diff -up shippy-1.5.0/shipsdl2.c~ shippy-1.5.0/shipsdl2.c

--- shippy-1.5.0/shipsdl2.c~	2019-05-18 17:27:52.000000000 +0200

+++ shippy-1.5.0/shipsdl2.c	2019-05-20 17:10:32.618036429 +0200

@@ -1,4 +1,5 @@

 #include <string.h>

+#include <stdbool.h>

 #include <stdlib.h>

 #include <SDL2/SDL.h>

 #include <SDL2/SDL_mixer.h>

@@ -29,6 +30,7 @@ SDL_Texture *BackBuffer = NULL;

 SDL_Texture *Graphics = NULL;

 SDL_Joystick *Joystick = NULL;

 Uint8 key[1337];

+static bool fullscreen = true;

 SDL_Rect src;

 SDL_Rect dest;

@@ -212,8 +215,10 @@ void SYSTEM_CLEANBMP()

 void SYSTEM_SETVID()

 {

 	Uint32 flags = SDL_WINDOW_FULLSCREEN;

-	if (start_windowed)

+	if (start_windowed) {

 		flags &= ~SDL_WINDOW_FULLSCREEN;

+		fullscreen = false;

+	}

 	screen = SDL_CreateWindow("Shippy1984 by Ryan Broomfield SDL2 VERSION", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, screen_width, screen_height, flags);

 	SDL_ShowCursor(SDL_DISABLE);

 	renderer = SDL_CreateRenderer(screen, -1, 0);

@@ -482,6 +487,12 @@ void SYSTEM_IDLE()

 				key[keyIndx] = 0;

 			}

 		}

+		if ((event.type == SDL_KEYDOWN) && key[SHIPPY_LALT] &&

+		    (event.key.keysym.sym == SDLK_RETURN)) {

+			fullscreen = !fullscreen;

+			SDL_SetWindowFullscreen(screen,

+					fullscreen ? SDL_WINDOW_FULLSCREEN : 0);

+		}

 	}

 }