commit a9173b09d799006ab09e3def8c4b43b6b8668c1a
Author:     Fabian Greffrath <fabian@greffrath.com>
AuthorDate: Fri Sep 18 08:20:56 2015 +0200
Commit:     Fabian Greffrath <fabian@greffrath.com>
CommitDate: Fri Sep 18 08:20:56 2015 +0200

    create a new texture only if the upscale factor has changed
---
 src/i_video.c | 24 ++++++++++++++++++------
 1 file changed, 18 insertions(+), 6 deletions(-)

diff --git a/src/i_video.c b/src/i_video.c
index 73447780..de001a53 100644
--- a/src/i_video.c
+++ b/src/i_video.c
@@ -1016,11 +1016,7 @@ static void CreateUpscaledTexture(int w, int h)
     const int w_scale = (w / SCREENWIDTH) + 1;
     const int h_scale = (h / SCREENHEIGHT) + 1;
     int upscale;
-
-    if (texture_upscaled)
-    {
-        SDL_DestroyTexture(texture_upscaled);
-    }
+    static int upscale_old;

     // When the screen or window dimensions do not match the aspect ratio
     // of the texture, the rendered area is scaled down to fit
@@ -1029,11 +1025,27 @@ static void CreateUpscaledTexture(int w, int h)

     // Limit upscaling factor to 6 (1920x1200)

-    if (upscale > 6)
+    if (upscale < 2)
+    {
+        upscale = 2;
+    }
+    else if (upscale > 6)
     {
         upscale = 6;
     }

+    if (upscale == upscale_old)
+    {
+        return;
+    }
+
+    upscale_old = upscale;
+
+    if (texture_upscaled)
+    {
+        SDL_DestroyTexture(texture_upscaled);
+    }
+
     // Set the scaling quality for rendering the upscaled texture to "linear",
     // which looks much softer and smoother than "nearest" but does a better
     // job at downscaling from the upscaled texture to screen.