Spit and polish

* On the failure (but still success) dialog on Survival Mode levels
  (e.g. Azulian Tag): make the default be to retry the level but
  show a "pity" Next Level button below, as the level is marked as
  completed (silver score) and the next one is unlocked.

pkg/level/chunker.go

@@ -43,6 +43,7 @@ type Chunker struct {
 	requestsN1            map[render.Point]interface{} // chunks accessed last tick
 	requestsN2            map[render.Point]interface{} // 2 ticks ago (to free soon)
 	chunksToFree          map[render.Point]uint64      // chopping block (free after X ticks)
+	ctfMu                 sync.Mutex                   // lock for chunksToFree
 	requestMu             sync.Mutex
 
 	// The palette reference from first call to Inflate()
@@ -299,6 +300,11 @@ func (c *Chunker) GetChunk(p render.Point) (*Chunk, bool) {
 	chunk, ok := c.Chunks[p]
 	c.chunkMu.RUnlock()
 
+	// Was it on the chopping block for garbage collection?
+	c.ctfMu.Lock()
+	delete(c.chunksToFree, p)
+	c.ctfMu.Unlock()
+
 	if ok {
 		// An empty chunk? We hang onto these until save time to commit
 		// the empty chunk to ZIP.
@@ -392,6 +398,7 @@ func (c *Chunker) FreeCaches() int {
 
 		// Chunks requested 2 ticks ago but not this tick, put on the chopping
 		// block to free them later.
+		c.ctfMu.Lock()
 		for coord := range requestsN2 {
 			// Old point not requested recently?
 			if _, ok := requestsThisTick[coord]; !ok {
@@ -411,6 +418,7 @@ func (c *Chunker) FreeCaches() int {
 			delete(c.chunksToFree, coord)
 			c.FreeChunk(coord)
 		}
+		c.ctfMu.Unlock()
 
 		// Rotate the cached ticks and clean the slate.
 		c.requestsN2 = c.requestsN1

pkg/modal/end_level.go

@@ -18,11 +18,13 @@ type ConfigEndLevel struct {
 	Success bool // false = failure condition
 
 	// Handler functions - what you don't define will not
-	// show as buttons in the modal.
+	// show as buttons in the modal. Buttons display priority
+	// is as follows these docs in the source code.
+	OnNextLevel       func() // Next Level (victory window)
+	OnRetryCheckpoint func() // Retry from Checkpoint (failed)
+	OnPityNextLevel   func() // Pity "Next Level" (Azulian Tag)
 	OnRestartLevel    func() // Restart Level
-	OnRetryCheckpoint func() // Continue from checkpoint
-	OnEditLevel       func()
-	OnNextLevel       func() // Next Level
+	OnEditLevel       func() // Edit Level (if came from editor)
 	OnExitToMenu      func() // Exit to Menu
 
 	// Set these values to show the "New Record!" part of the modal.
@@ -152,6 +154,10 @@ func makeEndLevel(m *Modal, cfg ConfigEndLevel) *ui.Window {
 			Label: "Restart Level",
 			F:     cfg.OnRestartLevel,
 		},
+		{
+			Label: "Next Level",
+			F:     cfg.OnPityNextLevel,
+		},
 		{
 			Label: "Edit Level",
 			F:     cfg.OnEditLevel,

pkg/play_scene.go

@@ -561,8 +561,8 @@ func (s *PlayScene) FailLevel(message string) {
 
 	if s.Level.GameRule.Survival {
 		s.ShowEndLevelModal(
-			true,
-			"Level Completed",
+			false,
+			"You've died!",
 			fmt.Sprintf(
 				"%s\nCongrats on surviving for %s!",
 				message,
@@ -639,6 +639,15 @@ func (s *PlayScene) ShowEndLevelModal(success bool, title, message string) {
 		config.OnEditLevel = s.EditLevel
 	}
 
+	// Survival Mode failure? The level is considered completed even if you
+	// die (silver high score) but the default button should be Retry rather
+	// than Next Level.
+	var survivalFailure bool
+	if !success && s.Level.GameRule.Survival {
+		survivalFailure = true
+		success = true // level is completed
+	}
+
 	// Beaten the level?
 	if success {
 		config.OnRetryCheckpoint = nil
@@ -688,6 +697,14 @@ func (s *PlayScene) ShowEndLevelModal(success bool, title, message string) {
 		}
 	}
 
+	// Survival Mode failures: the Retry buttons should be higher
+	// priority than Next Level but they still get the (pity)
+	// Next Level button.
+	if survivalFailure {
+		config.OnPityNextLevel = config.OnNextLevel
+		config.OnNextLevel = nil
+	}
+
 	// Show the modal.
 	modal.EndLevel(config, title, message)