Color(float v): r(v), g(v), b(v), a(1) { }
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(float v): r(v), g(v), b(v), a(1) { }
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_) { }