LambertianMaterial.cc

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#include "LambertianMaterial.h"
#include "HitRecord.h"
#include "Light.h"
#include "Point.h"
#include "Primitive.h"
#include "Ray.h"
#include "RenderContext.h"
#include "Scene.h"
#include "Vector.h"
#include "Math.h"
using namespace std;

LambertianMaterial::LambertianMaterial(const Color& color, float Kd, float Ka)
    :color(color), Kd(Kd), Ka(Ka)
{
}

LambertianMaterial::~LambertianMaterial()
{
}

void LambertianMaterial::shade(Color& result, const RenderContext& context,
                               const Ray& ray, const HitRecord& hit, const Color&, int) const
{
    const Scene* scene = context.getScene();
    const vector<Light*>& lights = scene->getLights();
    Point hitpos = ray.origin()+ray.direction()*hit.minT();
    Vector normal;
    hit.getPrimitive()->normal(normal, context, hitpos, ray, hit);
    double costheta = Dot(normal, ray.direction());
    if(costheta > 0)
        normal = -normal;

    const Object* world = scene->getObject();

    Color light = scene->getAmbient()*Ka;

#if 0
    for(vector<Light*>::const_iterator iter = lights.begin(); iter != lights.end(); iter++){
#else
        Light * const * begin = &lights[0];
        Light*const* end = &lights[0]+lights.size();
        while(begin != end){
#endif
            Color light_color;
            Vector light_direction;
            double dist = (*begin++)->getLight(light_color, light_direction, context, hitpos);

            Vector unit_dir = light_direction;
            unit_dir.normalize();
            double cosphi = Dot(normal, light_direction);
            if(cosphi > 0){
                // Cast shadow rays...
#if 0
                HitRecord shadowhit(dist);
                Point new_origin = hitpos + light_direction * 1e-3;
                Ray shadowray(new_origin, light_direction);
#else
                HitRecord shadowhit(dist, 1e-5);
                Ray shadowray(hitpos, light_direction);
#endif
                world->intersect(shadowhit, context, shadowray);
                if(!shadowhit.getPrimitive())
                    // No shadows...
                    light += light_color*(Kd*cosphi);
            }
        }
        result = light*color;
    }

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