From c9a244f49888d2ee24b91ee681e5a90f7be4f6e0 Mon Sep 17 00:00:00 2001
From: Hajime Hoshi <hajimehoshi@gmail.com>
Date: Mon, 30 Apr 2018 03:03:12 +0900
Subject: [PATCH] inpututil: Admit some functions to return nil

---
 inpututil/inpututil.go | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/inpututil/inpututil.go b/inpututil/inpututil.go
index 4d84b05aa..8a10b5610 100644
--- a/inpututil/inpututil.go
+++ b/inpututil/inpututil.go
@@ -227,9 +227,11 @@ func MouseButtonPressDuration(button ebiten.MouseButton) int {
 
 // JustConnectedGamepadIDs returns gamepad IDs that are connected just in the current frame.
 //
+// JustConnectedGamepadIDs might return nil when there is no connected gamepad.
+//
 // JustConnectedGamepadIDs is concurrent safe.
 func JustConnectedGamepadIDs() []int {
-	ids := []int{}
+	var ids []int
 	theInputState.m.RLock()
 	for id := range theInputState.gamepadIDs {
 		if _, ok := theInputState.prevGamepadIDs[id]; !ok {
@@ -243,9 +245,11 @@ func JustConnectedGamepadIDs() []int {
 
 // JustDisconnectedGamepadIDs returns gamepad IDs that are disconnected just in the current frame.
 //
+// JustDisconnectedGamepadIDs might return nil when there is no disconnected gamepad.
+//
 // JustDisconnectedGamepadIDs is concurrent safe.
 func JustDisconnectedGamepadIDs() []int {
-	ids := []int{}
+	var ids []int
 	theInputState.m.RLock()
 	for id := range theInputState.prevGamepadIDs {
 		if _, ok := theInputState.gamepadIDs[id]; !ok {
@@ -298,9 +302,11 @@ func GamepadButtonPressDuration(id int, button ebiten.GamepadButton) int {
 
 // JustPressedTouches returns touch IDs that are created just in the current frame.
 //
+// JustPressedTouches might return nil when there is not touch.
+//
 // JustPressedTouches is concurrent safe.
 func JustPressedTouches() []int {
-	ids := []int{}
+	var ids []int
 	theInputState.m.RLock()
 	for id, s := range theInputState.touchDurations {
 		if s == 1 {