commit ff884786c79364a6d3da1121c3339d669d814fd2
Author:     Simon Howard <fraggle@soulsphere.org>
AuthorDate: Tue May 31 22:31:16 2016 +0100
Commit:     Simon Howard <fraggle@soulsphere.org>
CommitDate: Tue May 31 22:31:16 2016 +0100

    video: Fix up behavior for fullscreen mode change.

    The existing code had (and has) some assumptions that it will only
    ever run in fullscreen or non-fullscreen mode. Because now we can
    change between the two dynamically, we must fix these.

    First, always set the SDL_WINDOW_RESIZABLE property on windows now so
    that we can resize windows if we start in fullscreen mode and switch
    to windowed.

    Second, set the window size when switching to windowed mode, since
    the window size was not set if we started in fullscreen mode. Adjust
    window sizes to have the correct aspect ratio both on startup and
    when switching.
---
 src/i_video.c | 87 ++++++++++++++++++++++++++++++++++++++++-------------------
 1 file changed, 60 insertions(+), 27 deletions(-)

diff --git a/src/i_video.c b/src/i_video.c
index a47eba7e..e54484c3 100644
--- a/src/i_video.c
+++ b/src/i_video.c
@@ -169,8 +169,6 @@ static boolean window_focused = true;
 // Window resize state.

 static boolean need_resize = false;
-static unsigned int resize_w, resize_h;
-static unsigned int last_resize_time;

 // Gamma correction level to use

@@ -266,8 +264,37 @@ void I_StartFrame (void)

 }

+// Adjust screen_width / screen_height variables to be an an aspect
+// ratio consistent with the aspect_ratio_correct variable.
+static void AdjustWindowSize(void)
+{
+    int h;
+
+    if (aspect_ratio_correct)
+    {
+        h = SCREENHEIGHT_4_3;
+    }
+    else
+    {
+        h = SCREENHEIGHT;
+    }
+
+    if (screen_width * h <= screen_height * SCREENWIDTH)
+    {
+        // The +1 here stops us from repeatedly shrinking the screen size
+        // with each call.
+        screen_height = (screen_width + 1) * h / SCREENWIDTH;
+    }
+    else
+    {
+        screen_width = screen_height * SCREENWIDTH / h;
+    }
+}
+
 static void HandleWindowEvent(SDL_WindowEvent *event)
 {
+    int flags;
+
     switch (event->event)
     {
 #if 0 // SDL2-TODO
@@ -282,9 +309,13 @@ static void HandleWindowEvent(SDL_WindowEvent *event)

         case SDL_WINDOWEVENT_RESIZED:
             need_resize = true;
-            resize_w = event->data1;
-            resize_h = event->data2;
-            last_resize_time = SDL_GetTicks();
+            // When the window is resized (we're not in fullscreen mode),
+            // save the new window size.
+            flags = SDL_GetWindowFlags(screen);
+            if ((flags & SDL_WINDOW_FULLSCREEN_DESKTOP) == 0)
+            {
+                SDL_GetWindowSize(screen, &screen_width, &screen_height);
+            }
             break;

         // Don't render the screen when the window is minimized:
@@ -325,13 +356,26 @@ static boolean ToggleFullScreenKeyShortcut(SDL_Keysym *sym)
 #if defined(__MACOSX__)
     flags |= (KMOD_LGUI | KMOD_RGUI);
 #endif
-    return (sym->scancode == SDL_SCANCODE_RETURN && sym->mod & flags);
+    return sym->scancode == SDL_SCANCODE_RETURN && (sym->mod & flags) != 0;
 }

 static void I_ToggleFullScreen(void)
 {
-    Uint32 flags = SDL_GetWindowFlags(screen) & SDL_WINDOW_FULLSCREEN_DESKTOP;
-    SDL_SetWindowFullscreen(screen, flags ^ SDL_WINDOW_FULLSCREEN_DESKTOP);
+    unsigned int flags = 0;
+
+    fullscreen = !fullscreen;
+
+    if (fullscreen)
+    {
+        flags |= SDL_WINDOW_FULLSCREEN_DESKTOP;
+    }
+    SDL_SetWindowFullscreen(screen, flags);
+
+    if (!fullscreen)
+    {
+        AdjustWindowSize();
+        SDL_SetWindowSize(screen, screen_width, screen_height);
+    }
 }

 void I_GetEvent(void)
@@ -566,11 +610,9 @@ void I_FinishUpdate (void)
     if (noblit)
         return;

-    if (need_resize && SDL_GetTicks() > last_resize_time + 1000/TICRATE)
+    if (need_resize)
     {
         CreateUpscaledTexture();
-        screen_width = resize_w;
-        screen_height = resize_h;
         need_resize = false;
         palette_to_set = true;
     }
@@ -992,9 +1034,13 @@ static void SetVideoMode(int w, int h)
         screen = NULL;
     }

-    // Set the video mode.
+    // In windowed mode, the window can be resized while the game is
+    // running.
+    flags = SDL_WINDOW_RESIZABLE;

-    flags = 0;
+    // Set the highdpi flag - this makes a big difference on Macs with
+    // retina displays, especially when using small window sizes.
+    flags |= SDL_WINDOW_ALLOW_HIGHDPI;

     if (fullscreen)
     {
@@ -1002,17 +1048,6 @@ static void SetVideoMode(int w, int h)
         // draw to the entire screen by scaling the texture appropriately".
         flags |= SDL_WINDOW_FULLSCREEN_DESKTOP;
     }
-    else
-    {
-        // In windowed mode, the window can be resized while the game is
-        // running.  This feature is disabled on OS X, as it adds an ugly
-        // scroll handle to the corner of the screen.
-        flags |= SDL_WINDOW_RESIZABLE;
-    }
-
-    // Set the highdpi flag - this makes a big difference on Macs with
-    // retina displays, especially when using small window sizes.
-    flags |= SDL_WINDOW_ALLOW_HIGHDPI;

     // Create window and renderer contexts. We set the window title
     // later anyway and leave the window position "undefined". If "flags"
@@ -1149,9 +1184,7 @@ void I_InitGraphics(void)
     }
     else
     {
-        // SDL2-TODO: sanity check screen_width/screen_height against
-        // screen modes listed as available by LibSDL, and auto-adjust
-        // when the selected mode is not available.
+        AdjustWindowSize();
         SetVideoMode(screen_width, screen_height);
     }