add SDL2 example

Author: MESYETI

examples/sdl.cal

@@ -0,0 +1,49 @@
+# Compile with:
+# cac examples/sdl.cal -i std -bo use-libc -l SDL2
+
+include "cores/select.cal"
+include "std/io.cal"
+
+const SDL_INIT_VIDEO 32
+const SDL_RENDERER_ACCELERATED 2
+const SDL_RENDERER_PRESENTVSYNC 4
+const SDL_QUIT 0x100
+
+extern C i32  SDL_Init u32 end
+extern C addr SDL_CreateWindow addr i32 i32 i32 i32 u32 end
+extern C addr SDL_CreateRenderer addr i32 u32 end
+extern C i32  SDL_PollEvent addr end
+extern C void SDL_DestroyWindow addr end
+extern C void SDL_DestroyRenderer addr end
+extern C void SDL_Quit end
+
+struct SDL_Event
+	array 56 u8 pad
+end
+
+let addr window
+let addr renderer
+
+"Init " printstr
+SDL_INIT_VIDEO SDL_Init printdec new_line
+
+"Window " printstr
+"Callisto\0" Array.elements + @ 0 0 320 240 0 SDL_CreateWindow window !
+window @ printdec new_line
+
+"Renderer " printstr
+window @ -1 SDL_RENDERER_PRESENTVSYNC SDL_RENDERER_ACCELERATED or SDL_CreateRenderer renderer !
+renderer @ printdec new_line
+
+while true do
+	let SDL_Event e
+	while e SDL_PollEvent do
+		if e d@ SDL_QUIT = then
+			"Bye!\n" printstr
+			renderer @ SDL_DestroyRenderer
+			window @ SDL_DestroyWindow
+			SDL_Quit
+			0 exit
+		end
+	end
+end