials in a Rhino model can refer to the same 
  // RDK material id.  In V5 this value is stored in user data.  In V6 it is
  // saved in the m_rdk_material_id field.
  ON_UUID m_rdk_material_instance_id = ON_nil_uuid;

public:
  ON_Color m_ambient = ON_Color::Black;
  ON_Color m_diffuse = ON_Color::Gray126;
  ON_Color m_emission = ON_Color::Black;
  ON_Color m_specular = ON_Color::White;
  ON_Color m_reflection = ON_Color::White;
  ON_Color m_transparent = ON_Color::White;

private:
  bool m_bShareable = false;

private:
  bool m_bDisableLighting = false;

private:
  bool m_bUseDiffuseTextureAlphaForObjectTransparencyTexture = false;

private:
  bool m_bFresnelReflections = false;

private:
  unsigned int m_reserved1 = 0;

public:
  double m_reflectivity = 0.0; // 0.0 = none, 1.0 = 100%
  double m_shine = 0.0;        // 0.0 = none to GetMaxShine()=maximum
  double m_transparency = 0.0; // 0.0 = opaque to 1.0 = transparent (1.0-alpha)

  /*
  m_reflection_glossiness:
    Default is 0.0. 
    Values from 0.0 to 1.0 make sense.
    - 0.0 reflections are perfectly specular.
    - t > 0.0 permits reflection ray direction to vary
      from the specular direction by up to t*pi/2.
  */
  double m_reflection_glossiness = 0.0;

  /*
  m_refraction_glossiness:
    Default is 0.0. 
    Values from 0.0 to 1.0 make sense.
    - 0.0 refractions are perfectly specular.
    - t > 0.0 permits refraction ray direction to vary
      from the specular direction by up to t*pi/2.
  */
  double m_refraction_glossiness = 0.0;

  /*
  m_index_of_refraction:
    Default is 1.0.
    Physically, the index of refraction is >= 1.0 and is 
    the value (speed of light in vacum)/(speed of light in material).
    Some rendering algorithms set m_index_of_refraction to zero or
    values < 1.0 to generate desirable effects.
  */
  double m_index_of_refraction = 1.0;

  /*
  m_fresnel_index_of_refraction:
    Default is 1.56.
    This is the value ON:Material::FresnelReflectionCoefficient() passes 
    as the first parameter to ON_FresnelReflectionCoefficient().
    - Glass material types can be simulated with 
      m_index_of_refraction ~ 1.56
      m_fresnel_index_of_refraction ~ 1.56
    - Thin glass can be simulated with 
      m_fresnel_index_of_refraction = 1.56
      m_index_of_refraction = 0.0
    - Porcelain type materials can be simulated with 
      m_fresnel_index_of_refraction = 1.56
      m_index_of_refraction = 1.0
      m_transparency = 0.0
  */
  double m_fresnel_index_of_refraction = 1.56;

  /*
  Parameters:
    N - [in]
      3d surface normal
    R - [in]
      3d reflection direction
  Returns:
    If m_bFresnelReflections is false, then 1.0 is returned.
    If m_bFresnelReflections is true, then the value of the fresnel 
    reflection coefficient is returned. In typical rendering applications,
    the reflection term is multiplied by the fresnel reflection coefficient
    before it is added to the diffuse color.
    If any input is not valid or the calculation fails, then 1.0 is returned.
  Remarks:
    When m_bFresnelReflections is true, the calculation is performed by 
    calling ON_FresnelReflectionCoefficient() with m_fresnel_index_of_refraction
    as the fresnel index of refraction.
  */
  double FresnelReflectionCoefficient(
    ON_3dVector N, 
    ON_3dVector R
    ) const;

  /*
  Description:
    Searches for a texure with matching texture_id.
    If more than one texture matches, the first match
    is returned.
  Parameters:
    texture_id - [in]
  Returns:
    >=0 m_textures[] index of matching texture
    -1 if no match is found.
  */
  int FindTexture(
    ON_UUID texture_id
    ) const;

  /*
  Description:
    Searches for a texure with matching filename and type.
    If more than one texture matches, the first match
    is returned.
  Parameters:
    filename - [in]  If nullptr, then any filename matches.
    type - [in] If ON_Texture::no_texture_type, then
                any texture type matches.
    i0 - [in] If i0 is < 0, the search begins at 
              m_textures[0], if i0 >= m_textures.Count(),
              -1 is returnd, otherwise, the search begins
              at m_textures[i0+1].
  Example:
    Iterate through all the the bitmap textures on 
    a material.

