Fix crash when switching CPU modes in lagless vsync.

diff --git a/od-win32/win32gfx.cpp b/od-win32/win32gfx.cpp
index 3aff52150f42668232bd4fb4a69393237930dfd6..27e598dde9c5662732e66536932fe70fce0f2dcc 100644 (file)
--- a/od-win32/win32gfx.cpp
+++ b/od-win32/win32gfx.cpp
@@ -490,7 +490,7 @@ static void display_vblank_thread(struct AmigaMonitor *mon)
                return;
        // It seems some Windows 7 drivers stall if D3DKMTWaitForVerticalBlankEvent()
        // and D3DKMTGetScanLine() is used simultaneously.
-       if (os_win8 && ap->gfx_vsyncmode && pD3DKMTWaitForVerticalBlankEvent && wait_vblank_display->HasAdapterData) {
+       if (os_win8 && ap->gfx_vsyncmode && pD3DKMTWaitForVerticalBlankEvent && wait_vblank_display && wait_vblank_display->HasAdapterData) {
                waitvblankevent = CreateEvent(NULL, FALSE, FALSE, NULL);
                waitvblankthread_mode = 1;
                unsigned int th;