src/PointLight.h

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#ifndef POINTLIGHT_H
#define POINTLIGHT_H

#include "Light.h"


class PointLight : public Light
{
public:
    PointLight( const RGBAColor &   intensity,
                const Vec3f &       position )
        : Light(),
            mPosition(position),
            mIntensity(intensity)
    {
    }

    void setNumberOfRays(unsigned int) {}

    RGBAColor illuminate(Vec3f & dir, const Vec3f & org, unsigned int /*index = 0*/) const
    {
        // ray points towards point light position from the surface
        Ray ray;
        dir = mPosition - org;
        float length = dir.length() - EPSILON;
        dir.normalize();
        ray.init(org, dir, length);

        // check for occlusion
        if (mScene->castShadows() && mScene->intersect(ray) && ray.hit()->castShadows() && ray.t() > EPSILON)
            return RGBAColor(0, 0, 0, 1);

        // compute linear attenuation
        // see http://www.gamasutra.com/features/20050729/lacroix_01.shtml
        float att = 1.0f / (length * length); // linear attenuation
        return RGBAColor(att * mIntensity.rgb());
    }
    
private:
    Vec3f       mPosition;

    RGBAColor   mIntensity;
};

#endif

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