#ifndef __LIGHTS
#define __LIGHTS

interface Light {
    float3 illuminate(float3 p, out float3 L);
};

struct PointLight : Light {
    float3 Plight, Clight;
    float3 illuminate(float3 P, out float3 L) {
        L = normalize(Plight - P);
        return Clight;
    }
};

struct SpotLight : Light {
    float3 Plight, Clight, target;
    float3 illuminate(float3 P, out float3 L) {
        L = normalize(Plight - P);
        float3 shine = normalize(Plight - target);
        float costheta = dot(L, shine);
        return Clight * smoothstep(0.98, 1., costheta);
    }
};




#endif