You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: sprite.go
    path of file: ./repos/pixel
    
    the code of the file until where you have to start completion: package pixel

import "image/color"

// Sprite is a drawable frame of a Picture. It's anchored by the center of it's Picture's frame.
//
// Frame specifies a rectangular portion of the Picture that will be drawn. For example, this
// creates a Sprite that draws the whole Picture:
//
//   sprite := pixel.NewSprite(pic, pic.Bounds())
//
// Note, that Sprite caches the results of MakePicture from Targets it's drawn to for each Picture
// it's set to. What it means is that using a Sprite with an unboun
    
func (s *Sprite) calcData() {
	var (
		center     = s.frame.Center()
		horizontal = V(s.frame.W()/2, 0)
		vertical   = V(0, s.frame.H()/2)
	)

	(*s.tri)[0].Position = Vec{}.Sub(horizontal).Sub(vertical)
	(*s.tri)[1].Position = Vec{}.Add(horizontal).Sub(vertical)
	(*s.tri)[2].Position = Vec{}.Add(horizontal).Add(vertical)
	(*s.tri)[3].Position = Vec{}.Sub(horizontal).Sub(vertical)
	(*s.tri)[4].Position = Vec{}.Add(horizontal).Add(vertical)
	(*s.tri)[5].Position = Vec{}.Sub(horizontal).Add(vertical)

	for i := range *s.tri {
		(*s.tri)[i].Color = s.mask
		(*s.tri)[i].Picture = center.Add((*s.tri)[i].Position)
		(*s.tri)[i].Intensity = 1
		(*s.tri)[i].Position = s.matrix.Project((*s.tri)[i].Position)
	}

	s.d.Dirty()
}