go-opengl-pixel/sprite.go

112 lines
2.6 KiB
Go

package pixel
import "image/color"
// Sprite is a drawable Picture. It's anchored by the center of it's Picture.
//
// To achieve different anchoring, transformations and color masking, use SetMatrix and SetColorMask
// methods.
type Sprite struct {
tri *TrianglesData
bounds Rect
d Drawer
matrix Matrix
mask NRGBA
}
// 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.matrix = IM
s.mask = NRGBA{1, 1, 1, 1}
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()
s.calcData()
}
// Picture returns the current Sprite's Picture.
func (s *Sprite) Picture() Picture {
return s.d.Picture
}
// SetMatrix sets a Matrix that this Sprite will be transformed by. This overrides any previously
// set Matrix.
//
// Note, that this has nothing to do with BasicTarget's SetMatrix method. This only affects this
// Sprite and is usable with any Target.
func (s *Sprite) SetMatrix(matrix Matrix) {
s.matrix = matrix
s.calcData()
}
// Matrix returns the currently set Matrix.
func (s *Sprite) Matrix() Matrix {
return s.matrix
}
// SetColorMask sets a color that this Sprite will be multiplied by. This overrides any previously
// set color mask.
//
// Note, that this has nothing to do with BasicTarget's SetColorMask method. This only affects this
// Sprite and is usable with any Target.
func (s *Sprite) SetColorMask(mask color.Color) {
s.mask = ToNRGBA(mask)
s.calcData()
}
// ColorMask returns the currently set color mask.
func (s *Sprite) ColorMask() NRGBA {
return s.mask
}
// Draw draws the Sprite onto the provided Target.
func (s *Sprite) Draw(t Target) {
s.d.Draw(t)
}
func (s *Sprite) calcData() {
var (
center = s.bounds.Center()
horizontal = X(s.bounds.W() / 2)
vertical = Y(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 = s.mask
(*s.tri)[i].Picture = center + (*s.tri)[i].Position
(*s.tri)[i].Intensity = 1
}
// matrix and mask
for i := range *s.tri {
(*s.tri)[i].Position = s.matrix.Project((*s.tri)[i].Position)
(*s.tri)[i].Color = s.mask
}
s.d.Dirty()
}