123 lines
2.9 KiB
Go
123 lines
2.9 KiB
Go
package pixel
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import "image/color"
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// Sprite is a drawable frame of a Picture. It's anchored by the center of it's Picture's frame.
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//
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// Frame specifies a rectangular portion of the Picture that will be drawn. For example, this
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// creates a Sprite that draws the whole Picture:
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//
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// sprite := pixel.NewSprite(pic, pic.Bounds())
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//
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// To achieve different anchoring, transformations and color masking, use SetMatrix and SetColorMask
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// methods.
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type Sprite struct {
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tri *TrianglesData
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frame Rect
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d Drawer
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matrix Matrix
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mask RGBA
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}
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// NewSprite creates a Sprite from the supplied frame of a Picture.
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func NewSprite(pic Picture, frame Rect) *Sprite {
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tri := MakeTrianglesData(6)
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s := &Sprite{
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tri: tri,
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d: Drawer{Triangles: tri},
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}
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s.matrix = IM
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s.mask = Alpha(1)
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s.Set(pic, frame)
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return s
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}
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// Set sets a new frame of a Picture for this Sprite.
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func (s *Sprite) Set(pic Picture, frame Rect) {
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s.d.Picture = pic
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if frame != s.frame {
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s.frame = frame
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s.calcData()
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}
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}
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// Picture returns the current Sprite's Picture.
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func (s *Sprite) Picture() Picture {
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return s.d.Picture
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}
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// Frame returns the current Sprite's frame.
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func (s *Sprite) Frame() Rect {
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return s.frame
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}
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// SetMatrix sets a Matrix that this Sprite will be transformed by. This overrides any previously
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// set Matrix.
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//
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// Note, that this has nothing to do with BasicTarget's SetMatrix method. This only affects this
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// Sprite and is usable with any Target.
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func (s *Sprite) SetMatrix(matrix Matrix) {
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if s.matrix != matrix {
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s.matrix = matrix
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s.calcData()
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}
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}
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// Matrix returns the currently set Matrix.
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func (s *Sprite) Matrix() Matrix {
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return s.matrix
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}
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// SetColorMask sets a color that this Sprite will be multiplied by. This overrides any previously
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// set color mask.
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//
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// Note, that this has nothing to do with BasicTarget's SetColorMask method. This only affects this
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// Sprite and is usable with any Target.
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func (s *Sprite) SetColorMask(mask color.Color) {
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rgba := ToRGBA(mask)
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if s.mask != rgba {
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s.mask = ToRGBA(mask)
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s.calcData()
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}
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}
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// ColorMask returns the currently set color mask.
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func (s *Sprite) ColorMask() RGBA {
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return s.mask
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}
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// Draw draws the Sprite onto the provided Target.
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func (s *Sprite) Draw(t Target) {
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s.d.Draw(t)
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}
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func (s *Sprite) calcData() {
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var (
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center = s.frame.Center()
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horizontal = X(s.frame.W() / 2)
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vertical = Y(s.frame.H() / 2)
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)
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(*s.tri)[0].Position = -horizontal - vertical
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(*s.tri)[1].Position = +horizontal - vertical
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(*s.tri)[2].Position = +horizontal + vertical
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(*s.tri)[3].Position = -horizontal - vertical
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(*s.tri)[4].Position = +horizontal + vertical
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(*s.tri)[5].Position = -horizontal + vertical
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for i := range *s.tri {
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(*s.tri)[i].Color = s.mask
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(*s.tri)[i].Picture = center + (*s.tri)[i].Position
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(*s.tri)[i].Intensity = 1
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}
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// matrix and mask
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for i := range *s.tri {
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(*s.tri)[i].Position = s.matrix.Project((*s.tri)[i].Position)
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(*s.tri)[i].Color = s.mask
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}
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s.d.Dirty()
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}
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