87 lines
1.6 KiB
Go
87 lines
1.6 KiB
Go
//go:build example
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// +build example
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package system
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import (
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"code.rocketnine.space/tslocum/gohan"
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"code.rocketnine.space/tslocum/gohan/examples/twinstick/component"
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"github.com/hajimehoshi/ebiten/v2"
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)
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type MovementSystem struct {
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ScreenW, ScreenH float64
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Player gohan.Entity
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}
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func (s *MovementSystem) Name() string {
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return "Movement"
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}
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func (_ *MovementSystem) Needs() []gohan.ComponentID {
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return []gohan.ComponentID{
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component.PositionComponentID,
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component.VelocityComponentID,
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}
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}
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func (s *MovementSystem) Uses() []gohan.ComponentID {
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return nil
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}
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func (s *MovementSystem) Update(ctx *gohan.Context) error {
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position := component.Position(ctx)
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velocity := component.Velocity(ctx)
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bullet := ctx.Entity != s.Player
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// Check for collision.
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if position.X+velocity.X < 16 {
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if bullet {
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ctx.RemoveEntity()
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return nil
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}
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position.X = 16
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velocity.X = 0
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} else if position.X+velocity.X > s.ScreenW-16 {
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if bullet {
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ctx.RemoveEntity()
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return nil
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}
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position.X = s.ScreenW - 16
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velocity.X = 0
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}
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if position.Y+velocity.Y < 16 {
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if bullet {
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ctx.RemoveEntity()
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return nil
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}
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position.Y = 16
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velocity.Y = 0
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} else if position.Y+velocity.Y > s.ScreenH-16 {
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if bullet {
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ctx.RemoveEntity()
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return nil
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}
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position.Y = s.ScreenH - 16
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velocity.Y = 0
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}
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position.X, position.Y = position.X+velocity.X, position.Y+velocity.Y
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if !bullet {
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velocity.X *= 0.95
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velocity.Y *= 0.95
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}
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return nil
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}
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func (_ *MovementSystem) Draw(ctx *gohan.Context, _ *ebiten.Image) error {
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return gohan.ErrSystemWithoutDraw
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}
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