White Azulian, Respawn invincibility timer

* Respawning from a checkpoint grants 3 seconds of immunity in case
  enemies are spawn camping.
* Add the white Azulian as an even faster and harder enemy than the red
  Azulian: twice as fast, jumps higher, and can detect the player from
  further away.

dev-assets/doodads/azulian/Makefile

@@ -14,6 +14,11 @@ build:
 	doodad edit-doodad --tag "color=red" azu-red.doodad
 	doodad install-script azulian.js azu-red.doodad
 
+	doodad convert -t "White Azulian" white-front.png white-back.png \
+		white-wr{1,2,3,4}.png white-wl{1,2,3,4}.png azu-white.doodad
+	doodad edit-doodad --tag "color=white" azu-white.doodad
+	doodad install-script azulian.js azu-white.doodad
+
 	# Tag the category for these doodads
 	for i in *.doodad; do\
 		doodad edit-doodad --tag "category=creatures" $${i};\

dev-assets/doodads/azulian/azulian.js

@@ -9,9 +9,17 @@ var playerSpeed = color === 'blue' ? 2 : 4,
 	direction = "right",
 	lastDirection = "right";
 
+// white Azulian is faster yet than the red
+if (color === 'white') {
+	aggroX = 1000;
+	aggroY = 400;
+	playerSpeed = 8;
+	jumpSpeed = 16;
+}
+
 function setupAnimations(color) {
-	let left = color === 'blue' ? 'blu-wl' : 'red-wl',
-		right = color === 'blue' ? 'blu-wr' : 'red-wr',
+	let left = color === 'blue' ? 'blu-wl' : color+'-wl',
+		right = color === 'blue' ? 'blu-wr' : color+'-wr',
 		leftFrames = [left + '1', left + '2', left + '3', left + '4'],
 		rightFrames = [right + '1', right + '2', right + '3', right + '4'];
 

dev-assets/doodads/bird/bird.js

@@ -106,6 +106,8 @@ function main() {
 // A.I. subroutine: scan for the player character.
 // The bird scans in a 45 degree angle downwards, if the
 // player is seen nearby in that scan it will begin a dive.
+// It's not hostile towards characters that can fly (having
+// no gravity).
 function AI_ScanForPlayer() {
 	let stepY = 12, // number of pixels to skip
 		stepX = stepY,
@@ -130,7 +132,7 @@ function AI_ScanForPlayer() {
 		scanX += stepX;
 		scanY += stepY;
 		for (let actor of Actors.At(Point(scanX, scanY))) {
-			if (actor.IsPlayer()) {
+			if (actor.IsPlayer() && actor.HasGravity()) {
 				state = states.diving;
 				return;
 			}

pkg/balance/numbers.go

@@ -88,6 +88,10 @@ var (
 	PlayModeIdleTimeout = 2200 * time.Millisecond
 	PlayModeAlphaStep   = 8 // 0-255 alpha, steps per tick for fade in
 	PlayModeAlphaMax    = 220
+
+	// Invulnerability time in seconds at respawn from checkpoint, in case
+	// enemies are spawn camping.
+	RespawnGodModeTimer = 3 * time.Second
 )
 
 // Edit Mode Values

pkg/play_scene.go

@@ -70,6 +70,7 @@ type PlayScene struct {
 	antigravity         bool      // Cheat: disable player gravity
 	noclip              bool      // Cheat: disable player clipping
 	godMode             bool      // Cheat: player can't die
+	godModeUntil        time.Time // Invulnerability timer at respawn.
 	playerJumpCounter   int       // limit jump length
 
 	// Inventory HUD. Impl. in play_inventory.go
@@ -404,6 +405,9 @@ func (s *PlayScene) SetCheckpoint(where render.Point) {
 
 // RetryCheckpoint moves the player back to their last checkpoint.
 func (s *PlayScene) RetryCheckpoint() {
+	// Grant the player invulnerability for 5 seconds
+	s.godModeUntil = time.Now().Add(balance.RespawnGodModeTimer)
+
 	log.Info("Move player back to last checkpoint")
 	s.Player.MoveTo(s.lastCheckpoint)
 	s.running = true
@@ -421,11 +425,12 @@ func (s *PlayScene) BeatLevel() {
 
 // FailLevel handles a level failure triggered by a doodad.
 func (s *PlayScene) FailLevel(message string) {
-	if s.godMode {
+	if s.godMode || s.godModeUntil.After(time.Now()) {
 		return
 	}
 	s.SetImperfect()
 	s.d.FlashError(message)
+
 	s.ShowEndLevelModal(
 		false,
 		"You've died!",