From bc911f8c466f61c6edeab1db52938e0bbc01d3dd Mon Sep 17 00:00:00 2001
From: Jyrki Vesterinen <sandgtx@gmail.com>
Date: Sat, 23 Sep 2017 17:43:19 +0300
Subject: [PATCH] Fix another crash on startup with SDL 2.0.6

Caused by the same commit. SDL freed the old framebuffer even though we had
a reference to it, and when we passed it to SDL_FreeSurface(), it attempted
to free it again. It resulted in a crash depending on the C standard
library implementation and optimization level.
---
 src/sdl/surface.hpp | 3 +++
 src/video.cpp       | 3 +++
 2 files changed, 6 insertions(+)

diff --git a/src/sdl/surface.hpp b/src/sdl/surface.hpp
index 8139bf7d680a..b45c6487bdbe 100644
--- a/src/sdl/surface.hpp
+++ b/src/sdl/surface.hpp
@@ -54,6 +54,9 @@ class surface
 		return *this;
 	}
 
+	// Intended to be used when SDL has already freed the surface
+	void clear_without_free() { surface_ = nullptr; }
+
 	operator SDL_Surface*() const { return surface_; }
 
 	SDL_Surface* get() const { return surface_; }
diff --git a/src/video.cpp b/src/video.cpp
index edd4d402cb5d..5be0e524be77 100644
--- a/src/video.cpp
+++ b/src/video.cpp
@@ -196,6 +196,9 @@ void CVideo::update_framebuffer()
 	if(!frameBuffer) {
 		frameBuffer = fb;
 	} else {
+		// Because SDL has already freed the old framebuffer,
+		// ensure that we won't attempt to free it.
+		frameBuffer.clear_without_free();
 		frameBuffer.assign(fb);
 	}
 }