105 lines
2.7 KiB
Go
105 lines
2.7 KiB
Go
package engine
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import (
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"image"
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"io/fs"
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"github.com/hajimehoshi/ebiten/v2"
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)
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// Bounder components have a bounding rectangle.
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type Bounder interface {
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BoundingRect() image.Rectangle
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}
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// Collider components have tangible form.
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type Collider interface {
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CollidesWith(image.Rectangle) bool
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}
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// Drawer components can draw themselves. Draw is called often.
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// Each component is responsible for calling Draw on its child components
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// (so that hiding the parent can hide the children, etc).
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type Drawer interface {
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Draw(screen *ebiten.Image, opts ebiten.DrawImageOptions)
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}
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// DrawOrderer components can provide a number for determining draw order.
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type DrawOrderer interface {
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DrawOrder() float64
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}
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// DrawUpdater components can be both drawn and updated.
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// Same comments as for Drawer and Updater.
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type DrawUpdater interface {
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Drawer
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Updater
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}
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// Hider components can be hidden.
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type Hider interface {
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IsHidden() bool
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Hide()
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Show()
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}
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// Identifier components have a sense of self. This makes it easier for
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// components to find and interact with one another.
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type Identifier interface {
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Ident() string
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}
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// Loader components get the chance to load themselves. This happens
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// before preparation.
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type Loader interface {
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Load(fs.FS) error
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}
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// ParallaxScaler components have a scaling factor. This is used for
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// parallax layers in a scene, and can be thought of as 1/distance.
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type ParallaxScaler interface {
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ParallaxFactor() float64
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}
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// Prepper components can be prepared. It is called after the component
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// database has been populated but before the game is run. The component can
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// store the reference to game, if needed, and also query the component database.
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type Prepper interface {
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Prepare(game *Game)
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}
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// Scanner components can be scanned. It is called when the game tree is walked
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// (such as when the game component database is constructed).
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// Scan should return a slice containing all immediate subcomponents.
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type Scanner interface {
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Scan() []interface{}
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}
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// Scener components are a scene (Scene or SceneRef).
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type Scener interface {
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// Q: Why not make Scener a small interface with just Scene() ?
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// A: Everything in the engine would then need to type switch for Scener or SceneRef, i.e.
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// switch x := i.(type) {
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// case Drawer:
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// i.Draw(screen, opts)
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// case Scener:
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// i.Scene().Draw(screen, opts)
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// }
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// It seems cleaner to let the engine assert only for the interface it needs at that moment.
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Bounder
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Drawer
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DrawOrderer
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Hider
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Identifier
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Prepper
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Scanner
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Updater
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}
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// Updater components can update themselves. Update is called repeatedly.
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// Each component is responsible for calling Update on its child components
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// (so that disabling the parent prevents updates to the children, etc).
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type Updater interface {
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Update() error
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}
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