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c++raytracingradiance

weird direct illumination in custom problem

I am currently implementing a custom ray tracing renderer and I am stick with problem of direct illumination Here my result :

normalOnLight enter image description here

sphereNormal enter image description here

max(normalOnLight.dot(sphereNormal), 0.0) enter image description here

I do not understand the last result, i think the first and the second are right but not the last (the dot..) the light is a point light.

    const Vec4<double> LambertianSampler::radiance(const Ray& ray, const Scene& scene) const
  {
     Context ctx;
     ctx.setCamtoWorld(scene.getCamera()->getLookAt());
     Vec4<double> maxColor(1.0, 1.0, 1.0, 1.0);
     Vec4<double> ambient(0.4, 0.4, 0.4, 1.0);

     Vec4<double> finaleRadiance = ambient;
     for(const auto & light : scene.getLights())
     {
       for(const auto & shape : scene.getShapes())
       {
          shape->intersect(ray, ctx);
       }

      if(ctx.intersectionFound())
      {
      Vec3<double> lightPosition = light->getPos();
      Vec4<double> lightColor    = light->getRadiance();
      Vec3<double> lightNormal   = ctx.getPoint() - lightPosition;
      lightNormal = Vec3<double>(std::fabs(lightNormal.x()), std::fabs(lightNormal.y()), std::fabs(lightNormal.z()));
      lightNormal.normalize();

      Vec3<double> sphereNormal = ctx.getNormal();
      sphereNormal   = Vec3<double>(std::fabs(sphereNormal.x()), std::fabs(sphereNormal.y()), std::fabs(sphereNormal.z())) ;
      sphereNormal.normalize();

      double dot     = lightNormal.dot(sphereNormal);
      finaleRadiance = maxColor*std::max(0.0,dot);
      finaleRadiance = Vec4<double>(finaleRadiance.x(), finaleRadiance.y(), finaleRadiance.z(), 1.0);

      //finaleRadiance = Vec4<double>(sphereNormal.x(), sphereNormal.y(), sphereNormal.z(), 1.0);
      //finaleRadiance = Vec4<double>(lightNormal.x(), lightNormal.y(), lightNormal.z(), 1.0);

    }
  }
  return finaleRadiance;
}

Do my dot result is right ? because i think my lightNormalOnSphere and sphereNormal are right i think ..

Solution

  • I fix my problem by remplace the :

    lightNormal = Vec3<double>(std::fabs(lightNormal.x()), std::fabs(lightNormal.y()), std::fabs(lightNormal.z()));

    by 

    lightNormal = Vec3<double>((lightNormal.x()+1)*0.5, (lightNormal.y()+1)*0.5, (lightNormal.z()+1)*0.5);