func (c *RGBA) SetColors(r, g, b, a float64) {
	c.rgba.red = C.gdouble(r)
	c.rgba.green = C.gdouble(g)
	c.rgba.blue = C.gdouble(b)
	c.rgba.alpha = C.gdouble(a)
}
func (c *RGBA) SetColors(r, g, b, a float64) {
	c.rgba.red = C.gdouble(r)
	c.rgba.green = C.gdouble(g)
	c.rgba.blue = C.gdouble(b)
	c.rgba.alpha = C.gdouble(a)
}
// SetColors sets all colors values in the RGBA.