Color(float r_, float g_, float b_): r(r_), g(g_), b(b_), a(1) { }
Color(float r_, float g_, float b_, float a_): r(r_), g(g_), b(b_), a(a_) { }
Color operator*(float f) const { return Color(r*f, g*f, b*f, a); }
Color(float r_, float g_, float b_): r(r_), g(g_), b(b_), a(1) { }
Color(float r_, float g_, float b_, float a_): r(r_), g(g_), b(b_), a(a_) { }
Color operator*(float f) const { return Color(r*f, g*f, b*f, a); }