func (f *Framebuffer) Fill(c *opengl.Context, clr color.Color) error {
if err := f.setAsViewport(c); err != nil {
return err
}
cr, cg, cb, ca := clr.RGBA()
const max = math.MaxUint16
r := float64(cr) / max
g := float64(cg) / max
b := float64(cb) / max
a := float64(ca) / max
return c.FillFramebuffer(r, g, b, a)
}