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OpenDiablo2/d2core/d2screen/screen_manager.go
2020-09-18 16:10:52 -04:00

105 lines
2.6 KiB
Go

package d2screen
import (
"log"
"github.com/OpenDiablo2/OpenDiablo2/d2common/d2interface"
"github.com/OpenDiablo2/OpenDiablo2/d2core/d2gui"
"github.com/OpenDiablo2/OpenDiablo2/d2core/d2ui"
)
// ScreenManager manages game screens (main menu, credits, character select, game, etc)
type ScreenManager struct {
uiManager *d2ui.UIManager
nextScreen Screen
loadingScreen Screen
loadingState LoadingState
currentScreen Screen
guiManager *d2gui.GuiManager
}
// NewScreenManager creates a screen manager
func NewScreenManager(ui *d2ui.UIManager, guiManager *d2gui.GuiManager) *ScreenManager {
return &ScreenManager{uiManager: ui, guiManager: guiManager}
}
// SetNextScreen is about to set a given screen as next
func (sm *ScreenManager) SetNextScreen(screen Screen) {
sm.nextScreen = screen
}
// Advance updates the UI on every frame
func (sm *ScreenManager) Advance(elapsed float64) error {
switch {
case sm.loadingScreen != nil:
// this call blocks execution and could lead to deadlock if a screen implements OnLoad incorreclty
load, ok := <-sm.loadingState.updates
if !ok {
log.Println("loadingState chan should not be closed while in a loading screen")
}
if load.err != nil {
log.Printf("PROBLEM LOADING THE SCREEN: %v", load.err)
return load.err
}
sm.guiManager.ShowLoadScreen(load.progress)
if load.done {
sm.currentScreen = sm.loadingScreen
sm.loadingScreen = nil
sm.guiManager.ShowCursor()
sm.guiManager.HideLoadScreen()
}
case sm.nextScreen != nil:
if handler, ok := sm.currentScreen.(ScreenUnloadHandler); ok {
if err := handler.OnUnload(); err != nil {
return err
}
}
sm.uiManager.Reset()
sm.guiManager.SetLayout(nil)
if handler, ok := sm.nextScreen.(ScreenLoadHandler); ok {
sm.guiManager.ShowLoadScreen(0)
sm.guiManager.HideCursor()
sm.loadingState = LoadingState{updates: make(chan loadingUpdate)}
go func() {
handler.OnLoad(sm.loadingState)
sm.loadingState.Done()
}()
sm.currentScreen = nil
sm.loadingScreen = sm.nextScreen
} else {
sm.currentScreen = sm.nextScreen
sm.loadingScreen = nil
}
sm.nextScreen = nil
case sm.currentScreen != nil:
if handler, ok := sm.currentScreen.(ScreenAdvanceHandler); ok {
if err := handler.Advance(elapsed); err != nil {
return err
}
}
}
return nil
}
// Render renders the UI by a given surface
func (sm *ScreenManager) Render(surface d2interface.Surface) error {
if handler, ok := sm.currentScreen.(ScreenRenderHandler); ok {
if err := handler.Render(surface); err != nil {
return err
}
}
return nil
}