Lighting.h

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#ifndef LIGHTING_H_
#define LIGHTING_H_

#include "Vector.h"
#include "Color.h"

class Lighting {
public:
        Lighting(Vector<> l = Vector<>(0,-1,-1).normalize(), const Vector<>& v = Vector<>(0,0,1), Color lightColor = Color(255,255,255,255),
                                float kD = 0.5, float kS = 1.0, float sE = 10);
        ~Lighting();
        
        void updateH();
        
        void setV(const Vector<>& v);
        void setL(const Vector<>& l);

        void setKDiffuse(float newKD);
        float getKDiffuse() const;
        
        void setKSpecular(float newKS);
        float getKSpecular() const;

        void setSExponent(float newSE);
        float getSExponent() const;
        
        Color getColor(const Color& c, const Vector<>& n) const{//alpha is c.A() !
                int R,G,B;
                float cosAlphaDiff = n.dotProduct(mL);
                if (cosAlphaDiff < 0) cosAlphaDiff = 0; 
                
                float specularCoeff = n.dotProduct (mH);
                if (specularCoeff < 0) specularCoeff=0;
                else specularCoeff = pow(specularCoeff, mSE);


                R = (int) (c.R() * mKD * cosAlphaDiff + mLightColor.R() * mKS * specularCoeff);
                G = (int) (c.G() * mKD * cosAlphaDiff + mLightColor.G() * mKS * specularCoeff);
                B = (int) (c.B() * mKD * cosAlphaDiff + mLightColor.B() * mKS * specularCoeff);
                
                if (R < 0) R = 0;
                else if (R > Color::maxChannelValue) R = Color::maxChannelValue;

                if (G < 0) G = 0;
                else if (G > Color::maxChannelValue) G = Color::maxChannelValue;

                if (B < 0) B = 0;
                else if (B > Color::maxChannelValue) B = Color::maxChannelValue;

                return Color(R, G, B, c.A());
        }
        
        void printVectors() const{
                printf("mL: (%f,%f,%f)\n",mL.x(),mL.y(),mL.z());
                printf("mV: (%f,%f,%f)\n",mV.x(),mV.y(),mV.z());
                printf("mH: (%f,%f,%f)\n\n",mH.x(),mH.y(),mH.z());
        }


private:
        Vector<> mL;    //normalized vector in direction of light source
        Vector<> mV;    //View-Vector normalized vector in direction of observer
        Vector<> mH;    //Half-Vector of Phong-Blinn lighting model... mH = mV * mL; mH.normalize()

        Color mLightColor;

//      float ka;       //ambient reflection coefficient        //not used... due to performance issues
        float mKD;      //diffuse reflection coefficient
        float mKS;      //specular reflection coefficient
        float mSE;      //specular Exponent

};

#endif

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