Add workaround for fix alt-tab issue in SDL2.

Also add option to enable/disable this workaround.

4 files changed, 62 insertions, 3 deletions

diff --git a/src/input/inputmanager.cpp b/src/input/inputmanager.cpp
index dbe82d5da..42a4e3b25 100644
--- a/src/input/inputmanager.cpp
+++ b/src/input/inputmanager.cpp
@@ -594,6 +594,14 @@ bool InputManager::handleEvent(const SDL_Event &restrict event) restrict2
     {
         case SDL_KEYDOWN:
         {
+#ifdef USE_SDL2
+            if (keyboard.ignoreKey(event))
+            {
+                BLOCK_END("InputManager::handleEvent")
+                return true;
+            }
+#endif  // USE_SDL2
+
             keyboard.refreshActiveKeys();
             updateConditionMask();
             if (handleAssignKey(event, InputType::KEYBOARD))
@@ -620,6 +628,14 @@ bool InputManager::handleEvent(const SDL_Event &restrict event) restrict2
         }
         case SDL_KEYUP:
         {
+#ifdef USE_SDL2
+            if (keyboard.ignoreKey(event))
+            {
+                BLOCK_END("InputManager::handleEvent")
+                return true;
+            }
+#endif  // USE_SDL2
+
             keyboard.refreshActiveKeys();
             updateConditionMask();
             keyboard.handleDeActicateKey(event);
diff --git a/src/input/joystick.cpp b/src/input/joystick.cpp
index 1e53af5b1..10ed33924 100644
--- a/src/input/joystick.cpp
+++ b/src/input/joystick.cpp
@@ -180,7 +180,8 @@ void Joystick::logic()
 
     mDirection = 0;
 
-    if (mUseInactive || settings.inputFocused)
+    if (mUseInactive ||
+        settings.inputFocused != KeyboardFocus::Unfocused)
     {
         // X-Axis
         int position = SDL_JoystickGetAxis(mJoystick, 0);
@@ -350,7 +351,8 @@ bool Joystick::validate() const
     if (mCalibrating || !mEnabled || !mCalibrated)
         return false;
 
-    return mUseInactive || settings.inputFocused;
+    return mUseInactive ||
+        settings.inputFocused != KeyboardFocus::Unfocused;
 }
 
 void Joystick::handleRepeat(const int time)
diff --git a/src/input/keyboardconfig.cpp b/src/input/keyboardconfig.cpp
index 1ce317db7..e90d126a5 100644
--- a/src/input/keyboardconfig.cpp
+++ b/src/input/keyboardconfig.cpp
@@ -23,6 +23,9 @@
 #include "input/keyboardconfig.h"
 
 #include "configuration.h"
+#ifdef USE_SDL2
+#include "settings.h"
+#endif  // USE_SDL2
 
 #include "input/inputmanager.h"
 
@@ -42,7 +45,8 @@ KeyboardConfig::KeyboardConfig() :
     mRepeatTime(0),
     mKeyToAction(),
     mKeyToId(),
-    mKeyTimeMap()
+    mKeyTimeMap(),
+    mBlockAltTab(true)
 {
 }
 
@@ -52,6 +56,7 @@ void KeyboardConfig::init()
     delete [] mActiveKeys2;
     mActiveKeys2 = new uint8_t[500];
     mRepeatTime = config.getIntValue("repeateInterval2") / 10;
+    mBlockAltTab = config.getBoolValue("blockAltTab");
 }
 
 void KeyboardConfig::deinit()
@@ -270,3 +275,33 @@ void KeyboardConfig::resetRepeat(const int key)
     if (it != mKeyTimeMap.end())
         (*it).second = tick_time;
 }
+
+#ifdef USE_SDL2
+
+bool KeyboardConfig::ignoreKey(const SDL_Event &restrict event)
+{
+    if (!mBlockAltTab ||
+        mActiveKeys == nullptr)
+    {
+        return false;
+    }
+    const int key = event.key.keysym.scancode;
+    if (key == SDL_SCANCODE_TAB)
+    {
+#if SDL_VERSION_ATLEAST(2, 0, 5)
+        // SDL_WINDOWEVENT_TAKE_FOCUS not triggered after focus restored
+        if (settings.inputFocused != KeyboardFocus::Focused2)
+            return true;
+#endif // SDL_VERSION_ATLEAST(2, 0, 5)
+
+        if (mActiveKeys[SDL_SCANCODE_LALT] != 0)
+            return true;
+    }
+    else if (key == SDL_SCANCODE_LALT)
+    {
+        if (mActiveKeys[SDL_SCANCODE_TAB] != 0)
+            return true;
+    }
+    return false;
+}
+#endif  // USE_SDL2
diff --git a/src/input/keyboardconfig.h b/src/input/keyboardconfig.h
index 1759e4bb9..ef3f056b7 100644
--- a/src/input/keyboardconfig.h
+++ b/src/input/keyboardconfig.h
@@ -129,6 +129,10 @@ class KeyboardConfig final
 
         void resetRepeat(const int key);
 
+#ifdef USE_SDL2
+        bool ignoreKey(const SDL_Event &restrict event) A_WARN_UNUSED;
+#endif  // USE_SDL2
+
     private:
         bool mEnabled;                   /**< Flag to respond to key input */
 
@@ -143,6 +147,8 @@ class KeyboardConfig final
         KeyToIdMap mKeyToId;
 
         KeyTimeMap mKeyTimeMap;
+
+        bool mBlockAltTab;
 };
 
 extern KeyboardConfig keyboard;