//
// Computergraphik II
// Prof. Dr. Juergen Doellner
// Wintersemester 2001/2002
// 
// Rahmenprogramm fuer Aufgabenzettel 3
//
// Autoren: Florian Kirsch (kirsch@hpi.uni-potsdam.de)
//          Marc Nienhaus (nienhaus@hpi.uni-potsdam.de)
//          Juergen Doellner (doellner@hpi.uni-potsdam.de)
//

#ifndef CG_COLOR_H
#define CG_COLOR_H

#include <iostream.h>

class Color {
public:
    Color(double grey=0);
    Color(double red, double green, double blue, double alpha = 1.0);
        /* A color is specified by the red, green, and blue coefficients
          and the alpha (e.g., transmission) coefficient. All coefficients
          are clamped to the double interval [0.0, 1.0]. */

    bool operator==(const Color&) const;
    bool operator!=(const Color&) const;

    Color operator+(const Color& col) const;
    Color operator-(const Color& col) const;
    Color operator*(double coef) const;
        /* These operators transform the red, green, and blue components.
          They do *not* apply to the alpha value. The result of each
          operation is clamped to [0.0, 1.0]. */

    double operator[](int i) const;
    double& operator[](int i);
        /* The four components are indexed by R=[0], G=[1], B=[2], and A=[3].
          The index is checked for out of range errors. */

    static Color hsv(double hue, double saturation, double value, double alpha=1.0);
    double hue() const;
    double saturation() const;
    double value() const;
        /* Provide the conversion between the RGB and HSV color models.
          `hsv' can specify achromatic (gray-scale) colors by
          setting `s' to 0.0 and `v' to the gray coefficient between [0,1].
          The `hue' factor must be specified in degrees in the range [-360,360].
          If hue is smaller 0, 360 degrees are added before the conversion
          is invoked.
          Both saturation and value must be in the range [0,1]. */

	static Color InterpolateRGB(const Color& from, const Color& to, double dPercentage);
	static Color InterpolateHSV(const Color& from, const Color& to, double dPercentage, bool bClockwise = true);

    friend ostream& operator<<(ostream&, const Color&);
    friend istream& operator>>(istream&, Color&);

private:
    double rgba_[4];
};

#endif // CG_COLOR_H