animation handling, screens, vp changes

engine/types/screen.go

@@ -0,0 +1,88 @@
+package types
+
+import (
+	"lab.zaar.be/thefish/alchemyst-go/util"
+)
+
+type Screen interface {
+	Enter()
+	Exit()
+	Render()
+	HandleInput(input string)
+	UseEcs() bool
+}
+
+type ScreenManager struct {
+	ctx util.ClientCtx
+	Screens map[string]Screen
+	CurrentScreen Screen
+	PreviousScreen Screen
+}
+
+// NewScreenManager is a convenience/constructor method to properly initialize a new ScreenManager
+func NewScreenManager(ctx util.ClientCtx) *ScreenManager {
+	manager := ScreenManager{
+		ctx:ctx,
+		Screens: make(map[string]Screen),
+		CurrentScreen: nil,
+	}
+	return &manager
+}
+
+func (sm *ScreenManager) AddScreen(screenName string, screen Screen) {
+	// Check to see if a screen with the given screenName has already been added
+	if _, ok := sm.Screens[screenName]; !ok {
+		// A screen with the given name does not yet exist on the ScreenManager, go ahead and add it
+		sm.Screens[screenName] = screen
+	} else {
+		sm.ctx.Logger().Warn().Msgf("A screen with name %v was already added to the ScreenManager %v!", screenName, sm)
+	}
+}
+
+// RemoveScreen will remove a screen from the ScreenManager. This can be useful when a temporary screen needs to be
+// created, as it can be quickly added (rather than registering at game creation), and then removed when it is no
+// longer needed
+func (sm *ScreenManager) RemoveScreen(screenName string, screen Screen) {
+	// Check if the given screenName exists in the ScreenManager
+	if _, ok := sm.Screens[screenName]; ok {
+		delete(sm.Screens, screenName)
+	} else {
+		// A screen with the given name does not exist
+		sm.ctx.Logger().Warn().Msgf("A screen with name %v was not found on ScreenManager %v!", screenName, sm)
+	}
+}
+
+// SetScreen will set the current screen property of the screen manager to the provided screen
+func (sm *ScreenManager) SetScreen(screen Screen) {
+	// Call the exit function of the currentScreen, and set the currentScreen as the previousScreen
+	// Only do this if there is a currentScreen
+	if sm.CurrentScreen != nil {
+		sm.CurrentScreen.Exit()
+		sm.PreviousScreen = sm.CurrentScreen
+	}
+
+	// Set the provided screen as the currentScreen, and call the enter() function of the new currentScreen
+	sm.CurrentScreen = screen
+	sm.CurrentScreen.Enter()
+}
+
+// SetScreenByName takes a string representing the screen desired to navigate to. It will then transition the
+// ScreenManager to the specified screen, if one is found.
+func (sm *ScreenManager) SetScreenByName(screenName string) {
+	// Check if the given screenName exists in the ScreenManager
+	if _, ok := sm.Screens[screenName]; ok {
+		// Call the exit function of the currentScreen, and set the currentScreen as the previousScreen
+		// Only do this if there is a currentScreen
+		if sm.CurrentScreen != nil {
+			sm.CurrentScreen.Exit()
+			sm.PreviousScreen = sm.CurrentScreen
+		}
+
+		// Set the provided screen as the currentScreen, and call the enter() function of the new currentScreen
+		sm.CurrentScreen = sm.Screens[screenName]
+		sm.CurrentScreen.Enter()
+	} else {
+		// A screen with the given name does not exist
+		sm.ctx.Logger().Warn().Msgf("A screen with name %v was not found on ScreenManager %v!", screenName, sm)
+	}
+}