fix SDL bug where freeing the surface screen did not work properly

3 files changed, 37 insertions, 1 deletions

diff --git a/src/library_sdl.js b/src/library_sdl.js
index 3d96a693..d90484ad 100644
--- a/src/library_sdl.js
+++ b/src/library_sdl.js
@@ -411,6 +411,10 @@ var LibrarySDL = {
       _free(info.pixelFormat);
       _free(surf);
       SDL.surfaces[surf] = null;
+
+      if (surf === SDL.screen) {
+        SDL.screen = null;
+      }
     },
 
     touchX: 0, touchY: 0,
@@ -1036,7 +1040,7 @@ var LibrarySDL = {
     // Free the old surface first.
     if (SDL.screen) {
       SDL.freeSurface(SDL.screen);
-      SDL.screen = null;
+      assert(!SDL.screen);
     }
     SDL.screen = SDL.makeSurface(width, height, flags, true, 'screen');
     if (!SDL.addedResizeListener) {
diff --git a/tests/sdl_free_screen.cpp b/tests/sdl_free_screen.cpp
new file mode 100644
index 00000000..01a849c5
--- /dev/null
+++ b/tests/sdl_free_screen.cpp
@@ -0,0 +1,29 @@
+#include <stdio.h>
+#include <SDL/SDL.h>
+
+
+extern "C" int main(int argc, char** argv) {
+
+  SDL_Init(SDL_INIT_VIDEO);
+  SDL_Surface *screen = SDL_SetVideoMode(256, 256, 32, SDL_SWSURFACE);
+  printf("freeing screen...\n");
+  SDL_FreeSurface(screen);
+  printf("recreating...\n");
+  screen = SDL_SetVideoMode(256, 256, 32, SDL_SWSURFACE);
+  printf("seems ok!\n");
+
+  if (SDL_MUSTLOCK(screen)) SDL_LockSurface(screen);
+  for (int i = 0; i < 256; i++) {
+    for (int j = 0; j < 256; j++) {
+      // alpha component is actually ignored, since this is to the screen
+      *((Uint32*)screen->pixels + i * 256 + j) = SDL_MapRGBA(screen->format, i, j, 255-i, (i+j) % 255);
+    }
+  }
+  if (SDL_MUSTLOCK(screen)) SDL_UnlockSurface(screen);
+  SDL_Flip(screen); 
+
+  SDL_Quit();
+
+  return 0;
+}
+
diff --git a/tests/test_browser.py b/tests/test_browser.py
index f0343669..cf893eb5 100644
--- a/tests/test_browser.py
+++ b/tests/test_browser.py
@@ -1587,6 +1587,9 @@ void *getBindBuffer() {
   def test_sdl_surface_refcount(self):
     self.btest('sdl_surface_refcount.c', expected='1')
 
+  def test_sdl_free_screen(self):
+    self.btest('sdl_free_screen.cpp', reference='htmltest.png')
+
   def test_glbegin_points(self):
     shutil.copyfile(path_from_root('tests', 'screenshot.png'), os.path.join(self.get_dir(), 'screenshot.png'))
     self.btest('glbegin_points.c', reference='glbegin_points.png', args=['--preload-file', 'screenshot.png', '-s', 'LEGACY_GL_EMULATION=1'])