BlinnBRDF.h

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/* $Id: BlinnBRDF.h,v 1.1 2002/12/05 15:02:18 cvs Exp $ */

#ifndef __BLINN_BRDF_H
#define __BLINN_BRDF_H

#include <esg/Definitions.h>
#include <esg/visitor/MatVisitor.h>
#include <esg/brdf/SpecularBRDF.h>
#include <esg/brdf/PhongBRDF.h>

namespace esg {
    
class OGSCENE_EXPORT BlinnBRDF : public SpecularBRDF {
protected:
        virtual void _duplicate_attributes (const BRDF& src) {
            SpecularBRDF::_duplicate_attributes(src);
        }
    
public:
        BlinnBRDF (void) : SpecularBRDF(true) {}

        
        virtual RetVal reflectance(const MatVisitor& visitor,
                                   const Vector3*    L,
                                   const Vector3*    V,
                                   const Vector3*    N,
                                   Vector3&          color) {
            static Vector3 H;
            if (!N || !L || !V) return BAD_PARAMS;
            register double nl = N->dot(*L);
            if (nl <= 0.0) return NL_NEGATIVE;
            register double lv = L->dot(*V);
            if (lv > 0.0) return ZERO_CONTRIB;
            H.set(*L);
            H.add(*V);
            register double hn = H.dot(*N); // H is not normalized
            if (hn < 0.0) return NL_OR_NV_NEGATIVE;
            color.set(visitor.specular());
            color.scale(pow(hn / sqrt(2. * lv + 2.),(double)visitor.intRoughness()) / nl);
            return NONZERO_CONTRIB;
        }
        
        virtual RetVal reflectanceVNL(const MatVisitor& visitor,
                                      const Vector3*    L,
                                      const Vector3*    V,
                                      const Vector3*    N,
                                      double            NV,
                                      double            NL,
                                      Vector3&          color) {
            static Vector3 H;
            if (!N || !L || !V) return BAD_PARAMS;
            H.set(*L);
            H.add(*V);
            register double hn = H.dot(*N); // H is not normalized
            if (hn < 0.0) return NL_OR_NV_NEGATIVE;
            color.set(visitor.specular());
            color.scale(pow(hn/sqrt(2.*L->dot(*V)+2.),(double)visitor.intRoughness()) / NL);
            return NONZERO_CONTRIB;
        }
        
        virtual RetVal reflectanceNL(const MatVisitor& visitor,
                                     const Vector3*    L,
                                     const Vector3*    V,
                                     const Vector3*    N,
                                     double            NL,
                                     Vector3&          color) {
            static Vector3 H;
            if (!N || !L || !V) return BAD_PARAMS;
            H.set(*L);
            H.add(*V);
            register double hn = H.dot(*N); // H is not normalized
            if (hn < 0.0) return NL_OR_NV_NEGATIVE;
            color.set(visitor.specular());
            color.scale(pow(hn/sqrt(2.*L->dot(*V)+2.),(double)visitor.intRoughness()) / NL);
            return NONZERO_CONTRIB;
        }
        
        virtual BRDF* clone (void) const { return new BlinnBRDF(); }

        virtual double albedo (const MatVisitor& visitor,
                               const Vector3&    N,
                               const Vector3*    V) const {
            PhongBRDF aux;
            return aux.albedo(visitor, N, V); // TO DO!
        }
        
        virtual void importanceSample(const MatVisitor& visitor,
                                      const Vector3&    D,
                                      double            r1,
                                      double            r2,
                                      Vector3&          dir,
                                      double*           pPDFVal) {
            // TO DO!
            PhongBRDF aux;
            aux.importanceSample(visitor, D, r1, r2, dir, pPDFVal);
        }

        virtual Vector2 dir2uv (const MatVisitor& visitor,
                                const Vector3&    N,
                                const Vector3&    D) const {
            // TO DO!
            PhongBRDF aux;
            aux.dir2uv(visitor, N, D);
        }
};

}; // namespace

#endif // __BLINN_BRDF_H

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