State Machine

github.com/mechanical-lich/mlge/state

A stack-based state machine for managing game states such as menus, gameplay, pause screens, and cutscenes.

StateInterface

type StateInterface interface {
    Update() StateInterface
    Draw(screen *ebiten.Image)
    Done() bool
}

Method	Description
Update	Called each frame. Returns a new state to push, or nil to continue
Draw	Renders the state to the screen
Done	Returns true when the state should be popped

StateMachine

type StateMachine struct{}

Methods:

Method	Signature	Description
PushState	(state StateInterface)	Push a new state onto the stack
PopCurrentState	()	Remove the top state
Update	()	Updates the top state; handles push/pop transitions
Draw	(screen *ebiten.Image)	Draws the top state

Usage

sm := &state.StateMachine{}
sm.PushState(&MenuState{})

// In game loop
func (g *Game) Update() error {
    g.stateMachine.Update()
    return nil
}

func (g *Game) Draw(screen *ebiten.Image) {
    g.stateMachine.Draw(screen)
}

Example: Game States

type MenuState struct {
    done     bool
    nextState state.StateInterface
}

func (m *MenuState) Update() state.StateInterface {
    if startPressed {
        m.done = true
        return &PlayState{}  // Push PlayState
    }
    return nil
}

func (m *MenuState) Draw(screen *ebiten.Image) {
    // Draw menu UI
}

func (m *MenuState) Done() bool {
    return m.done
}

When Update() returns a non-nil state, the state machine pushes it onto the stack. When Done() returns true, the state is popped, revealing the previous state underneath.