go-opengl-pixel/graphics.go

62 lines
1.4 KiB
Go

package pixel
// Sprite is a drawable Picture. It's always anchored by the center of it's Picture.
type Sprite struct {
tri *TrianglesData
bounds Rect
d Drawer
}
// NewSprite creates a Sprite from the supplied Picture.
func NewSprite(pic Picture) *Sprite {
tri := MakeTrianglesData(6)
s := &Sprite{
tri: tri,
d: Drawer{Triangles: tri},
}
s.SetPicture(pic)
return s
}
// SetPicture changes the Sprite's Picture. The new Picture may have a different size, everything
// works.
func (s *Sprite) SetPicture(pic Picture) {
s.d.Picture = pic
if s.bounds == pic.Bounds() {
return
}
s.bounds = pic.Bounds()
var (
center = s.bounds.Center()
horizontal = V(s.bounds.W()/2, 0)
vertical = V(0, s.bounds.H()/2)
)
(*s.tri)[0].Position = -horizontal - vertical
(*s.tri)[1].Position = +horizontal - vertical
(*s.tri)[2].Position = +horizontal + vertical
(*s.tri)[3].Position = -horizontal - vertical
(*s.tri)[4].Position = +horizontal + vertical
(*s.tri)[5].Position = -horizontal + vertical
for i := range *s.tri {
(*s.tri)[i].Color = NRGBA{1, 1, 1, 1}
(*s.tri)[i].Picture = center + (*s.tri)[i].Position
(*s.tri)[i].Intensity = 1
}
s.d.Dirty()
}
// Picture returns the current Sprite's Picture.
func (s *Sprite) Picture() Picture {
return s.d.Picture
}
// Draw draws the Sprite onto the provided Target.
func (s *Sprite) Draw(t Target) {
s.d.Draw(t)
}