57 lines
1.4 KiB
Go
57 lines
1.4 KiB
Go
package engine
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import "github.com/hajimehoshi/ebiten/v2"
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var _ interface {
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Drawer
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DrawManager
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Scanner
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} = &DrawDFS{}
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// DrawDFS is a DrawLayer that does not add any structure. Components are
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// drawn in the order in which they are encountered by a depth-first search
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// through the game tree, without any extra sorting based on Z values or
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// consideration for DrawOrderer).
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type DrawDFS struct {
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Components []interface{}
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Hides
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}
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func (d *DrawDFS) Draw(screen *ebiten.Image, opts *ebiten.DrawImageOptions) {
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if d.Hidden() {
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return
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}
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for _, component := range d.Components {
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d.draw(component, screen, *opts)
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}
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}
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// exists to satisfy interface
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func (DrawDFS) ManagesDrawingSubcomponents() {}
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func (d *DrawDFS) draw(component interface{}, screen *ebiten.Image, opts ebiten.DrawImageOptions) {
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// Hidden? stop drawing
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if h, ok := component.(Hider); ok && h.Hidden() {
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return
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}
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// Has a transform? apply to opts
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if tf, ok := component.(Transformer); ok {
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opts = concatOpts(tf.Transform(), opts)
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}
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// Does it draw itself? Draw
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if dr, ok := component.(Drawer); ok {
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dr.Draw(screen, &opts)
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}
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// Is it a DrawManager? return early (don't recurse)
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if _, ok := component.(DrawManager); ok {
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return
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}
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// Has subcomponents? recurse
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if sc, ok := component.(Scanner); ok {
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for _, ch := range sc.Scan() {
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d.draw(ch, screen, opts)
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}
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}
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}
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func (d *DrawDFS) Scan() []interface{} { return d.Components }
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