From 6d0ae714166fc0a5007431823f9cf65f2739ab99 Mon Sep 17 00:00:00 2001
From: Holger Schemel <info@artsoft.org>
Date: Wed, 12 Feb 2025 20:02:57 +0100
Subject: [PATCH] fixed clearing off-screen areas in window mode after resizing
 window

---
 src/events.c         |  1 +
 src/libgame/sdl.c    | 15 +++++++++++++--
 src/libgame/sdl.h    |  1 +
 src/libgame/system.c |  5 +++++
 src/libgame/system.h |  1 +
 5 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/src/events.c b/src/events.c
index 3939deb9..e331aac2 100644
--- a/src/events.c
+++ b/src/events.c
@@ -667,6 +667,7 @@ void HandleWindowEvent(WindowEvent *event)
 	UpdateMousePosition();
 
 	SetWindowTitle();
+	SetWindowResized();
 
         // required if executed from outside setup menu
         SaveSetupIfNeeded();
diff --git a/src/libgame/sdl.c b/src/libgame/sdl.c
index da27429e..a8bdf962 100644
--- a/src/libgame/sdl.c
+++ b/src/libgame/sdl.c
@@ -31,6 +31,7 @@ static SDL_Renderer *sdl_renderer = NULL;
 static SDL_Texture *sdl_texture_stream = NULL;
 static SDL_Texture *sdl_texture_target = NULL;
 static boolean fullscreen_enabled = FALSE;
+static boolean window_resized = FALSE;
 static boolean limit_screen_updates = FALSE;
 
 
@@ -205,9 +206,11 @@ static void UpdateScreenExt(SDL_Rect *rect, boolean with_frame_delay)
   }
 #endif
 
+  boolean clear_complete_render_target = (fullscreen_enabled || window_resized);
+
   // clear render target (complete screen in fullscreen mode to clear visible off-screen areas)
   // (this is especially important for touch buttons on Android and for different window sizes)
-  if (fullscreen_enabled)
+  if (clear_complete_render_target)
     SDL_RenderClear(sdl_renderer);
 
   // set renderer to use target texture for rendering
@@ -216,7 +219,7 @@ static void UpdateScreenExt(SDL_Rect *rect, boolean with_frame_delay)
     SDL_SetRenderTarget(sdl_renderer, sdl_texture_target);
 
   // clear render target (target texture only to fix black flickering with Metal window on Mac)
-  if (!fullscreen_enabled)
+  if (!clear_complete_render_target)
     SDL_RenderClear(sdl_renderer);
 
   // copy backbuffer texture to render target buffer
@@ -250,6 +253,8 @@ static void UpdateScreenExt(SDL_Rect *rect, boolean with_frame_delay)
 
   // show render target buffer on screen
   SDL_RenderPresent(sdl_renderer);
+
+  window_resized = FALSE;
 }
 
 static void UpdateScreen_WithFrameDelay(SDL_Rect *rect)
@@ -882,6 +887,11 @@ void SDLSetWindowTitle(void)
   SDL_SetWindowTitle(sdl_window, program.window_title);
 }
 
+void SDLSetWindowResized(void)
+{
+  window_resized = TRUE;
+}
+
 void SDLSetWindowScaling(int window_scaling_percent)
 {
   if (sdl_window == NULL)
@@ -898,6 +908,7 @@ void SDLSetWindowScaling(int window_scaling_percent)
   video.window_height = new_window_height;
 
   SetWindowTitle();
+  SetWindowResized();
 }
 
 void SDLSetWindowScalingQuality(char *window_scaling_quality)
diff --git a/src/libgame/sdl.h b/src/libgame/sdl.h
index c2b55c24..c2e40269 100644
--- a/src/libgame/sdl.h
+++ b/src/libgame/sdl.h
@@ -422,6 +422,7 @@ void SDLSetScreenRenderingMode(char *);
 void SDLSetScreenVsyncMode(char *);
 void SDLRedrawWindow(void);
 void SDLSetWindowTitle(void);
+void SDLSetWindowResized(void);
 
 void SDLLimitScreenUpdates(boolean);
 void SDLInitVideoDisplay(void);
diff --git a/src/libgame/system.c b/src/libgame/system.c
index c9a72bbe..107de5d5 100644
--- a/src/libgame/system.c
+++ b/src/libgame/system.c
@@ -140,6 +140,11 @@ void SetWindowTitle(void)
   SDLSetWindowTitle();
 }
 
+void SetWindowResized(void)
+{
+  SDLSetWindowResized();
+}
+
 void InitWindowTitleFunction(char *(*window_title_function)(void))
 {
   program.window_title_function = window_title_function;
diff --git a/src/libgame/system.h b/src/libgame/system.h
index c8cb2f09..21a36f73 100644
--- a/src/libgame/system.h
+++ b/src/libgame/system.h
@@ -2045,6 +2045,7 @@ void InitNetworkInfo(boolean, boolean, boolean, char *, int);
 void InitRuntimeInfo(void);
 
 void SetWindowTitle(void);
+void SetWindowResized(void);
 
 void InitWindowTitleFunction(char *(*window_title_function)(void));
 void InitExitMessageFunction(void (*exit_message_function)(char *, va_list));
-- 
2.34.1