From 888ee0497f046c51100416e0a033ec35d77fb45c Mon Sep 17 00:00:00 2001
From: Holger Schemel <info@artsoft.org>
Date: Tue, 14 Jul 2020 23:03:10 +0200
Subject: [PATCH] fixed text event handling for newer SDL versions on Android

Using the previous code with newer SDL versions on Android, when
entering text using the screen keyboard, all keys were processed
twice, because of different handling of text events and modifier
keys in recent SDL versions.

The new, more generic approach should work for all SDL versions
on all platforms.
---
 src/events.c         | 28 ++++++++++------------------
 src/libgame/sdl.h    | 11 +++++++++--
 src/libgame/system.c |  5 +++++
 src/libgame/system.h |  1 +
 4 files changed, 25 insertions(+), 20 deletions(-)

diff --git a/src/events.c b/src/events.c
index c32f35e9..2678fa28 100644
--- a/src/events.c
+++ b/src/events.c
@@ -1380,13 +1380,9 @@ static void HandleButtonOrFinger(int mx, int my, int button)
   }
 }
 
-static boolean checkTextInputKeyModState(void)
+static boolean checkTextInputKey(Key key)
 {
-  // when playing, only handle raw key events and ignore text input
-  if (game_status == GAME_MODE_PLAYING)
-    return FALSE;
-
-  return ((GetKeyModState() & KMOD_TextInput) != KMOD_None);
+  return (textinput_status && KSYM_PRINTABLE(key));
 }
 
 void HandleTextEvent(TextEvent *event)
@@ -1404,16 +1400,12 @@ void HandleTextEvent(TextEvent *event)
 	GetKeyModState());
 #endif
 
-#if !defined(HAS_SCREEN_KEYBOARD)
-  // non-mobile devices: only handle key input with modifier keys pressed here
-  // (every other key input is handled directly as physical key input event)
-  if (!checkTextInputKeyModState())
-    return;
-#endif
-
-  // process text input as "classic" (with uppercase etc.) key input event
-  HandleKey(key, KEY_PRESSED);
-  HandleKey(key, KEY_RELEASED);
+  if (checkTextInputKey(key))
+  {
+    // process printable keys (with uppercase etc.) in text input mode
+    HandleKey(key, KEY_PRESSED);
+    HandleKey(key, KEY_RELEASED);
+  }
 }
 
 void HandlePauseResumeEvent(PauseResumeEvent *event)
@@ -1470,8 +1462,8 @@ void HandleKeyEvent(KeyEvent *event)
 
   HandleKeyModState(keymod, key_status);
 
-  // only handle raw key input without text modifier keys pressed
-  if (!checkTextInputKeyModState())
+  // process all keys if not in text input mode or if non-printable keys
+  if (!checkTextInputKey(key))
     HandleKey(key, key_status);
 }
 
diff --git a/src/libgame/sdl.h b/src/libgame/sdl.h
index ad7dca8c..c49894f6 100644
--- a/src/libgame/sdl.h
+++ b/src/libgame/sdl.h
@@ -350,6 +350,15 @@ typedef struct UserEventInfo	UserEvent;
 #define KSYM_FKEY_LAST		KSYM_F12
 #define KSYM_NUM_FKEYS		(KSYM_FKEY_LAST - KSYM_FKEY_FIRST + 1)
 
+#define KSYM_PRINTABLE(k)	(((k) >= KSYM_space &&			\
+				  (k) <= KSYM_z)        ||		\
+				 (k) == KSYM_Adiaeresis ||		\
+				 (k) == KSYM_Odiaeresis ||		\
+				 (k) == KSYM_Udiaeresis ||		\
+				 (k) == KSYM_adiaeresis ||		\
+				 (k) == KSYM_odiaeresis ||		\
+				 (k) == KSYM_udiaeresis)
+
 #define KMOD_None		KMOD_NONE
 #define KMOD_Shift_L		KMOD_LSHIFT
 #define KMOD_Shift_R		KMOD_RSHIFT
@@ -371,8 +380,6 @@ typedef struct UserEventInfo	UserEvent;
 				 KMOD_Meta    |	\
 				 KMOD_Alt)
 
-#define KMOD_TextInput		(KMOD_Shift | KMOD_Alt_R)
-
 // SDL function definitions
 
 boolean SDLSetNativeSurface(SDL_Surface **);
diff --git a/src/libgame/system.c b/src/libgame/system.c
index af3e0536..9a8d117b 100644
--- a/src/libgame/system.c
+++ b/src/libgame/system.c
@@ -57,6 +57,7 @@ int			button_status = MB_NOT_PRESSED;
 boolean			motion_status = FALSE;
 int			wheel_steps = DEFAULT_WHEEL_STEPS;
 boolean			keyrepeat_status = TRUE;
+boolean			textinput_status = FALSE;
 
 int			redraw_mask = REDRAW_NONE;
 
@@ -1753,6 +1754,8 @@ KeyMod GetKeyModStateFromEvents(void)
 
 void StartTextInput(int x, int y, int width, int height)
 {
+  textinput_status = TRUE;
+
 #if defined(HAS_SCREEN_KEYBOARD)
   SDL_StartTextInput();
 
@@ -1767,6 +1770,8 @@ void StartTextInput(int x, int y, int width, int height)
 
 void StopTextInput(void)
 {
+  textinput_status = FALSE;
+
 #if defined(HAS_SCREEN_KEYBOARD)
   SDL_StopTextInput();
 
diff --git a/src/libgame/system.h b/src/libgame/system.h
index 221d1eef..02f396d7 100644
--- a/src/libgame/system.h
+++ b/src/libgame/system.h
@@ -1760,6 +1760,7 @@ extern int			button_status;
 extern boolean			motion_status;
 extern int			wheel_steps;
 extern boolean			keyrepeat_status;
+extern boolean			textinput_status;
 
 extern int			redraw_mask;
 
-- 
2.34.1