/*
 * This program source code file is part of KiCad, a free EDA CAD application.
 *
 * Copyright (C) 2015-2016 Mario Luzeiro <mrluzeiro@ua.pt>
 * Copyright (C) 1992-2016 KiCad Developers, see AUTHORS.txt for contributors.
 *
 * This program 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.
 *
 * 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, you may find one here:
 * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
 * or you may search the http://www.gnu.org website for the version 2 license,
 * or you may write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
 */

/**
 * @file  cmaterial.h
 * @brief
 */

#ifndef _CMATERIAL_H_
#define _CMATERIAL_H_

#include "ray.h"
#include "hitinfo.h"


/// A base material class that can be used to derive a material implementation
class  CMATERIAL
{
public:
    CMATERIAL();
    CMATERIAL( const SFVEC3F &aAmbient,
               const SFVEC3F &aEmissive,
               const SFVEC3F &aSpecular,
               float aShinness,
               float aTransparency,
               float aReflection );

    const SFVEC3F &GetAmbientColor()  const { return m_ambientColor; }
    const SFVEC3F &GetEmissiveColor() const { return m_emissiveColor; }
    const SFVEC3F &GetSpecularColor() const { return m_specularColor; }

    float GetShinness()     const { return m_shinness; }
    float GetTransparency() const { return m_transparency; }
    float GetReflection()   const { return m_reflection; }

    /**
     * @brief SetCastShadows - Set if the material can receive shadows
     * @param aCastShadows - true yes it can, false not it cannot
     */
    void SetCastShadows( bool aCastShadows ) { m_cast_shadows = aCastShadows; }

    bool GetCastShadows() const { return m_cast_shadows; }

    /**
     * @brief Shade - Shades an intersection point
     * @param aRay: the camera ray that hits the object
     * @param aHitInfo: the hit information
     * @param NdotL: the dot product between Normal and Light
     * @param aDiffuseObjColor: diffuse object color
     * @param aDirToLight: a vector of the incident light direction
     * @param aLightColor: the light color
     * @param aShadowAttenuationFactor 0.0f total in shadow, 1.0f completely not in shadow
     * @return the resultant color
     */
    virtual SFVEC3F Shade( const RAY &aRay,
                           const HITINFO &aHitInfo,
                           float NdotL,
                           const SFVEC3F &aDiffuseObjColor,
                           const SFVEC3F &aDirToLight,
                           const SFVEC3F &aLightColor,
                           float aShadowAttenuationFactor ) const = 0;

protected:
    SFVEC3F m_ambientColor;

    // NOTE: we will not use diffuse color material here,
    // because it will be stored in object, since there are objects (i.e: triangles)
    // that can have per vertex color

    SFVEC3F m_emissiveColor;
    SFVEC3F m_specularColor;
    float   m_shinness;
    float   m_transparency;     ///< 1.0 is completely transparent, 0.0 completely opaque
    float   m_reflection;       ///< 1.0 completely reflective, 0.0 no reflective
    bool    m_cast_shadows;     ///< true if this object will block the light
};


/// Blinn Phong based material
/// https://en.wikipedia.org/wiki/Blinn%E2%80%93Phong_shading_model
class  CBLINN_PHONG_MATERIAL : public CMATERIAL
{
public:
    CBLINN_PHONG_MATERIAL() : CMATERIAL() {}

    CBLINN_PHONG_MATERIAL( const SFVEC3F &aAmbient,
                           const SFVEC3F &aEmissive,
                           const SFVEC3F &aSpecular,
                           float aShinness,
                           float aTransparency,
                           float aReflection ) : CMATERIAL( aAmbient,
                                                            aEmissive,
                                                            aSpecular,
                                                            aShinness,
                                                            aTransparency,
                                                            aReflection ) {}

    // Imported from CMATERIAL
    SFVEC3F Shade( const RAY &aRay,
                   const HITINFO &aHitInfo,
                   float NdotL,
                   const SFVEC3F &aDiffuseObjColor,
                   const SFVEC3F &aDirToLight,
                   const SFVEC3F &aLightColor,
                   float aShadowAttenuationFactor ) const;
};

#endif // _CMATERIAL_H_