          ON_Material& mat = ...;
          int ti = -1;
          int bitmap_texture_count = 0;
          for(;;)
          {
            ti = mat.FindTexture( 
                        nullptr, 
                        ON_Texture::TYPE::bitmap_texture, 
                        ti );

            if ( ti < 0 )
            {
              // no more bitmap textures
              break;
            }

            // we have a bitmap texture
            bitmap_texture_count++;
            const ON_Texture& bitmap_texture = mat.m_textures[ti];
            ...
          }

  Returns:
    >=0 m_textures[] index of matching texture
    -1 if no match is found.
  */
  int FindTexture(
    const wchar_t* filename,
    ON_Texture::TYPE type,
    int i0 = -1
    ) const;

  /*
  Description:
    If there is already a texture with the same file name and
    type, then that texture is modified, otherwise a new texture
    is added.  If tx has user data, the user data is copied
    to the m_textures[] element.
  Parameters:
    tx - [in]
  Returns:
    Index of the added texture in the m_textures[] array.
  Remarks:
    This is intended to be a quick and simple way to add
    textures to the material.  If you need to do something
    different, then just work on the m_textures[] array.
  */
  int AddTexture( 
    const ON_Texture& tx
    );

  /*
  Description:
    If there is a texture with a matching type, that texture's
    filename is modified, otherwise a new texture is added.    
  Parameters:
    filename - [in] new filename
    type - [in]
  Returns:
    Index of the added texture in the m_textures[] array.
  Remarks:
    This is intended to be a quick and simple way to add
    textures to the material.  If you need to do something
    different, then just work on the m_textures[] array.
  */
  int AddTexture(
    const wchar_t* filename,
    ON_Texture::TYPE type 
    );

  /*
  Description:
    Deletes all texures with matching filenames and types.
  Parameters:
    filename - [in]  If nullptr, then any filename matches.
    type - [in] If ON_Texture::no_texture_type, then
                any texture type matches.
  Returns:
    Number of textures deleted.
  */
  int DeleteTexture(
    const wchar_t* filename,
    ON_Texture::TYPE type 
    );

  ON_ObjectArray<ON_Texture> m_textures;

  /*
  Description:
    Used to provide per face material support. 
    The parent object reference a basic material. 
    When a brep face or mesh facet wants to use
    a material besides the base material, it specifies
    a channelSupports material channel.  The default
    material channel is 0 and that indicates the base
    material.  A channel of n > 0 means that face
    used the material with id m_material_channel[n-1].
    If (n-1) >= m_material_channel.Count(), then the base
    material is used.  The value of 
    m_material_channel[n].m_id is persistent.  The
    value of m_material_channel[n].m_i is a runtime
    index in the CRhinoDoc::m_material_table[].  If 
    CRhinoDoc::m_material_table[m_i].m_uuid != m_id,
    then m_id is assumed to be correct.
  */
  ON_SimpleArray<ON_UuidIndex> m_material_channel;
  
private:
  ON_UUID m_plugin_id = ON_nil_uuid; 

private:
  bool Internal_ReadV3( ON_BinaryArchive& archive, int minor_version );
  bool Internal_WriteV3( ON_BinaryArchive& archive ) const;
  bool Internal_ReadV5( ON_BinaryArchive& archive );
  bool Internal_WriteV5( ON_BinaryArchive& archive ) const;
};

ON_DECL
bool operator==(const ON_Material&, const ON_Material&);

ON_DECL
bool operator!=(const ON_Material&, const ON_Material&);

#if defined(ON_DLL_TEMPLATE)
ON_DLL_TEMPLATE template class ON_CLASS ON_SimpleArray<ON_Material*>;
ON_DLL_TEMPLATE template class ON_CLASS ON_SimpleArray<const ON_Material*>;
ON_DLL_TEMPLATE template class ON_CLASS ON_ObjectArray<ON_Material>;

// NO! // ON_DLL_TEMPLATE template class ON_CLASS ON_ClassArray<ON_Material>;
//  It is a serious error to have an ON_ClassArray<ON_Material> and crashes 
//  will occur when user data back pointers are not updated.
#endif

#endif

