cloudy-raytracer/shader/shader.h

#ifndef SHADER_H
#define SHADER_H

#include "common/color.h"
#include "common/ray.h"

// Forward declarations
class Scene;

class Shader
{
public:
    // Constructor / Desctructor
    Shader() = default;

    virtual ~Shader() = default;

    // Get
    virtual bool isTransparent() const
    { return false; }

    /**
     * Especially used for lighting calculations.
     * @brief Returns the light let through the shader in opposite direction of the given ray.
     * @param ray Origin and direction of the desired path.
     * @return 0 if the shader is opaque, 1 if the shader is transparent, for each color channel.
     */
    virtual Color transparency(Scene const &scene, Ray const &ray) const
    { return isTransparent() ? Color(1, 1, 1) : Color(0, 0, 0); }

    // Shader functions
    virtual Color shade(Scene const &scene, Ray const &ray) const = 0;
};

#endif