commit fe9a6a864d1a3f34ae7dbecf803fb6803c7d8ae7
Author:     Fabian Greffrath <fabian@greffrath.com>
AuthorDate: Tue Dec 3 09:30:50 2019 +0100
Commit:     Fabian Greffrath <fabian@greffrath.com>
CommitDate: Tue Dec 3 09:30:54 2019 +0100

    video: if renderer creation failed, try again without acceleration

    Currently, we enable hardware acceleration by default. If SDL fails to
    create a matching renderer for that, e.g. because the graphic hardware
    or driver do not properly support hardware acceleration, we show an
    error message and quit. At this point users do either complain or turn
    their back on our software and never come back. Whenever users complain,
    we recommend them to enable the force_software_renderer option and
    try again.

    However, we can do better and try again ourselves without hardware
    acceleration if the renderer creation failed with the default flags.
    If it still fails even then, we know for sure that something is
    really wrong.
---
 src/i_video.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/src/i_video.c b/src/i_video.c
index c3b2e5f8..3f9ff26f 100644
--- a/src/i_video.c
+++ b/src/i_video.c
@@ -1246,6 +1246,23 @@ static void SetVideoMode(void)

     renderer = SDL_CreateRenderer(screen, -1, renderer_flags);

+    // If we could not find a matching render driver,
+    // try again without hardware acceleration.
+
+    if (renderer == NULL && !force_software_renderer)
+    {
+        renderer_flags |= SDL_RENDERER_SOFTWARE;
+        renderer_flags &= ~SDL_RENDERER_PRESENTVSYNC;
+
+        renderer = SDL_CreateRenderer(screen, -1, renderer_flags);
+
+        // If this helped, save the setting for later.
+        if (renderer != NULL)
+        {
+            force_software_renderer = 1;
+        }
+    }
+
     if (renderer == NULL)
     {
         I_Error("Error creating renderer for screen window: %s",